'Breakthrough' geothermal tech produces 3.5 megawatts of carbon-free power | Hacker News Reader

'Breakthrough' geothermal tech produces 3.5 megawatts of carbon-free power

engadget.com

31 pointsSignez31 comments

Here's an excellent podcast that goes in depth on the potential of enhanced geothermal of the same sort described above. Essentially they drill two holes and then frack the rock between them. This makes it possible to setup geothermal in many more places. https://api.substack.com/feed/podcast/74977669/bb712d64d007e...

For reference:

3.5MW is a single largish wind turbine.

PV solar is ~200W/m2, so 17,500 square meters of solar panels.

A single nuclear reactor is commonly >1GW (1,000MW).

The number of megawatts doesn't really matter - what matters is the cost per megawatt.

If it is cost competitive, then millions of these sites can be installed to get as much power as needed.

I would argue the lower amount from fossil fuel sources matters most. Cost per megawatt should be secondary since the costs of adapting to a warming planet in the future will swamp any marginal per unit costs today.

This would be a carbon free option for places where the wind doesn’t blow reliably, the sun doesn’t shine enough, and either doesn’t need the scale of a nuclear reactor or needs a solution quicker than the long lead times for nuclear plants.

Notice how they carefully omitted the word "fracking" and went with "injecting rocks with chemicals to create fractures".

Cool. Wind turbines are unreliable though

Depends strongly on location as do the other sources. Some locations have both strong and consistent wind. There is no one size fits all.

In practice, the amount of power you can "rely" on a wind farm to produce is so small as to be almost useless from a grid planning POV. Yes, dispatchable generation can have unplanned outages too. But the differences in those probabilities and the amount of power you can plan on getting is so vastly different that they just aren't in the same class.

In practice, Altamont Pass is still one of the largest concentrations of wind turbines in the world, with a capacity of 576 megawatts, producing about 125MW on average and 1.1 terawatt-hours yearly.

As long as it reduces the need to ramp up fossil fuel plants, it's a win.

Ironic you put it that way, since it actually increases the need to ramp up and down dispatchable generation. Average is literally a smoothing function. If you look at an hourly output graph of wind farms it's often hopelessly spiky.

IMO VRE farms should be required to use energy storage to establish some semblance of control of their output. Instead of being allowed to simply dump whatever energy happens to show up and making it everyone else's problem. It would reduce emissions too since gas peakers emit less in steady state.

And they are usually connected to a larger grid. If you cover an area large enough, the numbers will tend to be more constant.

The are already developing much larger plant in Utah

(Hard to say how much larger as the tech journalists only use "households powered" units)

They specified a conversion rate of 1 MW : 750 "homes". So if the Utah project can power 750 "homes", that's 400 MW.

It's common to use a conversion rate of 1.4 kW for a home, so that's really close to the 1MW == 750 homes equation.

I know you're trying to compare geothermal to these sources, but I'm now in shock from the comparison between solar and wind. 1 large wind turbine (3MW) is equivalent to 7,500 x 400W solar panels. That's mind blowing.

Well... A large wind turbine is... a very large thing. I was very surprised the first time I saw one up close - I thought they looked small from the distance, but they kept getting bigger and bigger while I was still quite far.

yes, that too. I think another mistake people make is assuming they're all sort of the same size. But the offshore ones are immense.

The W rating of wind turbines is misleading, because it's the max output, which is very rarely attained. The real average output is usually just 10 to 20%.

Nuclear can typically deliver 90% of its max output.

> Nuclear can typically deliver 90% of its max output.

Even more than 100% rated power, if you allow it to Chernobyl itself.

They can also use power in certain situations. If the wind is especially weak, they're usually kept spinning using electricity because it takes more wind to start one from a stop than to keep it going.

I've seen one that's sometimes a net-loser on days where the other turbines are standing still. (based on what a landowner said, from the stats the operator gives him)

Geothermal wells often cool down and become ineffectual with time.

A starting temperature of just 180C doesn't sound very promising either. Normally the higher the temperature the more energy you can extract and the faster you can extract it with a given amount of water/turbines/pipes.

Depends where. Some in New Zealand have been going since IIRC the 1950s

Some are quite a lot larger than this one too - 160MW ish.

https://en.m.wikipedia.org/wiki/Geothermal_power_in_New_Zeal...

I'm pretty sure the individual wells have been redrilled a few times in that time though, even if a site has been operating for 70 years?

They should call those "volcanothermal" energy. Sounds cooler.

Can they be conserved for a longer time if they are used for a fraction of the day, like night?

lava monsters do not sleep

Yes. The 'expiry' of a well is pretty much entirely proportional to how much energy you extract from it.

However, you can normally drill a new well a few hundred yards away and start afresh - so really it becomes a matter of how cheaply you can drill wells. And the US is a leader in well drilling, so I think could do it pretty cost competitively.

Or drill horizontal, from your current well.

oh my frack

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