Best Off Grid Electricity Conversions

thomashenderson

My combined gas and Electricity bills have jumped from £7 to £220 (we were overpaying for some time!), but either way we're facing the same high prices as everyone else.

I would prefer to pay this much a month to a company who would fit solar panels, a wind turbine, with a battery and remove myself from contributing to the usual energy firm fat cat profits.

Which companies offer such installations, and do any of you MSE forum members have any experience of these installations?

Thanks,
Tom.

Mstty

You won't get enough power with those options off grid to make it through a winter unless you have a wood burning stove to huddle round.

thomashenderson

We're one step ahead there, got a very good Burley 5kw wood burner which keeps our living room cosy during the winter.

We don't use a huge amount of power, but of course it does vary depending on what we're up to. A few days ago we clocked 14kwh between gas and electricity but normally we float around half that.

QrizB

thomashenderson said:

I would prefer to pay this much a month to a company who would fit solar panels, a wind turbine, with a battery and remove myself from contributing to the usual energy firm fat cat profits.

A 6kWp solar PV system will cost around £9k at current prices. Adding a 8kWh battery will be another £5k for a total of £14k.

If you have a good south-facing aspect that size of system will generate 5-6000kWh/yr, but more in the summer when you don't need it and less in the winter when you do.

Unless you live on the side of a hill, your grounds extend at least 100m from your house in all directions and you think "golly it's windy" every time you go outside, a wind turbine is likely to be a complete waste of time and money.

thomashenderson said:

We don't use a huge amount of power, but of course it does vary depending on what we're up to. A few days ago we clocked 14kwh between gas and electricity but normally we float around half that.

That's what, 3000kWh/yr, 250kWh/month? Roughly the national average.
The 6kWp system mentioned above would get you through 8-9 months of the year but in November / December / January it won't. Here's a link to the output of a 6kWp system in the Midlands; in December 2021 it produced less than 3kWh/day, on average. During the winter you'll be best served by buying power from the grid; this will also let you sell your surplus during the summer.

chris_n

You would need a battery much bigger than 8kW, think more in terms of 3 x daily use. You would also need a generator for when there is no sun or wind but as mentioned unless you own a field and can get the turbine high enough to reduce turbulence. The first thing you would need to do would be to reduce your usage to a minimum.

[Deleted User]

chris_n said:

You would need a battery much bigger than 8kW, think more in terms of 3 x daily use. You would also need a generator for when there is no sun or wind but as mentioned unless you own a field and can get the turbine high enough to reduce turbulence. The first thing you would need to do would be to reduce your usage to a minimum.

The balance between array size; battery size and home energy use is an interesting question: particularly, as a battery is the component with longest payback period. 

It is worth bearing in mind that the one thing that you cannot control is the export limitation set by the DNO. Clearly, having a 3-phase supply helps in this regard but for many this comes at a cost of many £k.

chris_n

There is no export if you are off grid.

TadleyBaggie

chris_n said:

There is no export if you are off grid.

Pretty sure exporting wasn't in their plans.

chris_n

TadleyBaggie said:

chris_n said:

There is no export if you are off grid.

Pretty sure exporting wasn't in their plans.

Exactly my point, it was a reply to the last paragraph of the previous post.

TadleyBaggie

chris_n said:

TadleyBaggie said:

chris_n said:

There is no export if you are off grid.

Pretty sure exporting wasn't in their plans.

Exactly my point, it was a reply to the last paragraph of the previous post.

Then quote it then, it wasn't clear.

gazapc

Going completely off grid is very difficult in a normal domestic setting. It's why most people don't do that.

Things you'd likely need:

- a significantly oversized PV system
- a battery system to cover say 3-5 days of very low generation
- alternative power source (wind, small hydro etc..) if possible
- last resort power in the form of a generator
- wood burner, ideally with a back boiler, and a significant supply of good value logs.

Before all this I would go super aggressive on insulation and demand reduction.


It almost certainly won't be financially viable if cost is the only driver.  I'd suggest investigating individual elements but staying on grid provides a potentially optimal solution.