Geothermal's path to relevance: cheap drilling

Cheap drilling would be a large boon for geothermal, considering the cost of surveying&#x2F;exploring&#x2F;drilling is &gt; 50% of the cost of the development of a geothermal site.<p>I don&#x27;t understand the articles goal of 300C target, though. While some types of geothermal plants do require temperatures that high, binary cycle power plants can use lower temperatures (130C) [1], which seems to open up more area for geothermal development since we expect most gradients between the surface and bottom of the crust to be ~2.5-3.1C &#x2F; 100M. A lower temperature requirement would in turn allow you to drill less deep, which could consequently also decrease drilling costs.<p>Another thing the article doesn&#x27;t mention: another interesting approach (aside from improving the technology, like drill bits) is with financing innovation. There have been &#x2F; are government programs to de-risk the exploration&#x2F;drilling cost by reimbursing the costs of drilling (80% for failed wells, for example) which also likely adds well data that could better characterize the underlying geothermal resources in regions (which would allow more accurate future development).<p>Really glad to see a deeper dive on geothermal though; its non-intermittency is a valuable characteristic separating it from other renewables that we&#x27;re currently favoring (solar&#x2F;wind). Because we generally break down energy generation to LCOE, it omits advantages like uptime of the renewable resource.<p>[1] <a href="https:&#x2F;&#x2F;www.energy.gov&#x2F;eere&#x2F;geothermal&#x2F;electricity-generation" rel="nofollow">https:&#x2F;&#x2F;www.energy.gov&#x2F;eere&#x2F;geothermal&#x2F;electricity-generatio...</a>

Are ground-source heatpumps considered &#x27;geothermal&#x27;?<p>Its much less sexy than a giant plant connected to a magma stream, but if we made these routine for all new suburban constructions, alongside passivhaus standards, we could eliminate residential fossil fuel connections for huge sections of the Western world.<p>Like another commenter mentioned, we could even have communal systems for individual streets, drilled beneath roads, to service townhouses and apartment blocks.<p>You can run the ground-source for heating and cooling, alongside a single wall-mounted air conditioner for dehumidification in the summer.

I live in Ithaca, and Cornell is about to start drilling a test borehole in the coming year. Once the borehole is completed and some tests made, they&#x27;ll drill a pair of production boreholes about 10,000ft deep.<p>The goal is to pump water down one, and extract it from the other borehole and then use a heat exchanger to pull the anticipated 160F to 180F temperature to provide heat to the entirety of the campus.<p>It&#x27;s similar to the University&#x27;s Lake Source Cooling system, which they use the naturally cold water temperature of the local Cayuga lake. At the 250&#x27; depth they draw the water in, it&#x27;s a constant 39F year-round. The cooling system is used to provide chilled water to all the buildings, and a few thousand homes, removing the need for standard air conditioners.<p>The Lake Source Cooling system has saved the university 20 million Kwh a year, an 85% reduction in power usage, since it was made in 2000. It&#x27;s hoped that the Earth Source Heat project will have the same kind of impact on the energy necessary for heating.<p>There are a lot of unknowns. Nobody has drilled a borehole so deep in this area before because there hasn&#x27;t been a reason to do it before.<p>[1] <a href="https:&#x2F;&#x2F;earthsourceheat.cornell.edu" rel="nofollow">https:&#x2F;&#x2F;earthsourceheat.cornell.edu</a> [2] <a href="https:&#x2F;&#x2F;fcs.cornell.edu&#x2F;departments&#x2F;energy-sustainability&#x2F;utilities&#x2F;cooling-home&#x2F;cooling-production-home&#x2F;lake-source-cooling-home&#x2F;how-lake-source-cooling-works" rel="nofollow">https:&#x2F;&#x2F;fcs.cornell.edu&#x2F;departments&#x2F;energy-sustainability&#x2F;ut...</a> [3] <a href="https:&#x2F;&#x2F;fcs.cornell.edu&#x2F;departments&#x2F;energy-sustainability&#x2F;utilities&#x2F;cooling-home&#x2F;cooling-production-home&#x2F;lake-source-cooling" rel="nofollow">https:&#x2F;&#x2F;fcs.cornell.edu&#x2F;departments&#x2F;energy-sustainability&#x2F;ut...</a>

Drilling cost is usually estimated as ~depth^2.<p>So, a 1km geothermal well? Break even, and you are limited to only a few places in the world.<p>A 5km geothermal well (needed for broad power availability)? 25x the cost...<p>So, sure, if you can get a 25x cost reduction in an already cutthroat industry, all power to you (no pun intended).

From the article: <i>Traditional geothermal wells target rare hydrothermal resources</i><p>Florida geothermal systems pull cool water from the aquifer, use it for A&#x2F;C and return it via a 2nd well. They&#x27;re about the only wells that water management districts will rubberstamp.<p>Geothermal cooling (in FL) becomes cost efficient above 15k-20k sq ft (based on my 2010s exp). That led me to an idea that neighborhoods could be cooled by small geothermal utilities. I wonder about increased heat energy down the line but I&#x27;ve seen a doz+ chillers work efficiently, from one 4&quot; well. On a larger scale, downstream heat buildup might be mitigated via a more distributed water system.

I am always a bit bearish on geothermal, because the energy flow through the earths crust is just so damn low. Per surface area, it is about 3 orders of magnitude less than solar irradiation, which means that the circumstances in which it really makes sense to exploit geothermal are those where you can effectively harvest flows from a much larger area, most likely due to convection of water or magma. My understanding is that it will never make sense for e.g. every house in a suburban setting to have their own heat probe and pull energy from that, they will be competing with their neighbors and effective energy gained will be negligible.

I was wondering if extracting geothermal energy could prematurely cool the Earth&#x27;s core.<p>Here&#x27;s a few answers:<p><a href="https:&#x2F;&#x2F;earthscience.stackexchange.com&#x2F;questions&#x2F;2302&#x2F;can-the-overuse-of-geothermal-energy-become-an-environmental-concern" rel="nofollow">https:&#x2F;&#x2F;earthscience.stackexchange.com&#x2F;questions&#x2F;2302&#x2F;can-th...</a>

This seems to be a sequel to <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=27775927" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=27775927</a><p>i.e. &quot;Is Geothermal Really Going to be a Thing?&quot; <a href="https:&#x2F;&#x2F;austinvernon.site&#x2F;blog&#x2F;geothermal.html" rel="nofollow">https:&#x2F;&#x2F;austinvernon.site&#x2F;blog&#x2F;geothermal.html</a>

Technology aside, rollout of such technology in Europe would be sabotated by russkies in the same way shale gas&#x2F;oil was (sadly successfully). This must be accounted and planned for. Fossil wholesaler of the Siberia does not want you to be gass&#x2F;oil independant.

Could there be a completely novel way of digging ? Maybe with Laser ? maybe a chemical process ? or a high pressure water cutter ? what if you could cut small block of stone in the hole without using so much energy reducing it to sand ?

Anecdotally, I looked into this when building our house, and can confirm - the bulk of costs was drilling, and it was expensive. When I did the math at the time, the cost of ground source heat pump over air source heat pump was several times more. Energy bills would be much less, but the payoff was around 20 years, assuming the unit lasted that long.

I wonder if Elon Musk would be interested in getting into this area. Granted SpaceX is more exciting -- this would be, comparatively, the boring company.