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- Oct 5, 2001
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I think a whole cost-of-supply needs to be considered. People want cheap energy, but they also want reliable energy.Well, yes. In fact one of the issues that made the Iberian blackout this year worse was most nuclear reactors were stopped in the peak solar hours because electricity was so cheap it was not profitable to have them running.
But then all this sounds like a problem of traditional generation methods becoming obsolete more than a problem of solar energy, along the issue with turbines being damaged for being stopped. Technology must adapt to how humans use it not the other way around. It also explains why in Australia electricity is more expensive despite price of electricity being negative thanks to solar. Should make it clear where is indeed the problem.
As a proponent of solar, how do you think a grid should be comprised?
OK - I will infer that you think it is reasonable to replace unnecessary turbines that 'make electricity more expensive' and have a solar-powered grid with batteries. Let's look at how feasible this really is.About inertia, the lack of inertia wasn't the primary cause of the blackout either. It made it worse and more extended though. The primary cause is still unknown. In fact still without inertia correction, in Spain photovoltaic solar power reaches the 50% of the mix or more everyday and nothing happens. It will need a solution of course to make it sure such kind of blackouts don't happen again and to go over that 50% safely (at the moment of the blackout photovoltaic was 60%), but it will be solved, and sooner than later I bet. And if we can have turbines running unnecessarily making electricity more expensive, I guess we can also have some batteries as backup too.
Spain typically uses around 700 GWh / day of electricity. Let's keep the numbers simple, and assume that 2/3rds of this is required during the day, and 1/3 at night, and that solar can supply all of this on its own (solar generation varies throughout the day with the angle of the sun, but lets say that this is compensated with sun-following servos, and just ignore the early morning and late afternoon when the sun is low). So assume that battery storage needs to provide ~230 GWh of electricity / day.
The world's largest BESS (according to this)has a capacity of 3.28 GWh. That's enough to power Spain for about 10 minutes...
So to store enough electricity for Spain's overnight demand, you need to take the world's largest BESS, and build 70 copies of it. And what would that cost? Hard to estimate, but let's assume around €250 / kWh (€250,000,000 / GWh). You need 230 GWh, so that's around €57,500,000,000.
So your "free" solar really costs nearly €60 billion, or more correctly, that's the absolute minimum cost to provide grid back-up for solar under perfectly ideal conditions, where it just has to get the country through one night after a perfect day of generation. What if you have a rainy day? That battery storage needs to be 3x the size. Or a rainy week? 21x the size.
Free solar isn't free. Yes, I'm providing capital costs where your point was mainly about operational (fuel) costs, but they are related by a total cost of ownership.
Solar needs back-up, and this back-up costs money. The back-up can either be via things like batteries (expensive, as illustrated above), or via gas / coal / hydro / nuclear, where a decision is made to recognize that the reduced utilization of those alternatives increases the unit cost of those back-ups. The increased unit-cost of hydro / gas / coal / nuclear is because of the solar. Those other systems actually need back-up, too. But their back-up is not required because of "night time" or "bad weather", they are for maintenance or breakdowns. You also don't get common-mode failures: one gas turbine out of 30 breaking down is a lot easier to cover than (say) a rainy day taking out the entire solar generation capacity for a country.
Sure, there is a place for solar in the generation mix. Where solar is providing a moderate amount of reliable baseload, and the back-up can be provided by other baseload generators (or batteries), then it may help reduce the overall electricity price.
When the solar penetration is so high that you have to have idle back-up for 60% of the grid, just to get you through a rainy day? That most definitely isn't cheaper. Sounds like a political strategy, not an economic of thermodynamic one.