Moss Landing

Everybody knows that the problem with sustainable energy is that it is intermittent. For wind, the wind doesn't always blow. Solar can suffer from clouds, but most obviously the sun doesn't shine at night. Other forms of sustainable energy, such as geothermal and hydroelectric, are not so variable but for some reason a lot of people refuse to count these as acceptable. And nuclear is not variable at all but if you care about carbon dioxide emissions it is the best solution (in my opinion). It has no emissions at all, but it remains controversial. For example, Germany closing down all of its nuclear power stations while France, next door, gets 70% of its energy from nuclear and has just announced plans to build another dozen stations. France is the biggest electricity exporter in the world as a result (so Germany can import nuclear power from France while it burnishes its green credentials by having none of its own). California does the same, importing over 30% of its energy from neighboring states, even as it closes down its largest power station, Diablo Canyon, purely on the basis that it is nuclear. However, it does have a partially owned nuclear plant in Arizona, conveniently below the radar, from which it imports a lot of power.

Electricity is extremely difficult to store in grid-level quantities. The only two good solutions are batteries and pumped storage. For batteries, see the rest of this post. Pumped storage consists of two lakes, an upper and lower one. When power is abundant, water is pumped from the lower lake to the upper. When power is required, water falls from the upper lake to the lower and the equipment switches from pumping to generating. I wrote about this in my post How Many Journalists per Square Acre? in the context of a situation where MW/h really is the right unit. I was surprised to see in this List of Power Stations in California that there are 6 pumped storage schemes in the state.

I realize that a lot of the readers of Breakfast Bytes do not live in Silicon Valley, and so have no idea where Moss Landing is. But if you do live in Silicon Valley, you've almost certainly driven down Highway 1 to Monterey at some point, and you can't miss Moss Landing. Or at least the power station there. Its two huge chimneys are visible for miles. Those chimneys are associated with a gas-powered power station. There used to be another larger power station there but that was closed down leaving an empty turbine hall, but it's an empty turbine hall with the best connection to the electricity grid you can imagine. It would be the perfect place to put a large battery to even out fluctuation in wind and solar power as the wind varies and as the sun goes down late in the afternoon when people's air conditioners are at peak usage. That is just what has been done. Moss Landing is the largest grid-scale battery in the world, although the batteries are outside, not in the old turbine hall which just contains equipment. It's an interesting transition since Moss Landing used to be the largest power station in California.

As a brief aside, it is nice to see a description of a battery using correct units. Sometimes, people say 500MW and you don't know if they really mean 500MWh (which is actually a battery capacity). Sometimes they put 500MWh on the screen and then say 500 "megawatts per hour" which is a rate of change of power.

Anyway, there are two phases at Moss Landing. The first is 300MW/1200MWh, which means it holds 1200MWh and can discharge it all in four hours (300MW). It was turned on in December 2020 (but see below). The second phase is smaller at 100MW/400MWh (so still four hours worth but only a third the capacity). From a fire point of view, it is good to know that the two phases are in separate buildings. The batteries are all made by Tesla.

To put that in perspective, Diablo Canyon nuclear power station (down near San Luis Obispo) is rated at 2256MW, and the Vistra Energy plant running on the same Moss Landing site (built in 1950) is 1036MW. Or another datapoint, an entry level Tesla model 3 has 50KWh of battery, so Moss Landing (both phases) is 3,200 cars worth.

Moss Landing has been in the news recently because there was a fire in the second phase. There was a fire in the first phase in September last year. You probably assumed it was a lithium battery fire but it is far more Keystone Cops than that. A bearing on a fan overheated, a smoke detector noticed, but instead of responding as it was meant to, it drenched the entire battery installation in water, causing it to overheat, and put it out of action. The "fire" was never a fire, just an overheating fan bearing.

Here's one description I found:

The suspected bearing failure is presumed to have set off the very early smoke detection apparatus (VESDA), which in turn armed the heat suppression system. Vistra stated that due to ‘failures of a small number of couplings on flexible hoses and pipes’, water sprayed directly onto additional battery racks, causing short circuiting and arcing, which damaged the batteries and made more smoke. The additional smoke set off more alarms and caused even more water to spray from the failed couplings.

As I type this, there is little public information about the latest fire. It seems a similar "fire" that is not actually a battery fire but another "series of cascading events" resulted in ten battery packs melting down.

So currently both phases of Moss Landing are offline. There are plans for a third phase of 350MW/1,400MWh, planned to be online June 2023, but with these two fires, I suspect it is likely to be delayed.

Electric Vehicle Fires

Talking of battery fires, since you hear so much about them you might assume that electric vehicle fires are common. But, in fact, it is more that they are so rare that they always make the news. According to the National Highway Traffic Safety Administration, as reported by InsideEEVs:

Fully electric vehicles, on the other hand, were deemed far safer than both hybrids and gas cars; they are far less likely to catch fire, with just 25.1 fires per 100,000 sales. That’s compared to 3,474 hybrid fires and 1,529 ICE fires per 100,000 sales respectively.

I have no idea why hybrids seem to be so much more prone to fires than regular gas-powered cars (ICE...internal combustion engine). Of course, it's not a fair comparison based on the percentage of EV vs ICE vehicles, but in a year (2020) there were 52 EV fires and 200,000 ICE fires. However, EV battery fires are much harder to extinguish since just denying them oxygen does not work (they bring their own oxygen) and lithium is highly reactive (remember your high school chemistry lessons on group I elements: Li, Na, K...).

Food

If you are passing Moss Landing and want some food with your batteries, I recommend The Whole Enchilada for Mexican food, and Sea Harvest for fish. There are other restaurants, but these are the two I have been to several times.

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