Battery-swap networks are preventing emergency blackouts

41 points5
neallindsay4 hours ago

There's lots of talk about grid-scale batteries to shift cheap electricity from solar panels into the night time. But batteries at the periphery can also help a lot because they can just stop charging (like the example in this article) or even feed energy back into the grid. Electric cars mostly don't have the circuitry to do this yet, but they're becoming a huge resource that will be tappable this way. Most of them are massively over-provisioned for the way that they're used 350 days out of the year.

pfdietz3 hours ago

Even lower hanging fruit would be increasing the dispatchability of demand in homes. Simply allowing heating and cooling to be dispatched would be very helpful. In the past this was done with bespoke add-ons to furnaces and AC compressors, but now it's done with smart thermostats.

mauvehaus3 hours ago

Green Mountain Power does exactly this in Vermont: they have a program that'll install a pair of powerwall batteries at customer homes and charge them off peak to draw on them on peak, particularly to avoid GMP having to buy peak-rate power from their upstream suppliers. In return, they leave the batteries charges when the weather is turning bad and the customer has battery backup.

The deal is structured as a 10 year lease, and the total cost is vastly less than that of owning the batteries outright. Their installation allowance is pretty good too; it didn't cover splitting our panel, but it covered everything else.

Not affiliated other than being a very happy GMP customer.

onionisafruit3 hours ago

You say they leave the batteries charged when the power is turning bad. Do you have a benefit of hosting the batteries at other times? For instance if the power goes out when the weather isn’t bad, do you typically have enough charge to make it through the outage?

I’m also curious if your neighbors benefit from your battery during outages.

mauvehaus3 hours ago

De jure, I think they're pretty free to do with them what they want. De facto they leave the batteries pretty fully charged most of the time.

AIUI, they'd have to have a disconnect somewhere upstream of us to let us back feed the grid during an outage, otherwise they couldn't safely work on the lines. And they'd need a way to enable and disable back feeding remotely[0] to allow them to work on anything between that hypothetical disconnect and us.

At the moment, none of that exists, so only we benefit from the powerwalls. It's also 34kwh in the pair of batteries. That wouldn't add up to too many household-days if you started adding households. You'd have to do some fancy switching to not overwhelm the relatively few powerwalls in an outage.

For context, based on our usage, we're at about three days of backup just for us [1]. It doesn't take much imagination to come up with a scenario where that happens where we are. We are the very last pole.

[0] Which in turn requires connectivity. The cell network here is sparse, to put it mildly. We just got fiber, but that's hanging on the same poles as the power. The fail-safe mode for no grid and no connectivity is to not backfeed, but at that point, you're back where you are today.

[1] It's the fridge, mostly.

rthomas64 hours ago

I wish it were standard practice to have some kind of house battery (what Tesla calls "Powerwall") for new construction homes. They could smooth out peak usage in this exact way, in addition to making individual homes more resilient to occasional power outages.

t_tsonev4 hours ago

On-demand charging is very much happening today. All chargers communicate the available charging current with the vehicle and some can adjust it dynamically.

As for control, there are proprietary and OSS solutions (shout out to that allow you to control the charging process based on price, grid load, local PV generation, etc.

ckdarby4 hours ago

I see the basic version of this already with the Tesla vehicles where if you plug in another appliance on the same breaker the car will decrease its draw to prevent triggering the breaker.

robocop_legacy4 hours ago

“ According to numbers provided by the company, 590 Gogoro battery-swap locations (some of which have more than one swap station) stopped drawing electricity from the grid, lowering local demand by a total six megawatts—enough to power thousands of homes.”

From the title I thought the batteries would stabilize the grid by discharging back into it but apparently that capability is not implemented yet. Still interesting that the stations increase demand enough that grid stabilization can occur by simply disabling battery charging.

cesarb4 hours ago

> Still interesting that the stations increase demand enough that grid stabilization can occur by simply disabling battery charging.

That trick is not limited to battery stations. Another thing which is done in some places (at least my country does that), is to have some circuits from substations configured so that they cut power when the frequency drops too low and/or too fast, preventing a generalized blackout at the cost of temporarily losing power to parts of the system (the circuits to be powered down in each step are chosen so that important loads like hospitals do not lose power). In the country-wide blackout last year (, that mechanism stabilized power in the southern part of the country, allowing it to recover quickly (the northern part, where the disturbance originated, unfortunately lost too much transmission and generation, and needed a black start).

redleader554 hours ago

I'm bivalent on this topic. On one hand 6MW is very little, compared to 3,200 MW lost power during the earthquake, especially when spread over 580 stations. It's likely the feature to disconnect when frequency drops is designed to protect the station, rather than the grid. In general, this sounds like a feel-good story rather than a something real.

That being said, I see this as a huge opportunity to stabilize the grid by having large-ish battery stations discharging their stored power when frequency drops. It's likely this will need to be grid controlled rather than individual and decentralized completely. It's hard (for me) to say what needs to be built first: an automatic way to reduce power draw from the grid by large consumers that are non-essential (eg. industry) or battery stations that can keep the frequency stable in case of brownouts.

lanthade3 hours ago

I agree, more of a feel good/marketing piece. Bad electric coming into a system can cause damage so protection circuits are built in to prevent that damage from happening. I wonder how many UPSs kicked in and also lowered demand. What about poorly designed devices that stopped working?

ljf3 hours ago

I spent a short while going down the rabbit whole of the meaning of bivalent, and how that applies to this scenario/phrasing - before I realised it was likely a typo for ambivalent.

datadrivenangel3 hours ago

I wrote a book on the topic of virtual power plants, and it's amazing how supply and demand have to match exactly in an electrical system, so reducing power use is the same thing as increasing power use!

ggm4 hours ago

Demand management is fantastic, batteries are just amazing and can sink power, provide power, manage reactive power and frequency and do it in milliseconds.

gorbypark3 hours ago

Once upon a time (~15 years ago!), I worked at a ski resort in New Zealand that had a fancy new "automated" snowmaking system. When all 200 (give or take) snow guns were running, along with the required water pumps/air compressors, the system could draw megawatts of power. Generally it didn't get below zero very often in the closest city to the resort (Queenstown), but when it did, people would turn on their electric heaters, and demand would go through the roof. The way it was explained to me is that the power company actually sent a signal through the power supply which would trigger our snowmaking system to shut itself off. It was pretty cool to see and also infuriating, because of course you can make much more snow when it's cold.

Being a giant nerd I of course asked if this was really happening via some network connection, but I was told they actually modulated the frequency of the entire grid in a very small, but predictable way. Some sort of device sat there and when it picked up the pattern in the frequency changes it would then trigger the shutdown.

I've spent a while doing some searches about such a system but couldn't find any information. Anyways, your comment about demand management made me think of this and how it's been possible in one way or another for a long time (albeit not milliseconds!).

flakeoil3 hours ago

Are you sure they modulated the frequency of the actual AC power (typically 50 or 60 Hz) and didn't overlay it with a high frequency signal? It's very common with power line communication or power line modems. You modulate a data signal on top.