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Comment by hamilyon2 | Hacker News Reader

Comparing the problem at hand to other problems isn't going to make it tiny little bit less.

Even coal doesn't necessarily produce waste. It is our choice not to capture waste/harmful byproducts makes it so dangerous and "bad".

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Coal necessarily produces waste. It's an inviolable law of thermodynamics. Burning coal cannot produce enough energy to capture the waste products of burning coal.

Solar, on the other hand, can account for its own waste stream, even in energy terms, because the source of its energy comes from outside the system boundary.

No, it's very much feasible to cool the CO2 down to ambient temperature and separate it from the nitrogen, in preparation for sequestering it.

Now, without setting a net-0 carbon dioxide emissions goal, which isn't feasible without salable atmospheric carbon dioxide capturing, there won't be enough incentives to capture the exhaust co2 from a coal power plant.

I'm no fan of coal, but to be fair "integrated gasification combined cycle" plants [1] are way cleaner than conventional coal plants without violating laws of thermodynamics. You can drastically reduce emissions of e.g. heavy metals, sulphur oxides, carbon monoxide, and particulate matter, while being amenable to pre-combustion carbon capture.

[1]: https://en.wikipedia.org/wiki/Integrated_gasification_combin...

This is largely theoretical. The Kemper demo plant is a disaster in terms of massive cost overruns, many years of delays, and inconsequential net energy production. They ultimately abandoned the project.

I think that is the point they are making though. PV is still harmful to the environment in its current form but it isn't as bad as Coal is in its current form.

Both can be clean and zero-impact however in practice neither are.

PV is still "cleaner" than coal in its current form but neither are truly clean. It's the significant lesser of two evils until we make the effort to go net-zero.

No energy source will ever be purely clean. PV is several orders of magnitude less polluting than Coal.

How much cleaner is solar thermal than PV? I assume that depends on how dirty it is to produce the metal for the turbines (steam or air, in the case of solar towers).

All of these are very clean compared to coal.

Solar thermal is vulnerable to attacks from media articles about dead birds and the fact that some of them have to burn natural gas to start the plant in the morning. You can find both varieties of article courtesy of Fox News:

https://www.foxnews.com/politics/taxpayer-backed-solar-plant...

https://www.foxnews.com/science/emerging-solar-plants-scorch...

Solar thermal does have one huge advantage over PV: the plants contain their own short-term energy storage and keep running well after dark. Unfortunately due to market forces solar thermal is currently dead in America. All planned plants have been canceled.

Not clean enough to offset the higher cost per kWh currently. The PV price collapse kneecapped several alternative power sources. Plus solar thermal requires big centralized power plants, where PV can be distributed easily.

Solar thermal has a larger footprint, considering turbines and such, but would tend to be more easily recyclable out of the waste stream.

Not sure what you mean there. Everything I've read about "clean" coal seemed like greenwashing to me.

Is there a working example of any of these perceived waste capture mechanisms? How much more expensive are they to operate?

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