Heat pumps

matt_drummer

My solar panels and batteries are key to making the heat pump work for me financially.

What I export now more than covers the cost of the electricity that I need to import when solar generation is reduced.

The batteries allow me to buy the electricity I need to import at the lowest price.

I have just moved to Octopus Flux tariff and will move back to an E7 tariff in November.

I have been on Outgoing Octopus for about 6 weeks but Flux makes more sense.

I am now predicting an excess of exports over imports amounting to between £500 and £1,000 a year.

Since I enlarged our generation and storage system in March we haven't imported any electricity save for the small amounts caused by the reaction time of the inverter to changes in load. In May we imported just over 5 kWh.

Reed_Richards

matt_drummer said:

My solar panels and batteries are key to making the heat pump work for me financially....

Perhaps I should clarify my own situation?  I have a 6.5 kW battery with an effective capacity of 90% of that figure.  My average daily electricity usage by the heat pump was 36.8 kWh last December (which was particularly cold) or 29.0 kWh last January (more normal for that time of year).  Thus I would need a vastly greater storage capacity to make good use of tariffs which give a period of cheap electricity.  Actually, I don't have a smart meter and therefore have no access to tariffs that rely on one.    

FreeBear

oliver1951 said:

brewerdave said:

Re gas boiler replacement cost - relation just had a new boiler (not combi), pump and diverter valve done by local plumber for £2400 (as an aside - BG quoted ~ £5.5k ! ) .If you don't have to upsize rads and pipework gas much cheaper than ASHP

Well for me it wasn’t like that. I’ve had 5 quotes for replacement gas boilers incl rads and piping and they were from £9k upwards! Perhaps it’s more expensive here. Or maybe it’s because my existing system is so old and has to be replaced. For sure if you are only taking out an old combi and putting a new one in then it’s not too expensive. That’s not the case here.

I've been busy replumbing my heating system with a combi boiler due to be fitted next month. New, larger radiators all round, and bigger pipes with an eye on the future when heat pumps become a viable option (for me). The amount I've spent on copper was quite a shock to the credit card, and I won't have an exact price until the statement comes through. I suspect it is going to be around £500.

matt_drummer

Reed_Richards said:

matt_drummer said:

My solar panels and batteries are key to making the heat pump work for me financially....

Perhaps I should clarify my own situation?  I have a 6.5 kW battery with an effective capacity of 90% of that figure.  My average daily electricity usage by the heat pump was 36.8 kWh last December (which was particularly cold) or 29.0 kWh last January (more normal for that time of year).  Thus I would need a vastly greater storage capacity to make good use of tariffs which give a period of cheap electricity.  Actually, I don't have a smart meter and therefore have no access to tariffs that rely on one.    

I have 38 kWh of usable battery storage and 13.3 kW of solar panels.

The capital cost of those and my panels is our energy costs for the next ten years.

I also have a net income from the export  as a contingency.

Reed_Richards

matt_drummer said:

I have 38 kWh of usable battery storage and 13.3 kW of solar panels.

The capital cost of those and my panels is our energy costs for the next ten years.

I also have a net income from the export  as a contingency.

Wow, that's very impressive - but also makes you an exceptional case amongst those of us with solar panels and a battery.  Off topic, but how much power are you allowed to export?  

oliver1951

Wow that really is a huge system. I’ve heard that locally it’s very difficult to get approval for any system over the 4-5 kWh. But why so large are you using that kind of electricity. As a separate issue what am I doing wrong. I can’t seem to select a portion of text for the quote, it keeps trying to dump in the total message.
And as a by the way I’m having terrible problems with the planning authority who have now demanded whole hosts of other information. Truly tearing my hair out now.

SeanSocks

I applied to BG for a survey. After giving details the Agent quoted me over £6 thousand on top of the Grant. I said that's a bit steep seeing as I won't need bigger Rads. or Pipework(We live in Penzance,it seldom freezes here) .....He answered, "You must have them by Law"...................a couple of weeks later I applied again and got a different agent, same price......but she said I could get a reduction if I do not need bigger Rads. or Pipes......

matt_drummer

Reed_Richards said:

matt_drummer said:

I have 38 kWh of usable battery storage and 13.3 kW of solar panels.

The capital cost of those and my panels is our energy costs for the next ten years.

I also have a net income from the export  as a contingency.

Wow, that's very impressive - but also makes you an exceptional case amongst those of us with solar panels and a battery.  Off topic, but how much power are you allowed to export?  

As I said, the panels and batteries are key to my plan.

I would think my set up is much bigger than most people would go for, but it's not as outrageous as it sounds.

At the moment my exports are earning me about £450 per month. I would expect that to continue until the end of August.

I haven't had it all for long enough to make any accurate predictions for a whole year, but I am confident that it will cover all the costs of running our heat pump in the winter.

I have no export limitation.

I export about 9 kWh at the peak from the solar panels.


I could export from my batteries if I chose to at times, but I don't do that. 

matt_drummer

oliver1951 said:

Wow that really is a huge system. I’ve heard that locally it’s very difficult to get approval for any system over the 4-5 kWh. But why so large are you using that kind of electricity. As a separate issue what am I doing wrong. I can’t seem to select a portion of text for the quote, it keeps trying to dump in the total message.
And as a by the way I’m having terrible problems with the planning authority who have now demanded whole hosts of other information. Truly tearing my hair out now.

I have had no trouble with the DNO here. 

We live in the centre of Ipswich, I guess my setup is irrelevant to the overall power used here.


I installed enough batteries to run our house and heat pump from Economy 7 electricity on all but the worst of days in the winter. I have yet to find out how close we will be to covering the worst day but I am confident I am close.

Then I just installed as many panels as I could, it maximises our generation in the winter when we need it most. The other reason for doing it is to generate the funds to pay for what we will need to import in the winter.

So far, the export is going really well. I moved to an export tariff in the middle of April this year and so far we have generated enough to pay for our expected winter imports. 

The rest of the exports over the next three months will be a bonus and go toward the capital cost making the payback quicker

Reed_Richards

matt_drummer said:

I have no export limitation.

I export about 9 kWh at the peak from the solar panels.

That's very fortunate.  But surely your DNO must have set some limit?  In principle you might export simultaneously from your panels and from your battery and blow the mains fuse?