coal pollution mitigation

File:Figure 1- Sample Layout of Emissions Controls at a Coal Power Plant (7315637538) (cropped).jpg]]

Coal pollution mitigation is a series of systems and technologies that seek to mitigate health and environmental impact of burning coal for energy. Burning coal releases harmful substances that contribute to air pollution, acid rain, and greenhouse gas emissions. Mitigation includes precombustion approaches, such as cleaning coal, and post combustion approaches, include flue-gas desulfurization, selective catalytic reduction, electrostatic precipitators, and fly ash reduction. These measures aim to reduce coal's impact on human health and the environment.

The combustion of coal releases diverse chemicals into the air. The main products are water and carbon dioxide, just like the combustion of petroleum. Also released are sulfur dioxide and nitrogen oxides, as well as some mercury. The residue remaining after combustion, coal ash often contains arsenic, mercury, and lead. Finally, the burning of coal, especially anthracite, can release radioactive materials.{{cite book |doi=10.1002/0471238961.0315011222151818.a01.pub3 |chapter=Coal |title=Kirk-Othmer Encyclopedia of Chemical Technology |date=2016 |last1=Hower |first1=James |pages=1–63 |isbn=978-0-471-48494-3 }}

Mitigation technologies

Mitigation of coal-based pollution can be divided into several distinct approaches. Coal pollution mitigation seek to minimize negative impacts of coal combustion.{{cite book |doi=10.1002/0471238961.0312050103080901.a01 |chapter=Coal Conversion Processes, Cleaning and Desulfurization |title=Kirk-Othmer Encyclopedia of Chemical Technology |date=2000 |last1=Chiang |first1=Shiao-Hung |last2=Cobb |first2=James T. |isbn=978-0-471-48494-3 }}

=Precombustion=

Prior to its combustion, coal can be cleaned by physical and by chemical means.

Physical cleaning of coal usually involves gravimetric processes, often in conjunction with froth flotation Such processes remove minerals and other noncombustible components of coal, exploiting their greater density vs that of coal. This technology is widely practiced.

Coal can also be cleaned in part by chemical treatments. The concept is to use chemicals to remove deleterious components of coal, leaving the combustible material behind. Typically, coal cleaning entails treatment of crushed coal with acids or bases. This technology is expensive and has rarely moved beyond the demonstration phase. During World War II, German industry removed ash from coal by treatments with hydrofluoric acid and related reagents.

=Post-combustion=

The wastes produced by the combustion of coal can be classified into three categories: gases, particulates, and solids (ash). The gaseous products can be filtered and scrubbed to miminize the release of SO_x, NO_x, mercury:

{{SO2}} can be removed by flue-gas desulfurization
{{chem2|NO2}} can be removed by selective catalytic reduction (SCR).
Mercury emissions can be reduced by up to 95%.{{cite web |title=Mercury control from coal combustion |url=http://web.unep.org/globalmercurypartnership/our-work/mercury-control-coal-combustion |archive-url=https://web.archive.org/web/20180817060407/http://web.unep.org/globalmercurypartnership/our-work/mercury-control-coal-combustion |url-status=dead |archive-date=August 17, 2018 |publisher=UNEP}}

Electrostatic precipitators remove particulates. Wet scrubbers can remove both gases and particulates.

=Ash=

The solid residue, coal ash, requires separate set of technologies but usually involves landfilling or some immobilization approaches. Reducing fly ash reduces emissions of radioactive materials.

=Carbon capture=

Several different technological methods are available for carbon capture:

Pre-combustion capture – This involves the gasification of a feedstock (such as coal) to form synthesis gas, which may be shifted to produce an {{chem2|H2}} and {{CO2}}-rich gas mixture, from which the {{CO2}} can be efficiently captured and separated, transported, and ultimately sequestered,{{cite web |title=Pre-combustion Carbon Capture Research |url=http://energy.gov/fe/science-innovation/carbon-capture-and-storage-research/carbon-capture-rd/pre-combustion-carbon |access-date=22 July 2014 |website=Energy.gov |publisher=Office of Fossil Energy, U.S. Department of Energy}} This technology is usually associated with Integrated Gasification Combined Cycle process configurations.{{Cite web |title=Picking a Winner in Clean-Coal Technology |work=Technology Review |url=http://www.technologyreview.com/Energy/18398/ |last1=Bullis |first1=Kevin }}
Post-combustion capture – This refers to capture of {{CO2}} from exhaust gases of combustion processes.
Oxy-fuel combustion – Fossil fuels such as coal are burned in a mixture of recirculated flue gas and oxygen, rather than in air, which largely eliminates nitrogen from the flue gas enabling efficient, low-cost {{CO2}} capture.{{cite web |title=R&D Facts - Oxy-Fuel Combustion |url=http://www.netl.doe.gov/publications/factsheets/rd/R&D127.pdf |url-status=dead |archive-url=https://web.archive.org/web/20141031153144/http://www.netl.doe.gov/publications/factsheets/rd/R%26D127.pdf |archive-date=31 October 2014 |access-date=22 July 2014 |publisher=National Energy Technology Laboratory, U.S. Department of Energy}}

=Satellite monitoring=

Satellite monitoring is now used to crosscheck national data, for example Sentinel-5 Precursor has shown that Chinese control of SO₂ has only been partially successful.{{cite journal |title= Quantifying coal power plant responses to tighter SO₂ emissions standards in China|journal=Proceedings of the National Academy of Sciences|volume=115|issue=27|pages=7004–09|doi=10.1073/pnas.1800605115|pmid=29915085|pmc=6142229|year=2018 |last1=Karplus |first1=Valerie J. |last2=Zhang|first2=Shuang|last3=Almond|first3=Douglas|bibcode=2018PNAS..115.7004K |doi-access=free}} It has also revealed that low use of technology such as SCR has resulted in high NO₂ emissions in South Africa and India.{{cite news |title=New satellite data analysis reveals world's biggest NO₂ emissions hotspots |url=https://www.greenpeace.org/international/press-release/19072/greenpeace-analysis-of-new-satellite-data-reveals-worlds-biggest-no2-emissions-hotspots/ |publisher=Greenpeace International}}

=Combined cycle power plants=

A few Integrated gasification combined cycle (IGCC) coal-fired power plants have been built with coal gasification. Although they burn coal more efficiently and therefore emit less pollution, the technology has not generally proved economically viable for coal, except possibly in Japan although this is controversial.{{cite web |title=Universal failure: How IGCC coal plants waste money and emissions Nove |url=http://www.kikonet.org/wp/wp-content/uploads/2016/11/IGCC-and-emissions_eg_final.pdf |archive-url=https://web.archive.org/web/20161219175414/http://www.kikonet.org/wp/wp-content/uploads/2016/11/IGCC-and-emissions_eg_final.pdf |archive-date=2016-12-19 |url-status=live |publisher=Kiko Network |access-date=13 November 2018}}{{cite news |title=Japan says no to high-emission coal power plants |url=https://asia.nikkei.com/Politics/Japan-says-no-to-high-emission-coal-power-plants |work=Nikkei Asian Review |date=26 July 2018}}

Case studies

In conjunction with enhanced oil recovery and other applications, commercial-scale CCS is currently being tested in several countries.^{[by whom?]} Proposed CCS sites are subjected to extensive investigation and monitoring to avoid potential hazards, which could include leakage of sequestered CO2 to the atmosphere, induced geological instability, or contamination of water sources such as oceans and aquifers used for drinking water supplies. As of 2021, the only demonstrator for CCS on a coal plant that stores the gas underground is part of the Boundary Dam Power Station.{{Citation needed|date=December 2023}}

The Great Plains Synfuels plant supports the technical feasibility of carbon dioxide sequestration. Carbon dioxide from the coal gasification is shipped to Canada, where it is injected into the ground to aid in oil recovery. A drawback of the carbon sequestration process is that it is expensive compared to traditional processes.

The Kemper County IGCC Project, a proposed 582 MW coal gasification-based power plant, was expected to use pre-combustion capture of {{CO2}} to capture 65% of the {{CO2}} the plant produces, which would have been utilized and geologically sequestered in enhanced oil recovery operations.{{cite web |title=IGCC Project Examples - Kemper County IGCC Project |url=http://www.netl.doe.gov/research/Coal/energy-systems/gasification/gasifipedia/project-examples#kemper |access-date=22 July 2014 |website=Gasifipedia |publisher=National Energy Technology Laboratory, U.S. Department of Energy |archive-date=17 March 2014 |archive-url=https://web.archive.org/web/20140317074158/http://www.netl.doe.gov/research/coal/energy-systems/gasification/gasifipedia/project-examples#kemper |url-status=dead }} However, after many delays and a cost runup to $7.5 billion (triple the initial budget),{{Cite news |last=Urbina |first=Ian |date=2016-07-05 |title=Piles of Dirty Secrets Behind a Model 'Clean Coal' Project (Published 2016) |language=en-US |work=The New York Times |url=https://www.nytimes.com/2016/07/05/science/kemper-coal-mississippi.html |access-date=2021-02-03 |issn=0362-4331}} the coal gasification project was abandoned and as of late 2017, Kemper is under construction as a cheaper natural gas power plant.{{cite news |last1=Geuss |first1=Megan |date=2017-06-29 |title=$7.5 billion Kemper power plant suspends coal gasification |publisher=Ars Technica |url=https://arstechnica.com/business/2017/06/7-5-billion-kemper-power-plant-suspends-coal-gasification/ |access-date=2017-07-01}}

The Saskatchewan Government's Boundary Dam Integrated Carbon Capture and Sequestration Demonstration Project will use post-combustion, amine-based scrubber technology to capture 90% of the {{CO2}} emitted by Unit 3 of the power plant; this {{CO2}} will be pipelined to and utilized for enhanced oil recovery in the Weyburn oil fields.{{cite web |title=Boundary Dam Integrated Carbon Capture and Sequestration Demonstration Project |url=http://www.globalccsinstitute.com/project/boundary-dam-integrated-carbon-capture-and-sequestration-demonstration-project |url-status=dead |archive-url=https://web.archive.org/web/20140810095512/http://www.globalccsinstitute.com/project/boundary-dam-integrated-carbon-capture-and-sequestration-demonstration-project |archive-date=10 August 2014 |access-date=22 July 2014 |publisher=Global CCS Institute}}

File:Oxyfuel CCS fossil fuel power plant operation.png

An early example of a coal-based plant using (oxy-fuel) carbon-capture technology is Swedish company Vattenfall’s Schwarze Pumpe power station located in Spremberg, Germany, built by German firm Siemens, which went on-line in September 2008.{{cite web |title=Vattenfall's Project on CSS |url=http://www.vattenfall.com/www/co2_en/co2_en/index.jsp |url-status=dead |archive-url=https://web.archive.org/web/20101026074817/http://www2.vattenfall.com/www/co2_en/co2_en/index.jsp |archive-date=2010-10-26 |publisher=Vattenfall}}http://discovermagazine.com/2009/feb/25-can-clean-coal-actually-work/?searchterm=clean%20coal "Can Clean Coal Actually Work?" article in Feb. 2009 issue, p. 18, Retrieved 2009-05-11 The facility captures {{CO2}} and acid rain producing pollutants, separates them, and compresses the {{CO2}} into a liquid. Plans are to inject the {{CO2}} into depleted natural gas fields or other geological formations. Vattenfall opines that this technology is considered not to be a final solution for {{CO2}} reduction in the atmosphere, but provides an achievable solution in the near term while more desirable alternative solutions to power generation can be made economically practical.

Other examples of oxy-combustion carbon capture are in progress. Callide Power Station has retrofitted a 30-MWth existing PC-fired power plant to operate in oxy-fuel mode; in Ciuden, Spain, Endesa has a newly built 30-MWth oxy-fuel plant using circulating fluidized bed combustion (CFBC) technology.{{cite web |title=Overview of Oxy-fuel Combustion Technology for {{CO2}} Capture |url=http://cornerstonemag.net/overview-of-oxy-fuel-combustion-technology-for-co2-capture/ |access-date=22 July 2014 |website=Cornerstone Magazine |publisher=World Coal Association}} Babcock-ThermoEnergy's Zero Emission Boiler System (ZEBS) is oxy-combustion-based; this system features near 100% carbon-capture and according to company information virtually no air-emissions.[leads nowhere previously cited - http://ww25.thermoenergy.com/Zm9yY2VTUg]

Other carbon capture and storage technologies include those that dewater low-rank coals. Low-rank coals often contain a higher level of moisture content which contains a lower energy content per tonne. This causes a reduced burning efficiency and an increased emissions output. Reduction of moisture from the coal prior to combustion can reduce emissions by up to 50 percent.{{Cite journal |last1=Ge |first1=Lichao |last2=Zhang |first2=Yanwei |last3=Xu |first3=Chang |last4=Wang |first4=Zhihua |last5=Zhou |first5=Junhu |last6=Cen |first6=Kefa |date=2015-11-05 |title=Influence of the hydrothermal dewatering on the combustion characteristics of Chinese low-rank coals |url=https://www.sciencedirect.com/science/article/pii/S1359431115006808 |journal=Applied Thermal Engineering |language=en |volume=90 |pages=174–181 |doi=10.1016/j.applthermaleng.2015.07.015 |bibcode=2015AppTE..90..174G |issn=1359-4311|url-access=subscription }}{{Citation needed|date=April 2009}}

In the late 1980s and early 1990s, the U.S. Department of Energy (DOE) conducted projects called the Clean Coal Technology & Clean Coal Power Initiative (CCPI).{{cite web | url=http://energy.gov/fe/science-innovation/clean-coal-research/major-demonstrations/clean-coal-power-initiative | publisher= U.S. Department of Energy | title= Clean Coal Technology & The Clean Coal Power Initiative }}{{cite web |url= http://www.netl.doe.gov/technologies/coalpower/cctc/ccpi/index.html# |archive-url= https://web.archive.org/web/20060924181707/http://www.netl.doe.gov/technologies/coalpower/cctc/ccpi/index.html |url-status= dead |archive-date= September 24, 2006 |title= Major Demonstrations: Clean Coal Power Initiative (CCPI) |publisher= NETL |access-date= 1 May 2012 }}

Financial impact

Whether carbon capture and storage technology is adopted worldwide will "...depend less on science than on economics. Cleaning coal is very expensive."{{cite web|url=https://www.wsj.com/articles/SB123751110892790871|title=Coal Hard Facts: Cleaning It Won't Be Dirt Cheap|last=Ball|first=Jeffrey|date=2009-03-20|website=The Wall Street Journal}}

=Cost of converting a single coal-fired power plant=

Conversion of a conventional coal-fired power plant is done by injecting the {{CO2}} into ammonium carbonate after which it is then transported and deposited underground (preferably in soil beneath the sea).{{cite web|url=http://ngm.nationalgeographic.com/2014/04/coal/nijhuis-text|archive-url=https://web.archive.org/web/20140316135510/http://ngm.nationalgeographic.com/2014/04/coal/nijhuis-text|url-status=dead|archive-date=March 16, 2014|title=Can Coal Ever Be Clean?|last=Nijhuis|first=Michelle|date=April 2014|website=National Geographic}} This injection process however is by far the most expensive. Besides the cost of the equipment and the ammonium carbonate, the coal-fired power plant also needs to use 30% of its generated heat to do the injection (parasitic load). A test-setup has been done in the American Electric Power Mountaineer coal-burning power plant.

One solution to reduce this thermal loss/parasitic load is to burn the pulverised load with pure oxygen instead of air.

=Cost implications for new coal-fired power plants=

Newly built coal-fired power plants can be made to immediately use gasification of the coal prior to combustion. This makes it much easier to separate off the {{CO2}} from the exhaust fumes, making the process cheaper. This gasification process is done in new coal-burning power plants such as the coal-burning power plant at Tianjin, called "GreenGen".

Country by country experiences

Local pollution standards include GB13223-2011 (China), India,{{cite journal |title=How can Indian power plants cost-effectively meet the new sulfur emission standards? Policy evaluation using marginal abatement cost-curves |journal=Energy Policy|volume=121|pages=124–37|doi=10.1016/j.enpol.2018.06.008|year=2018 |last1=Sugathan |first1=Anish |last2=Bhangale|first2=Ritesh|last3=Kansal|first3=Vishal|last4=Hulke|first4=Unmil|bibcode=2018EnPol.121..124S |s2cid=158703760}} the Industrial Emissions Directive (EU) and the Clean Air Act (United States).

=China=

Since 2006, China releases more {{CO2}} than any other country.{{cite web|url=https://www.nytimes.com/2018/01/25/business/china-davos-climate-change.html|title=China's Emissions: More Than U.S. Plus Europe, and Still Rising|website=The New York Times|language=en|date=2018-01-25}}{{cite news|url=https://www.thetimes.com/world/asia/article/chinese-coal-fuels-rise-in-global-carbon-emissions-2j0kvrd2z|title=Chinese coal fuels rise in global carbon emissions|website=The Times|language=en|date=2017-11-14}}{{cite web|url=https://www.forbes.com/sites/rrapier/2017/10/24/yes-the-u-s-leads-all-countries-in-reducing-carbon-emissions/#69229dfc3535|title=Yes, The U.S. Leads All Countries In Reducing Carbon Emissions|website=Forbes|language=en|date=2017-10-24}}{{cite web|url=https://www.theguardian.com/news/datablog/2011/jan/31/world-carbon-dioxide-emissions-country-data-co2|title=World carbon dioxide emissions data by country: China speeds ahead of the rest|website=The Guardian|language=en|date=2011-01-31}}{{cite web|url=https://www.pbl.nl/en/news/2007/20070619Chinanowno1inCO2emissionsUSAinsecondposition|title=China now no. 1 in {{CO2}} emissions; USA in second position|website=PBL Netherlands Environmental Assessment Agency|date=19 June 2007|language=en|access-date=2018-03-20|url-status=live|archive-url=https://web.archive.org/web/20190709191743/https://www.pbl.nl/en/dossiers/Climatechange/Chinanowno1inCO2emissionsUSAinsecondposition|archive-date=2019-07-09}} Researchers in China are focusing on increasing efficiency of burning coal so they can get more power out of less coal.{{cite news|url=https://www.newscientist.com/article/2101780-chinas-drive-to-clean-up-its-coal-power-one-plant-at-a-time/|title=China's drive to clean up its coal power, one plant at a time|work=New Scientist|access-date=2017-05-04|language=en-US}} It is estimated that new high efficiency power plants could reduce {{CO2}} emission by 7% because they won't have to burn as much coal to get the same amount of power.

{{As of|2019}} costs of retrofitting CCS are unclear and the economics depends partly on how the Chinese national carbon trading scheme progresses.{{Cite web|url=https://www.ifri.org/en/publications/etudes-de-lifri/carbon-capture-storage-and-utilization-rescue-coal-global-perspectives|title=Carbon Capture, Storage and Utilization to the Rescue of Coal? Global Perspectives and Focus on China and the United States|website=www.ifri.org|language=en|access-date=2020-01-25}}

=India=

Pollution led to more than 2.3 million premature deaths in India in 2019, according to a new Lancet study. Nearly 1.6 million deaths were due to air pollution alone, and more than 500,000 were caused by water pollution. India has developed instruments and regulatory powers to mitigate pollution sources but there is no centralized system to drive pollution control efforts and achieve substantial improvements," the study said adding that in 93% of the country, the amount of pollution remains well above the World Health Organization (WHO) guidelines.{{Cite web |last= |title=Carbon capture and coal gasification can be a game changer for India - Opinion by Atanu Mukherjee {{!}} ET EnergyWorld |url=https://www.bbc.com/news/world-asia-india-61489488 |access-date=2020-01-25 |website=ETEnergyworld.com |language=en}}

=Canada=

In 2014 SaskPower a provincial-owned electric utility finished renovations on Boundary Dam's boiler number 3 making it the world's first post-combustion carbon capture storage facility.{{cite web|url=https://www.nationalgeographic.com/environment/great-energy-challenge/2014/worlds-first-full-scale-clean-coal-plant-opens-in-canada/|archive-url=https://web.archive.org/web/20190112064633/https://www.nationalgeographic.com/environment/great-energy-challenge/2014/worlds-first-full-scale-clean-coal-plant-opens-in-canada/|url-status=dead|archive-date=January 12, 2019|title=World's First Full-Scale 'Clean' Coal Plant Opens in Canada|last=Danko|first=Pete|website=National Geographic Society|date=2014-10-02|access-date=2017-04-27}} The renovation project ended up costing a little over $1.2 billion and can scrub out {{CO2}} and toxins from up to 90 percent of the flue gas that it emits.

=Japan=

Following the catastrophic failure of the Fukushima I Nuclear Power Plant in Japan that resulted from the 2011 Tōhoku earthquake and tsunami, and the subsequent widespread public opposition against nuclear power, high energy, lower emission (HELE) coal power plants were increasingly favored by the Shinzō Abe-led government to recoup lost energy capacity from the partial shutdown of nuclear power plants in Japan and to replace aging coal and oil-fired power plants, while meeting 2030 emission targets of the Paris Agreement. 45 HELE power plants have been planned, purportedly to employ integrated gasification fuel cell cycle, a further development of integrated gasification combined cycle.{{cite news|url=https://www.abc.net.au/news/rural/2017-01-31/japan-coal-power-plants/8224302|title=Japanese government planning to build 45 new coal fired power stations to diversify supply|last=McHugh|first=Babs|date=2017-02-23|access-date=2017-02-23|newspaper=ABC Online}}{{cite news|url=https://www.bloomberg.com/news/articles/2015-11-10/want-to-burn-coal-and-save-the-planet-japan-touts-a-solution|title=Want to Burn Coal and Save the Planet? Japan Touts a Solution|last=Watanabe|first=Chisaki|date=2015-11-10|access-date=2017-02-23|newspaper=Bloomberg}}

Japan had adopted prior pilot projects on IGCC coal power plants in the early-1990s and late-2000s.

=U.S.=

In the United States, clean coal was mentioned by former President George W. Bush on several occasions, including his 2007 State of the Union Address. Bush's position was that carbon capture and storage technologies should be encouraged as one means to reduce the country's dependence on foreign oil.

During the US Presidential campaign for 2008, both candidates John McCain and Barack Obama expressed interest in the development of CCS technologies as part of an overall comprehensive energy plan. The development of pollution mitigation technologies could also create export business for the United States or any other country working on it.

The American Reinvestment and Recovery Act allocated $3.4 billion for advanced carbon capture and storage technologies, including demonstration projects.

Former Secretary of State Hillary Clinton has said that "we should strive to have new electricity generation come from other sources, such as clean coal and renewables", and former Energy Secretary Dr. Steven Chu has said that "It is absolutely worthwhile to invest in carbon capture and storage", noting that even if the U.S. and Europe turned their backs on coal, developing nations like India and China would likely not.

During the first 2012 United States presidential election debate, Mitt Romney expressed his support for clean coal, and claimed that current federal policies were hampering the coal industry.{{cite news|url=https://www.npr.org/2012/10/03/162258551/transcript-first-obama-romney-presidential-debate|title=Transcript And Audio: First Obama-Romney Debate|date=2012-10-03|publisher=Federal News Service|website=NPR|access-date=2013-05-24}}

During the Trump administration, an {{vanchor|Office of Clean Coal and Carbon Management}} was set up within the United States Department of Energy, but was abolished in the Biden administration.

References

External links

{{cite web|url=https://www.iea-coal.org/ |title=International Energy Agency - Clean Coal Centre}}
{{cite web|url=http://www.netl.doe.gov/cctc/ |title=National Energy Technology Laboratory compendium homepage |archiveurl=https://web.archive.org/web/20080829110646/http://www.netl.doe.gov/cctc/ |archivedate=2008-08-29 }}
{{cite web|url=http://www.icse.utah.edu/ |title=Institute for Clean & Secure Energy |archiveurl=https://web.archive.org/web/20090302183516/http://www.icse.utah.edu/ |archivedate=2009-03-02 }}
{{cite web|url=https://www.energy.gov/fe/science-innovation/office-clean-coal-and-carbon-management |title=US federal Office of Clean Coal and Carbon Management}}
{{Cite web|url=http://www.fossil.energy.gov/programs/powersystems/cleancoal/|title=Clean Coal Technology & The Clean Coal Power Initiative|publisher=US Department of Energy|access-date=2009-03-29}}
{{Cite web|url=http://www.netl.doe.gov/cctc/|title=Clean Coal Technology Compendium|publisher=National Energy Technology Laboratory|access-date=2009-03-29|archive-date=2008-08-29|archive-url=https://web.archive.org/web/20080829110646/http://www.netl.doe.gov/cctc/|url-status=dead}}
{{Cite web|url=http://www.uc3.utah.edu/|title=Utah Clean Coal Program|publisher=University of Utah|access-date=2009-03-29|archive-date=2009-03-02|archive-url=https://web.archive.org/web/20090302183941/http://www.uc3.utah.edu/|url-status=dead}}
{{Cite web|url=http://www.icse.utah.edu|title=Institute for Clean & Secure Energy|publisher=University of Utah|access-date=2009-03-29|archive-date=2009-03-02|archive-url=https://web.archive.org/web/20090302183516/http://www.icse.utah.edu/|url-status=dead}}