How green is blue hydrogen?
onlinelibrary.wiley.com
onlinelibrary.wiley.com
I think carbon capture is a valid approach for power plants and will be effective if done well.
What's not effective are these carbon compensation schemes, where you can pay a few pennies to have somebody sign a paper that they'll let a tree grow for another year, as if that would somehow compensate the release of fossil CO2. It's no better than an indulgence letter you bought from from the Pope.
TL; DW: planting 20 million trees would equal roughly the CO2 emissions of the USA for half a day.
The optimum would be to bury the harvested forest in a deep, deep hole, where light and water can't get, and seal it there permanently.
Imagine you have a bathtub with a closed drain and an open faucet. It starts to fill with water. This proposal is an equivalent of putting a bucket in that bathtub, filling it with water, and then putting that bucket on the floor. Yes, it took some water out. No, it doesn't matter, because the faucet is still open and more water keeps flowing.
The solutions that matter are ones that involve reducing emissions - at the very least, making them grow linearly instead of exponentially - and those that continuously remove carbon from the air. With forests, that means continuously growing them, cutting them down, and burying the wood where it can't decompose.
Every single power plant carbon capture attempt has been a failure, at least as far as I know. If there has ever been a success, I'd love to hear about it to give me some hope
But the biggest failures are all the plants that were announced with CCS and then built without. (Or announced that they'd be retrofitted with CCS which never happened.)
https://www.carboncommentary.com/blog/2021/7/30/the-struggle...
(Question for dang...)
Just build an assembly line for small modular reactors.
What companies like about it is it’s a thermal power plant so they can run it 24/7 by burning fossil fuels while selling “green” power.
There's a recent proof of concept plant using bauxite particles instead of a liquid or gas as the thermal mass. It should help quite a bit in cost and reliability. Rather than a bunch of high-pressure tubing for liquid salts and such, it works with grain lifts.
One nice thing about using solar thermal for hydrolysis is that much hotter water is much easier to split with electricity. So if you use some of the heat mass to heat water steam to 600 or 700 C, you can use a lot less of the power post-conversion.
A CO2 heat loop might be more efficient than a water steam one, so if the plant isn't dedicated to hydrolysis it might end up with two generation loops.
Net result, PV + batteries simply cost less for more reliable power unless you have backup fossil fuel for heat. If the goal was say 80% reduction of fossil fuels then concentrated solar is ok, it just doesn’t really work for a zero emissions grid because you need just as much storage somewhere else in the system.
Heat mass plants provide storage as part of their electric generation process. That's the whole purpose of transferring the heat into the heat mass rather than directly to the turbine loop.
PV extracts more electrical energy per area of solar collector and it isn’t cost effective to clean them or currently to track the sun. Concentrating solar takes a larger hit when it skips either, which is just one of the reasons it’s not cost effective.
It's an interesting paper and I think a valuable contribution to the discussion. Though it should be noted that the authors make a lot of assumptions (naturally) and some of them are quite controversial. They consider three different methane leakage rates, which are probably a good range for what's happening in the US, but it's expected that some european sources have much lower rates. Their assumptions on CCS are more pessimistic compared to what other people expect, but you could argue compared to existing CCS projects they're actually optimistic.
Then there's a whole debate around GWP20 vs. GWP100, which is whether you look at the greenhouse effect of methane vs. co2 over 20 or 100 years. The authors prefer GWP20, which is not the mainstream climate science position, but they do some of their calculations also with GWP100.
tl;dr It's definitely worth a read and the authors make good points, but consider that other people see things differently.
The point here was to get things like cars and factories that use gas ready to use hydrogen instead, by making it abundant and supported. Then switch over to using solar panels and whatnot to synthesise the hydrogen. At no point in that story are the emissions of blue hydrogen an issue.
As plans go it is a pretty good one. I'd rather leave things up to market economics, but this is better than Europe collapsing because the oil gets cut off for 6 months.
They get the best of both worlds, appease the fossil fuel industry while having the appearance of doing the opposite to anyone who’s not paying attention.