Good as wind and solar energy can be to provide peak power, they are no substitute to coal fired or nuclear as base load power to provide electricity 24 hours a day. The increasing evidence is that planet earth needs a sharp reduction in carbon pollution, if the disastrous consequences of global warming are to be avoided. The question then arises can geothermal energy become an economic substitute to provide base load energy?
Earth Policy Institute (www.earth-policy.org) says YES.
While carbon capture and storage (CCS) can be a large
boon allowing a new and vigorous life for a low pollution
coal industry, practical application of this technology is
about 10 years away.
Even with the likelihood of low carbon coal power, now is the time for geothermal energy to come into its own. Earth Policy Institute says geothermal energy “originating from the earth’s core and from the decay of naturally occurring isotopes such as uranium, thorium and potassium, the heat energy in the uppermost six miles of the planet’s crust is 50.000 times greater than the energy content of all oil and natural gas resources.”
Chile, Peru, Mexico, United States, Canada, Russia, China, Japan, Philippines, Indonesia, Papua New Guinea, New Zealand, and other countries with high volcanic activity, encircling the basin of the Pacific Ocean are rich in geothermal energy. The Great Rift Valley of Africa including Kenya and Ethiopia is another geothermal hot spot. As Earth Policy Institute says 39 countries with a combined population of more than 750 million have rich geothermal energy resources sufficient to meet all their electricity needs.
Outside these countries, where shallow volcanic systems exist and are relatively cheap to exploit, the more expensive hot rock technology in the form of drilling very deep wells up to three miles where water is pumped underground, then heated, and the heat energy used to generate power opens the door to many more countries to tap geothermal resources.
The “hot rocks” are needed to be 150 degrees Celsius to produce
electricity, with temperatures rising the deeper the drill goes
into the earth’s crust. In all there are more than 70 countries with
the capacity to develop geothermal resources for conversion into
Iceland is the model country for renewable energy, with 70 per
cent of its energy coming from renewables. Currently, there is
420 MW electricity capacity from two geothermal power stations,
sourced from hot rock technology. 27 per cent of the country’s
electricity comes from geothermal energy, with the balance
coming from hydro power. Iceland has been a pioneer in hot rock
technology, and is now the first country in the world to
establish a public hydrogen power station, aimed at introducing
a hydrogen-based pollution-free traffic system.
Hydrogen buses have been extensively tested as an integral part
of the Reykjavik public transport system, with Iceland close to
its goal of being entirely carbon free.
The United States has the largest known geothermal resources in the
world. The US Geological Survey released in September 2008, the
first national geothermal resource survey in more than 30 years,
shows an estimated 9,057 MWe of power generation potential from
conventional identified geothermal systems. There is also 30,033
MWe of power generation potential from conventional undiscovered
Finally, there is a further 517,800 MWe of power generation
potential from unconventional (high temperature, low
permeability) enhanced geothermal systems (EGS). The
conventional geothermal resources are in the north western part
of the US-California, Nevada, Idaho and Oregon, Hawaii, and
parts of the north east of New England. The unconventional
resources, where hot dry rock or deep geothermal/EGS can be used
in almost all of the US, but is particularly applicable in the
southern and eastern parts of the country.
According to The Earth Policy Institute, as of August of this year,
the US had 2,960 MW geothermal installed capacity, with
California dominating with 2,555 MW. Most of this capacity is in
the Geysers, a geologically active region north of San
Francisco. In addition to installed capacity, there are up to
4,000 MW of capacity under development in 13 US states.
Outside the US, Philippines ranks No2, generating 23 per cent of
its electricity from geothermal resources, and plans to increase
it 60 per cent to 3,130 MW.by 2013. Ranking No 3 is Indonesia,
which aims to have 6,870 MW of geothermal energy capacity by
2020, at which stage geothermal energy would represent 30 per
cent of all energy installed.
Europe has little installed capacity, except for Italy, which
has 810 MW, and this is expected to double by 2020. Iceland as
reported before has 420MW, and Germany an insignificant 8 MW,
but is now showing renewed interest in geothermal resources in
The disappointing part of this story is that with all the
potential that geothermal resources could become as a major part
of the globe’s carbon free energy future, it is still largely
being pushed aside. Will this change when many more countries
introduce an emission trading scheme, and start effectively
taxing carbon? That remains to be seen.
In countries like the US, where a large part of the geothermal
resource is located, geothermal energy from conventional
geothermal resources is price competitive with natural gas, and
is carbon pollution free. This is not the case with hot rock or
deep geothermal/EGS, where a lot of research and money is still
needed to bring down the costs of drilling deep wells, where the
costs are currently too high.