The IEA says geothermal energy could account for only 3.5% of annual global electricity production and 3.9% of energy for heat (excluding ground source heat pumps) by 2050. But is this down to short term thinking? Geothermal could make a much bigger contribution to renewables, provided it is put onto the fast track like wind and solar, says Alexander Richter, President of the International Geothermal Association.
Energy from geothermal “not an option”? That’s what they said about wind and sun
There is a hidden source of energy right beneath our feet, which we however largely neglect. The arguments for not looking at this obvious type of energy range from we do not have volcanoes, it is too deep, too risky, it shakes the earth, it is too expensive or simply not possible. It can be a challenge to apply your imagination to a form of energy that you cannot feel or see; not unlike the wind blowing, or the sun shining, in your face. For this reason, geothermal energy simply is not a consideration for many people.
Let us look at what geothermal offers. Geothermal energy essentially is a source of heat, which can be used to generate electricity using steam to drive a turbine. With the core of the Earth having temperatures of up to 5,000°C, there is a large heat source. How easy it is to access a usable temperature, sufficient for steam and electricity generation, determines the economics of geothermal.
You don’t need to be on a tectonic fault line
Today, one can find most of the countries generating electricity with the help of geothermal energy along the tectonic plate boundaries of the world, e.g. along the western cost of the Americas, through the East African Rift Valley etc. But other countries with no obvious volcanic settings also utilise geothermal for electricity generation, such as Germany and France. Despite deeper drilling depths and more complex technology in those settings, it is still a valid and competitive source of energy.
Geothermal for direct heating, not just electricity generation
But the largest untapped potential for geothermal energy is utilising the heat directly for all kinds of applications needing heat. This ranges from heating homes, greenhouses for agri-food production, bathing, food-dehydration, or in a not too obvious example for cooling utilising a technology similar to your fridge at home. In Europe alone, heating and cooling represents about half of all energy demand, which includes transportation and electricity generation. This is a large part of the energy mix. In the context of climate change and the need to cut carbon emissions, the heating and cooling sector will play an important if not crucial role.
Today, around 100 countries utilise geothermal energy directly for heating (or cooling) purposes and in other industrial applications utilising heat. An obvious example of using geothermal heat directly is Iceland, where nearly all swimming pools are outdoors and open year-round, and vegetables are grown in greenhouses, and this despite a rough Arctic climate. A much less obvious example is Kenya: it is home to successful greenhouse operations that need heating and light over the night, despite hot temperatures over the day, and tap geothermal energy for that purpose.
Geothermal power generation: the list of nations is growing, but not fast enough
Today, geothermal power is generated in 27 countries with a total installed power generation capacity of 14,600 MW at the end of 2018. Having grown around 4,300 MW over a ten-year period, geothermal has shown steady growth, though not the fast growth shown by other renewable energy technologies.
During the past decade only two new countries joined the list of countries producing geothermal power: Chile and Croatia. The leading countries are the United States, followed by Indonesia and the Philippines. Turkey is a relative newcomer, having show incredible growth compared to past development: pushed by government support, favourable incentive schemes through feed-in-tariffs and a power-hungry economy, this has been the fastest entry into the 1 GW Geothermal Country Club of countries with more than 1,000 MW of installed power generation capacity.
Research by ThinkGeoEnergy shows the number of countries that could be producing electricity from geothermal resources could increase to 82 countries if plans for development materialise. The growth markets for geothermal in the near future are Indonesia, as well as Kenya and Ethiopia and North America.
Geothermal provides 30%-50% of Kenya’s electricity
But the interesting fact is the impact geothermal energy has in some of those countries. In Kenya, geothermal energy – representing roughly only around 30 percent of power generation capacity – has replaced unreliable hydro power due to droughts and provides often more than 50 percent of the electricity of the country.
“Geothermal power plants provide stable production output, unaffected by climatic variations, resulting in high capacity factors (ranging from 60% to 90%) and making the technology suitable for baseload production.” – IEA
Other countries where geothermal energy provides a significant percentage of electricity include Iceland, the Philippines, El Salvador, New Zealand and Costa Rica. With planned projects in the Caribbean, some of those island states could end up with all electricity supplied by geothermal energy, replacing costly diesel fuelled electricity generation.
More nations are testing geothermal’s potential
In a drive for sustainability and tapping clean energy sources, the Dutch greenhouse sector is also starting to utilise geothermal energy for heating purposes. Across Europe, there are various other efforts on geothermal district heating. In China, large-scale district heating efforts, with so far more than 500 wells drilled, push geothermal heating across various cities and regions to drive down the use of coal, already today improving air quality and the well-being of people.
In the agri-food sector, geothermal energy can also play an important role beyond heating greenhouses, e.g. for soil fertilisation. Post-harvest, geothermal can help dehydrate produce, e.g. in drying tomatoes. In food-processing, geothermal heat can be used for milk pasteurisation and related applications.
Like all renewables, it starts with long term thinking
Today, we are only scratching the surface of the overall potential for geothermal energy utilisation, particularly for direct use. We see a lot of innovation efforts looking at cutting down drilling costs, utilising super-critical heat for higher output per well, new approaches to deriving heat from below the surface, new business models in the development of projects, and new financing models.
How much geothermal energy for power generation will grow will depend on overall political support and long-term thinking for a source of energy that can provide an important and elementary role in the future energy supply. The geothermal sector is not standing still.
Alexander Richter is editor of the geothermal news platform ThinkGeoEnergy.com, and President of the International Geothermal Association