Hacker News Reader

Comment by paulyg | Hacker News Reader

Why are people comparing and debating "batteries vs combustion turbines"? Batteries only store energy and you still need to generate it somewhere. Probably from a CCGT plant.

And it's not risk aversion. Its buried subtly in the article but part of SoCal's gas infrastructure is shut down because of the leak. They literally can't provide enough gas to generate enough electricity for peak demand. So they will generate over capacity at night, store in the batteries, and discharge during the day.

Also what seems to be lost here is that Tesla created it's utility battery products as a renewables play, but are just taking advantage of extra-ordinary circumstances in this case.

View on HN

People are comparing them because they serve the same purpose here.

Base and peak loads on the grid can be wildly different. Without storage, if you want to avoid brownouts or blackouts, your generating capacity needs to match the peak load, even though you might only hit peak load a few times per year. The traditional way to handle this is to have power plants that can be spun up rapidly but sit idle 99% of the time. Because they're idle most of the time, the electricity they produce is extremely expensive.

Storage (including batteries, but also many other technologies) can substitute for these plants. You fill the storage when demand is low, then drain it when demand is high. Yes, the energy still needs to be generated somewhere, but you can generate it using existing plants during periods of low demand. If this is cheaper than maintaining peaking plants that mostly sit idle, it's a win.

Or you can use PHS: https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit...

You can't build and install pumped hydro in 3 months.

Wasn't Danielle Fong and folks doing pumped (and cooled) air for this? I wonder if that's still around and if maybe they lost this bid.

we didn't bid. we're still around though. we have plans :)

it will be interesting to see how Tesla makes money. it's probably mainly a test site.

Yes I know how all that works becuase I worked in the utility industry for over a decade.

My point was (1) when comparing peakers vs storage you need to consider the cost of: Off-peak generation + storage cost vs peaker cost. (2) This wasn't a cost driven thing. This is a demand driven thing.

People neglect the cost of off-peak generation because it's much cheaper than the other two parts of the equation.

It's still a cost driven thing. They could be emergency-buying or emergency-relocating gas infrastructure over the next few months.

Off-peak generation is really cheap, though. It doesn't affect the equation that much. In some places (I'm sure SoCal isn't one of them) it's cheaper than free sometimes.

And of course it was a cost driven thing. This is the cheapest way to meet the demand. If there were a cheaper way, they would have taken that.

Energy density of gas (at conventional pressure) is 100x lower than that of a charged battery. Storing gas instead of electricity might not be such a good option.

Otoh, a gas tank requires only O(E^(2/3)) material, while a battery requires O(E) material, where E = stored energy.

Reply on news.ycombinator.com