Promising form of renewable energy

What are the challenges associated with that energy source?

Each of the renewable energy forms has promise and limitations. The most promising of the less developed forms (solar, waves, biofuels, geothermal) is geothermal. It is the most developed, however, its use in the US is restricted to a smaller geographical area than the other sources, as shown in the figure below. The US maps shown in Reference 1 really show the impact and a comparison of the scope available for each type of power source.

US West Areas with Geothermal Potential   US Geological Service

I have been impressed by the use of alternative cycles (e.g. binary) that use other working fluids/gases and lower temperatures rather than depending solely on steam and the Rankine cycle. Based on information I had received before, I had expected sulfur levels to be a significant issue that required resolution.

Advantages

• Multiple methods available depending on temperature and steam quality
• Binary cycles available
• Technology has been developed

Challenges

• Limited in areas of the US available
• Considerable depths may be needed to use this resource
• Stimulating a fracture system along a fault system in a seismically active area
• Drilling noise mitigation in cities

Comments about other sources

• Solar is available to a large area of the United States, but it is costly.
• Ocean Wave Energy is still in its infancy.
• Biomass concerns me because the method does not eliminate carbon dioxide releases as the other 3 methods do.

References

1. Renewable Energy Sources in the United States , Nationalatlas.gov, http://www.nationalatlas.gov/articles/people/a_energy.html

2. The Future of Geothermal Energy, Massachusetts Institute of Technology, http://www1.eere.energy.gov/geothermal/pdfs/future_geo_energy.pdf

3. Geothermal Energy—Clean Power From the Earth’s Heat , US Geological Service, http://pubs.usgs.gov/circ/2004/c1249/c1249.pdf

Renewables Home - Virtual Nuclear Tourist - Tuesday March 29, 2011