Geothermal Energy - Turn Inwards to Seek the Heat
Digging Deep for One of Nature’s Hottest Resources
Welcome back to CC! After a short break, we are continuing our series on DERs with part four coming in hot. On today's menu - geothermal energy. Let's tap right into the heat 🔥🪨💨.
What is Geothermal Energy?
Geo means earth. Thermal means relating to or caused by heat. Taking heat from the earth. Harness that heat for useful applications such as electricity generation or direct heating and cooling. There you go, case closed.
Let’s dig a little deeper than that.
Geothermal power derives its energy from naturally occurring or man-made underground hot water reservoirs. Humans drill wells, ranging from a few feet up to several miles deep, into those reservoirs to tap into the source. Hot water or steam is pumped to the surface where it's used for the aforementioned purposes. Geothermal energy can be experienced in natural hot springs or geysers - looking at you Iceland. The best part about geothermal energy is that it’s clean and renewable and an abundance of it is sleeping beneath the earth's surface. And it’s available 24/7, 365 days a year whether or not the wind blows or the sun shines.
Where the heat underground is coming from? It’s coming directly from the earth’s crust. The crust heats the nearby water. The heat we extracted is relatively small compared to the amount of total heat stored beneath the surface.
There are various kinds of geothermal power plants that use slightly different approaches. In essence, they all work similarly: Take hot water/steam from underground, use heat to spin a turbine, create electricity or heating/cooling appliances, use cooling towers to handle waste heat from the turbine, and inject water back into the ground so that it can be reheated by the crust. It’s that simple.
It’s estimated that geothermal power and heat can provide up to 5% of the global energy demand in 2050.
As some of you might have already guessed - these reservoirs aren’t distributed fair and square across the globe. Some countries have excellent geothermal resources others don’t. As we have learned over the past couple of posts, it’s incredibly difficult to store renewable energy for longer periods of time so that it can be transported.
Who is Using Geothermal Power?
Most of you will probably think of Iceland. Every home in Iceland is heated with geothermal energy - 90% through district heating systems that use hot water from underground reservoirs and 10% through electricity which is generated from either geothermal steam or hydropower. Iceland shows that through long-term investment in necessary infrastructure and adoption of technology, it’s possible to have a green energy supply because it was not always like that. Back in the 80s and 90s, Iceland was heavily reliant on fossil fuels.
Now we know that Iceland is unique in its natural resources. But there are few other players in town who generate significant amounts of electricity from geothermal. The US is actually leading the pack in absolute numbers with a generation capacity of 3.9 gigawatts (GW) in 2023. But more interesting to me are the countries that get large chunks of their energy from geothermal.
Say hello to Kenya.
Kenya’s electricity mix is one of the cleanest on earth. On a good day, up to 95% of electricity generated comes from renewable and clean sources. A third to 50% comes from geothermal power (other renewables in the graph below). That makes the country the 7th largest producer of geothermal energy globally. Renewable energy has been on the country's agenda since the 1990s. Not only are they leading by example in geothermal power, but they are also involved in some of the largest solar and wind projects on the African continent. The government announced it to be 100% reliant on clean energy by 2030. Kenya is also exporting their expertise to neighboring countries trying to build up know-how around geothermal power.
Kenya’s electricity demand is lower than let’s say the US or Germany’s and the unique environmental conditions allow to harness geothermal to this extend. This progress has it’s dark sides as well. Local communities and project developers dispute over land ownership rights and how to preserve the ecological integrity. But it also serves as a great example of what forward looking investments and political will can achieve. The green transition is possible. It’s a question of willingness rather than feasibility. We need to figure out an equitable way to include all stakeholders in the process.
What Are the Opportunities?
Geothermal energy has great potential. The energy source
is always available
provides a reliant supply of heat & steam for a variety of use cases
is a predictable source of power
has a relatively small land footprint
shows significant advances on the technological front that increase efficiency and drive down cost
is the perfect opportunity to transfer workforce and skills from the oil and gas industry
What Are the Challenges?
On the flip side, geothermal energy faces several challenges including
the high upfront cost of exploring locations and building infrastructure
the location of geothermal reservoirs can't be moved
potent gases might leak into the atmosphere during digging for reservoirs
potentially causing earthquakes
geothermal plants need to be carefully managed to ensure the plant’s sustainability
So what do we do with all this information?
Dawn of Geothermal 2.0
Welcome to the future of geothermal energy.
The U.S. Department of Energy (DoE) published its report on the pathways to commercial liftoff for geothermal energy.
Recent advancements in geothermal plant technology and engineering battle the biggest challenge to date - the location-specific nature of geothermal energy reservoirs. Let’s hear from the report’s authors why this is such a big deal:
Next-generation geothermal technologies use modern engineering to expand access to geothermal potential across the entire United States. Next-generation geothermal technologies use drilling and/ or hydraulic fracturing advances that allow fluid to flow through hot rock that was previously impermeable. Because there is no unique geologic constraint to adhere to, next-generation geothermal technologies have vast potential.
The new technologies, called Enhanced Geothermal Systems (EGS) and closed-loop geothermal systems, allow to access resources deeper underground that were previously not accessible. The new wells are going deeper to pump fluid through different rock formations that heat the fluid along the way before it creates power on the surface. Similar to what heat pumps do with heating and cooling fluids. To throw some numbers at this to understand the scope we’re talking about (US-only estimations).
Conventional geothermal energy is estimated at 40 GW generation capacity. 9 GW of that potential is explored and only around ~ 4 GW actively produces power. The next-generation geothermal energy capacity is estimated at 5.500 GW. That is 138 times more than today’s capacity! That is enough to power the US for more than one thousand years.
In addition, the new plants are utilizing existing supply chains and infrastructure from the oil & gas industry that drastically decrease the upfront costs needed to get a geothermal plant up and running. Workforce and knowledge transfer included.
At the end of the day, the adoption of new energy sources comes down to one question: how cost-competitive are these sources compared to traditional oil & gas? As long as renewables can’t be as reliable and cost-competitive with oil & gas, we’re fighting an uphill battle. It’s less a resource-constrained problem rather than a techno-economics one. And as we’ve learned from solar and wind, the more we deploy, the cheaper they get.
So let’s get drilling, but in a safe, considered, and equitable manner.
I hope you learned something today that you can share in the next heated debate about which energy sources to use for the energy transition. It’s inevitable that geothermal will play a role in that. How big is yet to be seen.
Leave a comment below if you feel like this post was too hot or too cold with cool facts about geothermal energy. And if it was just right, comment with 🪨🤘🏼!
Stay electric,
Basti