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Power cuts and my solar power?

Ian Wallis

Nov 13, 2017
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Just a quick question that has been nagging at me for a while.
My grid tie solar on a good day kicks out 1.1 kw.
How on earth can I use this in my UK home when the national grid shuts down (and it will)?

Islanding is a total pain, short of switching to expensive batteries, a diesel generator is the only thing I can think of that will give us power when the lights go out (as if diesel fuel aint going to be expensive).

Your thoughts on this will be appreciated. Cheers.
 

dave9

Mar 5, 2017
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Obviously you can't, 1.1kwh/best-case is nowhere near enough for a modern standard of living. A modest battery array is a good idea, just enough to survive, power critical things.

You can pour a lot of money into more solar panels, pour some money into a solar water heater, pour some money into especially efficient *appliances*, better insulate your home, etc, etc.

It would be easier and cheaper to just get the generator, especially if it only has to tide you over for a few days outage.

"Lights go out" though, would be the least of my concerns. You can get by with a lot less light, say 3W per room is enough to navigate by and then only the rooms you are in at the time. Larger concerns to me are things like heating, and keeping refrigerated and frozen food cold, while you're trying to limit # of times you open fridge and freezer to keep them efficient.

On that front you can increase efficiency year round for practically free, by merely getting rid of dead space in the fridge and freezer so there is less air exchange every time you open them, filling any empty spaces with containers of water which will also help keep the freezer cold for days longer. I mean within reason, not some crazy burden just to fit the food inside too. :cool:

Do your vehicles run on diesel? If so it makes perfect sense to have some spare fuel for that as well as a generator. Power goes out, petrol stations can't pump. Store more than you need and sell it at a *slight* (so people don't club you to death for taking advantage in an emergency) profit.
 

Ian Wallis

Nov 13, 2017
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Simpatico.

Small array I know; but I live in a small place on a steep hill that faces north, roof tops facing east & west. You couldn't live in a worse house for solar or growing fruit & vegetables. No real room for any improvement.
Diesel car and diesel motorbike (diesel fuel dosn't evaporate), now I know what to do with my spare engine.

Cheers.
 

Bluejets

Oct 5, 2014
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Simpatico.

Small array I know; but I live in a small place on a steep hill that faces north, roof tops facing east & west. You couldn't live in a worse house for solar or growing fruit & vegetables. No real room for any improvement.
Diesel car and diesel motorbike (diesel fuel dosn't evaporate), now I know what to do with my spare engine.

Cheers.
Diesel fuel will stagnate if left in storage without recirculation. Even then, limited.
 

Audioguru

Sep 24, 2016
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Here in Canada, I am glad that only a few cars burn stinky, smokey diesel fuel. Nearly all trucks and buses use diesel and create lots of black smoke when they accelerate. I laugh when a diesel VW car is idling or running because it sounds like the terrible noises made by the engine is it falling apart.
 

kellys_eye

Jun 25, 2010
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Obviously you can't, 1.1kwh/best-case is nowhere near enough for a modern standard of living. A modest battery array is a good idea, just enough to survive, power critical things.
I disagree.

It depends entirely on HOW you live your life and what you consider important.

I use a 900W (realistically it's only 700W maximum), good quality inverter-generator (IG) that provides us with lights (15W of LED), TV (80-100W on modern set), internet (2W) and laptop/tablet (30-70W) operation as good as indefinitely ( a total, when run all at once, of only 200W-ish) - fuel availability depending of course. This leaves spare capacity for either longer running (lower load) or more lighting and/or fridge boosting - which can be awkward I admit.

I'd dearly love to convert the IG to propane as it's easier to store (legally), doesn't deteriorate and propane is already used for our hot water/cooking facilities. Main home heating is by woodstove.

Based on our typical usage the 200W could be used for (say) 8 hours/day which is only a paltry 1.6kWhr and easily handles by a pair of decent (120Ahr) leisure batteries and a solar system - but UK sunlight is iffy depending on where you live. My location precludes relying on solar recharging hence the petrol/propane use atm.

All I have left to do is fit an external connector for the IG and a changeover switch at the consumer unit (with appropriate breaker) and remember to NOT try plugging the kettle in!

Back up? That's a spare IG. Same make/model.

Re fridges..... the spare IG can start and run our domestic fridge/freezers individually but since we have a total of NINE on the premises this could be problematic if not simply a PITA with all the plug-swapping so we may invest in something more substantial purely for the freezers. If the SHTF then the freezer content would be run down by consumption anyway so perhaps a moot point?
 

Audioguru

Sep 24, 2016
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It sounds like you live on the moon. I have never seen such desolation except in a movie.
 

dave9

Mar 5, 2017
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I wrote modern standard of living, and within the assumption that the average person doesn't live alone so that increases consumption. Plus, 1.1kwh best-case is a lot lower average.

If you don't want that, it's your right to live however you choose but personally, I'd just move to a different location before I made that many concessions in my daily life in order to be able to exist off a power grid, then get more solar and a generator.

Anyone could get by with less but I'd glad I don't have to. 900W inverter wouldn't even allow me to run a single electric stove burner!
 
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Audioguru

Sep 24, 2016
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Who are you referring to? Me or the OP?
Both of you.
I went camping only one time, never again!
My electricity is reliable so I never used an inverter or a generator.
We cheer when the lights go out on a rare electricity outage.
Web celebrate "Earth Day" for one hour in the evening each year with no electricity used.
 

kellys_eye

Jun 25, 2010
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I live in a forest on the banks of a Scottish loch (Loch Awe). Private water, private sewage and (until recently) suffered many blackouts due to power lines constantly being brought down in high winds. The forestry commission eventually cleared the areas where the lines ran but it hasn't stopped blackouts completely hence our reliance on portable generators although we've never been without mains power for longer than 5 days (usually fixed within 48 hours).

Recent events made us re-evaluate our position and prepare for more drastic eventualities hence the IG units and greater self reliance in terms of energy/food etc. My ideal position would be total self-reliance including energy (possible through local micro hydro system) and food production - probably a step too far but who knows......?

Anyway, we're here by choice and enjoy the seclusion although a recent venture I started attracted national newspaper coverage so we became 'less invisible' than we really wanted to be! Either way, I'd rather be where I am now than in the middle of a city.
 

dave9

Mar 5, 2017
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I go camping all the time and have no problem doing without electricity or any type of fuel (except to get there, and not counting firewood as fuel), though I am ignoring having a few flashlights along with me.

Regular everyday life, 900W (really 700W?) won't power so many things I own, even if they're the only thing using power, from hair dryers to microwave, toaster oven, power tools, electric clothes dryer, stove & oven.

I love being in a suburban satellite city of a major city, just far enough away that it's not highly urban, but just close enough that I seldom have to drive more than 3 miles to get anything I *really* need, and live within walking distance of a dozen restaurants, hardware store, auto parts stores, gas stations, fire/emergency department, and there's always a police presence within a mile or so. I do have to put up with neighbors but we help each other out so it's as much a positive as negative.
 

Bluejets

Oct 5, 2014
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Mmmmm.... Well my 22 panels generate between 31kwh in summer and 15 in winter and usage ( which is considered below average down under) is 12 to 14 units a day.
Excess is returned to the grid and we receive credit.
Even though credit rate is only half of night time charge rate, the savings each quarter are considerable.
System will pay for itself in 4 years and carries a mandatory 20 year equipment guarantee.
Savings are such that even thinking about battery backup would qualify one for the nut farm.
Solar feed back is tightly controlled requiring application for the area in which one lives and a max of 5kw inverter for domestic. At one stage zero feedback relay systems were considered by the government to combat the problems created for the supply authorities but the outcry and inflated cost buried that idea quicksmart.
Have no idea where the 8 hours of solar would come from . Need a rethink there for sure.
When designing the system, I chose to add the 250 litre storage hot water system via a timer set to 9.00am-3.00pm which acts as energy storage, much better than batteries.
 
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kellys_eye

Jun 25, 2010
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I only ever think of solar systems as those that are fully independent and non-reliant on subsidies - anyone can make/run a system that 'someone else' is paying for........ a 'political' stance for sure but its also a principled one.

Such solar systems will always depend on location and use though. I consider solar/wind/hydro backup as precisely that - backup - and, as such, not intended for continual maintenance of 'every' system I own/use 100% of the time. I can wait (and have sufficient socks/skiddies) for supplies to return before turning on a clothes drier for example...... worse case I'll hang them out to dry.

The more you use the greater your store of fuel (assuming ICE driven supplies) needs to be too and as I inferred earlier there are legal limits (not to mention safety) to on-site fuel storage without going to the expense of full-on tanking. Propane can be stored safely without degradation and AFAIK in 'unlimited quantities'. I can certainly store enough (at 700W!!!) to go for weeks without a break in supplies. A standard 47kg bottle of propane would last me 30 hours at full load or about 14 days in 'normal' use (assuming I did the conversion from gasoline). I have a minimum of 10 days skiddie storage...........:D

Each to their own of course...... my (our) lifestyle is one of little need which I reckon will stand us in good stead should things go wrong at any time in the future.
 

bushtech

Sep 13, 2016
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kellys_eye: +1 for propane generator, great investment. Mine's been going for 10 years, no problems.
 
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