Storage of electricity is expensive, because batteries are expensive, and lose power over time. Batteries are getting less expensive all the time, though, and are easy to add to existing systems. Batteries are a good way to shift excess power from peak generation time to peak load. This was never something anyone had to even consider doing in the past, because it has only been recently that peak generation has out-produced demand during the daytime. So, traditionally, people only think of long-term storage needs, which batteries are not good for.
Molten salt is a better way to store solar energy, as you store the energy as heat before it is converted to electricity. To make electricity, you just pass the molten salt pipes through a boiler, cooling the salt and boiling the water. Electricity is then generated in a traditional way. Molten salt doesn't provide unlimited storage; the salt can't get too cool, or it won't flow, so it's not like you can store summer heat to use in the winter. You can easily enough build a plant that will produce electricity all through the night, though, and you can even vary the output to match demand.
Remember back in 2010, when people were saying that we had to build more Nuclear power plants, because renewable energy could not compete economically? I wrote a brief blog about that:
http://www.greenknowe.org/content/molten-salt-solar-plant-produces-electricity-less-nuclear
Now it is widely recognized that even PV is cheaper than Nuclear, and is even outperforming coal and petroleum. I'm surprised that molten salt doesn't get more press, though. I think our future energy needs will mostly be met by a combination of PV and molten salt solar, with other renewables hopefully outpacing the current big three. There's no reason to build any more coal plants, and we should be decommissioning the ones that remain as fast as possible, leaving just a few petroleum and nuclear to balance out the mix. Mostly we should be saving our petroleum for trucks and jets.
- Log in to post comments