Any battery storage system worth having ?

[Uklad]

I already have a 4kW PV system that will be 10 years old in September, just looking at how much my electricity cost will increase in March when my fixed rate ends i'm starting to wonder if any Battery storage system is worth investing in now that energy prices and going mental..

My Electricity usage for 2021 was 5528.60 kWh
My PV generation for 2021 was 3123.208 kWh

Any advice would be great..

 

[James]

How much are you exporting to the grid?

 

[Uklad]

Honestly, I don’t know I don`t have any export monitor not really had a need for one.

 

[James]

That information is key.
if you never export to the grid, you never have any excess solar energy for battery charging.

 

[Zerax]

I keep looking at the whole PV & Battery thing... for me, PV panels would cost about 15p/kWh over a lifespan of 25 years (optimistic)... when I can buy it from the grid for 5p/kWh (only for 4 hours per night though)... so that's PV out, and battery is still an option... but if you look at the cost of a battery solution, and with normal electricity at say 25p/kWh... it's like a 10 year payback... and that's right at the end of life for the equipment and batteries !

 

[Uklad]

That information is key.
if you never export to the grid, you never have any excess solar energy for battery charging.

That information is key.
if you never export to the grid, you never have any excess solar energy for battery charging.

Turns out my Smart meter has an export reading, its was installed around June July 2016 it's currently reading 7625.1 kWh

 

[Uklad]

I keep looking at the whole PV & Battery thing... for me, PV panels would cost about 15p/kWh over a lifespan of 25 years (optimistic)... when I can buy it from the grid for 5p/kWh (only for 4 hours per night though)... so that's PV out, and battery is still an option... but if you look at the cost of a battery solution, and with normal electricity at say 25p/kWh... it's like a 10 year payback... and that's right at the end of life for the equipment and batteries !

My PV has paid for its self now in pure FIT payment's not including any electricity savings.

My Electricity is currently 15.71p per kWh this will goto 20.139p in Match but depending on a price cap it could double to upto 30-38p

 

[Zerax]

My PV has paid for its self now in pure FIT payment's not including any electricity savings.

My Electricity is currently 15.71p per kWh this will goto 20.139p in Match but depending on a price cap it could double to upto 30-38p

Yes... but I don't have a FIT... it's all changed now. Largely, PV is only viable with a generous FIT.

 

[Deleted account]

Fit a solar i boost to a 3 Kw storage heater. Any excess electricity gets put in heater as heat during day with slow output over night. Opposite of e7.

im in process of designing an off grid system for my property to supply 2 storage heaters. It’s a hell of a lot cheaper than convensional solar systems.

ideally I would have them heating a water tank, but the cost implications for that are not viable as I have a combi boiler.

im quite concerned with the increase in prices. This is why I’m doing this now to beet the rise in cost of materials.

anyone know a good supplier out there they could recommend?

 

[Zerax]

im in process of designing an off grid system for my property to supply 2 storage heaters.

Interesting stuff... so you'll have a PV array.. the output of which will be used to charge the storage heaters ? What about in the summer months when you'll have oodles of output but need no heat ? Where will the output go then ?

 

[pc1966]

We looked at solar as our site has a lot of open ground doing not much, but at this sort of latitude it won't even pay for itself over 20 years, so really not worth while.

One of the guys we work with was keen, and thinking it might do as backup power instead of our plane for a generator, but when we are mote likely to need it in winter we will get sod-all solar power compared to our average load of around 2.2kW (e.g. at worst on Dec 22nd we get a mean of 0.3kWh per kW of panel. so would need at least 176kW of panels to break even during that period.

So it might help a bit, but without a generous FIT it is simply not worth it over other options to invest similar sums in either backup generation or other money-making ventures.

 

[Zerax]

So it might help a bit, but without a generous FIT it is simply not worth it over other options to invest similar sums in either backup generation or other money-making ventures.

Agreed... that's my conclusion too. If you have the space, what about a wind turbine then ? That would give you output for all 24hrs on almost every day of the year ??

Aren't they mega popular up on Shetland/Orkney ?

 

[pc1966]

Certainly wind helps, as often when you have a low pressure system with cloud cover you get winds, but it is not reliable enough for backup power, though it could help offset demand / mains cost.

But fundamentally it is the same issue, if you have grid power it is cheaper than PV/wind at this sort of scale, so no special FIT then not economically viable.

 

[Deleted account]

Interesting stuff... so you'll have a PV array.. the output of which will be used to charge the storage heaters ? What about in the summer months when you'll have oodles of output but need no heat ? Where will the output go then ?

That’s why I will have two 3 kw storage heaters that store more than 3 kw in heat within the bricks. so it will suck up all available power.
However I may need another storage heater for those real good days in summer, need to do more calcs.

 

[DPG]

That’s why I will have two 3 kw storage heaters that store more than 3 kw in heat within the bricks. so it will suck up all available power.
However I may need another storage heater for those real good days in summer, need to do more calcs.

But surely you won't need all that extra heat during the summer?

 

[Deleted account]

We looked at solar as our site has a lot of open ground doing not much, but at this sort of latitude it won't even pay for itself over 20 years, so really not worth while.

One of the guys we work with was keen, and thinking it might do as backup power instead of our plane for a generator, but when we are mote likely to need it in winter we will get sod-all solar power compared to our average load of around 2.2kW (e.g. at worst on Dec 22nd we get a mean of 0.3kWh per kW of panel. so would need at least 176kW of panels to break even during that period.

So it might help a bit, but without a generous FIT it is simply not worth it over other options to invest similar sums in either backup generation or other money-making ventures.

Interesting calcs.

with the increases in energy prices these repayment timescales are going to geatly reduce.

 

[Deleted account]

But surely you won't need all that extra heat during the summer?

True.

it’s a bit in the paper calc stage at moment. As I said earlier storing heat in water would be better, but cost implications….

gravity fed hot water system, cylinder can do myself but materials all adds up price wise.

 

[DPG]

True.

it’s a bit in the paper calc stage at moment. As I said earlier storing heat in water would be better, but cost implications….

gravity fed hot water system, cylinder can do myself but materials all adds up price wise.

I'll be interested in seeing what you come up with. As will many I expect!

 

[pc1966]

Interesting calcs.

with the increases in energy prices these repayment timescales are going to geatly reduce.

Not 100% sure they are right, the mean daily solar power might be kWh per m^2 of land. The figures I was using for our site were from this web site:

Errol Climate, Weather By Month, Average Temperature (United Kingdom) - Weather Spark

In Errol, the summers are cool and partly cloudy and the winters are long, very cold, windy, and mostly cloudy. Over the course of the year, the temperature typically varies from 33°F to 66°F and is rarely below 24°F or above 73°F.

weatherspark.com

The "beach / pool" graph is predictably miserable!

Further down you see the solar energy data.

With our average of 2.2kW that is 52.8kWh per day, so if you only have an average of under an hours of "full sunshine" in a day you are going to need quite an array of panels (and matching battery!) to cover it. The solar you get obviously depends on the length of the day (around 7 hours mid-winter), the resulting low elevation of the sun (not much more than 10 deg max, mid-winter for us), and the typical cloud cover (70% overcast or mostly cloudy here mid-winter).

 

[pc1966]

However, if we try typical on-line solar calculators they come to the same economic conclusion, that it won't pay for itself these days.

Of course if you are off-grid or powering a much smaller load then PV and/or wind is useful, a lot of automated remote weather stations use that sort of combination at higher latitudes where solar alone is challenging mid-winter.