Research, discovery, creativity and innovation have a way of coming forward with seemingly high user costs that come down as ideas grow into larger markets.  A prime example is wind power that we’ve seen grow from nearly invisible to forests of wind turbines across swaths of North America.  Many wonder what is so slow about geothermal.

The answer is fundamental.  It’s the cost to get to the heat source.  In geologically active areas of the world like Iceland, Indonesia, and Chile the heat is very close to the surface requiring low access costs.  Iceland can take advantage of this low-hanging energy by directly circulating that heat from naturally occurring hot fluids through buildings for heating.  While there is heat to had for the taking across much of the planet’s land surface area – it’s not so easy as the heat is found deeper.

But geothermal is impervious to weather conditions. That independence means it provides excellent base load electricity.  Geothermal is going to grow, here’s why.

Using enhanced geothermal systems (EGS) that are in development now will offer two major advancements.  First are hot rocks that are artificially fractured, perhaps even at great depths.  Then water, other fluids and perhaps gases are injected to contact the hot rocks and then drawn back to the surface where the heat energy is captured and used to generate electricity.  So far, these are very expensive ventures, with costs in excess of $10 million dollars.  That’s ten times the cost of a conventional shallow geothermal well, 2 to 5 times the cost of a shale formation natural gas well.  It’s a major investment.

It’s worth it though. In Australia, a relatively advanced EGS experimental systems in granites produces high heat due to radioactive decay at depths greater than 3 km, are seen as viable geothermal reservoirs.  In fact for South Australia alone, some 23 companies have filed for licenses covering 110,000 sq km where suitable hot granite is believed to exist at accessible depths. The key there is once the system is built on a good site it will be tapped into a constant, virtually limitless supply of energy that’s available without cost.  The investments are in getting to the heat and the plant to handle it.  As more plants are built and improved from experience the investment and operating costs will come down.

The second advancement is binary geothermal power plants (BGPP).  These are plants that intersect the heat flow with a heat exchanger simplifying the management of the circulating fluids back and forth to the hot rock.  Then on the other side of the heat exchanger a closed system will move the heat and extract it into energy forms such as electricity.  The closed system allows highly refined engineering, optimized heat management and avoidance of introducing a wealth of contaminates from the deep circulating fluids into high speed or finely tuned metering machinery.   More costly to build, but much less costly to operate, BGPP offers reduced operating expenses.  Small units are already in use with larger units likely to be announced soon.

Are the watt on grid costs worth it?  Pawing through the U.S. Energy Commission site shows coal and natural gas are getting to the grid at about 4¢ to 5¢/kWhr.  Other pages show BGPP at about 6.5¢/kWhr.  How good those numbers are is debateable, but its very early in the geothermal industry, there are several problems to work out, yet the energy itself in the form of heat is free it you can get there.

In the renewable energy field geothermal clubs solar and wind senseless. There is no dependency on daylight or weather; the heat energy is there 24 hours a day 365 days each year for years.  The dependable electricity production makes it easy for geothermal companies to entice long-term energy agreements without concerns about underproduction or wasting over production.

The capital costs will come down, solar has gotten cheaper to make but installations at commercial scale are stunningly expensive.  Solar can get to $10,000 per kWhr and wind up to $3,000 per kWhr.  Geothermal can get to $3,000 per kWhr but runs 24/365, nearly a three-fold advantage over wind.  Those geothermal costs compare to suggestions about coal-fired facilities costs that must include some capture carbon.

More interesting is that geothermal needs less land than solar or wind, and permitting would be easier than coal or nuclear as the hazards are not there.

For the hard nosed green eyeshade types geothermal offers high load factors, the difference between the rated capacity and the actual production.  Wind tops out at 40% and solar even less.  But geothermal competes with nuclear when good engineering gets to 90% production.

For “green tech” geothermal is the top prospect for long-term growth. While geothermal is centuries behind wind progress and hidden behind the solar excitement, geothermal could compete head on with coal, natural gas and nuclear as the technological improvements come into use.  Meanwhile the U.S. government is pouring incentives, funding opportunities and subsidies into renewables.  Check the Geothermal Org site here.

It won’t be long now, the main issues are boring into hot hard rock and the fracturing issues, and research money is out and more is coming.  The above groundwork is pretty much on the shelf or needs scaling up.  The down hole work will get solved.  After all, the prize is bigger and better than an oil well.


2 Comments so far

  1. Jagdish on December 16, 2009 12:45 AM

    Drilling continues to locate oil and gas. Failed holes can be used for the Consolation ‘Prize’ of geothermal heat.
    Licensing authorities should, as part of conditions, require a temperature chart along with a strata chart to be submitted after drilling. In time a thermal temperature map can be built up.

  2. TYRYR on April 21, 2010 4:12 AM


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