Your tech and how it works for you

Think you need to revisit your ROI calcs for solar panels, I'm in N Scotland and generated 4,200 kWh in 2024, even if I just exported it all @15p per kWh that's £630. My PV setup (4.8kw panels, 3.6kw inverter) now is probably £3.5 to £4k installed. I used about 40% domestically, 20% diverted to my tank immersion and exported the remainder. This year the YTD solar generation is up 20%.

Battery costs have also plummeted but ROI is still a few years more than PV.

p.s. also have A2A 👍

I think this is a key aspect in any green energy strategy. You are correct in looking at each setup being unique which does beg the question of how to put everything together for mass market adoption.

I have noted my reasons for moving a few times but the capability to make use of existing tech (already installed solar PV etc) within a tariff on offer is important when choosing a supplier.

The ability to make use of off-peak rates is needed whatever the meter installed (I’m not talking about non-smart meters). With the move to half hour settlement expected, the facility to match this in billing for meter reads would be a huge step forward.

I guess I should say right up front that my primary motivation is not financial but reducing my long term impact on the planet. Having said that I have so much to say on this topic but i’ll start with my view on ROI (Return On Investment). This is very different from pay back period.

ROI is how much return you get on the money you have invested in your technology. I am lucky enough to have had the spare income to have saved hard all my life. I now have a substantial private pension pot. If this is invested for guaranteed income I can get roughly 4% return. If I take this money and invest in solar PV, Heat Pump, Insulation, Battery, EV etc. I can do my part to reduce my families fossil fuel use while also getting a better return on my money.

For instance £10 000 invested gives me £400 per year income. If I take that £10 000 and spend it on solar PV and battery I can save much more than £400 per year on my electricity bill.

I haven't  even considered how long it will take to pay off the £10 000 because it’s income(reduced outgoings) that’s important to me. I could spend the £10 000 on a cruse but get much less pleasure and satisfaction.

I did using my detailed energy use vs daily and seasonal production and the installation costs are much higher due to the last round of inflation. My direct energy use is about 32% but I'm only paying 19p per unit so the rest would go to SEG. Given achievable values of cost and SEG my payback time is 11 years in my particular case assuming there are no maintenance costs (replacement inverters etc). This is where individual circumstances make one case viable and not in another. You need the detailed calculation for generation (quantity and shape) , use (quantity and shape), supply cost (variable in my case**) and SEG rate (could be fixed or variable).

The payback time for a battery (~5kWh but strangely it doesn't change much with size) is longer than the lifetime of the battery. The advantage of having a battery though is if future SEG rates fall. They are likely to do with the very large solar farms coming on line in the near future and Octopus are only renewing SEG with time of use (generation) rates. It's very true that battery costs per kWh are falling quickly but even the installation cost kills the idea although power arbitrage (buying cheap overnight, selling during the peak) may prove to be profitable.

The A2AHP is a clear winner though.

Peter

**Agile complicates the calculation because the rate changes every half hour. Over the past month a lot of sunny, windy afternoons have meant my rate has been near zero.

​@brichard Thank you for your very considered and reasoned reply. I have said in previous blogs that if your motivation is to go green and reduce your impact then ROI or payback time is not even a consideration. You have the money, you invest in the tech and then reap the rewards in terms of an income and reduced impact.

In terms of ROI I have had recent fixed rate online bonds mature that have returned 4.5-5%. If you have a mortgage at 5-6% then it is arguable thet you will get a better return paying off the loan and I've always said that high mortgage rates will affect decisions on investing in green tech. A question is: What is the price for helping to save the planet? The answer is: The price you can afford. Green tech should always be affordable for those who have to choose between one option or another.

This thread was about getting people to talk about their particular circumstances, experiences with the hope that this would help others navigate a green path without making an expensive mistake because they hadn't considered their particular circumstances. I'm tring to get people to ask WHY they are considering these solar panels, that battery system or tariff. I'm also hoping that OVO staff will look at the responses to see how best they can help their customers or potential customers make the right decision and perhaps look at the tariffs they have and see if something else can be offered which is both profitable to them and cost effective for their customers.

Peter

​@BPLightlog We've had a number of useful discussions recently and you've always been spot on. I particularly liked: If you have the tech already then go an find a tariff that makes the best use of it.

If you are starting out from scratch then try and find a combination that works but the whole thing is very much a dynamic situation. SEG rates change. Suppliers come out with different tariffs. The prices of solar and battery change.

Here's a thought. Instead of fitting solar panels how about investing in a solar farm (if indeed that is possible). But, there was a scheme in the north called Ripple which was a wind farm investment that went badly wrong for a number of reasons so it has its caveats.

Peter

Strangely enough, I did also put my hat in the ring on the Ripple investment. The existing projects are actually still producing as once set up and construction is underway, they are then owned by a separate company.

GIven the state of things, it’s a shame that Ripple didn’t survive but there are other options

The point about this thread is that it is here to promote a discussion amongst a group of people who have experience or other information and it was the point about investing in renewables rather than fitting them that led me to this 🙂

https://solarfast.co.uk/blog/solar-farms/

PLEASE, please, please - THIS IS NOT AN INVESTMENT GUIDE! That figure is probably the free-wheeling downhill + following wind return value and I would be expecting something more modest but it does indicate that investing rather than fitting is possibly an option. I would consider doing that as I would see that as being just as green as house solar panels. It also means I wouldn’t be tied to the house waiting for it to be paid off or be concerned about recouping the investment if I needed to sell.

The reason for the return to profit after such a short time is basically the economy of scale. They buy cheaper in bulk and can strike a lower rate for the installation and maintenance.

Peter

To add some more information on my journey and how I got to where I am today. 1930s partially extended house with lots of solid 9 inch brick walls always cold. External Wall Insulation for solid brick work Feb 2022, ASHP with radiators installed Nov 2024, 8kW peak solar panels and 16kWh of battery.

It all started when I applied for a grant to have the house insulated. This improved the could house but not by much, it was still cold. I have never been happy burning loads of gas to keep the house warm. So I started looking at heat pumps and radiator upgrades. I got quotes form 3 suppliers which suggested I needed a 10kW heat pump which would require planning permission due to it’s physical size. I applied and was staggered to be turned down even though the heat pump was 8 meters from my closest neighbor and this is not a quiet neighborhood. I did some more research and talk with my suppliers further and decided to have a 7kW uni t installed with radiator upgrades. The supplier did a reasonable job and really understood how to design an efficient heat pump system. The system has been running all through the 2024-25 winter and I’m really pleased. The house was so much warmer and the cost was just a bit more than I was paying for gas. If I had heated my house with gas to the same extent I have with the heat pump the cost of the gas would have been 50% more than the electricity I used.

To complete my plan I has the solar PV system installed at the end of May 2025 so it’s all still quite new. But I haven't used ant electricity from the gid since the solar was switched on and have exported 580 kWh. At a SEG price of 12p per Kwh from OVO that is £70 in less than a month. Now I know that this is probably one of the best months of the year and I won’t see much solar in the winter but I’m hopeful of having a close to zero energy bill over the whole year.V which I have had for several years.

I’m still weighing up which tariff to go for. I currently have an OVO tariff fixed until September so I’ll decide then. Octopus Go is looking possible but I may well stay with OVO. I would love to se OVO do a battery charging add on so that I could charge my battery ar cheap night time rate to drive my heat pump through the long dark winter days. Octopus SEG price is 15p kWh I think so I would be good if OVO could get close to that.

Please ask any questions if you think my experience might be helpful.

Bruce

Personal view, but I wouldn’t go near any green investment schemes as in my opinion the entire renewables sector is still very much struggling to find a way forward, not helped by a vague net zero ambition that can change dramatically depending on the political ambitions, another good reason to have your own power station on your roof, personal energy security! And its tax free - at the moment.

Yes, everyone’s personal circumstances can impact the viability of renewable installations, for me the Scottish Government 5 year zero interest loan for the PV installation was a big positive and knocked a year of the ROI, probably between 6 and 7 years at current rates.

I’m also with Octopus, was on tracker till April this year, might venture back into tracker but we’re importing so little electricity this year I can’t get excited about it just now, Agile is too much like hard work for me. I’m a big fan of Octopus and their forward thinking strategy that give customers options based on their personal circumstances.

2nd house with the A2A is OVO, was THTC with storage, so A2A is a real revelation, instant heat, fraction of the previous energy use, can, and do, control it remotely. At the end March the house used 8kwh/day to maintain the temp at 20 deg C from 8am till midnight, 2 bed, 2 storey, 50’s built. Of course no government assistance available, but zero VAT at least.