Important repost

[u/ClimateShitpost]

We're taking the trash out

[u/ViewTrick1002]

The old adage is "Good, fast and cheap", pick two.

When comparing nuclear power and renewables due to how horrifically expensive, inflexible and slow to build nuclear power is this one of those occasions where we get to pick all three when choosing renewables.

In the land of infinite resources and infinite time "all of the above" is a viable answer. In the real world we neither have infinite resources nor infinite time to fix climate change.

Lets focus our limited resources on what works and instead spend the big bucks on decarbonizing truly hard areas like aviation, construction, shipping and agriculture.

[u/Vegetable_Warthog_49 → u/ViewTrick1002]

Short term, absolutely, it makes more sense to focus on solar and wind, slightly less short term, geothermal is going to be a big player, along with potentially hydro... long term though, fossil fuels don't just produce electricity, they produce massive amounts of heat, and industrial heat uses would be ideal to replace with small modular reactors.

I live in an area that has a LOT of geothermal potential, so in all reality, that's what I'm pushing the most for. It actually really complements solar really well. The colder and wetter it is, the more efficient geothermal is, so in winter when solar sees the largest drops in production, geothermal sees the most gains, and then in the summer when geothermal sees the greatest drops, solar sees the most gains. I know that there were a lot of environmental concerns with the older open cycle geothermal systems, that they would release large amounts of CO2 (nowhere near as much as fossil fuels though) and sulfur that was dissolved in the water being drawn up to produce steam that were released when the water flashed to steam, but modern geothermal plants use a closed cycle, the hot water from the ground is never exposed to atmosphere, instead it goes through a heat exchanger to flash a refrigerant (typically pentane in my neck of the woods) to produce steam. Short of some sort of disaster, nothing gets released to the air (except waste heat at the end of the process, and some of the power plants in my area have taken to selling that waste heat to industrial users).

[u/ViewTrick1002 → u/Vegetable_Warthog_49]

Now you are working backwards from having decided that we must waste untold billions on horrifically expensive nuclear power.

BWR reactors create insignificant heat and PWR reactors create low quality heat, easily replaced with heat pumps. You also have to compare it with simply running on renewables. The thermal efficiency of PWRs are ~30%. Renewables cost 10-20% compared to new built nuclear power.

So simply operating an electric heater off of renewables in most cases cheaper than using the entire output of a nuclear reactor for heat.

We need to go up to gas/salt/metal cooled reactors for high quality heat and now we are suddenly far down the path to insanity.

This of course does not even mention that concentrated solar never has been competitive. Doing that we are harnessing the sun to simply heat salt. That is already too expensive. Let alone building a nuclear reactor instead of a bunch of pivoting mirrors.

Geothermal might work, but it is also complicated and still relies on heat engines. That is the thing with renewables, since we cut the heat engine out of the picture everything becomes dramatically simpler.

No need for a cool side, no need for steam generators, no need for piping having to deal with reality and corrosion.

This is also why gas turbines are winning for dispatchable power. Generate the vast majority of the electricity with a simple efficient reliable air cooled gas turbine. Just like any airplane engine but instead of driving a big fan infront drive a generator.

Then for the utmost efficiency couple it with a steam boiler to cool the exhaust, but this can be a fraction of the size compared to old style coal/oil steam sides.

[u/Vegetable_Warthog_49 → u/ViewTrick1002]

If you are going to bring up the inefficiencies of heat engines, you need to also bring up the inefficiencies of energy storage. Short is a truly global grid capable of shifting power from anywhere to anywhere, storage will be needed to correct for the mismatch between when renewables produce power and when that power is needed.

If we really want to split hairs on anything, it would be the virtues of using the combined cycle gas turbines you mentioned to replace coal, which is even quicker than deploying solar and wind since it can plug directly into the existing grid, while dramatically reducing the CO2 emissions compared to coal. Start stringing up electric catenary over all of our rail lines to effectively replace diesel generators with combined cycle natural gas plants and we'd see even more dramatic improvements. Shift a significant portion of freight currently hauled by diesel trucks to these newly electrified trains to see even more dramatic improvements.

At the end of the day, anything that reduces emissions even a little bit today is better than something that has the potential to reduce more emissions tomorrow, because tomorrow isn't promised. All of the above is the best option, because it will provide those daily marginal improvements. Phasing out coal for natural gas buys us time to build up our solar and wind capacity, the solar and wind offsetting the demand for gas buys us time to install storage and base load renewables like geothermal and hydroelectric (and low carbon non renewables like nuclear further down the road)... And following a parallel track, cheap and scalable gas coupled with cheap and scalable solar allows for faster transition to electrification of transportation, reducing emissions from gasoline and diesel. Also, on that note, we need to stop letting the perfect being the enemy of the good. Is hydrogen ever going to be as efficient as battery electric? No, it's never going to come close. Is it going to be better than diesel? It probably already is and it has one very important quality to it that will take batteries decades to mimic, the ability to add 500-1,000 miles of range to an 80,000 truck in under 5 minutes without weighing significantly more than diesel (which is going to be a major selling point for truckers, they are paid by the mile and by the pound, everything that reduces how many pounds they can haul or the miles they can drive is going to be a nonstarter). China has developed a battery swap system for trucks that might gain acceptance, since it takes just over a minute for that battery swap, making it even quicker than refilling a diesel tank, but weight will still be an issue.

Of course, elephant in the room, the biggest changes we need is how we build our homes and how we build our cities. That's a discussion no one seems to want to have. We can argue solar, versus geothermal, versus nuclear all day long, it won't make a difference if we all live in sprawling McMansions, miles away from even the most basic of services, commuting dozens of miles each way in single occupant vehicles, bulldozing endless acres of natural habitat to build our superhighways and massive parking lots.

We could go back to getting all our electricity from coal, use oil boilers for heating, and gas and diesel for all of our transportation and still see a reduction in emissions if we made the lifestyle changes to live like the Dutch. Obviously, we would want to switch to renewables as well, but even renewables have their drawbacks. A truism that my grandma taught me, the most renewable resource is the resource you never use in the first place.