Our quest for Net Zero one year on

QrizB

I'm still investigating it, but it's trying to find someone to get in to assess it who isn't biased! Most companies just want to sell me an installation and so will tell me anything to get me to agree.

If you know the dimensions of each aspect of your roof (you can get a reasonable estimate from Google Maps), you can model how many panels will fit and then get a reasonable estimate of annual output using PVGIS.

sheenas

https://forums.moneysavingexpert.com/discussion/comment/82056682#Comment_82056682

What no one talks about, in terms of efficiency we have around 50 GW wind and 20 GW solar generation capacity and we are using today around 16 GW. So not very efficient. I work in the Industry and the Industry recommended Nuclear, because it cost effective and known to work. Look at France, commercial electricity half ours. Look at Norway electricity variable across the day 8-12p.

Loosing the countries farming and manufacturing is a very high price to pay, further importing with extra shipping does not help global warming, it moves it to another country. IMHO the national interest to invest in Nuclear power stations from the likes of South Korea, which cost them 5bn dollars to build. Wind and Solar have a place, but not until cost effective storage solutions are found.

Domestic Solar and Battery are an important elements, but how ever much you spend on it, you need the grid as backup. Add a heat pump to install of solar and battery and you not getting much change out of 20K.

DIY Solar and Battery in Germany has 1m known and most likely many more. I suspect a battery with inverter and panels will set you back £1500. They comply with G98, but due to the complex paperwork I guessing few will complete it. The big saving being no scaffolding or installer needed. A flat roof or garden area is all you need.

Due to out of date infrastructure it will force national grid to fixing domestic supply in areas of high up take, but that is a good thing.

JKenH

I have had panels on east/west roofs for 8 years and at the end of last year added some south facing panels. The big takeaway for me is that while east and west roofs do generate significantly less per sqm, (particularly in winter), when it is overcast they generate as much per sqm as a south facing roof. You can also get twice as many panels on an E/W roof as on a south roof so in overcast conditions you have the potential make up some of what is lost by not having a south facing roof.

Jemma01

https://forums.moneysavingexpert.com/discussion/comment/82058994#Comment_82058994

and quotes are free. He can get as many quotes and ask the right questions (after doing his own research), and hopefully filter out the sale pitch.

Desktop quotes recommended less panels for me, so having ppl come and measure maximised my panels count, so I recommend you look for at least 1 that would visit the house @jimi_man work out the size of the roof + the angle of the roof.

The hardest part is figuring out how much sun you'll get, there are website that help with this, I personally found them too technical and not user friendly when I was researching, but my roof is South facing leaning slightly west, so no brainer.

QrizB

What no one talks about, in terms of efficiency we have around 50 GW wind and 20 GW solar generation capacity and we are using today around 16 GW. So not very efficient.

Capacity factor does not equal efficiency. That's why no-one should to conflate the two.

... the Industry recommended Nuclear

I don't think that's true. Can you provide a link to an industry report which makes that recommendation?

Ideally one not authored solely by EDF, Hiachi and Rolls Royce.

Look at France, commercial electricity half ours.

France has only built one nuclear plant in the last 20 years. Nuclear power generation peaked in the middle 2000s. Renewables have taken up the slack.

Look at Norway electricity variable across the day 8-12p.

Norway's power is 90% hydroelectric, zero nuclear. Not something we can realistically emulate.

Wind and Solar have a place, but not until cost effective storage solutions are found.

Renewables plus storage is already cheaper than new nuclear. There was an announcement of several new storage schemes only last week.

Loosing the countries farming and manufacturing is a very high price to pay

UK agricultural output depends largely on government policy towards environmental stewardship. Use of land for solar PV or wind is a negligible impact. More land is used to grow cereals for 5% bioethanol in petrol than is required to produce enough electricity to supply the entire UK EV fleet.

https://www.gov.uk/government/statistics/agricultural-land-use-in-the-united-kingdom/agricultural-land-use-in-united-kingdom-at-1-june-2025

.Loss of manufacturing capacity is also a result of Government policy. Loss of manufacturing *jobs* however is largely a result of automation; mass blue-collar employment on production lines is simply not coming back.

QrizB

Note that this thread is currently highlighted on MSE's forum home page:

We might get some new visitors to the Green & Ethical forum!

jimi_man

https://forums.moneysavingexpert.com/discussion/comment/82058957#Comment_82058957

Hi. Some good information there, thanks.

Ultimately everyone's situation will be different and I think that's key. We don't have an EV and have no real plans to get one yet. Our oil boiler is A rated and only 3 years old. With a plastic double skinned tank we are probably good for another 15-20 years so it doesn't make much sense to replace it now. In 15 years time it will be a different matter and I'd probably go for a heat pump (I might have no choice then!) as the maths stacks up a bit more in our favour as we'd have to replace with something, but at the moment the figures don't really work since if I replace it now with a heat pump I'd likely have to do it again in 15-20 years. If, as in your case, your boiler needs replacing now then that balances the maths a little more.

With solar it's a little more nuanced. I've read similar stuff about E/W roofs and also that West facing ones give energy when houses need it the most (late afternoon). Presumably a battery evens that out and makes it less of an issue hence having them on both roofs. But to install something that gives us net zero electricity costs is going to be in the ballpark of £15k with a decent battery (from what I've read on here and elsewhere) which will save us £800 a year.

I should add that I'm not knocking heat pumps or panels. I like the idea of saving the planet a bit and both of those things help towards that. I'm trying to find a way to justify it, but at the moment cost effectiveness isn't it.

I suspect, as you've said, that it's the sum of all parts so it pays to have everything done within the same timeframe and working towards the same goal (EVs etc).

We're not at that point yet but once we start going down the line of replacing cars/boilers then there will be some decisions to be made and cost effectiveness won't be the whole picture.

QrizB

But to install something that gives us net zero electricity costs is going to be in the ballpark of £15k with a decent battery (from what I've read on here and elsewhere) which will save us £800 a year.

I think you've overlooked export payments in that calculation.

If you're spending £800 a year on electricity (as opposed to standing charges) that's perhaps 3500kWh.

If you spend £15k on solar PV you'll get maybe 20 500-watt panels and a PW3. Split E-W you might generate 8000kWh/yr, rather than the 10000 that you'd get from an idealised south-facing array.

You'll use 3500 of those, saving your £800 of import payments. You'll export the remaining 4500kWh, earning another ~£500. So that's £1300/yr of benefit and a 12-year payback.

After 12 years you might need to replace the PW3 but the panels on your roof should be good for at least double that life.

Martyn1981

https://forums.moneysavingexpert.com/discussion/comment/82059076#Comment_82059076

I know exactly what you mean, and tbf it's also a bit scary when all this stuff is thrown at you.

QrizB beat me to it, suggesting your £800pa income on £15k PV and batts, seems a bit low. But if you're not ready for batts yet, and it is still a marginal decision*, then a big system, as QrizB describes, may be about £8k for PV. Solar consumption without batts will be a bit lower, but export earnings a bit higher, so maybe £1k to £1.2k of savings pa, so again a good return I think.

Not lecturing you, nor saying you should do this, just chatting and pondering, and hopefully spreading ideas - food for thought, as you're clearly interested, but understandly skeptical for now. The good news though, is that the technology keeps improving and costs keep falling (give or take inflationary increases).

*Where batts really improve economically, is when you have cheap rate, to charge them in the low generation times of the year. So you still get to avoid day rate prices by buying cheap rate (rather than generating it all yourself). And from there suddenly they boost the savings on heatpumps, by again reducing dayrate imports, and some of the best cheap rates link to BEV's ….. so the benefits stack. But only as and when folk are ready for each additional part.

Screwdriva

https://forums.moneysavingexpert.com/discussion/comment/82059076#Comment_82059076

@jimi_man A 8+ KWp system (16 X 515W Eurener bifacial panels) and a Tesla Powerwall 3 with Gateway 2 can be had for ~£12K, and that this system will generate around 7MWh per year on an E/W roof (assuming no shading). Each homeowner's usage will vary but assuming that each KWh generated is worth 22p, that's £1500 a year or ~12.5% return or an ~8 year ROI. Add in lucrative tariffs like Octopus Intelligent Flux, and/ or more panels if they'll fit on your roof, and that drops further to around ~7 years.

I haven't factored in future energy inflation etc. Hope this helps clarify Solar for you!