Google datacenters in Nevada to go full steam ahead with geothermal energy Google has signed a deal with NV Energy to help power its Nevada datacenters using geothermal energy under an arrangement the megacorp claims is more progressive than existing renewable energy contracts. The Mountain View-based biz described the agreement as a "clean energy partnership" with NV Energy, a subsidiary of …
Good news if their geothermal pilot is going to successfully scale up.
Bad news on the fuel cells. Methane fuel cells had a lot of promise to improve the conversion efficiency to electricity, but also be viable for on-site cogen in colder parts as all the waste heat is available to use as well. Shame they don't seem to be getting across the viability line.
Doesn't a gas turbine also create waste heat?
It's a lot more power-dense too, more reliable, cheaper, more available and fewer exotic materials. Not 'poisoned' by impure fuel either.
But, i'm struggling to find many figures on the efficiency of methane fuel cells. Google suggests 60%, which is definitely better, but not _that much_ better than gas turbines.
Geothermal, fine, so long as their next site isn't Yellowstone.. :P
Yes, but solid oxide fuel cells sit quietly** making electricity at 60% efficiency. It is (bypothetically) viable for onsite power and heat in a way that a combined cycle gas turbine is not.
Combined cycle, means you have a gas turbine and a steam turbine using the waste heat from the gas turbine. Just a gas turban is not very efficient. (Aside: I was expecting the Capstone turban-generators to become a thing, but they also seemed to fizzle out)
It's not really small, quiet or cheap in the way you could easily put it in 20' or 40' container to provide power and district heat for factories/offices/houses. While the efficiency is fairly good, the waste heat is mostly lost as it's usually uneconomic to pump lots of low grade heat long distances from a power station to the consumers.
Using waste heat when it is in the basement or in a container out the back of your campus is perfectly viable.
**except for the compressor pumping air into it.
By capstone turb[ine] do you mean this: https://www.capstonegreenenergy.com/products/capstone-microturbines/c1000s
It looks like a plain OCGT with CHP, which is exactly what I meant in my first reply. Lots of high quality waste heat if you can use it, but if you can't then it's only 33% efficient.
But it's so much cheaper and more reliable than a fuel cell that it out-competes them despite the efficiency.
I agree though, a fuel cell would be nice for residential use where noise is an issue. But why methane and not hydrogen?
Yes those Capstone turbines have been around for years. They are (superficially) simple, but they remain uneconomic.
Where I live, gas is 1/3 elect, so a Capstone@33% would make electricity at the same (buy) price as electricity.
Now here's where it gets interesting. I am (right now!) working on (solar) powering a factory, where we use ~100kW elec, and 300kW of gas for the ovens.
You get to see that Capstones would make the power and oven heating for 1/2 the price of both.
The catch is that solar payback is now only 2.2 years, and after that there is zero fuel cost. When we don't use it, we can sell the power. Capstone power would cost more than we can sell it for when we can't use the waste heat.
I might revisit the Capstone, but they would have to be a hell of a lot cheaper than they used to be.
I suspect they are a victim of US venture capitalist pricing: They price the product to "make a killing" and thus it is uneconomic, and they don't get much volume. In China, they would have built a huge factory, and priced them to sell.
The advantage methane FCs over Hydrogen is simply being able to drop straight into todays world, and get a big gain in efficiency.
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