There’s no telling how low or how high humanity will go in its quest for more energy. The deepest oil well to date, the Z-44 well in Sakhalin Island, Russia (just north of Japan), for example, reaches an astounding depth, drilling through more than 12 kilometers of rock. 

But green energy promises to go even deeper. The next generation of geothermal companies are looking to drill an amazing twelve miles underground.

Other energy innovators are looking upward. They’re dreaming of wind turbines and solar arrays that tower over even the loftiest skyscrapers.

Here we press both buttons. What can renewable energy gain by going ever higher? And is there still more to be gained by digging down?

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Going Down

1.  Turning up the heat. The Earth is hot. And it gets hotter the deeper you go. In fact, if you go anywhere on the planet and drill about four kilometers down, on average, the rock itself gets so hot that it can boil water. And yet geothermal currently accounts for less than 1% of the world’s energy production. Why? It’s partly because, except in a few select areas, it’s just too hard to drill deep enough and extensively enough to get good returns. But there’s new tech in the works. Quaise Energy is developing something called a millimeter-wave drill. It uses a beam of energy rather than a drill-bit to vaporize rock. They claim it can reach up to 20 kilometers down, where the rock is a blistering 500 Celsius. Combine that with a few tricks engineers learned from the fracking boom and we might be able to vastly increase geothermal’s share.

Source: Clean Air Task Force

2.  Going nuclear. And if the Earth itself isn’t hot enough, maybe a little nuclear fuel can help. This April, Anthropocene did a fascinating article on Deep Fission, a Berkeley-based company that’s proposed what they’re calling “assisted geothermal.” Namely, putting small nuclear fission reactors kilometers underground. These reactors would be comparatively tiny, each sitting snugly in a water-filled borehole only 75 centimeters wide (that’s smaller than the front door of a house). The advantage to doing this would be that, hidden away so deep, we could make the Earth itself function as the reactor’s container, heatsink, and radiation-shield (and possible hideaway for any waste), all in one. No expensive, giant, Simpsons-style concrete building needed.

3.  Filling up on gas. In addition to heat, another thing the deep Earth may have in abundance is hydrogen—if we can figure out how to get to it. In the last decade or so, scientists have realized that natural chemical reactions between water and certain types of iron-rich rock tens of kilometers down might be continually producing huge quantities of this gas (which we can use as carbon-free fuel for trucks or ships). There’s just one problem: scientists still need to figure out where exactly it forms, where it collects, and, importantly, how to drill down and retrieve it. But if they do, we may be sitting on thousands of years worth of supplies.

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Going Up

1.  Scraping the sky. Let’s talk about wind energy. It turns out that the higher you get off the ground, the stronger and more consistent winds tend to be (partly thanks to there being less stuff, like trees and buildings, to slow things down). And developers have been chasing these super-productive winds. In 2023, the average offshore wind turbine was already a whopping 124 meters at its rotor—roughly the height of a 30-story building. And that number’s been growing about 6% each year. But that might be puny compared to one turbine currently being constructed in Brandenburg, Germany, which would stand 300 meters at its rotor. Put next to the 95-story Shard tower in London, the top of its blades would nearly reach the top!

Source: Bloomberg New Energy Finance

2.  Slipping the surly bonds of Earth. But if we really want to reach new heights, perhaps the answer is to leave the ground altogether. Airborne wind energy technologies (which use kites or other aircraft either equipped with their own turbines or which can pull tethers on the ground) are designed to reach at least 800 meters off the ground, with some targeting as high as two kilometers or more. While tech is still largely only found as (pun unintended) pilot projects, airborne tech would need significantly less raw material and be easier to set-up than grounded wind energy. And it could be a real powerhouse. One assessment found it had the potential to produce as much as half the electricity the world uses in a year. 

2.  Knocking on Heaven’s door. And yet, we can go even higher still. If you go all the way up to the edge of space, the sun shines more than ten times as intensely on average than on the ground. Using solar panels shot into orbit, a single space-based solar energy satellite could laser beam as much power down to Earth as an entire nuclear plant. There’s still a lot to figure out, but the idea’s captured the imagination of engineers all around the world. Last year Caltech wrapped up a technological test run while both the European Union and China have announced plans for their own test runs.

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What To Keep An Eye On

1. China and other competitors. With the new Trump administration, with its slashed science budgets and apparent ire towards green energy in particular, the U.S. seems to have ceded its influence over the global market. In the meantime, China and the EU have been happy to forge ahead, with China in particular now making up a third of the world’s clean energy investment. If there are new breakthroughs, they may not be coming from the USA.

 2. The price tag. Any new technology is going to have to compete with existing wind and solar technologies, and these are continuing to drop in price year over year. Wind in particular has become cheaper than fossil fuels in all major markets. No matter how cool any given technology is, it’ll either need to compete on price or offer something current tech doesn’t have if it’s going to survive on the market.

3. Diving instead of digging. We’ve explored ways to harness energy from the earth and sky, but what about the ocean as well? On the clean energy side of things, a technology known as ocean thermal energy conversion uses a combination of warm, surface water and cold, deep ocean water to drive turbines to provide carbon-free energy, for instance. Meanwhile some fossil fuel researchers are eyeing frozen methane deposits found scattered across the ocean floor as well. Maybe the deep ocean will be the next place clean vs. carbon-based energy dukes it out.

Top image ©Anthropocene Magazine