#09 Geothermal Energy
Using the heat beneath our feet
Read time: 4 minutes
In this week’s issue you will learn about a renewable energy source that’s great for producing electricity and the best for heating: Geothermal Energy
“Just 0.1% of the Earth’s total heat content could meet our energy needs for two million years” - Advanced Research Projects Agency for Energy
Top Geothermal Energy News 🗞️
US Funding Geothermal: The Department of Energy (DOE) has announced $15 Million to drive down costs of geothermal drilling. The goal is to power at least 40 million American homes with renewable geothermal power by 2050!
Burning Man and Geothermal: The festival organizers have sued the US Government to stop the development of a geothermal energy project in northern Nevada.
EU Funds: The EU innovation fund will finance the first commercial-scale implementation of innovative closed-loop geothermal technology.
Let’s dive in 🧠
Solar and wind are great but since they require storage, many companies are still looking for other energy generation options like geothermal.
It’s the energy generated and stored inside the Earth (we don’t drill past the crust).
That heat inside the Earth can be used for 2 things:
Generating electricity ⚡
There are several ways to do this but the principle is pretty much the same for all of them:
Drill between 2 and 5 kms deep. (The center is 6300kms deep)
Access a hot water reservoir (a couple hundred degrees) or create one by pumping water down there.
Get that hot water to come back up and turn into steam to power a turbine or use it to heat another liquid with a lower boiling point which is then used to power a turbine as well.
Get the electricity generated from the turbine to the grid.
Source: Energy.gov
This is the most common type nowadays. Due to the change in pressure the hot underground liquids turn into steam and power a turbine.
Geothermal might not always beat solar or wind in terms of costs to generate electricity, since it depends a lot on the location.
Heating’s a different story…
Heating 🔥
Geothermal can be used to heat buildings much more cost-effectively and directly than any other renewable energy source.
This is key since between 50% and 70% of all energy used in homes goes towards heating and cooling.
Here’s where geothermal heat pumps come in.
They are systems of tubes and a heat exchanger located just a couple meters underground.
They take advantage of the constant temperature of the soil to keep your house warm in the winter and cold in the summer.
All of this is great but we are still using very little geothermal energy.
And if we want to meet our Net Zero targets we need much more…
So if geothermal has so much potential to help decarbonize the economy why are we struggling to use it more?
Cons
Location: Most geothermal energy plants today are located in tectonic plates’ boundaries where hot water comes out more easily.
To get really hot temperatures in places which are not in such places you need to drill much deeper. That’s why the countries in the “Ring of Fire” area have so much geothermal energy potential.
Costs: Exploring the terrain, drilling and setting up the whole infrastructure is costly. Once the plant is built it’s quite cheap and efficient to run.
Earthquakes: It’s very rare but some types of geothermal drilling can cause earthquakes.
These cons do not apply to geothermal heat pumps :)
Top Geothermal Energy Startups 💰
Dandelion Energy: A US startup that used to be part of Alphabet and is now independent. They replace air conditioning and heating equipment with a heat pump that keeps the house warm in the winter and cold in the summer.
Quaise: They have created a new approach to drilling, that’s 90% cheaper, can reach deeper, can stand higher temperatures, and is more sustainable than any other method. They use millimetric electromagnetic waves to pulverize the rock.
Also check out Eavor, making closed-loop geothermal systems, and Fervo, developing projects by drilling horizontally in geothermal reservoirs.
❗Extreme knowledge area❗
You want more? Here are some extra resources:
Geothermal Heat Pumps: This video is great for understanding how geothermal heating and cooling systems work. The channel is great for anything related to climate tech btw.
Geothermal Energy Deep Dive: Here’s a detailed article covering all the details about geothermal from Climate Tech VC, an excellent source for anything related to climate tech.
Geothermal Energy Visualization: This great infographic by Visual Capitalist provides a very complete crash course on geothermal energy.
That’s it for today, 1 climate tech topic in under 5 minutes.
Next week… Sustainable Fertilizer! 🤯
If you enjoyed today’s issue, the best compliment you could pay me would be to share it with one person who you think would benefit from it :)