The article says we still need better battery technology, and there's truth to that. But even without batteries, just providing power on days when air conditioners run continuously, solar could make a huge difference in the energy picture.
Once solar is significantly cheaper than coal and demand pricing kicks in, a lot of time-shifting of energy use could occur. Right now, night-time electricity is cheaper because demand is lower at night, but if the supply of daylight electricity increases dramatically, any activity which currently benefits from cheap nighttime electricity could be shifted back to the daylight hours.
Data centers currently consume something like 2% of electricity -- it is probably possible to shift at least some of that to bright, sunny days. It may stop being cost-effective to run night shifts at factories, especially if your manufacturing process is energy-intensive. We might end up charging our electric cars at our offices during the day instead of over night at our homes. It'd be pretty silly to fill a battery with solar electricity during the day just to transfer it to another battery at night.
Even without batteries, solar energy could still pick up a lot of our current nighttime energy usage because a lot of our nighttime energy usage doesn't actually have to be at night.
To be clear-- the reason energy is cheap at night is not JUST because it is used less-- it is also because there are certain continuous energy sources. Nuclear power, geothermal, tidal, wave and wind power are all producing energy round the clock and if you don't harvest it, it's lost.
We are not heading towards a world where we have a single power source (solar), and most of our power uses cannot be rescheduled. As fossil fuels are one of the few sources which can be turned on and off at our choosing, I would expect they will function to fill in temporary gaps between supply and demand once renewables capacity is large enough to take the average load. I don't see these gaps occurring predominantly at night.
> ... Nuclear power, geothermal, tidal, wave and wind power are all producing energy round the clock and if you don't harvest it, it's lost.
This isn't true of nuclear power plants; the fission rate, and thus the heat generation rate, can be throttled up and down as needed. In pressurized water reactors this happens automatically as the throttle is opened and closed, thus increasing or decreasing output from the "steam side" of the heat-exchange boilers, a.k.a. steam generators [1]. (In a prior life I was a Navy nuclear engineering officer.)
I think the idea is that with nuclear power plants while you can bring down the output you don't want to because it saves you very little money. Most of your costs are huge and fixed.
That's true, but does this make the fuel last longer, and anyway what are fuel costs as a percentage of total operational costs? My impression is it doesn't make sense to operate a nuclear reactor at less than full power.
Yes. Heat is generated by fission of fissile material such as uranium. Fuel rods have X amount of fissile material in them. Higher power -> faster depletion of the fissile material.
> what are fuel costs as a percentage of total operational costs?
Around 30%, according to the Nuclear Energy Institute. This compares with 80% for coal, natural gas, and oil.[2]
> My impression is it doesn't make sense to operate a nuclear reactor at less than full power
I would think that'd be true of almost any machinery, but that's almost a tautology: You design your machinery for an optimized balance of performance versus wear-and-tear, then try to operate at (what you call) "full power" as much as you can, so as to reap maximum value from your investment.
In any event, the original comment was that excess power is inevitably generated by nuclear plants (at least during some time periods) and therefore must be dumped somehow. That's not the case; nuclear plants can be throttled up and down as needed.
You can still store extra energy to buffer those gaps. Where I live, pumped-storage hydroelectricity has probably a great future. Thermal storage seems to reasonably efficient too, although I'm not quite sure how much of what I've seen is a little "too enthusiastic".
I'm now thinking of amazon EC2's 'spot instances' where you launch an instance, do some computation then shut down, but only if the price per hour is less than some choosen point. (Basically a stock market for computation).
If solar took off, i can see a correlation between price per hour and sunny days, as more machines are turned on when it's cheaper to run, hence increasing supply, and decreasing price. :P
This already happens, both at the energy generation level (power companies broker energy futures (excess supply/demand) between each other - see Enron for more) and at the energy consumer level (big businesses like refineries and foundries and the like pay less for electricity pulled in off-peak hours).
And using electric cars for battery storage too for excess power generation.
Just imagine the world if it was 10 cents per watt instead of $1 a watt for solar. I hope I live long enough to see it. Dare we dream 1 cent per watt, just like what has happened with CPU development in the past three decades? Could we have 1 cent per watt solar in 30 years? 50 years? 100?
If current trends[1] continue, it will take about 15-25 years for solar energy to become cheaper than fossil fuels, which seems like a reasonable length of time for a trend to continue.
To get the installation cost down from an estimated $1.40 in 2020 to $0.10 and $0.01 with the same trend would take 30-50 and 60-100 years, respectively. 70-110 years is definitely further in the future than I am comfortable peering; 40-60, also a little shaky.
But given current trends, it looks like 2050-2070 is roughly what you need to shoot for to live to see $0.10 / Watt solar energy. If you were born in America after 1976, I'd aim for 2076; it'd be nice to see the Tricentennial.
