FIT 3Kwp System from 2014. Should I be adding batteries?

Talk Electrician Forum

Help Support Talk Electrician Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Still trying to justify or not spending 5k or more of my savings on a battery store system to reduce my home energy costs.
Using last years imported energy as a baseline, I thought rather than costing each kwh used from the battery to justify purchase, I would first see how much energy is actually costing me now.
I imported 2511kwh @ lets say the rate I pay now which is .336p/kwh plus .406p/day standing charge.
I cant believe those rates, that's incredibly low. How long will you be on that tariff before you have to renew? Or are you rates a more realistic 33.6p kWh and 40.6p per day?

So my costs in 12 months were £843 plus standing charge of £148 Total £991 plus vat @ 5% £1040.
I think my guess above is correct looking at these totals.

My (long since paid for) solar panels generated around 3800kwh which paid me £790 in that year.

So offsetting my solar payout against my usage £1040-£790 Leaves just £250 as my years electric energy cost.

That's £20/month or 69p/day. Not very much is it.

Now providing my solar keeps producing, its FIT payments subsidize my bill quite nicely.
I'm not sure how adding batteries to a FITS system affects the FITS payments including AC coupled ones.

I do "waste" a considerable amount of my solar generation by exporting it to the grid.
I exported around 2473kwh last year worth at todays rates £830 if that amount was being imported.
The ability to time shift when I could use some of the excess solar via battery storage would be useful but unless I shut down my gas central heating and buy oil filled radiators for every room to use up this in a battery store I cant see payback being any time in the next few years.
Jesus, dont used oil filled heaters, theyre very slow, expensive and expensive to run. Use an aircon unit, you get 3.5 kW of heat for 1kWh of energy.

The solar wont always fill batteries, in winter I still need to buy energy at say 10p/kwh night rate to charge them each night.
So it looks to me like 15-20yrs payback and I am unlikely to be around to see the end of that!
My battery payback is running at less than 2.7 years.

Looks to me like I need a gas generator :)
Plenty of backed beans and or sprouts plus a length of Gardena hosepipe :)

Comments? Have I missed anything?
Probably yes but I dont know enough about FITS.
 
Or are you rates a more realistic 33.6p kWh and 40.6p per day?
Yes John, I was quoting as .336 of a pound.

I'm not sure how adding batteries to a FITS system affects the FITS payments including AC coupled ones.
I'm not adding anything to the FIT system, It would be AC coupled, just using the generated income to offset against the unit cost.

Jesus, dont used oil filled heaters, theyre very slow, expensive and expensive to run. Use an aircon unit, you get 3.5 kW of heat for 1kWh of energy.
I was using the rads as any example of use of "spare" generated kw. I already have whole downstairs aircon/reverse heat pump with 5.4kw of heat/cool for 1.8kw input. Its the upstairs rooms that would require some form of electric heating should I try to cut the gas use to just a hob and water heating.

My battery payback is running at less than 2.7 years.
But I am looking that how much my bottom line is currently, not how much I could save to justify a battery store. My current costs are £20/month or 69p/day. Not very much is it. To recover those costs would take 20yrs.
So ok I could not "waste" the exported unused solar by having batteries but I would then need to purchase energy at night to top up the batteries and find more stuff to use the energy with. If I didn't have the FIT payments it would be viable, but I do so they offset the kwh rate we are having to pay.
As much as I would like to play with batteries I don't think I can make a case for having them.
 
Yes John, I was quoting as .336 of a pound.


I'm not adding anything to the FIT system, It would be AC coupled, just using the generated income to offset against the unit cost.


I was using the rads as any example of use of "spare" generated kw. I already have whole downstairs aircon/reverse heat pump with 5.4kw of heat/cool for 1.8kw input. Its the upstairs rooms that would require some form of electric heating should I try to cut the gas use to just a hob and water heating.


But I am looking that how much my bottom line is currently, not how much I could save to justify a battery store. My current costs are £20/month or 69p/day. Not very much is it. To recover those costs would take 20yrs.
So ok I could not "waste" the exported unused solar by having batteries but I would then need to purchase energy at night to top up the batteries and find more stuff to use the energy with. If I didn't have the FIT payments it would be viable, but I do so they offset the kwh rate we are having to pay.
As much as I would like to play with batteries I don't think I can make a case for having them.
I tend to agree with you, your usage is also relatively low, I use 12000 kWh per year, I have no FITS so the numbers work for me.
 
A very useful thread. What options and considerations do we need to worry about in regards to this standing charge?
Im with sse and the standing charge seems to have gone in the wrong direction for customers.
 
This installer is adding a new system to a customer who already has a FIT reg'd install. Some might find it useful.
 
Top