Geothermal Potential

Wind and solar get the lion’s share of attention when it comes to discussing renewable energy and the portfolio of options for zero carbon electricity generation.  Nuclear energy is brought up by its proponents as part of the solution, but the cost and risk, in regards to both the project liability and the waste disposal issue, preclude it from being a serious part of the discussion.  Hydropower is definitely part of the solution because it is well proven and can provide consistent power, but it is unlikely that any new major hydropower projects are going to be built because of the damage existing facilities have done to our waterways.  Any gain in hydropower will be achieved through wringing out more electricity from currently running facilities, replacing derelict power generation facilities, or retrofitting existing dams to accommodate hydropower.  Granted, there is probably a lot of potential in those three options but I am no expert.

One renewable energy source that is consistently overlooked is geothermal.  Maybe it’s because we cannot picture a geothermal plant or, if we can, it conjures up images of Iceland.  However, geothermal power is an excellent source of base load renewable power.  What do I mean by base load?  This is the power that is available consistently 24 hours a day.  Wind and solar are intermittent and variable, so it is hard to go to a system that depends upon such power.  This is the argument that the coal and natural gas lobbies use to defend the construction and operation of their facilities.  Geothermal power, however, is there all the time.

But what is the potential for the power?  Not everyone lives in a place like Iceland or Hawaii where the hot core of the earth is literally bursting at the seams and pouring out as lava.  Here is what the National Renewable Energy Laboratory (NREL) worked up using date from Southern Methodist University:


The western United States is brimming with potential for geothermal power.  Even my little portion of southeast Iowa looks like it might be sitting on a potential spot for favorable, if not optimum, conditions.

Iceland, a country known for its volcanic activity and hot springs, gets an estimated 30% of its electricity from geothermal sources.  Now, imagine a world where everyone got 30% of their electricity from geothermal and what that would represent in terms of closures of dirty fossil fuel plants.

Don’t think it can be done in the U.S.?  Why not?

Let’s look at Iowa, my home state, for a moment.  According to the Energy Information Administration (EIA) the production of electricity in January 2013, the latest month for which data is available publicly, looked like this:

Chart Energy

Iowa is already getting almost one-third of its electricity from renewables, a combination including a small amount of hydroelectric, with the rest coming primarily from coal.  At these levels there is approximately 100 GWh of coal fired electricity being generated per day.  Using my crude mathematics skill—100 GWh per day = 100,000 MWh per day = 4167 MW per hour—you would need to install ~4200 MWs of capacity to totally supplant coal.  Granted, no facility is 100% efficient so assuming 75% efficiency the installed capacity would have to be rated at approximately 5,500 MW.

Now, the U.S. as a whole does not have that much installed capacity for geothermal but I was trying to replace all coal fired generation.  There is nothing to say that coal cannot be supplanted by a portfolio of options, one of which could be geothermal.  I am just trying to show that there is a place in the conversation for geothermal energy.

The more research that I do into the issue the more I am left with the distinct feeling that no one really knows how much geothermal power potential exists.

The problem is that there does not appear to be a lot of movement to develop these resources in any cohesive national way.  We hear a lot about the production tax credit for wind power or feed-in tariffs for solar energy, but there is no equivalent government incentive for geothermal that would spur development.  Why?

As we look to transition to a carbon neutral economy a solution like geothermal power cannot be ignored.


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