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November 30, 2007- Biomass - Biomass conversion consists of harnessing the potential chemical energy within carbonaceous matter through burning and gas conversion. Early technologies converted biomass directly into heat. Advances in production and chemical and genetic engineering have found new uses for biomass, including conversion into liquid fuel and hydrogen. Realizing commercial-scale energy output is still largely dependent on creating efficiency gains in production technology and outsized investment in production facilities.
- Hydrogen from Algae - Algae can be engineered to produce hydrogen instead of oxygen during photosynthesis through sulfur deprivation. Prolonged sulfur deprivation has negative effects on the algae, so this process currently can occur only in short cycles. Continued research is required to lengthen sulfur-deprivation periods. Furthermore, commercial scale generation requires large, open bioreactors to harness the power of a critical mass of algae. There are currently no bioreactors large enough to accomplish this. If successful, though, sulfur-deprived algae could be the most efficient and sustainable means of creating hydrogen.
- Biomass Gasification - Gasifying organic material (wood pellets, leaves, tree bark and livestock and poultry manure) consists of burning this material at high temperatures while mixing it with oxygen, which breaks down the carbon monoxide and hydrogen contained in the organic material. The result is a clean-burning, carbon-neutral synthetic gas. Inorganic matter left over from this process can be used as fertilizer. Syngas can be further converted into biomethane and methanol or carbon-neutral synthetic fuel with continued catalyst processing.
Hydrogen From Algae LiveFuels, Inc. GreenFuel Technologies Corp. Biomass Gasification Biomass Technology Group >ZeroPoint Clean Tech, Inc. - Geothermal Power - Underground thermal energy is nearly limitless. Geothermal-power plants pump underground steam and hot water and use the heat supplied to spin turbine generators. Major costs of geothermal-power plants come from exploration and excavation, and current technology is only cost-effective in areas with active underground tectonic movement observable through geysers and volcanic activity. Research on stimulating underground heat and creating artificial heat reservoirs might make geothermal power a promising source for base-load power.
- Enhanced Geothermal Systems (EGS) - EGS might provide a cost-effective work-around for areas where available geothermal power is located far below ground. These systems create permeable rock layers through high-pressure water injection, which is heated through contact with newly fractured rocks. The water is then pumped back above ground and used to spin turbine generators. Stimulating underground heat production and artificially engineering heat reservoirs is expensive, though, and requires vestment in pilot plants to prove its usability.
- Hydrothermal Power - Hydrothermal is the more traditional form of geothermal power. It relies exclusively on existing reservoirs lying under permeable rock that are saturated with steam or heated water. Geographic limitations notwithstanding, areas where these resources are readily available at short distances below the surface will benefit from adopting this technology.
Nuclear Power - Generating electricity from controlled nuclear reactions appears to be an efficient method of providing pervasive base-load power, though safety, environmental effects and costs must not be disregarded. Nuclear reactors are costly, upwards of $2 billion, though once built the power plants can run continuously. Internalizing costs across the fuel-production process increases the electricity costs from "too cheap to meter" to thousands of dollars per kilowatt-hour. There is also widespread debate about whether nuclear power is truly renewable, as it requires uranium fuel -- a depleting mineral -- for fission. Less than 2 percent of uranium is fissionable. Another substantial problem is thermal water pollution and reactor waste disposal. Neither problem has yet been solved. Public skepticism and fear also are major factors preventing the widespread adoption of nuclear power. These fears are not unfounded.
Several new theoretical technologies for nuclear reactors are currently under research. These new designs focus primarily on cooling mechanisms and non-uranium 235 fueling, including hydrogen-based nuclear fusion. Although the last commercial reactor in the U.S. was completed in 1996, nuclear power makes up nearly 16 percent of global electricity production. It has a particularly strong presence in Western Europe, Japan and Russia. Both General Electric and Westinghouse are currently seeking approval for new reactor designs from the U.S. Nuclear Regulatory Commission, the first such submissions in 30 years.
| Enhanced Geothermal Systems (EGS) | ||
| Altarock Energy | Geodynamics | Geopower Basel |
| Hydrothermal Power | |
| Nevada Geothermal Power | Enel Green Power |
| EarthEnergy | Ormat Technologies, Inc. |