Author Topic: California tests off-the-grid solutions to power outages (Yosemite mentioned)  (Read 2706 times)


ergophobe

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Yeah, that's been making a lot of news around here. They just had a big feature in the local paper.

In essence, rather than just putting new power lines back up, which have to be powered down every time fire danger gets high, they are building a local power system that doesn't tie into the grid.

We've actually decided to go forward with our solar panel + battery system. It won't generate power in the winter, but the batteries will still work, they'll just have to be powered back up with either grid power (short outage) or generator. I couldn't even begin to count the 1-day power outages we've had, but the 3-5 day outages are probably about every 3 years on average. That said, in 2017, we were losing power for a couple times a week for two months and outage times were typically at least a few hours and often 8-12 hours. Damn hard to get any work done if your work requires electricity.

rcjordan

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>decided to go forward with our solar panel + battery system

Update?  Specs?

ergophobe

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Installed. Unfortunately, the inverter that shipped from the manufacturer had a problem and the new one is on backorder. So we've had two 4-6 hour outages without being able to use the backup.

We have six panels and I believe they are 380w each for a nominal 2.2KW system. This is really small. Our electrician decided to bias toward spending on the backup components since we don't have a great location anyway.

We have a bank of three Simpliphi 3.8KWH batteries for a total of 11.4KWH. Again, not a big system, but with the electric dryers and the A/C off the critical load panel, that's a couple days of juice.

With us doing normal things like using the computer and having a few lights on, I've seen our load at -1.9KW. It's commonly at -1.5KW or higher for at least a few hours in the middle of the day when it's getting good sun. On days we don't run dryer loads, we typically end the day with a lower meter reading than we started, but we more than make up for it at night. When the system went online in mid-August we were at about equilibrium and the meter reading only moved a couple of KWH in five days. Already, with days shortening and the sun lower in the sky (which makes the trees steal more light), we're not staying at equilibrium.

I think in May, June, July, we'll generate more than we use. Electric dryers are a killer though. Friends who are trying to zero out their load completely have twice as many panels as us.


Once the inverter is online, it will have the following capabilities

 - can sell juice back to PGE for net metering

 - rapid failover to battery in a power outage (under 1 second). You can get millisecond failover, but that adds almost $5,000 to the cost. Much cheaper to just keep the routers connected to the UPS.

 - can charge the batteries via solar, line power or portable or large generator. This was one of the huge downsides of the Tesla system - you could only charge from one source. They've since approved it for two sources, but we spec'd this out before that change.

 - can charge the battery with solar during an outage, which lets you then draw that power. So in June, we should be able to go weeks without drawing power if needed.

It's all pretty modular. Adding panels and batteries is easy. So if it goes well and it's worth it, we can expand the system. We want to run it for a year and see how it goes. The system is not free in terms of dollars and it is not free in terms of carbon footprint of panels and batteries, so we want to see how it goes before building bigger.

Total cost will be about $19,000 when all said and done (all labor and materials minus tax credits). Because of our location, I figure the payoff in terms of electrical bill will be maybe 15 years (TBD after a full 12 months), but that was not why we did it. We have so many power outages that we were either going to spend that money on this system or a propane generator, which I really did not want.*

As I mentioned, just in the past two weeks we've been without power for about 10 hours over two outages. Those outages were because they were installing new "hair trigger" transformers and they said that once those went into service, our outages would be "more frequent and last longer than in the past." It was already pretty bad, so we're anxious to get the new inverter and get the system fully operational.

*propane generator has a huge upside: it can crank out 20KW and just run everything in the house. The downsides are:
 - burns fossil fuels
 - never returns any money, only uses it
 - has to run weekly for at least 30 mins and requires annual maintenance
 - noisy
 - runs 24 hours a day during an outage even if nobody wants electricity. So our neighbors generators kick in at 2am and run for 3 hours even though nobody needs it. Even in standby, it's about .75gal/hr and in full mode it's 1.5gal. So they can run through $100 and who knows how many kg of CO2 during a power outage while 90% of the capacity is unused.
 - we had one neighbor during and extended outage run down his entire propane tank. At that point he could heat water or cook either.

All that considered, we decided that our more limited, but quieter and more eco-friendly system was better. I love the idea that for much of the year it's doing actual work rather than sitting idle except during outages.
« Last Edit: September 11, 2021, 06:51:31 PM by ergophobe »

rcjordan

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Update us after you get the inverter running and had a good session or two.

ergophobe

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Okay. I'm really excited for the power to go out once we're fully up and running. I'm sad we didn't get a chance to test it during the long summer days.

ergophobe

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New inverter came in and was installed.

Electrician forgot the monitoring device (which was also backordered and came in, but he realized when he was halfway here he didn't load it in the truck). So right now we're fully operational, but don't have metrics.

We have another scheduled outage on Sep 28th from 8am to 4pm... that will be the true shakedown cruise.