Empirically Yours

Clean Energy Deep in the Earth


Sounds too good to be true, doesn’t it? But what if there is a way to just ditch the coal and switch over the turbines to hot water from the ground?

Quaise Energy, a startup company that emerged from MIT recently, has persuaded venture capitalists that it has devised a way to spin the turbines in typical coal plants by using extremely hot water pumped from holes drilled miles deep into the Earth’s crust. If we are to drastically reduce our dependence on CO2-generating fossil fuels, this sounds interesting. Here’s their pitch, as I understand it:

The plan is to use conventional drilling methods to go down a mile or two but then to go very deep by using very high-power millimeter wave energy made in a gyrotron. I think of this device as a distant cousin to a home microwave oven hooked up to a maser, which is a distant cousin of the more familiar laser. This form of energy can be focused into a beam so that it will vaporize rocks and make a miles-deep hole, forming a tube with vitrified walls. Paul Woskov, a research engineer at MIT’s Plasma Science and Fusion Center, realized he was onto something when he accidentally used this method to burn a hole in the wall of his lab.

Quaise believes it is feasible to drill much deeper than conventional steel pipe-based methods and reach depths of 10 to 15 miles. At these depths, the rock is quite hot, usefully hot: 500 to 1,000 degrees Celsius. Quaise says that after drilling, inject cold water down (in one pipe) and extremely hot water would come up to the surface (in another pipe). They speculate that (eventually) these wells can be drilled in only a few months and each well could generate 50 to perhaps 100 megawatts of recoverable energy.

At that rate, a few such wells could completely substitute for coal or natural gas in even a large generation plant that can produce up to a billion megawatts of power.

Imagine, if hot water could substitute for coal or gas in a typical electricity generating plant, it would mean that the existing turbines, the generators, the grid hook-up and the jobs could all stay. If there were no fossil fuels, there’s no need for carbon capture and sequestration, and no toxic ash accumulates. Quaise estimates that the wholesale electricity price from such a refueled plant would be 1 to 3 cents per kilowatt hour, compared to coal’s 3 cents per hour.

Rock hot enough to rejuvenate a coal or gas plant is everywhere under the surface of our planet if you simply go deep enough. This approach to geothermal energy is like wind and solar energy because it’s available to people everywhere, it’s carbon-free, renewable and scalable. Unlike wind and solar, geothermal ought to provide continuous, uninterrupted energy like today’s nuclear fission plants, but with no radioactive waste. Indeed, the heat in the Earth’s crust is itself derived from slow fission of mildly radioactive minerals. Who knew we’re all sitting on top of a benign fission reactor we call Earth?

Quaise Energy is a development-phase start-up company, not a government project, and they are forthright about the challenges they face. Can they really drill to depths of 10 to 15 miles if that’s what it takes? Will the heat source remain stable? Can they actually deliver useful amounts of super-hot water back up to a turbine? What will the lifetime of the entire system be?

Quaise admits these are challenges, but they believe they will complete a prototype of the drilling machines within two years, and in two more years dig miles-deep boreholes, and finally build or retrofit a fossil-fueled power plant by 2028.

Conventional renewable energy sources like hydroelectric, wind and solar are unable to scale to the amounts that will be needed by about 2050, or about 20 terawatts per year (one terawatt is 1 trillion watts). Today the U.S. consumes about 4 terawatt hours of electricity per year, but as we electrify more industry and transportation, the need for electricity could increase fivefold by 2050.

More conventional geothermal energy already exists, where near-surface water heated by geysers or volcanic activity makes steam to run generators. These plants are usually located near geologic faults or volcanoes. The oil and gas industry is getting interested in geothermal energy since they have a large workforce with the relevant skills. While helpful, the amount of energy recoverable from surface-level geothermal sources is limited by how rare these sites are around the world.

To me, a fundamental attraction of geothermal power, if it is successful, is that it ought to lead to a reinvention of how we generate electricity, shifting the rewards away from today’s fossil fuel establishment and institutions with vastly less geopolitics. How would Vlad the Invader pay for his next military adventure if Russia had no customers for its oil and gas?

Richard Gelinas, Ph.D., whose early work earned a Nobel prize, is a senior research scientist at the Institute for Systems Biology. He lives in Lakebay.

Links to additional sources of information on Quaise Energy and geothermal energy.