Photo by Viktor Kiryanov on Unsplash

To stop the self-made apocalypse that is climate change, we need to stop pumping the atmosphere full of carbon dioxide — something that is far easier said than actually done. Part of the issue is that our low-carbon power sources aren’t quite ready to entirely take over from fossil fuels. Solar and wind aren’t reliable enough, nuclear and hydroelectric are too expensive, and geothermal is too costly and impractical. But the Biden administration just announced their goal to make geothermal energy (arguably the most ecologically harmonious energy source) far cheaper and, in doing so, revolutionise energy grids across the world. But why geothermal power? How can it compete with other energy sources? And will this really make a difference?

Firstly, what is geothermal power? Well, to put it simply, geothermal power harnesses the heat of the Earth’s core to create extremely low-carbon energy. You start by drilling a hole until you reach temperatures hot enough to flash water into steam. You then hook up a turbine to the hole and pour water down it. The increase in pressure caused by the water turning to steam forces the steam out of the turbine at tremendous speeds, spinning it and generating electricity.

So why is geothermal energy so good for the environment? Well, it only emits 38g of carbon dioxide per kWh of energy produced. This comes from the carbon emissions of constructing the geothermal power plant and from volcanic gases seeping into the steam and being released. This is the sixth lowest carbon form of energy, coming in way below coal at 1,000g per kWh and natural gas at 185g per kWh. But it emits more than solar at 20g per kWh and nuclear at only 4g per kWh.

Unlike solar energy, geothermal energy is on-tap and can easily meet demand without the need for carbon-intensive batteries as energy backup. This is why we can’t yet 100% rely on wind and solar power, as it could leave our energy grid starved of electricity. What’s more, geothermal energy is super compact. In some situations, it is even more compact than nuclear, gas, or coal power stations, meaning they don’t cause habitat loss. But unlike nuclear power, geothermal energy needs no fuel, which means it requires no environmentally damaging intensive mining, refining, or shipping, and has no waste products. These plants even recycle their water. In essence, this means that running an energy grid entirely off geothermal power is possible, and as a bonus, it has one of the lightest ecological impacts of any energy source.

It isn’t like we are short of geothermal resources either. The US has a whopping 5 TW of potential geothermal power, which is enough to power all the energy grids in the world! So why is the US only using 3.7 MW of geothermal power, about 0.074% of its overall potential?

Well, for two reasons. Location and cost.

When geothermal heat is close to the surface at about 3.2 km down (like near geysers), it is very competitively priced at about $45 per MWh and upwards. For some comparison, natural gas averages $173.50 per MWh, nuclear power averages $167.50 per MWh, wind power averages $38 per MWh, and solar power is only $35.50 per MWh. This is why countries like Iceland can run almost entirely off geothermal power without having staggeringly high energy prices that would stall their economy.

But the vast majority of the potential geothermal power across the world (and the US) is far deeper, at about 8 km down, and to access this requires incredibly deep boreholes. It is incredibly difficult and costly to build and maintain structures capable of withstanding the pressures of geothermal power. So much so that deep geothermal power is currently commercially unviable with costs of around $350 per MWh.

This is an issue because the areas in the US that can host shallow geothermal power are far from areas of significant energy demand. But the losses that are incurred by transporting this energy (due to resistance in transmission cables) hundreds of miles to where it needs to be effectively jack up the price, again making it commercially unviable.

This is why the US hasn’t tapped into this incredible energy source yet. It simply isn’t practical to do so, and it is far too expensive.

This is why the DoE (Department of Energy) recently announced its goal to make geothermal power cost $45 per MWh, which is 90% cheaper than current costs, by the year 2035. But how?

The DoE plans to spend literally hundreds of millions of dollars on geothermal power research and development, as well as enable the oil industry to share advancements they have made. But why would they need the oil industry?

Well, we can deduce that they are talking about deep geothermal power here, as shallow plants are already beating this target. But as we know, the main cost of these deep geothermal plants is the incredibly long boreholes. The gas and oil industries are running out of shallow deposit sites and are having to dig deeper and deeper to access the black gold they seek, so they have the technology that could enable deep geothermal power to become commercially viable.

In fact, one of the companies likely to get support through the DoE is Quaise, which is developing a technology that oil companies have wanted for ages: millimetre wave drilling.

Millimetre wave drilling uses incredibly powerful millimetre wavelength radiation to literally vaporise rock and drill down with ease. This makes it far easier, quicker, and cheaper to drill many kilometres down to where the deep geothermal energy is. Quaise actually thinks that they can drill deep enough to unlock geothermal energy nearly anywhere on Earth (as long as it isn’t up a mountain), given that they can go up to 12 miles deep. So they plan to drill next to current coal and gas power stations and then switch the plant from using fossil fuels to geothermal power. That way, they can reuse the turbines and energy infrastructure, making geothermal power even cheaper.

(To read more, click here).

But can technology like this really make deep geothermal power cheaper? Well, Quaise reckons it can get these deep geothermal plants down to $10–$30 per MWh. So, in theory, it at least seems plausible.

Finally, will this actually make a difference?

The US currently emits 1.55 billion tonnes of carbon dioxide annually from energy generation. That is a massive 2.9% of global emissions. If geothermal can get this cheap and be available across the country, it will be surprisingly easy to get that figure down to zero tonnes without risking the energy grid’s stability (like solar and wind power can).

But this technology will be available to most countries, and with such a considerable cost and environmental advantage over nuclear power, the entire world could rapidly adopt this technology. If they do, our global emissions will tumble as 73% of our emissions come from energy generation.

So yes, the DoE has just set in motion an energy revolution that could change the tides of climate change. What’s more, if they can hit their deadline of 2035, then there is enough time for this technology to be widely adopted and have a massive impact before our climate goes past the point of no return.