|Stationary Energy||Transport||Carbon Drawdown|
|Geoengineering||Agriculture||Domestic & Industrial Efficiency|
In this section:
In comparing ways of generating electricity, there are several considerations:
This is a combination of the ongoing cost of operating the plant, the "opportunity cost" of the land dedicated to it, the capital cost of building it in the first place, and the transmission costs and losses.
The construction cost has to be amortised over the expected lifetime output. This involves several assumptions, so different authors arrive at different conclusions. This matters a lot where almost all the cost is capital expenditure, such as wind and solar. Of course, construction cost is not a problem for existing coal-fired power stations, but new coal-fired power stations are planned too, so comparisons made here are with new coal.
A standard measure is "levelised cost". This amortizes the capital cost over the lifetime of the plant, adds a percentage p.a. return expected by investors (the "discount rate") and the production cost (fuel and maintenance) to give a cost per unit of electricity. The result therefore depends on the rate of return required. Extreme examples are solar and gas. Gas has a very high fuel cost while solar (both PV and thermal) have very high construction costs. Wind is or is not competitive with gas within the usual range of values assumed.
For a simplified calculation, suppose solar PV is down to $1/W to install. If each 1W installed generates an average of 3Wh a day, it provides 1kWh in about a year. If lifetime amortised cost plus interest amounts to 10% pa, it's producing at 10c/kWh.
[Some argue that the construction cost for renewables shouldn't matter: if it avoids emissions then it's worth it. But construction might be expensive precisely because that uses a lot of energy, and that's being costed at today's prices. It could even happen that a "renewable" technology plant would cost more energy to make than it will deliver in its entire life.]
Where the technology is not yet mature, equipment costs can be expected to come down as the technology spreads. This is why government investment is necessary to achieve a rapid transition. Private sector investment focuses on the short term.
Transmission cost can be high because the source of energy is often a long way from the cities. Coal-fired power has the advantage here that distribution already exists in coal mining areas, and other industries have grown up around them.
Where a technology has high pollution cost, this should be factored in too. This too often ends up being borne by the taxpayer. Consider, e.g., the medical expenses of miners. In 2009 the Australian Academy of Technological Sciences & Engineering estimated $40-50/MWh on top of the wholesale price of $40MWh (including climate change). In the US, the NRC estimates $US32/MWh excluding climate change. More evidence of the health consequences of fossil fuels continues to emerge.
April 2011: Particles disrupt immune system
In NSW, the coal industry also receives about $1bn./year in direct and indirect subsidies.
Such indirect costs have not been included in the comparisons below.
Dec 2010: Georgia Inst of Tech & Duke Uni; Supporting renewables now will reduce power costs in 2030: http://www.sciencedaily.com/releases/2010/12/101216101839.htm
- Base load capability
I.e., can it guarantee to meet a predicted demand? At one extreme, wind and solar PV are intermittent; at the other, hydro can be used to store energy from other sources (by pumping water back up). In between, an energy source may be reliable but inflexible, - i.e. it's most efficient if you run it at constant output - or reliable and flexible ("dispatchable") but with no ability to absorb and store energy from other sources. This issue would be solved by large, cheap, efficient batteries, but there is no prospect of that any time soon.
In the grid, cheap unreliable energy sources can be mixed with flexible sources and storage to give the best overall system.
There is also an important distinction between intermittent and unpredictable. Unpredictability is what really hurts grids. If supply can be predicted even fifteen minutes in advance then the grid is much more manageable. Increasingly, wind and solar can be predicted hours in advance. Conversely, conventional large coal plant can fail with little warning.
Any technology can have negative impacts on the environment, even if it is just aesthetic. Some may have much reduced GHG output, but not zero.
Any technology which involves heat needs a way to get rid of the heat. The most efficient is to use water, but that may be scarce, so air must sometimes be used instead.
Some technologies are only practical as large centralised plant, while others can be built at any scale. Small scale has the advantage that it can be added to as needed, instead of having to guess the demand for decades in advance, and can be spread around the grid, reducing distribution losses.
(Reduced distribution loss is a key justification for a feed-in tariff, whereby suburban households may be paid a higher rate for electricity they feed into the grid than they pay for what they draw from the grid.)
I.e., how quickly can capacity be expanded? Given the urgency of climate change, we cannot wait 30 years for the ideal solution.
Fossil fuels, and that includes nuclear, are by definition a finite resource. To provide the whole world's electricity at current demand from known reserves and current technology, coal might last 200 years, nuclear 20, gas 100. (It's hard to be exact because progressively more expensive sources can be pressed into service.) There could easily be 10 times the known reserves of uranium, so nuclear could stretch to 200 years, longer if thorium is also used. Fourth generation nuclear fission could last for thousands of years, and nuclear fusion for millions.
But as they say, the Stone Age didn't end for lack of stones.
Studies demonstrating the feasibility of 100% renewables:
Aug 2013: US NREL compares land area requirements
July 2014: Four Corners "Power to the People"
In this section
Solar Thermal with storage
Combined Heat and Power
Carbon Capture + Storage ("Clean coal")
Carbon Capture with Algae
Nov 2014: European Innovations
Electricity from wind has been around for 120 years, with commercial generation since 1941. Current costs go as low as 6 to 7 cents/kWh for the most suitable sites, making it about the same as new coal-fired, and can be expected to fall a little as the technology evolves. Its main disadvantage is unpredictability, but mixed with other technologies could provide 20% of Australia's needs.
A looming technology is high-altitude windpower, which it's claimed would provide electricity at 2 to 5 cents/kWh.
At the low end, domestic wind turbines don't get enough wind, but other technologies might harness low wind speeds more effectively: http://www.newscientist.com/article/dn19274-innovation-reinventing-urban-wind-power.html
In September 2009, the Danish think tank CEPOS released a report critical of Denmark's commitments to windpower. Two main conclusions have been widely quoted by groups sceptical of renewable energy: (1) That most of Denmark's wind power is exported to other "Nord Pool" countries (hence, it would not be practical for those other countries to adopt the same level of windpower); and (2) that the cost of subsidising the windpower was responsible for Denmark's very high electricity prices.
Other researchers have found major errors in the CEPOS report. E.g. http://www.windpower.org/download/541/DanishWindPower_Export_and_Cost.pdf shows both of these charges to be without foundation.
June 2010: Turbine noise no health threat http://www.nhmrc.gov.au/publications/synopses/new0048.htm
Nov 2010: Minimising harm to bats: http://www.eurekalert.org/
North Seas Countries sign Memorandum of Understanding on joint grid: http://www.enn.com/energy/article/42089
Airborne windfarms considered: http://www.sciencedaily.com/releases/2010/12/101213111127.htm
Windfarms help crops nearby: http://www.ameslab.gov/news/news-releases/wind-turbines
Adaptive aderodynamics to improve turbine efficiency: http://www.sciencedaily.com/releases/2010/12/101220110856.htm
Jan 2011: Study on optimal windfarm layout; Johns Hopkins: http://www.eurekalert.org/pub_releases/2011-01/jhu-syb012011.php
Feb 2011: Torque vectoring gears simplify grid feed-in; Tech Uni Munich: http://www.sciencedaily.com/releases/2011/02/110223122423.htm
March 2011: New insight into bird collisions; Birmigham Uni: http://www.sciencedaily.com/releases/2011/03/110316222022.htm
March 2011: Wind may be too limited a resource; Max Planck Institute: http://www.newscientist.com/article/mg21028063.300-wind-and-wave-energies-are-not-renewable-after-all.htm ... April 2011: but read the blog comments by cphoenix at http://nextbigfuture.com/2011/03/maximum-wind-and-wave-power-limited-by.html
March 2011: Manufacturers plan 7MW and 10MW turbines: http://www.newscientist.com/blogs/onepercent/2011/03/green-machine-giant-wind-turbi.html
May 2011: Global Warming won't diminish wind resource; Indiana Uni: http://www.eurekalert.org/pub_releases/2011-05/iu-gww050211.php
May 2011: Genetic algorithm to optimise turbine placement; Uni of Adelaide: http://www.eurekalert.org/pub_releases/2011-05/uoa-elf050411.php
May 2011: Does noise from offshore turbines harm fish? Uni of Maryland: http://www.newscientist.com/blogs/shortsharpscience/2011/05/constant-noise-of-offshore-win.html
May 2011: Kite power to reach higher altitude winds http://www.makanipower.com
June 2011: Project to reduce turbine noise; Uni of Adelaide: http://www.adelaidenow.com.au/news/south-australia/university-of-adelaide-to-investigate-reducing-wind-turbine-noise/story-e6frea83-1226067109947
June 2011: Eddies harnessed for low-power application: http://www.newscientist.com/article/mg21028145.700-wind-power-harnesses-the-energy-of-galloping.html
June 2011: Trend towards larger turbines
July 2011: Turbine placement can make a tenfold difference in output; Caltech: http://www.eurekalert.org/pub_releases/2011-07/ciot-wpp071311.php
Aug 2011: Counter-rotating vertical-axis turbines feed off each other; Caltech: http://www.bbc.co.uk/news/science-environment-14452133
Aug 2011: Blades of Polyurethane and Carbon nanotubes; Case Western Reserve: http://www.sciencedaily.com/releases/2011/08/110830102159.htm
Sep 2011: "Wind lens" triples power for same size; Kyushu Uni: http://www.enn.com/energy/article/43227
Sep 2011: Wind at 10m height increasing in Australia; CSIRO: http://www.climatespectator.com.au/commentary/gale-force-gauging-wind-powers-potential
Oct 2011: Analysis of Australian anti-wind lobby: http://www.crikey.com.au/2011/10/13/the-web-of-vested-interests-behind-the-anti-wind-farm-lobby/
Oct 2011: Extendable blades would adapt to conditions: http://www.newscientist.com/article/mg21228356.500-wind-turbine-blades-reach-out-to-catch-the-breeze.html
Dec 2011: Jetstream winds not such a great resource as thought; Max Planck Institute: http://www.sciencedaily.com/releases/2011/11/111130100013.htm
June 2012: 14 myths about wind farms
June 2012: For wind turbines, bigger means greener
July 2012: Lower cost wind augmentation
Aug 2012: Guyed turbines cheaper for offshore
Sep 2012: Advances in Vertical Axis Turbines
Oct 2012: Portable 50kW turbine
Oct 2012: Siemens tests 154m rotor
Dec 2012: Taming tornado power
Jan 2013: Fe-based superconducting wires
Feb 2013: 13m waves can snap offshore turbines
Mar 2013: Oz wind farm output matching demand
Apr 2013: NHMRC rejects the Sarah Laurie syndrome
June 2013: GE adds to its Brilliant range
Aug 2013: Supercomputer to help plan wind farms
Aug 2013: No complaints in Alberta
Oct 2013: Advanced software boosts output 5%
Jan 2014: 8MW prototype enters test
April 2014: GE claims 50% capacity factor, 98% availability
May 2014: Preventing lightning damage
Nov 2014: Purple blades safer for wildlife
Dec 2014: Honda plant to be wind powered
Dec 2014: 99% seabirds avoid wind farms
Bladeless Vortex power pole waggles in the wind [be sceptical - Ed]
This concentrates the sun's rays and uses the heat as the source of power.
Without storage, the heat turns water to supercritical steam and drives a conventional turbine. But that competes head-to-head with PV, and, being based more on conventional technology, is not enjoying the same dramatic decline in costs.
More interestingly, the heat can be stored and used later, when the sun is no longer shining. The commonest storage medium today is molten salt, at around 500C. This is not table salt, but salts such as sodium and potassium nitrate (fertiliser). As needed, this is then used to generate steam to drive a turbine. Adequate salt storage and diverse sites in the grid make it suitable not just as baseload but as a flexible source to be mixed with unpredictable sources such as wind.
There are three main versions: linear Fresnel, parabolic trough and power tower. Linear Fresnel and parabolic trough only differ in the shape of the
mirrors. Each concentrates the sun onto a pipe that runs along the
focal points of the mirrors. In power tower arrays, all the mirrors concentrate the sun onto a receiver at the top of a single tower. Parabolic troughs have been expensive to construct. A new aluminium design helps, but still probably more expensive than power tower.
Current generation cost is around 15 cents/kWh, but is expected to fall to the same or less than (new) coal.
See also Heat-based Generation
June 2010: EU Sees Solar Power Imported From Sahara In 5 Years: http://planetark.org/enviro-news/item/58491
Nov 2010: Economically competitive within a decade; Boston Consulting Group http://planetark.org/enviro-
Jan 2011: Sahara project combines CST with reafforestation, desalination and biofuel: http://www.newscientist.com/blogs/onepercent/2011/01/green-machine-bringing-a-fores.html
May 2011: Summary of CST state of play: http://ecosmagazine.com/paper/EC10095.htm
May 2011: eSolar video on high-precision tracking
Sep 2012: Modular system developed
Nov 2012: Nanoparticles make solar steam engine
Apr 2013: Tonopah, Nevada, nears completion
Sep 2013: 377MW Ivanpah comes online
Nov 2013: US solar thermal to reach 1GW soon
Feb 2014: Study finds optimal storage between 6 and 9 hours [Depends on context, surely? - Ed]
June 2014: CSIRO lifts steam temperature to 570C
June 2014: 900C claimed for Calcium-based heat store
July 2014: Latent heat storage (PCM) aims for $15/kWh-thermal [how that translates into $/kWh-electric will depend on transition temperature - ed]
Jan 2015: Underground 500oC steam storage
Apr 2015: Changed algorithm prevents bird flaming
May 2015: Common sand as heat reservoir
Aug 2015: Oman 1GW CSP at only 60c/Wp
Aug 2015: 260 MW CSP with storage for Chile
Nov 2015: Latent heat of melting Silicon
This turns light directly into electricity, avoiding the inefficiencies of a heat stage and the need for water as a coolant. That also makes it viable for domestic scale generation. There is a range of technologies with widely differing costs, efficiencies, and applications. The fall in price of some has been dramatic across decades.
Concentrated PV (CPV) uses mirrors to concentrate the sunlight onto a relatively small area of very efficient, and expensive, solar cells.
There are many competing solar cell technologies. Some are very efficient, but expensive, while others quite inefficient but dirt cheap. Some come in the form of thin films which can be applied to existing surfaces. Some use only the infrared bands, allowing visible light through, so can be used on windows. Others attempt to use as much of the sun's bandwidth as possible. Advances in each technology play leapfrog.
Silicon Wire Arrays; Caltech: http://www.sciencedaily.com/releases/2010/02/100216140259.htm
Plant protein; Tel Aviv: http://www.aftau.org/site/News2?page=NewsArticle&id=11819
Algal electrons; Stanford: http://www.newscientist.com/article/dn18666-algaes-solar-electrons-hijacked-to-steal-power.html
CoS cathode, organic redox electrolyte; Quebec: http://www.sciencedaily.com/releases/2010/04/100406125545.htm
Graphene; Indiana: http://www.eurekalert.org/pub_releases/2010-04/iu-cio040910.php
Continuous flow thin film; Oregon: http://www.eurekalert.org/pub_releases/2010-04/osu-ami041610.php
Printable plastic strip cells; CSIRO: http://www.itwire.com/science-news/energy/23361-new-technology-enables-solar-cells-to-be-printed-like-money
Plastic fibre cells; Wake Forest: http://www.solarserver.de/solarmagazin/news-e.html#news2113
Multilayer fabrication of thin film GaAs; University of Illinois: http://www.sciencedaily.com/releases/2010/05/100520093036.htm
Grätzel cells take Millennium Prize; Lausanne: http://en.wikipedia.org/wiki/Michael_Grätzel
Quantum dots could double PV efficiency; University of Texas: http://www.eurekalert.org/pub_releases/2010-06/uota-hes061410.php
Longer life unsealed plastic solar cell; University of Alberta and the National Institute for Nanotechnology: http://www.eurekalert.org/pub_releases/2010-06/uoa-lop062110.php
Ultrathin cells save on silicon; Transform Solar: http://www.transformsolar.com/tech_sliver.php
Photon enhanced thermionic emission (PETE) uses both heat and light; Stanford: http://news.stanford.edu/news/2010/august/new-solar-method-080210.html
Embedding Selenium in Zinc Oxide increases capture; Lawrence Berkeley Lab, Ca.: http://www.eurekalert.org/pub_releases/2010-08/aiop-smm080310.php
Nickel can replace gold in colloidal quantum dot solar cell contacts; University of Toronto: http://www.eurekalert.org/pub_releases/2010-08/aiop-nis080310.php
Self-assembled monolayer helps charge dissociation in conjugated polymers; University of Cambridge: http://www.sciencedaily.com/releases/2010/08/100817090756.htm
Chlorophyll in stromatolites captures infrared; University of Sydney: http://www.newscientist.com/article/dn19338-infrared-chlorophyll-could-boost-solar-cells.html
Carbon nanotubes concentrate solar energy; MIT: http://www.eurekalert.org/pub_releases/2010-09/miot-mrd090810.php
Detergent renews solar cells; MIT: http://www.newscientist.com/article/mg20727775.700-bornagain-solar-cells-are-more-efficient.html
Solar cells as continuous flexible sheets; Binghamton University: http://www.eurekalert.org/pub_releases/2010-09/aiop-ciw091310.php
Artifical leaf; NCSU: http://news.ncsu.edu/releases/176mkvelevartificialleaves/
Ultra-thin solar cells cheaper, more efficient; Stanford: http://www.enn.com/energy/article/41824
Quantum dots give 2 electrons per photon; University of Wyoming: http://www.newscientist.com/article/dn19532-work-light-twice-as-hard-to-make-cheap-solar-cells.html
nanocrystals of copper indium diselenide in sprayable ink; University of Texas: http://www.newscientist.com/article/mg20827806.100-charge-your-phone-with-a-beach-towel.html
"excitons" can travel far further in organic solar cells than thought; Rutgers: http://www.eurekalert.org/
Sahara Solar Breeder Project: Sun and sand make silicon and power; Japanese/Algerian initiative: http://www.newscientist.com/article/dn19785-sun-and-sand-breed-sahara-solar-power.html
Capturing infrared too doubles power and even works at night; US DoE, National Lab, Idaho Falls: http://www.newscientist.com/article/mg20827915.000-is-night-falling-on-classic-solar-panels.html
Carbon nanotubes repair degraded dyes; Purdue Uni: http://www.purdue.edu/newsroom/research/2011/110104ChoiSolar.html
Orienting panels to target peak load; UC San Diego: http://www.sciencedaily.com/releases/2011/01/110111141351.htm
Antireflective coating improves light capture; Nagaoka University of Technology: http://www.eurekalert.org/pub_releases/2011-01/osoa-iei012011.php
Bloomberg recommends PV for domestic power in Persian Gulf: http://www.bloomberg.com/news/2011-01-19/solar-energy-competitive-with-oil-in-persian-gulf-new-energy-finance-says.html
World annual growth of PV doubled to 16GW in 2010: http://planetark.org/enviro-news/item/61201
Organic layer can triple output of quantum dot solar cells; Stanford: http://www.sciencedaily.com/releases/2011/02/110220091834.htm
Amorphous Si deposition could be 10 times faster; Tech Uni Delft: http://www.sciencedaily.com/releases/2011/03/110317102557.htm
Quantum dots boost cell efficiency; Colorado School of Mines: http://nsf.gov/news/news_summ.jsp?cntn_id=119058&org=NSF&from=news
Combined polymer PV and solar heating reaches 30% efficiency; Wake Forest Uni: http://www.eurekalert.org/pub_releases/2011-04/wfu-fps040411.php
Graphite nanoparticles boost solar heat transfer 10%; Arizona State Uni: http://www.eurekalert.org/pub_releases/2011-04/aiop-nis040411.php
Thin film gold electrode for organic cells; Warwick Uni: http://www.sciencedaily.com/releases/2011/04/110406085627.htm
Quantum coaxial cables realised; Xiamen Uni, China: http://www.sciencedaily.com/releases/2011/04/110412101638.htm
Magnetic effect could lead to radical alternative to existing solar cells; Uni of Michigan: http://www.eurekalert.org/pub_releases/2011-04/uom-spw041911.php
Woven polymer cheaper electrode than indium tin oxide in thin-film cells: http://www.sciencedaily.com/releases/2011/04/110419082659.htm
Viruses help assemble efficient solar cell; MIT: http://web.mit.edu/newsoffice/2011/solar-virus-0425.html
ZnO honeycomb allows thicker amorphous silicon layer; Czech Academy of Sciences: http://www.eurekalert.org/pub_releases/2011-05/aiop-cd050611.php
Mirrors reduce silicon needed; Japanese start-up: http://www.heraldsun.com.au/news/breaking-news/firm-develops-sun-chasing-solar-panels/story-e6frf7jx-1226068986519
Inverters reach 99% efficiency: http://www.sciencedaily.com/releases/2011/05/110526091250.htm
GaAs cell sets new record at 28.2% efficiency: http://www.solarfeeds.com/ecofriend/17277-alta-devices-announces-282-efficiency-gallium-arsenide-solar-cell
Cu2S coats CdS nanowires for solar cells; Berkeley Labs: http://www.eurekalert.org/pub_releases/2011-08/dbnl-dtt083111.php
Linked nanoparticles allow electron flow in quantum dot cells; TU Delft: http://www.sciencedaily.com/releases/2011/09/110926131401.htm
Copper nanowire coating for solar cells (and touch screens); Duke Uni: http://www.sciencedaily.com/releases/2011/09/110926132022.htm
Carbon nanotubes replace indium for flexible cells; Northwestern Uni: http://www.eurekalert.org/pub_releases/2011-09/nu-ruc092711.php
Record voltage achieved for organic cells; Warwick Uni: http://www.sciencedaily.com/releases/2011/10/111017141518.htm
Plasmons boost efficiency 30%; ANU: http://www.climatespectator.com.au/commentary/making-solar-cheaper-coal
Optical Cavity Furnace could quarter production cost; US DoE: http://www.climatespectator.com.au/commentary/making-solar-cheaper-coal
Trapezoidal grating traps greater range of wavelengths; Northwestern Uni: http://www.sciencedaily.com/releases/2011/11/111102125555.htm
Nano-antennas cheaper and more efficient than semiconductors; Tel Aviv University: http://www.aftau.org/site/News2?page=NewsArticle&id=15507
Orbiting solar plant feasible; NASA: http://www.climatespectator.com.au/news/exclusive-orbital-solar-power-plants-touted-energy-needs
Fool's Gold variant for cheap solar cells; Uni of Oregon: http://oregonstate.edu/ua/ncs/archives/2011/nov/%E2%80%9Cfool%E2%80%99s-gold%E2%80%9D-leads-new-options-cheap-solar-energy
PV in space, beamed to Earth by laser; International Academy of Astronautics: http://news.nationalgeographic.com/news/energy/2011/12/111205-solar-power-from-space/
PV on greenhouses turns excess sunlight into power: http://www.sciencedaily.com/releases/2012/01/120111103858.htm
CPV, Concentrated photovoltaic, still contending: http://www.planetark.org/enviro-news/item/64457
Embedded quantum dots let solar cells capture infrared too; SUNY: http://www.buffalo.edu/news/13138
Hybrid cell gets 2 electrons per photon, promises 44% efficiency; Cambridge Uni: http://www.climatespectator.com.au/news/new-solar-cell-could-boost-efficiency-25
Tandem polymer cells reach 10.6%; UCLA: http://www.eurekalert.org/pub_releases/2012-02/uoc--uec021312.php
Israeli start-up floats solar farm, literally; http://www.enn.com/energy/article/44015
Solar windows reach 170cm x 170cm: http://reneweconomy.com.au/2012/the-hot-news-in-cleantech-this-week-63083
Coating cuts reflection from 40% to 1%: http://www.innovationservices.philips.com/news/amolf-philips-research-develop-new-coating-solar-cell-efficiency-using-scil-lithography
SunTech reaches 20.3% efficiency: http://www.climatespectator.com.au/news/suntech-sets-record-203-pv-cell-efficiency
UK company targets domestic PV for African villages: http://www.enn.com/energy/article/44105
Cheap mirrors to concentrate onto large scale PV at $1/W fully installed: http://www.newscientist.com/blogs/onepercent/2012/03/an-astronomer-famous-for-desig.html
3D cells may double efficiency of static arrays: http://cleantechnica.com/2012/03/20/solar3d-thinks-its-solar-cells-can-produce-200-the-power-of-conventional-solar-cells
Plastic films still in the running: http://reneweconomy.com.au/2012/plastics-put-solar-on-the-verge-again-39304
SunPower's Maxeon cell claimed 24% efficient: http://reneweconomy.com.au/2012/mixed-greens-energy-savings-for-smes-68943
UK team targets 35c/W for thin film PV on windows: http://cleantechnica.com/2012/03/30/solar-windows-uk
Kyocera to launch integrated domestic PV with battery storage in Japan, summer 2012: http://global.kyocera.com/news/2012/0102_qpaq.html
Mar 2013: PV installation training videos
Nov 2011: Podcasts by American Chemical Society
"Conventional" geothermal energy relies on volcanic activity. This is used in e.g. NZ and Iceland. It generates electricity for about 2-4 cents/KWh, significantly cheaper than coal.
Australia's geothermal resource consists of hot rocks deep underground. The heat comes from gradual radioactive decay in granite, so is constantly renewed (but the temperature will drop if heat is extracted quickly). An Enhanced Geothermal System, or EGS (previously known as Hot Fractured Rock, or HFR), involves injecting water into these rocks. The water is recycled, but other water may be used as coolant. The total potential is many times Australia's demand, though some sites are much cheaper to exploit than others. This is the only renewable source which is inherently available 24x7. Other technologies require some kind of storage.
The key cost is the initial drilling; the hot rocks are deeper than most mines. Estimates of potential capacity and long-term cost vary. The Australian Geothermal Energy Association says 8-11 cents/kWh, with current policies leading to only 8% of total electricity demand by 2020. Geodynamics reckons 4-6 cents.
There is a worry that the injection of water may trigger earthquakes. In principle, this may only be bringing on earthquakes that would have happened one day in any event, but it remains at least a legal issue. This may rule out some sites.
There may be some amount of GHGs and other undesirable gases released from underground in the process.
A recent idea is to avoid drilling so deeply by choosing a place where there is a good insulating layer near the surface. It turns out that brown coal deposits are favorite!
See also Heat-based Generation
Oct 2010: West Virginia hotspot http://www.enn.com/energy/article/41847
May 2011: New technique avoids fracking http://gigaom.com/cleantech/gtherm-cutting-cost-quakes-from-geothermal-power/
June 2011: CO2 more efficient than water; Uni of Minnesota: http://www.sciencedaily.com/releases/2011/06/110606092746.htm
July 2011: At last, some good news for geothermal prospects in Australia: http://www.climatespectator.com.au/commentary/geothermal-getting-warmer
May 2012: Geothermal as back-up for solar PV
Dec 2012: Laser drilling proposed
Jan 2013: Naples looks to Mt Vesuvius
Apr 2013: 1MWe Habanero, SA, plant commissioned
Sep 2013: $88.8m written off Cooper Basin asset
Oct 2013: Vic govt pulls out of Geelong project
Oct 2013: Innamincka trial declared successful
June 2014: Iceland looks to export power to UK
June 2014: Iberian peninsula could be 100% geothermal
Aug 2014: Poor prospect for geothermal in Oz
Apr 2015: Satellite map to suggest sites
June 2015: Geothermal in the Paris suburbs
Oct 2015: EU group plans 2km drill in N. Italy
Biomass may be existing crop waste or purpose grown.
If crop waste, the energy density is low, and the main cost is gathering it from a broad area. Traditionally, this has led to small scale combustion, which in turn results in incomplete burning and smogs (which have a powerful greenhouse effect). A better option is pelletisation, reducing the cost of transporting to a centralised furnace and allowing it to be stockpiled.
If purpose grown, collection is still something of an issue, plus it may displace food crops.
Either way, it is unlikely to provide more than about 10% of world demand ever. It can provide a useful backup heat source for solar thermal.
Jan 2011: Improved roasting method of production; Uni of Leeds: http://www.newscientist.com/article/dn19906-christmas-trees-could-make-a-great-green-fuel.html
May 2011: By-products of whisky distillation power homes: http://www.guardian.co.uk/environment/2011/may/04/whisky-energy-biomass-scotland-speyside
Apr 2012: Forestry biomass will make matters worse
See also Biofuel
The designs for collecting wave power are more varied than for any other energy source. Several years of experiments are needed to select the best.
Current installations are achieving 15-20 cents/kWh, but this is expected to fall to 5-7 cents. Some estimates claim as low as 2-3 cents!
In Australia, there may be limited sites producing reliable energy and close to urban centres. Even so, it has been claimed that it could supply 35% of Australia's current demand.
August 2010: Wave energy hotspots around Australia
July 2012: Wave prediction can double power harvested
Aug 2013: Japanese wind & wave hybrid
Nov 2014: Siemens exits marine power sector
Feb 2015: Carnegie project feeds into WA grid
June 2015: Carnegie earns $1.5m milestone payment
Sep 2015: Bombora trial starts on Swan River
Sep 2015: 45kW trial to start off Bunbury, WA
Current installations are achieving 10-12 cents/kWh, but this is expected to fall to 4-6 cents. Given the high capital cost, it may surprise that the unit cost is expected to drop so. This may be because the land used is not considered of commercial value.
The necessary landscaping impacts wildlife and may cause GHG emissions as with hydro.
In Australia, there are few suitable sites.
March 2011: Estuaries could generate electricity from fresh/salt boundary; Stanford: http://www.eurekalert.org/pub_releases/2011-03/su-sru032911.php
Apr 2012: ... a study of its potential: http://www.eurekalert.org/pub_releases/2012-04/acs-rfi041812.php
July 2012: First commercial tidal plant in US
Oct 2012: UK Tidal potential put at 153GW
Dec 2014: Orkney tidal generator reaches 1GWh mark
Hydro comes in three flavours: run of river, single reservoir, or double reservoir. Double reservoir (a.k.a. pumped hydro) can draw power from the grid when demand is low to pump water from the lower reservoir to the upper one.
There may be significant GHG emissions from a reservoir. According to the World Commission on Dams report, where the reservoir is large compared to the generating capacity (less than 100 W/m2 of surface area) and no clearing of the forests in the area was undertaken, greenhouse gas emissions from the reservoir may be higher than those of a conventional oil-fired thermal generation plant.
The best sites produce very cheap electricity (about half the price of coal), but Australia already exploits most viable sites.
Oct 2010: Cost-effective design for small scale hydro; Technische Universität München: http://www.eurekalert.org/pub_releases/2010-10/tum-sib102010.php
CCGT stands for Combined Cycle Gas Turbine. This is the most efficient gas-based power generation to date. It is suitable for baseload generation, so competes with coal-fired and nuclear.
OCGT is Open Cycle. This is less efficient but can provide 'peaking' power, needed to cover peaks in demand over supply. That makes its competitors pumped hydro, CST+ (solar thermal with storage) and geothermal.
While natural gas combustion has only 50-60% of the CO2 emissions per unit of energy as coal, it is a more expensive fuel. There are also significant question marks over the total GHG footprint, since methane leaks are inevitable.
Until recently, the known reserves would only power humanity for 50 years at current demand. Vast new fields have been discovered. It is hard to judge whether this is good news or bad. On the one hand, it creates a relatively easy way to reduce emissions significantly over the next five to ten years. On the other, building the new gas-fired power stations diverts efforts from renewables, locking us into continuing emissions for an extra ten to twenty years.
See also Heat-based Generation
Jan 2011: IEA doubles estimate of reserves
April 2011: Methane emissions from fracking shale for gas worse than coal over 20 years; Cornell Uni: http://esciencenews.com/articles/2011/04/12/natural.gas.shale.contributes.global.warming
May 2011: Fracking can damage your health: http://www.telegraph.co.uk/finance/personalfinance/offshorefinance/8488166/Frack-and-ruin-the-rise-of-hydraulic-fracturing.html
Feb 2012: Fracking of shale didn't contaminate groudwater; Canadian report: http://www.eurekalert.org/pub_releases/2012-02/teia-nss021012.php
Aug 2012: Improved catalyst for burning methane
Mar 2014: More earthquakes from fracking
Apr 2014: Fugitive emissions 1000 times claimed
CHP systems replace conventional heating systems (water, space heating), usually in large establishments such as hospitals and factories. Rather than merely turn the power source, be it coal, gas or oil, into the desired heat, it uses some of that heat to generate electricity, just as in a fossil-fuel power station. This is very efficient because nothing is wasted; unlike a power station, the heat left over is useful. (See Heat-based Generation.)
The efficiency gain is possible because the temperature required for the hot water or hot air is much lower than the combustion temperature of the fuel. For example, if you were to generate 10 units of heat, but turn 4 of them into electricity, you could then use that electricity to drive a heat pump, bringing in maybe 20 units of heat from the outside air. So the net heating you achieve is 26 units instead of 10.
A new development (SOFC) replaces the combustion and power generation units with a gas or oil fuel cell.
November 2010: Technical Univ of Denmark; SOFC for Domestic MicroCHP http://www.risoe.dtu.dk/News_archives/News/2010/1126_Dantherm.aspx?sc_lang=en
In addition to the CO2 produced in combustion, some CO2 and other undesirable gases are released during mining. Capture reduces the carbon footprint 80-90%. The captured CO2 is stored in geological formations.
Despite the billions invested in trials, it shows no sign of being competitive with the best renewables, whether applied to new coal plant or retrofitted to existing plant.
One interesting idea is to supplement the coal feedstock with, say, 15% biofuel. Then it is only necessary to capture 85% of the CO2 produced in order for the process as a whole to have zero net emissions.
Even if the storage is safe for a thousand years, would we be leaving posterity a legacy they'd prefer to be without? The rationale is that the CO2 doesn't just sit there. Over time, it is absorbed into and reacts with the minerals, rendering it quite stable (until millennia later it reaches the tectonic plate boundary and is subducted). How long this takes depends on the chemistry of the formation.
An appropriate market-based test of viability would centre on the insurance: is it still commercial if having to fund adequate insurance on the open market against all future leaks and other untoward consequences? Goverment-enacted liability caps will constitute a subsidy of unknown value, and send a clear signal that the technology is not to be trusted.
More justifiable is the use of CCS where renewables don't help: cement production and metallurgical coal.
See also Heat-based Generation
May 2010: Tim Flannery withdraws support
July 2010: Trap the CO2 in bacteria
Sep 2010: Poor prospects in Europe
June 2011: Nano-foam could seal leaks
Nov 2011: The Economist's online debate
Dec 2011: $2bn pilot project blocked in Germany
Dec 2011: Warrnambool test claimed a success
Jan 2012: Cheap polymer efficient at CO2 capture
Aug 2012: Oxy-fuel test in Queensland
Dec 2012: EU CCS contest finds no winner
Jan 2013: Welsh pilot plant captures first tonne
Feb 2013: Nickel nanoparticle catalyst (as used by sea urchins) but where is the calcium to come from? - ed.
Apr 2013: Hopes fade for Illinois project
Sep 2013: Gas field to become CO2 store
Sep 2013: Norway scraps CCS plans
Feb 2014: World first gas with CCS announced in UK
Mar 2014: Pilot plant for SW WA
Jan 2015: Most of buried CO2 could leak back out - MIT study
Feb 2015: Most promising US project collapses
Mar 2015: Pollution down 85% at Qld pilot plant
July 2015: New zeolites trap CO2
One fossil fuel power station option is to capture carbon organically, using algae say, which can then be used as biofuel or cattle cake.
There are effectively two carbon cycles on earth: on a decades scale it cycles between air, ocean, soil, and biota. Over millennia, it can be bound into minerals as rocks weather and as organic matter becomes buried instead of decaying, and released later by tectonics. Our key problem is that burning coal and oil, and manufacturing cement, rapidly move carbon back to the short cycle. Capturing it in algae does not take it back out of the short cycle unless you then bury it. And if you do that, you may as well run the power station on the algae and leave the coal in the ground.
So algal capture is hardly a solution. If used as cattle cake it may reemerge as methane, and that could be worse than not having captured it at all.
Of course, if the algae were to capture CO2 directly from the air and not depend on a power station then that would be excellent, but there's no suggestion that would be viable.
See also Biofuels.
November 2010: Baking Soda Boosts Algal Oil Production; Montana SU: http://www.sciencedaily.com/releases/2010/11/101115091902.htm
March 2011: Protein converts fatty acids to ketones; Uni of Minnesota: http://www.eurekalert.org/pub_releases/2011-03/uom-uom032311.php
April 2011: Doubt cast on potential of biofuel from algae; Kansas State Uni: http://www.eurekalert.org/pub_releases/2011-04/ksu-epa040511.php
May 2011: Toxin pumps boost production; US DoE: http://www.eurekalert.org/pub_releases/2011-05/miot-msc051111.php
June 2011: Still far too expensive: www.planetark.org/enviro-news/item/62350
June 2013: Algal biofuel demo plant planned for Whyalla
It is essential that we stop using this ASAP. Coal has been storing excess carbon safely for millions of years. Once we release it into circulation it will be hard to take it back out. The other environmental and health costs of mining and burning coal, borne by the taxpayer, are huge.
See also Heat-based Generation
Feb 2011: Taxpayers bear 2/3 of real cost of coal; US study: http://planetark.org/enviro-news/item/61230
May 2011: Lung damage pathway from carbon nanoparticles identified: http://www.eurekalert.org/pub_releases/2011-05/uoih-cbn051811.php
Oct 2011: Yale economists put real cost coal at 2 to six times market price: http://www.climatespectator.com.au/commentary/coal-not-so-cheap
While no GHGs are emitted during operation of the generator, there is a large footprint from the vast quantities of concrete needed for construction of the plant, plus the ongoing impact of mining and transporting the ore.
Current nuclear power station production technology generates large quantities of radioactive waste that must be stored for centuries, some for millennia. At the same time, anticipated reserves would only meet the world's energy demand for 200 years.
The true cost of nuclear power remains an open question. Every nuclear-powered country on the planet caps the liability; what does that amount to as a subsidy? France keeps the details secret. Germany's cap is much larger than most, and the only European one that doesn't equate to exoneration. The US has the Price-Anderson Act. In 1992, their Energy Information Administration valued the effective subsidy to the nuclear power industry as a whole at US$3.05 billion annually.
Fast breeder reactors, still only experimental, could reuse existing waste, produce much less waste in future, employ sources other than uranium, and so extend the resource to thousands of years. A key obstacle is that material could be diverted for weapons.
For military-political reasons, thorium, in the form of a molten salt (LFTR), has been neglected. India has vast reserves. It is much safer than conventional nuclear power in many ways, and has little waste disposal headache. But LFTR is also highly corrosive. In late 1960s, an experimental plant at Oak Ridge, Tennessee, ran for four years, by which time the container was much degraded.
The dream has for decades been fusion, the power source of the sun. This 'burns' water and promises almost limitless power for very little radioactive waste. It is also far safer than a fission reaction, a catastrophe like Chernobyl being impossible. Over fifty years of international effort, it was always '30 years away' from becoming reality. The two leading designs are the Tokamak, which contains a sun-like plasma in a magnetic 'bottle', and laser inertial confinement fusion (Laser ICF). Recent breakthroughs in the laser systems are promising, but technical challenges remain.
A major issue is the source of Tritium. Currently this comes from conventional nuclear powered stations.
Dec 2012: S Korea to build test facility
A third option is hybrid fission-fusion. As well as enjoying the power output from the fusion component, this confers many of the advantages of the fast breeder process on the fission component.
See also Heat-based GenerationReferences:
December 2010: A report concludes that nuclear continues to be a viable power source but the current fuel cycle is not sustainable: http://www.sciencedaily.com/releases/2010/11/101130100405.htm
January 2011: China claims breakthrough in fuel reprocessing: http://planetark.org/enviro-news/item/60750
March 2011: EU climate commissioner "Wind now cheaper than nuclear" http://www.guardian.co.uk/environment/2011/mar/17/wind-cheaper-nuclear-eu-climate
April 2011: light ions for fast ignition; US Naval Research Lab: http://www.nrl.navy.mil/media/news-releases/52-11r/
May 2011: Governments have to pick up bill major accidents http://ipsnews.net/news.asp?idnews=55527
May 2011: China in quest for fusion power
May 2011: US NRC finds fault with new Westinghouse reactor design http://news.yahoo.com/s/ap/20110521/ap_on_re_us/us_nuclear_reactor
May 2011: UK subsidies for nuclear power continue http://www.nwemail.co.uk/news/government-s-hidden-nuclear-subsidies-blasted-1.839233?referrerPath=news/
July 2011: Chinese Fast Reactor goes on-grid: http://www.climatespectator.com.au/commentary/green-deals-get-ev-cook-dinner
Sep 2011: New fusion plant using "stellarator" design to be built in Germany: http://www.economist.com/node/21528216
Jan 2012: German report: full insurance would add from 20c/kWh to $3.40/kWh to cost of nuclear: http://www.bee-ev.de/_downloads/publikationen/studien/2011/110511_BEE-Studie_Versicherungsforen_KKW.pdf
Mar 2012: Simulation says Magnetised Inertial Fusion will generate useful output; Sandia National Labs: https://share.sandia.gov/news/resources/news_releases/z-fusion-energy-output/
Jun 2012: Key process developed in building tokamak core; Uni of Tennessee: http://www.eurekalert.org/pub_releases/2012-06/uota-uot060812.php
July 2012: US slashes funding for fusion research
Aug 2012: GE chief says nuclear too expensive
Dec 2012: UK's nuclear cleanups to cost $160b
July 2014: Nuclear industry continues global decline
Dec 2014: IEA sees nuclear as uncompetitive
July 2015: French fusion plans fallen 5 years behind
Aug 2015: Magnet technology brings fusion closer
but a hot month for fusion...
Several technologies involve the conversion of energy to heat first and then to electricity. The second step requires a lower temperature medium for the heat to flow to, usually water or air, and involves an inherent inefficiency. The higher the temperature difference the greater the efficiency. Conventional coal-fired stations manage about 45%, while a car engine is only 20%. This is why electric vehicles can reduce emissions even if the electricity comes from coal.
Where the heat comes from burning a gas (hydrocarbons), the burning fuel can drive a turbine or piston engine directly. This is "internal" combustion, and can employ the Brayton Cycle. Otherwise the heat is used to expand a gas, typically steam. In coal-fired power stations and solar thermal plants the (supercritical) Rankine Cycle is used.
In some situations, e.g. CHP, the spent heat is useful, raising the effective efficiency.
March 2011: Supercritical CO2 Brayton Cycle could raise efficiency of gas-fired to 50%: http://www.eurekalert.org/pub_releases/2011-03/dnl-scd030311.php
June 2011: Device gleans energy from low-level heat waste; Oregon State Uni: http://oregonstate.edu/ua/ncs/archives/2011/jun/prototype-demonstrates-success-advanced-new-energy-technology
Methods of generation can be combined to produce a better overall result.
A cheap source of heat at a moderate temperature can preheat the working fluid, which is then boosted to a higher, more useful temperature by a more expensive energy source.
A variable source, such as wind or solar PV, can be combined with a dispatchable source source, such as solar thermal with heat storage, or reservoir-based hydro, to provide a supply matched to demand.
As well as technologies for generating electricity, it is important to look at how we could distribute it across the grid more efficiently. The present system uses alternating current (AC), even though direct current (DC) is more efficient. High voltage DC (HVDC) loses only 3% per 1000km. For long-distance transmission, very high voltage levels are needed for efficiency. These must be stepped down to much lower voltages for domestic use. To transform voltage so, the current needs to be AC. When the grid was built, converting from DC to AC was inefficient, so the distribution itself was made AC.
Nowadays there are better ways to convert DC to AC, so a DC distribution network would save energy. And given a more efficient distribution network, there are more options for siting the power generation.
The cost of maintaining the distribution network is a major component of the retail electricity price. In 2011 major upgrades dramatically raised electricity prices. The upgrades were claimed needed because of:
- Aging infrastructure
State-owned retailers had kept prices low for political reasons and siphoned profits into general revenue. So no fund has been built up for future upgrades.
- Rising peak demand
The network has always been built to meet peak demand, which had risen inexorably. It has been calculated that for each $1 a household spends on installing air-conditioning, an extra $3 worth of distribution network is needed.
Home rooftop solar PV panels has reduced peak demand from the grid, which had been mid-afternoon in summer. The new peak, 5pm-7pm, is lower but stands in sharper contrast to average demand.
The solution to this would be demand management. Ultimately it may require smart metering. The vision is that the end-user price varies according to current total demand, and household appliances adjust in response.
May 2012: Visions of a smart grid future
Dec 2012: $130m HVDC link for Finland
Dec 2014: UK trial of smart grid
A cheap and efficient way to store lots of energy would help greatly in both ensuring baseload and meeting peak demands.
For stationary energy storage, dedicated conventional electrical batteries do not come close.
- Pumped Hydro uses spare energy to pump water from a lower reservoir to a higher. This has been used for many years, but the opportunities for it in Australia are limited.
- "Pumped gravel" is like pumped hydro but uses solid mass
Mar 2012: http://reneweconomy.com.au/2012/hot-news-in-cleantech-ski-lift-power-storage-3d-pv-and-wind-blimps-68143
- Molten Salt is used by some Solar Thermal systems
- Hot Gravel is a very recent idea.
- Compressed Air (CAES) has been gaining favour. A key issue is heat management.
- Phase Change Materials
- Molten glass
- Parked Electric vehicles
- Flywheels made viable by high tech materials
Apr 2015: Ireland to get Europe's first grid-connected flywheel
May 2015: Maglev 'train' in vacuum tube ($140/kWh)
The cost of storage has three aspects:
- The cost per unit of energy storable at one time ($/kWh). Typically in 100s.
- The cost per unit of maximum power deliverable when needed ($/kW). Typically in 1000s.
- How much energy is lost in process.
For example, suppose you have a windfarm rated at 10MW but you only rely on it for 3MW. Say you want to cover the possibility of 48 hours of below 3MW output, averaging only 1MW. So you will need 96MWh of storage, with a peak delivery capability of 3MW. If it costs $9.6m then that's $100/kWh and $3200/W.
If the basic cost of power from the windfarm was $2/W of rating, it cost $20m to build. The storage therefore adds 50% to the cost.
Note: Claimed storage costs can be confusing. Sometimes the cost is quoted in terms of stored energy at one instant (typically $100-$1000/kWh for non-heat) and recovery percentage, sometimes in terms of all the energy stored and recovered over the lifetime of the equipment (in the cents/kWh range). The first format is the one the manufacturer can quote with certainty; the second involves assumptions regarding usage pattern and generation cost.
The heat-storage options are only applicable where the energy is already converted to heat at some point, e.g. solar thermal.
For more information see
Mar 2012: Cheap cathode from pulp mill waste; Linköping Uni: http://www.eurekalert.org/pub_releases/2012-03/lu-bla031912.php
Jun 2012: Copper-graphene nano-coax capacitor
Oct 2012: Liquefied air energy storage
EVs plugged into the grid whenever possible can be charged up when other demand is low and feed back into the grid when demand is high. To be effective in practice, this may require charging points at places of work, which will complicate the accounting. Even so, trials are underway.
Transport energy storage must also be lightweight. Petrol has 50 times the energy / kg as the best batteries.
The special consideration for transport is portability.Comparison of transport footprints
Glossing over walking and cycling, clearly to be encouraged for their health benefits as well as being carbon-neutral and cheap, for land transport we have:
- Internal combustion
- Electric Vehicles
- Hybrid Vehicles
- Direct Production of Hydrocarbons
- Regenerative Braking
- Mass Transit
Air transport is tougher. Batteries being heavy, hydrocarbons are the only feasible technology today for commercial aircraft. But single- and two-seater electric aircraft do exist: http://en.wikipedia.org/wiki/Electric_aircraft.
As with carbon-based power stations, the hidden cost of poor air quality is huge.
Feb 2011: Dirty air triggers heart attacks; Hasselt Uni, Belgium: http://www.reuters.com/article/2011/02/24/us-heart-air-pollution-idUSTRE71N05920110224
May 2011: Bio-derived jet fuel possible; CSIRO: http://www.csiro.au/news/New-sustainable-bio-derived-jet-fuel-industry-is-achievable.html
June 2011: KLM to fly on recycled cooking oil
July 2012: Powering flight by laser from ground
Dec 2012: BA to build aviation biofuel plant
May 2013: Solar Impulse flies 1500km
Aug 2013: Airline cut emissions 18% in 8 years
Sep 2013: Aerofoil deck to cut drag on cargo ships
Apr 2014: C-footprint comparison of car types
May 2014: Airbus electric plane in maiden flight
June 2014: Flight path changes could curb contrails
Aug 2014: Jet fuel from tobacco
Oct 2014: Jet fuel from waste cooking oil
Dec 2014: 787 flies on 15% 'green diesel'
Jan 2015: Hybrid plane uses 30% less fuel
Oct 2011: Solar-powered cargo airships
June 2012: Cargo ship to run on wind and gas
Mar 2015: Marine propulsion gains 25% efficiency
The internal combustion engine is only about 20% efficient at turning the chemical energy into forward motion. In addition to CO2, it generates nitrogen oxides, harmful to health and also GHGs. As the readily available oil runs out, sources such as deep water reserves, tar sands, and oil from coal become economically viable, increasing the rate of environmental damage.
April 2011: Laser ignition improves efficiency, reduces smog; Japan National Inst of Natural Sci: http://www.eurekalert.org/pub_releases/2011-04/osoa-lsr042011.php
Mar 2012: Electricity to petrol; UCLA: http://www.eurekalert.org/pub_releases/2012-03/uoc--uer032912.php
Jan 2013: Air pollution killed 3.2m in 2010.
Nov 2014: Lightweight 2-stroke engine
May 2015: Hybrid engines save 15%
Even if the electricity is produced from fossil fuels, electric vehicles have a similar or lower carbon footprint than petrol and diesel vehicles. An internal combustion engine only achieves about 20%. Taking into account the energy used in producing petrol in the first place, that drops to 17%. Power stations convert fuel to electricity with an efficiency of up to 40%. Some is lost in the transmission of the electricity, but it still comes out ahead.
One problem with electric cars is that you might not hear them coming. This is being addressed.
A key problem has been the batteries, both their weight and their life expectancies. Lithium ion batteries and their derivatives have been a great advance, but still expensive.June 2010: carbon nanotubes in lithium batteries; MIT: http://www.eurekalert.org/pub_releases/2010-06/miot-ucn061710.php
June 2010: EU agrees standard for plugs and sockets for car recharging: http://www.reuters.com/article/idUSTRE65N43120100624
Oct 2010: Silicon boosts capacity of Li-ion; Rice Uni.: http://www.eurekalert.org/
Nov 2010: Toyota EV To Go Over 100 Km On Single Charge http://planetark.org/enviro-
Nov 2010: GE To Buy 25,000 Electric Cars http://planetark.org/enviro-
Nov 2010: Report says new energy storage technologies crucial; American Physical Society's Panel on Public Affairs: http://www.eurekalert.org/
Dec 2010: Lithium-ion battery to store 2.2MWh: http://www.economist.com/node/17647673
Dec 2010: Paris launches self-service electric car hire: http://planetark.org/enviro-news/item/6061
Jan 2011: Li-ion battery with "nanoscoops" charges 40 times faster; Rensselaer Polytechnic: http://news.rpi.edu/update.do?artcenterkey=2810
Feb 2011: Nanosheets promise supercapacitors; Trinity Dublin & Uni of Oxford: http://www.eurekalert.org/pub_releases/2011-02/tcd-nnu020111.php
Feb 2011: SnC anode with Li-ion cathode achieves long life, broad temperature range and 170Wh/kg; Uni of Rome: http://pubs.acs.org/stoken/presspac/presspac/full/10.1021/ja110522x
Feb 2011: Microspheres in the anode heal cracks, prevent fires in Li-ion batteries; Uni of Illinois: http://www.sciencenews.org/view/generic/id/70080/title/New_batteries_fix_themselves
March 2011: HCl improves capacity and temperature range of Va-redox batteries; US DoE: http://www.eurekalert.org/pub_releases/2011-03/dnnl-utv031711.php
March 2011: 3D nanostructure speeds charge/discharge 100x; Uni of Illinois: http://www.eurekalert.org/pub_releases/2011-03/uoia-bcq031711.php
April 2011: Nanowires make refuelling as fast as for petrol; Colorado State: http://www.newscientist.com/blogs/onepercent/2011/04/green-machine-electric-chargin.html
April 2011: Li-air battery would match petrol for energy density; Risø DTU, Denmark: http://www.risoe.dtu.dk/News_archives/News/2011/0328_Li_battery.aspx?sc_lang=en
May 2011: Activated Graphene; US DoE: http://www.eurekalert.org/pub_releases/2011-05/dnl-agm051111.ph
May 2011: Online auction to optimise recharging; Uni of So'ton: http://www.sciencedaily.com/releases/2011/05/110505124043.htm
May 2011: Vehicle-to-grid balancing could earn electric vehicle fleets $1000 a year per vehicle; UK National Grid study: http://www.climatespectator.com.au/news/electric-car-grid-balancing-options-limited-study
June 2011: Capacity and cycle lifetime of Na-ion rechargeables increased; US DoE: http://www.eurekalert.org/pub_releases/2011-06/dnnl-thi060711.php
June 2011: "Semi-solid flow" cells promise to halve size, cut price, extend range and speed recharge; MIT: http://www.climatespectator.com.au/commentary/cleantech-buzz-biggest-battery-breakthrough-ever
July 2011: Solar heat stored in carbon nanotubes; MIT: http://web.mit.edu/newsoffice/2011/update-energy-storage-0713.htmlJuly 2011: Graphene-tin nanocomposite boosts Li battery; Berkeley Lab: http://newscenter.lbl.gov/news-releases/2011/07/27/graphene-sandwich/
Sep 2011: Li-ion more efficient with anode binder from kelp; Georgia Inst of Tech.
Nov 2011: Silicon-graphene sandwich to charge Li-ion batteries ten times as much, ten times as fast ; Northwestern Uni
Nov 2011: Li-ion car battery ignites 3 weeks after crash test: http://theage.drive.com.au/drive-life/battery-fire-sparks-electric-car-investigation-20111126-1o08h.html
Jan 2012: Li-air battery life breakthrough promises 800km range: http://www.newscientist.com/article/mg21328466.200-air-battery-to-let-electric-cars-outlast-gas-guzzlers.html
Feb 2012: Electric trucks save money; MIT: http://web.mit.edu/newsoffice/2012/ctl-electric-powered-trucks-0201.html
Feb 2012: Company claims Li-ion battery half the weight, half the cost: http://enviasystems.com/announcement/
Oct 2012: Portable thin-film solar battery charger
Oct 2012: Fast charging coupler standard agreed
Oct 2012: Portable mains battery charger
Feb 2013: Italian company claims 1000km range, 10 minute charge time (!!)
Mar 2013: US online shopping deliveries by e-bike
Mar 2013: EVs beat biofuel for efficiency
Apr 2013: 7-fold advance in LiS battery cyclesTin nanocrystal anode increases storage in Li-ion
Apr 2013: Batteries may still reach 80% capacity after 20 years, and find other use beyond that (but they don't like going over 30C)
Apr 2013: Waste sulphur can be used in LiS
June 2013:Tesla demos 90-second battery swap
Nov 2013: Electric van does 1300km on one charge
Dec 2013: Results of 2 year EV fleet trial in WA
Dec 2013: Electric bus that recharges en route
June 2014:Solar-electric road concept Nanotubes boost power, life of Li-ion
See also Energy Storage
A hybrid attempts to combine the efficiency of an electric car for short journeys with the range of a petrol car when you need it. The downside is that your efficiency when running on petrol may be even worse than for a conventional car - you still have to carry that load of batteries around. On the plus side, though, you can get a boost from the battery when accelerating rapidly, e.g. from a standing start. Getting that bit extra from a petrol engine is particularly inefficient.
Another solution would be a network of battery-swap stations. This is more likely to succeed in high population density areas, such as western Europe. Given the weight of the batteries, swapping them is not so trivial as it may sound.
April 2011: Wave Disk Generator far more efficient than conventional internal combustion, works well in hybrid; Michigan State Uni: http://news.discovery.com/tech/new-car-engine-sends-shockwaves-through-auto-industry-110405.html#mkcpgn=rssnws1
Aug 2013: UNSW unveils solar hybrid
Sep 2013: Toyota Prius targets 4.3L/100km
The sugars are the most easily digested by both us and microbes, so the ethanol made today is from the edible parts of food crops, such as corn (maize). This has several rawbacks. It pushes up food prices internationally and uses such carbon-intensive methods as to neutralise the advantage over fossil fuels. It only succeeds commercially because of subsidies won by the farmers' lobbies.
Dec 2010: Georgia Inst of Tech.; Modified bacterium speeds ethanol production: http://www.sciencedaily.com/releases/2010/12/101209201940.htm
Dec 2010: Uni of Illinois; New yeast strain converts sugars in red seaweed 3 times as fast: http://www.sciencedaily.com/releases/2010/12/101215193100.htm
Aug 2011: Rice Uni; Glucose to butanol 10 times faster: http://www.eurekalert.org/pub_releases/2011-08/ru-mir081011.php
Jan 2012: Berkeley; Breakthrough in using seaweed: http://www.eurekalert.org/pub_releases/2012-01/spr-bal011312.php
Jun 2012: Cornell; stopping fermentation short of ethanol eases separation from water
Aug 2012: Illinois; copolymer captures butanol, doubling production and cutting costs
A key part of the technology is microbes that can digest the tougher plant matter, such as lignin (the woody bit), cellulose and hemicellulose. Hemicellulose breakdown product acetic acid is toxic to yeasts.
June 2010: North Carolina State University; ozone to break down lignin: http://news.ncsu.edu/releases/wmssharmalignin/
Sep 2010: Biotechnology and Biological Sciences Research Council; genes found that make lignin so hard to break down: http://www.eurekalert.org/pub_releases/2010-09/babs-bfi091310.php
Oct 2010: New Enzyme http://www.planetark.org/
Oct 2010: Denmark; 2nd gen ready for production: http://planetark.org/enviro-news/item/59857
Nov 2010: University of Illinois; field study on switchgrass and miscanthus: http://www.eurekalert.org/
Nov 2012: Bacterium discovered in garbage
Dec 2012: Expected 20-fold ramp up in 2013
June 2013: Structure of enzyme from wood borer decoded
Nov 2014: New catalyst cracks sawdustThis opens up two approaches
- Waste from crop plants
Fuel derived from the unusable parts of existing crops is the ideal. The only downside is the loss to the cropland of the compost it would otherwise have formed. But traditionally, much would have been burnt anyway, and the nitrogen etc. may still be available as fertiliser after biofuel extraction.
Jan 2011: Canadian start-up uses all parts of flax: http://planetark.org/enviro-news/item/60887
May 2011: Biowaste for aircraft fuel
Nov 2012: New process developed in Oz
Apr 2014: Corn waste no greener than petrol
Aug 2015: 400L ethanol per tonne grape refuse (marc)
- Purpose-grown crops
Leading contenders are grasses, such as switchgrass and Miscanthus.
If to be harvested on a worthwhile scale without displacing food crops, they will replace natural vegetation. This creates a "carbon debt" which it will take some years to recover.
25th May 2010: Miscanthus; UK Met Office: http://www.sciencedaily.com/releases/2010/05/100521092751.htm
November 2010: Economically competitive within a decade; Boston Consulting Group http://planetark.org/enviro-
Feb 2012: Low energy process gets 9 times the yield per acre from miscanthus than from corn, for 16c/l http://cleantechnica.com/2012/02/26/kitchen-stove-biorefinery-goes-from-grass-to-gasoline-in-one-hour/
Jan 2011: New yeast strain consumes both glucose and xylose; Uni of Illinois, Lawrence Berkeley National Laboratory, Uni of California and BP: http://www.sciencedaily.com/releases/2010/12/101227203428.htm
Jan 2011: Half the world's fuel could come from biofuels without displacing other crops; Uni of Illinois: http://www.news.illinois.edu/news/11/0110biofuel_cai.html
Jan 2011: Agave has promise; http://www.eurekalert.org/pub_releases/2011-01/w-afg012611.php
Jan 2011: Microbial genes from cow's rumen analysed; Uni of Illinois: http://www.eurekalert.org/pub_releases/2011-01/uoia-tlt012711.php
Feb 2011: Study casts doubt on US target of 30% biofuel by 2030; Uni of Illinois: http://www.news.illinois.edu/news/11/0216biomass_MadhuKhanna.html
Mar 2011: Problem overcome in getting bugs to make butanol; Uni of California: http://www.enn.com/business/article/42416
Mar 2011: Study considers land use emissions from sugarcane ethanol; Karlsruhe Inst of Tech: http://www.eurekalert.org/pub_releases/2011-03/w-sbe030211.php
Mar 2011: US DoE; microbe makes isobutanol directly from cellulose: http://www.ornl.gov/info/press_releases/get_press_release.cfm?ReleaseNumber=mr20110307-00
Mar 2011: Lund Uni; Enzymes from soil digest xylose (major component of hemicellulose): http://www.lunduniversity.lu.se/o.o.i.s?id=24890&news_item=5515
Aug 2011: Bioethanol from kelp: http://www.sciencedaily.com/releases/2011/08/110830101604.htm
Sep 2011: How fungi digest cellulose; Uni of York and others: http://www.eurekalert.org/pub_releases/2011-08/uoy-cca083111.php
Nov 2011: With support, wood-based biofuel could be viable by 2020; Uni Brit Columbia: http://www.sciencedaily.com/releases/2011/11/111108133045.htm
Dec 2011: Butanol from lignocellulose fraction; Aalto Uni: http://www.eurekalert.org/pub_releases/2011-12/au-cab121911.php
July 2012: BP targets production in 2014
July 2013: Gasification makes biofuel under $140/l
Oct 2013: Bacterium found to digest acetic acid
- Oils (and animal fats)
Oil from jatropha seeds is used in some countries, but there's generally not enough oil in plants to make it worth extracting as biofuel specifically.
A great deal of waste vegetable oil (and animal fat) is produced by existing food processing. These can only provide a small proportion of total demand, but are being used, mostly by the companies that generate the waste.
Bacteria might be engineered to produce oils.
Jan 2011: Jatropha less robust than claimed: http://www.reuters.com/article/idUSTRE70K4VU20110121
Aviation needs a particularly high energy to mass ratio, which means hydrocarbons. Algae may be useful here. This lowers the carbon footprint but does not yet eliminate it.
Feb 2011: Enzyme mix eliminates detox step; Virginia tech: http://www.eurekalert.org/pub_releases/2011-02/vt-ecc122310.php
Apr 2011: Alumina nano-particles improve biofuel efficiency; National Inst Tech, India: http://www.eurekalert.org/pub_releases/2011-04/aiop-nib040711.php
May 2011: Biofuels can have worse footprint than fossil fuels; MIT: http://www.eurekalert.org/pub_releases/2011-05/miot-msc051111.php
May 2011: Hydrotreated Renewable Jet fuel nears certification: http://news.nationalgeographic.com/news/energy/2011/05/110520-jet-fuel-biofuel-for-commercial-flights/
July 2012: BP plans two new biofuels by 2014
Aug 2012: MIT: continuous production from superbug
Oct 2012: Nanobowls protect biofuel catalysts
The hydrogen can be produced from electricity, particularly when there's surplus in the grid. It could also be produced directly from sunlight, as in photosynthesis.
To replace a given quantity of petrol you only need a third of the hydrogen by weight, but that is vastly more by volume at atmospheric pressure. So storage is a problem. It can be pressurised, as with LPG, or stored in a tank containing materials which absorb the hydrogen.
In the vehicle, the hydrogen can be burnt to drive a combustion engine much like that used with petrol, or it can be converted back to electricity in a fuel cell. The latter is much more efficient but there are major technical challenges still to be overcome.
Advances have been made both in generating the hydrogen (hydrolysis) and in using it in a fuel cell to form electricity, but it remains a very inefficient process overall - about 25% compared with 70% for battery power.
May 2010: FePt/Pd nanoparticle fuel-cell catalyst; Brown Uni: http://news.brown.edu/pressreleases/2010/05/core-shell
June 2010: Riversimple's open-source hydrogen car: http://green.autoblog.com/2009/06/16/riversimple-open-source-fuel-cell-car-could-cost-just-315-month/
June 2010: New process for storing and generating hydrogen; Purdue University: http://www.purdue.edu/newsroom/research/2010/100616VarmaHydrogen.html
August 2010: New platinum/titanium-oxide/tungsten-oxide catalyst more stable and cheaper; Cornell University: http://www.eurekalert.org/pub_releases/2010-08/cu-nco080210.php
August 2010: New nickel-borate catalyst 200 times more efficient at hydrolysis; MIT: http://www.eurekalert.org/pub_releases/2010-08/acs-2bi080910.php
August 2010: Lung-like fuel cell needs less platinum; Norwegian Academy of Sciences: http://www.newscientist.com/article/mg20727744.900-lungstyle-fuel-cell-needs-less-bling-for-more-oomph.html
September 2010: metallacarborane could store hydrogen; Rice University: http://www.eurekalert.org/pub_releases/2010-09/ru-hff093010.php
November 2010: palladium-gold core prolongs and enhances platinum catalyst; US DoE, Brookhaven: http://www.bnl.gov/bnlweb/
December 2010: a cyanobacterium that produces ten times the hydrogen; Washington University: http://www.eurekalert.org/pub_releases/2010-12/wuis-chm120710.php
February 2011: nanobeads of ammonia-borane hydride; Cella Energy, Didcot, UK: http://www.newscientist.com/article/dn20055-green-machine-fill-up-your-car-with-hydrogen-beads.html
March 2011: Nanocomposites for high density H2 storage; Berkeley: http://www.eurekalert.org/pub_releases/2011-03/dbnl-bls031111.php
March 2011: Carbon nanotubes dipped in polymer replace platinum catalyst, last longer; Case Western Reserve: http://www.eurekalert.org/pub_releases/2011-03/uoia-bcq031711.php
March 2011: TiO2 nanocrystals raise cell efficiency; TU Delft: http://www.tudelft.nl/live/pagina.jsp?id=03a2557b-f370-4b15-bccf-fb34959c834b&lang=en
March 2011: Nanowires of Bulk Metallic Glass boost efficiency; Yale School of Engineering: http://www.newscientist.com/blogs/onepercent/2011/03/green-machine-giant-wind-turbi.html
April 2011: First macro-scale thin-film solid-oxide fuel cell; Cambridge Uni, Mass.: http://www.eurekalert.org/pub_releases/2011-04/hu-msa040311.php
April 2011: Amorphous molybdenum sulphide (MoS2) replaces platinum catalyst in H2 production; Ec. Poly. Fed. de Lausanne: http://www.eurekalert.org/pub_releases/2011-04/epfd-acd041211.php
April 2011: Polymer-iron-cobalt catalyst replaces platinum in fuel cell; Los Alamos: http://www.eurekalert.org/pub_releases/2011-04/danl-sht041811.php
May 2011: MoS2 better when coated on silicon pillars; Stanford: http://home.slac.stanford.edu/pressreleases/2011/20110502.htm
May 2011: Atomic Layer Deposition protects Cu2O semiconductor; EPFL, Lausanne: http://www.eurekalert.org/pub_releases/2011-05/miot-msc051111.php
May 2011: US DoE finds high temperature ferrite process best at splitting water ...: http://colorado.edu/news/r/3f14672273942abdc95d82c996bf4b8f.html
May 2011: ... but how about Birnessite? Monash: http://www.monash.edu.au/news/show/splitting-water-to-create-renewable-energy-simpler-than-first-thought
May 2011: Structure of proteins that transport electrons; Uni of East Anglia: http://www.eurekalert.org/pub_releases/2011-05/uoea-dot051911.php
Aug 2011: Hydrogen from rooftop solar ; Duke Uni: http://www.eurekalert.org/pub_releases/2011-08/du-hss080911.phphttps://secure.mrsite.co.uk/cenet.aspx?adva=true&mode=creative&editcurrpage=25
Aug 2011: Catalyst speeds release from ammonia borane; USC: http://www.eurekalert.org/pub_releases/2011-08/uosc-bih083011.php
Aug 2011: GaN doped with Sb for H2 from sunlight; Kentucky Uni: http://www.eurekalert.org/pub_releases/2011-08/uok-nac083011.php
Sep 2011: Iron veins help Mg store H; US NIST: http://www.eurekalert.org/pub_releases/2011-08/nios-ia083111.php
Oct 2011: Cobalt compound speeds hydrolysis by factor of 10; MIT: http://www.enn.com/energy/article/43481
Nov 2011: Boron-nitrogen-based liquid-phase storage material; Uni of Oregon: http://www.eurekalert.org/pub_releases/2011-11/uoo-ucd112211.php
Dec 2011: Modified photosynthesis produces H2; Penn State Uni: http://www.abc.net.au/science/articles/2011/12/19/3392740.htm
Jan 2012: RMIT proposes hydrogen for trucks: http://www.climatespectator.com.au/commentary/finding-key-sustainable-trucking
Mar 2012: Nanowire forest produces H2 from sunlight: http://www.eurekalert.org/pub_releases/2012-03/uoc--nht030712.php
Mar 2012: Densely storing H2 as formic acid; Brookhaven: http://cleantechnica.com/2012/03/19/brookhaven-researchers-develop-low-cost-hydrogen-handling-for-fuel-cells
Mar 2012: FePtAu catalyst boosts performance and prolongs life of formic acid fuel cell: Brown Uni: http://cleantechnica.com/2012/03/21/gold-could-help-advance-fuel-cell-technology
May 2012: Ni-Mo-N nanosheet catalyst: low cost with high durability and output; Brookhaven National Lab: http://www.bnl.gov/bnlweb/pubaf/pr/PR_display.asp?prID=1414
Aug 2012: UNSW: Ni-NaBH nanoparticles store H2
Aug 2012: UK's first hydrogen powered train
Mar 2013: NiFeO thin film catalyst optimised
May 2013: Nanoforest uses sun to split water
May 2013: Rust+gold as hydrolysis catalyst
July 2013: Li helps MoS2 catalyse H2 production
July 2013: Co-Rho catalyst for H2 from ethanol
Sep 2013: Carbon catalyst and laser power
Jan 2014: MoS2 does best when one atom thick
July 2014: Exfoliation improves metal oxide catalysts
July 2014: Carbon nanotubes catalyse hydrolysis
Apr 2015: Cheaper H2 from corn stover
June 2015: Smoother haematite catalyst doubles yield
June 2015: NiFe oxides split water with 82% efficiency
Already widely used, but emits 80% as much CO2 as petrol and global reserves are limited.
Jan 2011: Cerium catalyst + Fischer-Tropsch produces hydrocarbons directly from water, CO2 and sunlight; CalTech: http://pr.caltech.edu/periodicals/EandS/articles/LXXII2/CO2_to_Fuel.pdf
[Note: As admitted in the article, this suffers from the same snag as using algae: it will need concentrated CO2. Today that can come from coal-fired power-stations, but that doesn't make for a zero-carbon economy. Turning the CO2 back into a fuel for transport is just a single recycling. The transport releases the CO2 into the air. The overall result is to slow the addition of CO2 to the main cycle, not to halt it. For road transport, electricity and hydrogen both remain much better options. The tough one is air transport.]
This is a way to save fuel rather than a fuel in itself. The idea has been around for decades - instead of turning all the kinetic energy of a moving vehicle into heat when you brake, turn some back into fuel.
Proposed schemes include:
- Electricity generation (dynamo)
- Compressed air
Aug 2010: University of York (2010, August 18). How to reduce UK transport carbon emissions by 76 per cent by 2050.
June 2013: Japanese Maglev reaches 500kph
Aug 2013: Elon Musk proposes Hyperloop
Aug 2013: Copenhagen helps cyclists use trains
Sep 2013: Japanese Maglev train reaches 500km/h
Sep 2014: London trial of wireless electric bus
Nov 2014: UK bus runs on sewage gas
Mar 2015: Another 290km range electric bus
June 2015: Fast overhead charger for electric bus
June 2015: PV roof for Indian Railway coaches
June 2015: Norway's electric ferry
July 2015: October trial for all-electric London bus
July 2015: Musk announces Hyperloop design competition
July 2015: Russia developing nuclear train
Since there is already more CO2 in the atmosphere than is safe (380+ ppm compared with 350), there is a need to draw CO2 back out. This can be done by
- natural means, such as increased forest,
- natural with intervention (biochar, ocean fertilisation), or by
- engineering (artificial trees).
Biochar is another name for charcoal; a fuel that will burn at the higher temperatures needed for some processes than would the biomass from which it was made. But calling it biochar puts the accent on an alternative use, namely, to sequester carbon. Some energy is still derived from the charring process, but much less than by burning the biomass completely. The resulting char is used to remediate soils, greatly improving their retention of water and nutrients, while also removing the carbon from circulation for a period. How long it stays out of circulation varies greatly (see table here). Any incentive paid to farmers would need to take that into account. It in no way removes the need to stop exploiting fossil fuels.
It has been calculated that carried out on a world scale, largely by peasant farmers, this could draw down enough carbon. Organising it would be a major challenge.
These are methods for extracting CO2 from the atmosphere, but still as CO2. It then has to be sequestered in the same way as with CCS. This may be cheaper than retrofitting CCS to existing plant because the scrubbers would be sited close to the repository.
Oct 2011: UK Engineers predict technology in 2018
July 2012: Advances in adsorptive materials
Nov 2015: Research project aims to use microalgae
Phytoplankton are the main photosynthesising organisms in the oceans. Their abundance is often limited by lack of iron, so the idea is to fertilise the oceans with iron and generate phytoplankton blooms to absorb CO2. Numerous experiments have been conducted, with varying results; in some cases the sequestration is only temporary. If it works, it is relatively cheap. The main concern is the inherent uncertainty in monkeying with ecology. Experiments continue.
February 2011: UN study says only 1-15% carbon sinks to depths: http://planetark.org/enviro-news/item/61047
March 2011: Phytoplankton only account for 1% of oceanic sequestration anyway; CNRS, France: http://www.enn.com/climate/article/42461
September 2011: Natural fertilisation with dust may have triggered glaciation: http://www.enn.com/climate/article/43192
The term geo-engineering has been used to cover rather a wide range of proposals.
- increase reflectivity ('albedo') in urban areas
Most proposals relate to rooves. In some places, this can pay for itself in reduced air-conditioning costs. However, the same savings might be made more cheaply with insulation, so an incentive is needed to encourage the whitening of rooves.
These last four are better described as carbon drawdown.
- block sunlight on the grand scale
E.g. by deliberate release of SO2 (after decades of trying to reduce SO2 emissions!) or by parasols in space. The SO2 would be pushed into the stratosphere where it will remain for years (at lower levels it rains out in a few days). This has many downsides:
- Does nothing to reduce the CO2 burden on the oceans.
- Plants need light more than they need heat. A cool planet isn't much use to them if it's also dark.
- Light enhances evaporation from oceans beyond the effect of its heat, so shading could lead to droughts.
- High tech is risky
- Large carbon footprint in the implementation
- Would lead to complacency about emissions
- Unilateral action could lead to international conflict
- Hard to undo if it goes wrong
This may be already happening accidentally (Science, DOI:10.1126/science.1182274).
Feb 2011: Ocean Fertilization: IGBP Policymakers' Summary; http://www.igbp.net/page.php?pid=542
Sep 2011: Oz conference on geo-eng: http://www.smh.com.au/environment/climate-change/australia-to-broach-radical-global-warming-solutions-20110908-1jzo8.html
Sep 2011: UK to trial geo-eng solutions: http://www.newscientist.com/article/mg21128294.000-geoengineering-trials-get-under-way.html
Jan 2012: Stratospheric sulphate risky and of limited effectiveness; Uni of Washington: http://www.eurekalert.org/pub_releases/2012-01/uow-isp012512.php
Mar 2012: Cloud seeding with salt water in Arctic could restore ice cap, protect permafrost, reduce methane emissions: http://www.thestar.com/news/world/article/1149983--global-warming-researchers-develop-technology-to-reduce-methane-gas-emissions-from-oceans
June 2012: Shading sunlight could cut rainfall
Aug 2012: Saltwater fountain to brighten clouds
Sep 2012: Sunshade costed at $5bn/y
Jul 2013: Cloud seeding could cool reef
Oct 2013: IPCC concedes it may be necessary
Nov 2013: Risk of global drought
July 2015: 'Seaspray' to whiten clouds
Nov 2010: UN Moratorium? http://www.enn.com/climate/
Agricultural methane is a major component of the GHGs for which humans are responsible. Although it naturally converts to CO2 in a few years, while it is methane it is many times as potent as a greenhouse gas. Averaged over 20 years, carbon atom-for-carbon atom, it's 35 times as potent as CO2.
Jan 2011: Strip tilling reduces nitrous oxide emissions; Uni of Missouri: http://www.sciencedaily.com/releases/2011/01/110113131427.htm
March 2011: Anaerobic digester cuts methane, produces energy; Unis Southampton & Reading UK: http://www.sciencedaily.com/releases/2011/03/110304091456.htm
April 2011: Diets to reduce emissions from livestock; UK Defra: http://planetark.org/enviro-news/item/61662
May 2011: Beer by-product in feed cuts methane emissions; Vic Dept of Primary Industries: http://www.theage.com.au/victoria/beer-byproduct-cuts-burping-cows-methane-emissions-20110522-1eyyb.html
July 2011: Low-methane bacteria in wallaby's gut might work for cattle: http://www.sciencedaily.com/releases/2011/06/110630142841.htm
Sep 2011: Rural bioenergy hubs: http://www.climatespectator.com.au/commentary/biofuels-or-bust-clean-energy-concept-revolutionise-farming
Dec 2011: Wine dregs in feed cut methane 20%: http://www.smh.com.au/environment/animals/gone-with-the-wind-study-finds-cows-fed-wine-dregs-emit-less-methane-20111207-1ojbl.html
Jan 2012: Anaerobic digester powers farm and provides better fertiliser http://www.clickgreen.org.uk/analysis/general-analysis/123023-does-hyacinth-the-cow-hold-the-key-to-a-more-sustainable-future.html
Feb 2012: Rotational grazing could reduce emissions: http://www.abc.net.au/rural/news/content/201202/s3432372.htm
Sep 2012: Fungi could undo carbon capture in soil
Apr 2013: Soil carbon not as stable as thought
Oct 2013: Solar powered irrigation pumps
Jan 2014: Ruminomics: cutting the methane cowbelch
Jan 2011: Current Technology Could Reduce Global Energy Demand by 85%: http://pubs.acs.org/cen/news/89/i04/8904scene1.html
Jan 2011: Efficiency could cut world's energy use 70%: http://www.newscientist.com/article/dn20037-efficiency-could-cut-world-energy-use-over-70-per-cent.html
Feb 2011: "Net-zero" house planned in Washington DC: http://www.washingtonpost.com/wp-dyn/content/article/2011/02/25/AR2011022502778.html
Nov 2011: DuPont says 40% efficiency savings easy
Mar 2012: New options for minimising bills http://reneweconomy.com.au/2012/hybrid-solar-how-to-kiss-the-grid-goodbye-59957
This differs from photovoltaic in that it does involve a heat stage, but also differs from solar thermal because the heat is turned straight to electricity instead of being used to push steam through a turbine.
The efficiency is low, but it has the advantages of being combinable with solar hot water systems and of being very cheap.
In today's electricity grids supply has to adjust to demand. This causes massive spikes in generation cost at times of peak demand. In a "smart grid ", some of the demand adjusts to match supply. This will be particularly useful for electric cars, allowing them to be charged at cheap rates.
May 2011: US EPRI calculates 4:1 payback over 20 years: http://planetark.org/enviro-news/item/62112
Being able to measure what appliances use how much and when can help greatly in getting the best out of PV on your roof and in minimising your bills if you're on time-of-day tariff.
June 2012: Sydney students develop home metering tool
April 2014: Google's vision of the intelligent house
Compact fluorescent bulbs are four times as efficient as incandescent and have largely replaced them in Australia. LEDs promise even more efficiency, greater lifetimes and less issues with toxic components in recycling, but it has been difficult achieving white light and scaling up the power to area lighting. The best currently available for domestic use are about the same efficiency as compact fluorescents (10%).
Another technology on the horizon is Electron Stimulated Luminescence (ESL).
April 2011: Progress in understanding what limits usefulness of LEDs http://www.eurekalert.org/pub_releases/2011-04/uom-spw041911.php
Nov 2012: More retrofittable LEDs on market
Jan 2013: LEDs set to overtake CFLs
Jan 2013: Firefly trick boosts LED efficiency 55%
Mar 2013: LEDs below $10/bulb
Nov 2013: US NRDC's guide to lightbulbs
Mar 2014: LEDs get cheaper, more reliable
June 2014: 9.5W LED equals 60W incandescent
July 2014: LEDs could cut energy for lighting by 95%
Nov 2014: LED efficiency up 50% in 2 years
June 2015: 10W (=60W incandescent) LEDs under $5 in US
Aug 2015: IKEA to sell only LED lights
Mar 2014: London to extract heat from Thames
Refrigeration and AC
June 2011: Using waste heat to cool
Apr 2012: Solar-powered air-con to cut peak demand
Jun 2012: White roof cuts A/C bill up to 20%
Jun 2012: "Cool blue" pigment reflects 40%
Jun 2012: Smart A/C cuts costs up to 30%
Jan 2013: Smart thermostats save money
Apr 2014: Red LEDs hit 90% efficiency
Mar 2015: US lab targets fridge using 1kWh/day
Aug 2015: Glass paint cools roof
April 2011: Low footprint bricks: http://www.abc.net.au/rn/scienceshow/stories/2011/3180096.htm#transcript
May 2011: Software aids natural cooling: http://www.eurekalert.org/pub_releases/2011-05/nios-nst052511.php
Nov 2011: Contractor offers makeovers for share of savings: http://www.climatespectator.com.au/news/free-energy-makeovers-drive-growth-siemens-0
Dec 2011: Thin film insulation for buildings: http://www.fraunhofer.de/en/press/research-news/2011/december/thinner-thermal-insulation.html
Jan 2012: Uni of Melbourne report on reflective roofing: http://www.melbourne.vic.gov.au/Environment/WhatCouncilisDoing/Documents/Cool_Roofs_Report.pdf
Feb 2012: Cross-laminated timber to replace concrete and steel? http://www.abc.net.au/worldtoday/content/2012/s3432089.htm
Feb 2012: Neo-classical cement: 60% of the cost and 3% of the CO2: http://www.drexel.edu/now/news-media/releases/archive/2012/February/Engineers-Develop-Cement-With-97-Percent-Smaller-Carbon-Dioxide-and-Energy-Footprint/
Mar 2012: CERN's high vacuum technology used in solar thermal panels: http://cleantechnica.com/2012/03/13/cern-technology-to-create-massive-solar-system-in-switzerland/
Mar 2012: Let the light in, turn the heat into power: http://reneweconomy.com.au/2012/solar-windows-could-cut-building-energy-use-by-half-96073
July 2012: Optimising window power
July 2012: Solar heating and cooling
Aug 2012: Solar-powered attic fan
Dec 2012: Biocement supports plant growth
Mar 2013: Adding straw to concrete
May 2013: Fibro retrofit
Nov 2014: Rooftop super mirrors save on A/C
May 2015: UTS develops super-cool white roof
Feb 2013: Smart electric motors are more efficient
Mar 2013: Graphene filter for cheaper desalination
May 2013: Carbon-free steelmaking
June 2013: New catalyst for destroying nitrous oxide
June 2014: White roads make cool cities
July 2015: Ultrasonic clothes dryer saves energy
Lots of downloadable presentations here: http://www.beyondzeroemissions.org/events/discussion-group