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Is solar thermal energy with storage ready to replace coal-fired power?
- Retric 10y agoSolar thermal is terrible for electric power. Photovoltaic solar is vastly better as it provides more power, does not need direct sunlight, and costs less. The real reason Solar thermal is still a thing is they can burn fossil fuels and produce base load power, while pretending to be 'green'.
- Tuna-Fish 10y ago> Photovoltaic solar is vastly better as it provides more power, does not need direct sunlight, and costs less. And produces nothing during the night. The big reason for solar thermal is that you can store hot molten salt for the night, and use it to generate power when PV doesn't do anything.
- toomuchtodo 10y agoSo then it comes down to which is cheaper: having hot molten salt maintained on site, or dropping cargo containers full of lithium batteries on-prem to provide dispatchability for the facility. I argue batteries will get cheaper, faster, than trying to manage hot molten salt.
- nickff 10y agoManaging a hot molten salt pool is not as difficult as trying to deal with many lithium cells. You mention dropping cargo containers on site, but that is not the whole problem; you need to manufacture these containers and have a way of continuously monitoring the cells, either finding and isolating the 'bad' ones, or replacing whole containers. In addition, the molten salt will last far more cycles than the batteries, while costing less to replace and being simpler to service.
- toomuchtodo 10y agohttps://www.teslamotors.com/powerpack https://www.teslamotors.com/powerpack That's the benefit though, right? I can write Tesla a check and they can ship me an entire utility scale energy storage system by rail/truck multi-modal. I can't do that with molten salt.
- nickff 10y agoYou are vastly underestimating the cost and complexity of running this system at an affordable cost. You would end up with Tesla running the majority of your facility (by cost), and consequently would not be a competitive plant. Let's do some simple math: An average natural gas plant seems to be around 800MW, and we might assume that they are running somewhere around 1/2 capacity when there is not much solar irradiation (evening and night), giving us an average power level of 400MW. Wikipedia says that Lithium Ion cells have a specific energy of about 100-240 W.h/kg, and I'll assume that Tesla uses some good 200W.h/kg cells. If the plant has to run with no irradiation for 10 hours at half capacity, it needs 4000 MW.h of energy in batteries, which is 4000M/200 = 20Mkg of batteries not including any losses during discharge or wasted energy for cooling. 20 million kilograms of batteries would be very expensive to store and maintain; they would also take up a lot of containers. A 20' container is usually maxed out at about 20 tons, so you would need a thousand of them. The basic problem is that unlike molten salt, there are no economies of scale to be had with batteries or photovoltaic panels.
- Retric 10y agoThere is no need for Li-Ion for grid storage as weight is a non issue it's just a question of cost. Don't forget we ship train loads of coal across several states just to burn it.
- nickff 10y agoI mentioned weight to give some idea of the amount of batteries that would be required, and how many containers would be needed (as I was responding to a suggestion of using containerized batteries), not because the weight is a significant factor.
- SAI_Peregrinus 10y agoAlso, if molten salt is good enough and cheap enough as an energy storage solution you can take an efficiency hit and use PV solar to melt the salt electrically.
- Retric 10y agoActual real world solar thermal plants are a long way from 24/7. EX: https://en.wikipedia.org/wiki/Solar_Energy_Generating_Systems https://en.wikipedia.org/wiki/Solar_Energy_Generating_System... Capacity factor 21%. That's 7 hours a day for 5 days a week. A huge problem is any cloud cover prevents them from working, so unless your willing to burn something they become useless randomly. PS: Molton salt sounds cool, but it's horribly inefficient as you can only really use a small temperature range before it's to cold so you need crazy amounts of the stuff and can't ever let it cool. https://en.wikipedia.org/wiki/Carnot_cycle#Efficiency_of_real_heat_engines https://en.wikipedia.org/wiki/Carnot_cycle#Efficiency_of_rea...
- rgbrenner 10y agoThe Crescent Dunes facility has a capacity factor of 52%. It doesn't use any natural gas or other fossil fuels. And it's not affected by intermittent cloud cover. https://en.wikipedia.org/wiki/Crescent_Dunes_Solar_Energy_Project https://en.wikipedia.org/wiki/Crescent_Dunes_Solar_Energy_Pr... http://www.digitaltrends.com/cool-tech/peek-inside-nevada-solar-plant-247-power-molten-salt/ http://www.digitaltrends.com/cool-tech/peek-inside-nevada-so...
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- Retric 10y agoYea, add in molten salt and they can almost get apoximatky PV capacity factor just even more random due to slight cloud cover being such an issue. Though, you will note 52% still needs backup power all for the low low cost of 13.5 cents per kWh vs sub 4 cents per kWh for PV. You can get PV + storage for 24/7 operation for less than 13.5 cents. PS: Which is why most places gave up on molton salt in the first place and burning stuff is the real backup that you know actually works.
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- davedx 10y agoWhat are you talking about? How does solar thermal power involve burning fossil fuels?
- amock 10y agoIt doesn't have to, but see https://en.wikipedia.org/wiki/Ivanpah_Solar_Power_Facility#Fossil_fuel_consumption https://en.wikipedia.org/wiki/Ivanpah_Solar_Power_Facility#F... for an example of how it can.
- Retric 10y agoIf are ok with a 21% capacity factor then you don't need fossil fuels. If you want to actually make power the other 79% of the time then you do. Milton salt lowers efficiency rather dramatically which is why it's not a real factor.
- gene-h 10y agoThe problem is, no one wants to fund solar thermal power. There are worries that advances in photovoltaics might make solar thermal power obsolete over the 30 year life of these plants.
- andrewfong 10y agoPhotovoltaics don't come with a built-in energy storage solution (needed if you want solar to be part of a base-load solution). The risk is really from photovoltaics + better batteries (or some other generic storage system).
- cjensen 10y agoThe Ivanpah solar thermal plant was funded [1] and many others [2]. Why do you say no one wants to? [1] https://en.wikipedia.org/wiki/Ivanpah_Solar_Power_Facility https://en.wikipedia.org/wiki/Ivanpah_Solar_Power_Facility [2] https://en.wikipedia.org/wiki/List_of_solar_thermal_power_stations https://en.wikipedia.org/wiki/List_of_solar_thermal_power_st...
- bronson 10y agoDid you read the third paragraph of your first link?
- cjensen 10y agoI was responding to the assertion that no one was investing in solar thermal -- I'm not defending the investment.
- PhantomGremlin 10y agoWhat I don't like about "cheerleading" articles like this is they didn't mention the problem installations such as Ivanpah. A few damning sentences from the Ivanpah Wiki: In November 2014, Associated Press reported that the plant was producing only "about half of its expected annual output". The California Energy Commission issued a statement blaming this on "clouds, jet contrails and weather". When you're blaming "jet contrails" for your problems, there's a whole lot of hurt being swept under the rug.
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- woodandsteel 10y agoI'm confused. The wikipedia article says Ivanpah has greatly under performed, but the linked article says electric companies are investing in a whole bunch of STF plants, including from the company that built the Ivanpah plant. So is this good idea or not?