Renewable + Law : Renewable Energy Lawyer & Attorneys : Stoel Rives Law Firm : Climate Change, Emissions, Carbon Markets, Wind, Solar, Biofuels : Western United States

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This might be an esoteric discussion point, but theoretically speaking, the geothermal resource of the earth could be considered a limited and fixed resource that does not renew itself. The temperature of the earth at the center may reach 10,000 degrees Fahrenheit but it is much cooler the closer you get to the surface. We tap into geothermal heat where it is close enough to the surface and hot enough to make it economic and efficient to do so. The question is, though, when we remove heat from the earth, is it a reservoir with a finite capacity, or is it a renewing resource? In other words are we depleting it? 

The answer, according to Gerald Bawden, a Ph.D. Geologist with the United States Geologic Survey  and Rick Adair, an energy industry writer with Newsdata Corp with a Ph.D. in Earth Science is that the heat in the earth is mostly a function of both radioactive decay of elements in the earth and a natural process occuring wherein the solid innner portion of the core is steadily crystalizing its outer liquid portion. That’s great news in the moral debate about whether geothermal energy is renewable since it means that the earth is still adding heat. So, as we continue to find and use more geothermal energy, we can rest assured that we are not depleting a limited reservoir. Of heat anyway. Many geothermal power plants that use water/ steam deal with the fact that the water resource in the area beneath plant may be limited. Fortunately the condensed steam can be injected back down to the heat source and various sources of non-potable water can be injected as well.

From a legal perspective, there is not much debate. Most laws passed so far that attempt to define renewable energy include geothermal energy. California’s Renewable Portfolio Standard (RPS) for instance, includes Geothermal electricity production as one type of renewable energy that the investor owned utilities can contract with to help meet their minimum required amount of renewable electricity.