Great News for Hot Dry Rock

Becoming a climate policy analyst is one of the world's most depressing careers because in the midst of the probable global collapse there is widespread apathy and lack of concern about the problem in Canada and most of the rest of the world, and the debate centers around the impact that saving future generations lives means in dollars. It is funny, when my generation has grandchildren and someone put a gun to their grandkid's head, people would be willing to pay a large ransom in order to save them, but if it means having 3% less money than one would have had otherwise in 2050... well... Yawn. It is very interesting how human evolution makes us so ill-suited to deal with issues of long-term environmental sustainability as evolution favoured those who could get the most resources compared to those who could manage resources for the long-term.

However, then there are somedays where even my most cynical jaded side says that we might just be able to solve this problem (Politically, I mean, the technological solutions to climate change are quite easy, they just cost slightly more money than the status quo) . One thing that has made climate action difficult is that much of it depends on non-conventional renewables such as wind and solar which face market barrier of intermittency and transmission constraints in the case of wind and cost and intermittency in the case of solar (See my upcoming post on Solar Baseload) make renewables a less attractive option for utilities as their penetration level is restricted if not combined with backup plants or supergrids and seems to be limited to around 30% of electricity generated if we don't build continental grids (Another future post).

However, we need very substantial emissions reductions that go far beyond 30% (Another post). Therefore what we need is a carbon-free, baseload, dispachable electrical source. One option is nuclear but is essentially politically unacceptiable, and there are some concerns about the safety although all energy sources including wind and solar inflict casualities. This essentially leaves us with Hydro (Dams not run of the river which is not dispatchable), some natural gas and yes, geothermal. Hot Dry Rock Geothermal is my favourite as it is a vast resource that would provide enough energy for the world at least a 100 generations. What it essentially does is injects water or liquid carbon dioxide into hot granite up to several kilometers deep. However, this requires deep drilling of up to 10 kilometers which is expensive. A technology from Potter Drilling called hydrothermal spallation may to change that. What it essentially does is shoot hot water at rock in order to fracture it prior to the drill bit hitting it which reduces wear. This will cut the cost of drilling hot-dry rock geothermal wells in half. One issue with HDR is that the fields only last 20 to 30 years until they need a 300 year period to renew themselves.

Here is some info on the MIT study on Enhanced Geothermal Systems (the boring engineering term for Hot Dry Rock) from Wikipedia:

1. Resource Size: The MIT report calculated the United States total EGS resources from 3–10 km of depth to be over 13,000 zettajoules, of which over 200 ZJ would be extractable, with the potential to increase this to over 2,000 ZJ with technology improvements — sufficient to provide all the world's current energy needs for several millennia.^[5] The report found that total geothermal resources, including hydrothermal and geo-pressured resources, to equal 14,000 ZJ — or roughly 140,000 times the total U.S. annual primary energy use.
2. Development Potential: With a modest R&D investment of $1 billion over 15 years (or the cost of one coal power plant), the report estimated that 100 GWe (gigawatts of electricity) or more could be installed by 2050 in the United States. The report further found that the "recoverable" resource (that accessible with today's technology) to be between 1.2–12.2 TW for the conservative and moderate recovery scenarios respectively.
3. Cost: The report found that EGS could be capable of producing electricity for as low as 3.9 cents/kWh. EGS costs were found to be sensitive to four main factors: 1) Temperature of the resource, 2) Fluid flow through the system measured in liters/second, 3) Drilling Costs, and 4) Power conversion efficiency.