Large scale geothermal has run into many maintenance problems mainly around pipe corrosion caused by dissolved materials in the well water that is circulated.
Closed loop systems are not usually seen in vertical systems going deeper than 400 feet and are usually found only in shallow horizontal systems.
In most cases closed loop systems are used for individual buildings and are not practical for large-scale power creation.
Nuclear energy makes a lot of sense on paper, but it’s main drawback is that post-Chernobyl, it’s been a highly-politicized source of energy.
But what about geothermal?
Damian Carrington writes at The Guardian that geothermal energy is so very underrated.
(As a reminder, geothermal plants send water in a closed-loop down holes to bring to the surface the heat from natural radioactive decay deep in the Earth’s mantle. In contrast, nuclear power mines and concentrates radionucleides, concentrates them and allows them to react.)
And with 99.9 percent of the Earth hotter than 212 degrees Fahrenheit, 24 hours a day, seven days a week, why on Earth aren’t we using more of it?
He writes about political hurdles on the other side of the pond:
The catch is this: you’d be awfully brave to invest in it right now. Unlike most European nations, there is no licensing system in the UK. So you could sink your test wells at the cost of millions of pounds, find the right spot, then see someone else set up in the next field. There is no feed-in tariff support for electricity from geothermal. And the Renewable Obligation Certificates (Roc) support scheme is set at 2 Rocs, compared to the equivalent of 4 Rocs in Germany.
Carrington’s outlines a few benefits of geothermal, including:
- At 24 hours a day, it’s “perfect” for baseload power.
- Because the water circulates in a closed-loop, it’s clean and sustainable.
- Plants have a small surface footprint — no NIMBY (”Not In My Back Yard”) necessary.
He also makes it relative: geothermal plants may trigger the occasional small earthquake, but that’s nothing compared to the nuclear waste you’re guaranteed to have pursuing nuclear power.
Among European nations, Germany’s the fastest growing; that’s why Carrington is issuing a call to cleantech arms for the U.K.
So how does the U.S. stack up here? Along with the Phillippines, it leads the world in installed capacity. (States with the most plants: California, Nevada, Utah, Wyoming.)
But as you can see in the graph to the right, geothermal still pales in comparison to nuclear in the U.S. energy portfolio: just one percent of the overall U.S. mix, compared to 9 percent from nuclear.
However, since 2005, the U.S. has made geothermal energy more of a priority. And most recently, the Dept. of Energy awarded $20 million for the development of advanced geothermal tech.
What do you think: is tapping the Earth for energy a good idea, or are humans playing with fire?
Diagrams: Geothermal Energy Association; USEIA
Related on SmartPlanet:
- Chevron: Solar, geothermal investments are key focus
- Volcano power: Saint Lucia to tap into geothermal energy
- Geothermal energy: too dangerous?
- Geothermal gives West a clean energy advantage
- U.S. geothermal infrastructure could support 7.2 million people
- Is geothermal energy too risky? Induced quake risk halts two major projects
