DIY solar package

[UncleEbenezer]

Yes there are always exceptions. With any subject you'll find people somewhere who have experienced an unfortunate event......but it's not the norm is it ?

Brief power cuts (under an hour) are pretty common.

Middling power cuts quite rare: last one I recollect was something over five hours in September 2007.

Long power cuts: that'll be Snorvey and Arwen.

[doolally]

Many thousands were affected by days long power cuts after Arwen (and the subsequent storm - I can't remember it's name) and if the climate bods are to believed, many more events like this are likely to happen.

Saying that, I did recall the National Grid saying that during Arwen the UK was running on 100% renewable energy for the first time ever. Every cloud I guess.

So Arwen produced the wind which drove the windmills which produced the electricity which could not reach the consumers because of the damage caused by Arwen.

Hmmm
doolally

[gryffron]

It’s dead easy to use solar+battery to push power back to the grid.
It’s dead easy to use solar+battery to power standalone devices.

It’s extremely difficult to do both. At first thought it sounds easy. But the issue is that your standalone sockets wouldn’t be synchronised to the grid when the grid comes back up. Big Bang! So after an outage there’s no way to re sync the sockets without disconnecting everything and starting it up again from scratch. Which is precisely what you don’t want to do with a standby generator. Sort of defeats the point.

The only way to do it would be to have TWO inverters off the same battery. One synchronised and pushing power to the grid. One independent and pushing power to the standalone sockets. But this is an expensive solution, and difficult to manage, and probably wouldn’t sell enough units to be worth the trouble.

Gryff

[9873210]

It’s dead easy to use solar+battery to push power back to the grid.
It’s dead easy to use solar+battery to power standalone devices.

It’s extremely difficult to do both. At first thought it sounds easy. But the issue is that your standalone sockets wouldn’t be synchronised to the grid when the grid comes back up. Big Bang! So after an outage there’s no way to re sync the sockets without disconnecting everything and starting it up again from scratch. Which is precisely what you don’t want to do with a standby generator. Sort of defeats the point.

The only way to do it would be to have TWO inverters off the same battery. One synchronised and pushing power to the grid. One independent and pushing power to the standalone sockets. But this is an expensive solution, and difficult to manage, and probably wouldn’t sell enough units to be worth the trouble.

Gryff

Resynchronization is not that hard. Once the grid comes back you monitor the grid frequency and run your island at 49Hz-51Hz for a minute or so until it synchs with the grid. Then you close the isolator to reconnect to the grid. In most systems this is all software. At most you might need a minor hardware change such as adding a monitor on the grid side of the isolator.

Also you are seriously misreading what a standby generator is for in a domestic context. Unless you're running a data center outages of a few seconds to a minute are fine*, the generator is to prevent outages of hours or days.

* At worst you have to reset a bunch of cheap clocks. If this is a problem buy better clocks.

[jaizan]

I'm surprised that this thread has migrated to discussing power cuts. In the past 20 years I don't believe we have had more than 3 short power cuts in that time.

In those last 20 years, we have been closing our coal plants and closing our nuclear plants.

We now rely more on wind and imported gas, however, the problems with this are obvious.
The wind output frequently drops to about 1% of installed capacity.
Russia is a major gas supplier to Europe.

So the risk of prolonged power cuts is increasing.

We don't even seem to do sensible things like dispersing the wind farms over a wider area -they seem to be keen on building more of them close together in the North Sea, rather than trying to disperse them, with more off the west coast and so on.

Also, global coal use for electricity generation was at record levels last year. Whilst we are pursuing an expensive energy policy that puts our manufacturers out of business and puts bills up for consumer, it's pretty pointless if countries like India and China keep building more coal fired electricity generating plants.

[DrFfybes]

It’s dead easy to use solar+battery to push power back to the grid.
It’s dead easy to use solar+battery to power standalone devices.

Gryff

I have been looking more and more at going totally off grid. It started with the shed, and is moving toawrds the whole house. We use about 12kWh per day, perhaps slightly more in winter as the fish tank needs more heating. For circa £15k (plus installation!) one can get a 10kW solar system with 40kWh effective storage (actually 80kWh storage, but apparently only half is available, but still enough for 3 days) assuming the 10kW system can provide 15kWh/day in winter in the midlands.

At current capped prices, our annual 4100kWh costs £1150, plus £164 standing charge, so £1300/year, which is only going to go up in the near future (long term who knows). It is teetering on the edge of being viable. In summer we would use the surplus to heat the water, so reducing the gas bill slightly (current gas use is about 8kWh/day, which is hot water and the hob for 15 min or so for tea) so another £15/month for much of the year.

Of course going off-grid completely removes the option of selling surplus back in summer, so there is some maths to be done.

Paul.

[ReformedCharacter]

It’s dead easy to use solar+battery to push power back to the grid.
It’s dead easy to use solar+battery to power standalone devices.

Gryff

I have been looking more and more at going totally off grid. It started with the shed, and is moving toawrds the whole house. We use about 12kWh per day, perhaps slightly more in winter as the fish tank needs more heating. For circa £15k (plus installation!) one can get a 10kW solar system with 40kWh effective storage (actually 80kWh storage, but apparently only half is available, but still enough for 3 days) assuming the 10kW system can provide 15kWh/day in winter in the midlands.

At current capped prices, our annual 4100kWh costs £1150, plus £164 standing charge, so £1300/year, which is only going to go up in the near future (long term who knows). It is teetering on the edge of being viable. In summer we would use the surplus to heat the water, so reducing the gas bill slightly (current gas use is about 8kWh/day, which is hot water and the hob for 15 min or so for tea) so another £15/month for much of the year.

Of course going off-grid completely removes the option of selling surplus back in summer, so there is some maths to be done.

Paul.

Thanks, interesting, I've been thinking about going off-grid too and planning to get our house rewired at some point. In theory I'd like to have solar + battery but with the option to switch to mains as a backup. The particular area we live in does not do well for sunshine during the Winter months, so battery only looks unfeasible but if a mains backup could be added at reasonable cost, it might be worth looking into a bit more.

RC