Tuesday, July 22, 2014

Large Scale Geothermal Power - Could it Work?

Large Scale Geothermal Power - Could it Work?

Large Scale Geothermal Power - Could it Work?
Geothermal power isn’t a new idea but researchers in Spain are thinking about the “Big Picture” and their work could have significant implications for the future of the global energy landscape.
You might remember a write-up in Resilient Strategies last year where I explained how home geothermal systems work to keep the average home comfortable year round by pumping water through a network of pipes located a few feet below the ground.
The reason this works is because despite sometimes radical temperature fluctuations on the surface of the Earth, if you dig down a few feet the ground maintains a consistent temperature around 55°F. This keeps the home cool in the summer and using a heat collector, amplifies the heat to keep the home warm in the winter.
The research being done at the University of Valladolid in Spain is based on geothermal principles but is nothing like the home systems described above.
Let me start with a question: Do you know how hot the center of the Earth is?
Believe it or not, it’s almost as hot as the surface of the Sun.
Another question: Why aren’t we using this energy to mitigate the growing energy crisis?
With any luck, that may change soon.

Enhanced Geothermal Systems

Rather than dig only a few feet under the surface to access the consistent temperatures commonly leveraged for residential geothermal systems, an Enhanced Geothermal System (EGS) digs thousands of meters into the ground to capture some of the intense heat that escapes from the Earth’s core.
This heat is used to boil water, which creates steam and ultimately drives turbines that generate power. Pretty much the same thing as current power plants except EGSs don’t need fossil fuels or radioactive fuel rods to make it happen.
If implemented successfully, we could generate power 24 hours a day without concerns about the rising costs of fossil fuels or the hazards associated with nuclear power plants.
Geothermal Power
And we’re not talking about a little bit of power either. Current estimates demonstrate that an EGS in Spain could produce up to 700 Gigawatts of power.
To put that into perspective, the U.S. generates approximately 1,000 Gigawatts of power during peak summer usage. A little over 700 Gigawatts of that power comes from coal-fired power plants.
In other words, a single EGS with similar capacity as the one proposed in Spain could eliminate fossil-fuel based power generation in the United States practically overnight.
Anyway, back across the ocean to Spain. The Iberian Peninsula has multiple areas where temperatures reach sufficient values at relatively shallow depths. Oh, by the way, relatively shallow means 3,000 – 10,000 meters below the surface.
That may seem extraordinarily deep but keep in mind that many oil holes are drilled in this depth range so the technology already exists to make it happen.
Perhaps the only real obstacle the modern EGS faces is that it is essentially a form of fracking – officially known as hydraulic fracturing. Despite the massive amounts of natural gas our country is now harvesting thanks to this process, there are some serious side effects associated with traditional fracking such as ground water contamination.
The difference when harnessing geothermal energy is that the pressures are lower, the chemicals are not as dangerous and the pressurized water would be injected into hot rocks below the surface – not near natural water supplies.
But to an environmentalist, fracking is fracking so I would expect EGS construction to face many of the same obstacles faced by natural gas companies using fracking to extract fuel from shale beds below the surface.
Even if the EGS weren’t approved, there is another way to use geothermal power although the results are not nearly as impressive. Researchers have determined that the Iberian Peninsula could generate approximately 3.2 Gigawatts of power just by using the heat that reaches the Earth’s surface naturally.
That means no drilling and no injecting water into the ground.
3.2 Gigawatts may not seem like a lot (certainly not when compared to 700 Gigawatts), but that is the equivalent of three nuclear power plants. Even that would offer a much more sustainable solution than our current energy infrastructure.
By the way, the graphic below shows the temperatures below the surface within the United States. Anything over 150°C can be used to generate power using an EGS and that includes most areas of the country so EGSs are a feasible alternative in this country as well.
US Heat Map
As interesting and potentially ground-breaking (pun intended) as this idea is, I’m certain it’s a long road ahead – especially in the United States. I recently wrote about Ohio’s decision to freeze current alternative energy requirements which I surmise has a lot to do with lobbyists associated with the massive fossil fuel industry in the state.
Why would an idea like this be any different? If I were a fossil fuel mogul, I’d be shivering in my boots to think that a single new technology could take out all the coal-fired power plants in the country simultaneously.
So, as usual, it comes down to government inefficiency and the unwillingness to change politicians so proudly display like an American Flag pin on the lapel of their jacket. All we can hope for at this point is that the project is a success in Spain. Verifiable results are much more difficult to argue with than a good idea and only time will tell.
To your resilience,
Paul Clarke

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