Using steam to produce electricity or perform work via steam turbines has been a thing for a very long time. Today it is still exceedingly common to use steam in this manner, with said steam generated either by burning something (e.g. coal, wood), by using spicy rocks (nuclear fission) or from stored thermal energy (e.g. molten salt). That said, today we don’t use steam in the same way any more as in the 19th century, with e.g. supercritical and pressurized loops allowing for far higher efficiencies. As covered in a recent video by [Ryan Inis], a more recent alternative to using water is supercritical carbon dioxide (CO2), which could boost the thermal efficiency even further.
In the video [Ryan Inis] goes over the basics of what the supercritical fluid state of CO2 is, which occurs once the critical point is reached at 31°C and 83.8 bar (8.38 MPa). When used as a working fluid in a thermal power plant, this offers a number of potential advantages, such as the higher density requiring smaller turbine blades, and the potential for higher heat extraction. This is also seen with e.g. the shift from boiling to pressurized water loops in BWR & PWR nuclear plants, and in gas- and salt-cooled reactors that can reach far higher efficiencies, as in e.g. the HTR-PM and MSRs.
In a 2019 article in Power the author goes over some of the details, including the different power cycles using this supercritical fluid, such as various Brayton cycles (some with extra energy recovery) and the Allam cycle. Of course, there is no such thing as a free lunch, with corrosion issues still being worked out, and despite the claims made in the video, erosion is also an issue with supercritical CO2 as working fluid. That said, it’s in many ways less of an engineering issue than supercritical steam generators due to the far more extreme critical point parameters of water.
If these issues can be overcome, it could provide some interesting efficiency boosts for thermal plants, with the caveat that likely nobody is going to retrofit existing plants, supercritical steam (coal) plants already exist and new nuclear plant designs are increasingly moving towards gas, salt and even liquid metal coolants, though secondary coolant loops (following the typical steam generator) could conceivably use CO2 instead of water where appropriate.
Must have read my mind. The comments to that video are interesting as well.
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blockquote>That said, today we don’t use steam in the same way any more as in the 19th century, with e.g. supercritical and pressurized loops allowing for far higher efficiencies.<\blockquote>
This sentence isn’t clear. Did we use supercritical and pressurised loops in 19th century or didn’t we. Do we today. I guess a sentence with “unlike” somewhere at the beginning may better convey the message.
So long as it is cheaper to not upgrade systems, they will not be upgraded.
or any downtime for that matter.
This would be beneficial for newly built power plants.
Finally some numbers @11:20 Efficiency of a steam turbine is apparently 40% and with supercritical CO2 this is expected to be increased to 50% and that is quite significant.
the local old coal fired powerplant here is 47% efficient making eletricity, it was the worlds best when it was build, but that is almost 30 years ago
This article is part of the multi million dollar effort of the fossil fuel industry trying to change how we think of CO2. Much like the stories where they talk about how there are other worse green house gasses or that ‘we need CO2’ messages on social media. At the end of the day, capturing sun energy and using that to heat CO2 to run a turbine is stupid. The less steps in the process the less losses. Battery tech is accelerating thanks to the universities around the world as is solar and wind / wave. If they spent one years of subsidies to nuclear and oil on green power generation the UK would be 100% self sufficient protecting us from would be dictators in the white house or the oil mafia of Russia. But the right hates that because they can’t embezzle oil subsidies.
brb, gonna go nuke some popcorn real quick
“If they spent one years of subsidies to nuclear and oil on green power generation the UK would be 100% self sufficient”
This is objectively false.
Conversely if all the green subsidies went to nuclear..
Green energy has been well proven to become self-sufficient under market terms after initial subsidies, nuclear power only ever exists at the treat of the taxpayer.
A nuclear plant can last for many decades, while wind and solar have to be constantly replaced and maintained.
Not really true on either count, Solar installs can and frequently have lasted longer than the nuclear power plants usual expected lifespan as solar is usually fit and forget in large part. Solar often don’t last that long only because the tech has been improving so massively its worth investing to replace the old with the new panels with 15% better efficiency (or maybe even more if you did manage to wait 20 odd years) and likely a much better expected degradation curve on that really good and already set up for solar location.
And wind is similar place, though does always require maintenance much of the replacements in practice have been because its easier and cheaper to replace a smaller turbine with one 3 times bigger than it is to get the the permissions to build a new farm of them somewhere else… Though Wind does come into another problem that has cost/benefits as they have scaled up so much – the tip speed and thus erosion of the blades gets worse on these larger turbines, but with larger catchment area they work in a wider wind speed and also produce more electricity overall.
Don’t get me wrong though Nuclear power is great, but it really isn’t maintenance free if you want to do it safely, and the expected lifespan and maintenance costs of a reactor is generally not very much if at all in their favour compared to many of the renewable options. The thing that really sells nuclear power as worth the investment (if you can get it) is the predictable and controllable nature of its output.
haha i’m gonna go at this from the opposite angle of foldi-one
everything takes a ton of maintenance, even solar, wind, and nuclear
It all comes down to power density.
It takes hundreds of wind turbines or thousands of solar panels in combination with huge batteries to replace one nuclear power plant. One cold winter can freeze an entire fleet of wind turbines. One show storm can cover an entire field of solar panels. Even a plain crash won’t stop a nuclear power plant.
You can build two or more nuclear reactors on the same spot if you want to save on costs.