By all means. There are a number of articles, but this one is a good example.

I'm generally very much in favour of hydroelectric storage and generation. My caution is in relation to its scalability in the UK, not its reliability or effectiveness.

I can see the carbon tax, etc being able to keep some battery production within the region, otherwise the countries that can overlook our typical concerns will still deliver them..

@scalextrix 

I'm not convinced that solar panels in the UK are a "guaranteed payback", especially with a Heat Pump.

How much electricity will you need in winter with a Heat Pump?

How much electricity can your solar produce during winter to cover this?

How useful is having solar in the summer when your HP is only producing hot water?

Export rates for solar are plummeting, so excess solar in summer will be sold back for less than is anticipated.

There is a benefit if you have an EV and do a fair few miles so could charge during the daytime, or if you have aircon at home, but not many households do.

The maths for me pointed to buying in cheap electricity overnight and storing it in a battery bank for use when you really need it, when your Heat Pump is guzzling units at a vast rate in the winter with solar panels sitting idle.

In the summer months looking at our data our batteries are discharging about 11kwh a day.

In the winter they are discharging about 25kwh a day and we haven't even got our Heat Pump yet.

Export rates have dropped for pretty much all suppliers recently, with Octopus holding out, but for how much longer?

Posted by: @bash

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@scalextrix 

I'm not convinced that solar panels in the UK are a "guaranteed payback", especially with a Heat Pump.

How much electricity will you need in winter with a Heat Pump?

How much electricity can your solar produce during winter to cover this?

How useful is having solar in the summer when your HP is only producing hot water?

Export rates for solar are plummeting, so excess solar in summer will be sold back for less than is anticipated.

There is a benefit if you have an EV and do a fair few miles so could charge during the daytime, or if you have aircon at home, but not many households do.

The maths for me pointed to buying in cheap electricity overnight and storing it in a battery bank for use when you really need it, when your Heat Pump is guzzling units at a vast rate in the winter with solar panels sitting idle.

I'd suggest it's not an either/or.

For us, the summer time is good not just for the solar export but also for covering the residual load (let's remember we have a 9-10 kWh daily load for all the stuff most households have). Having the battery allows us to avoid importing for most of the night too as well as taking advantage of negative pricing periods.

The winter is good because the battery allows us to import from grid and timeshift usage so taking us through the expensive stretches at non-peak prices. The PV also allows us to mitigate our normal usage and avoid some grid imports - even in the winter we can be generating several kWh per day.

In the shoulder months, there's enough PV to significantly offset the heat pump's appetite during the period when it's running pretty efficiently, and the time-shifting ability of the battery extends that further.

For us, having a system that can play the heat pump, the solar PV, the battery, the EV and the tariff off against each other means all the parts have a role to play rather than it being a simple choice of solar panels OR battery.

@majordennisbloodnok 

If you have a HP for me you should have battery storage if you can, so it's not necessarily one or the other, you really should already have batteries (ideally).

If you have a HP and battery storage, the question comes down to is it worth buying in more battery storage (which has a significant economy of scale as you have already paid for the inverter and system installation), or add solar (or both).

If you don't have enough storage in the winter you will need to buy in electricity at a higher price.

Is it a better ROI to invest in more batteries, or get some solar instead (you can obviously do both)?

Since we installed our batteries we have imported about 1% peak electricity, the rest at under 7p a kWh in the entire year.

If I had solar therefore my cost comparison for ROI is based on buying in electricity at 7p a kWh, with maybe some money back if I export excess in the summer months (all though these rates are dropping).

How many solar units would you need to generate and use to get a return on the solar panels at 7p kWh?

100,000? More?

Posted by: @majordennisbloodnok

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For us, having a system that can play the heat pump, the solar PV, the battery, the EV and the tariff off against each other means all the parts have a role to play rather than it being a simple choice of solar panels OR battery.

And perhaps even more importantly having the flexibility to adapt to any future changes in electricity pricing and export rates etc gives you the ability to mitigate against future shocks.

It's easy to analyse based on current usage and price structures, but the one thing we cannot know is what tariffs will look like in 1,2,3 years in the future. 

@old_scientist 

This is correct 

I asked myself this question. if I invest in renewable heating, electricity generation and storage what are my risks?

The biggest one is that the tariffs change.

With that in mind (and being from a financial background) I looked into this in more detail.

Without too long a post, the risk seemed more weighted to export rates going down as we don't get as much sun in this part of the world and looking at other countries who have a lot more sun they don't get much to export, if at all, so rates have plummeted.

Secondly we are installing huge amounts of wind generation on and around our island.

We already have a problem with wind energy being wasted, even paying companies to shut down turbines.

This energy overnight really needs to go somewhere and battery storage is the best way.

This led me to believe that overnight cheap rates should be around for a good while longer, whereas solar export rates will most likely fall.

Taking the plunge on a Heat Pump has been a long (and at times torturous) journey trying to decide if it's worth the risk and the cost of electricity going forward was at the forefront of that.

Agree with both of you, @bash and @old_scientist. @bash because your penultimate post is underlining that any choice of the best path is a relatively complex compromise and @old_scientist because the flexibility is the real crux - we don't know what will change but we do know something will.

@old_scientist Bit like the Stock Market innit?! ☹️

@bash The EV tariffs are of course, there for those with EV’s that can be charged when the energy is most abundant and would cost us all more due to wastage and compensation payments to producers were it not gobbled up. But wait a mo… why not extend that tariff to allow those with storage elsewhere around their home or garden rather than exclusively those storage system supported by 4 wheels? Toodles.

Posted by: @bash

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Export rates have dropped for pretty much all suppliers recently, with Octopus holding out, but for how much longer?

Hopefully export rates hold out during peak times. Future export rates, etc was my reason for cutting all the MCS costs...

For PV, I had a quote for £5k for 4kw max production - it will not have ROI, even setting aside the headache of getting anything done right. They say they already accounted for the inverter. But only someone doing it outside MCS could get close to the real cost. We would consume some of it with a heatpump but I suspect not enough and I also believe the overnight rates are likely to stay low...