How are people actually calculating their home base load?

TroubledTarts

https://forums.moneysavingexpert.com/discussion/comment/81965273#Comment_81965273

I went further on these so called plug in balcony systems than that in another thread and suggested the payback for lots of people would be as low as £50 in flats where their base load during 9am-5pm could be 100w per hour so a total of 800w that the solar could pay for each day. Given a maximum of that happening regularly 200 days a year that's 160kwh and pricing 1kwh at 25p that's £40 a year. (The 200 days was used to negate winter and cloudy days and could still be considered as generous) I haven't factored in weekend days where more could be used so call that 1kwh per weekend day for the same 200 days that's a potential 60kwh so 220 at 25p £55

It's all down to lifestyle

If someone is home during Mon-Fri 9-5pm they can definitely start to make the savings move up to the £100 mark

For us we have worked out we could save circa £90 with such a system with a setup cost of £200 so the payback is good. Those buying a kit for £400 and only saving £55 a year, not so good but that's ok too.

I suspect a proportion of people won't understand that the energy isn't all going to come off their bill and be disappointed but the winner of these systems is everyone with all that free power entering the grid it should reduce costs significantly in the summer (should)

Newbie_John

@TroubledTarts , fully agree.

Sadly a lot of people don't understand how solar works and just carry on with average estimations. Proper installation comes with export - and that's a big winner - people see money off the bills right away. Here, the start is great - you pay 5% of large set up costs and have your own solar system - so more open to many people who can't afford £6k.

But it comes with more limitations, if you're away from home Mo-Fri then it will take 10 years to pay back, sales people suggest battery - but let's be honest - it triples initial cost and doesn't help pay back time.

I'm in two minds because of being on Cosy with 10p rate between 13-16. We work from home great, but at the peak solar time energy is cheap for us, unless panels faced to south west and hope for as much coverage of 16-19 period as possible.

always_learning22

Came across a plug in solar calculator that seems a bit more data driven than most I’ve seen. It uses PVGIS for irradiance, factors in sun position throughout the day, and tries to account for base load usage rather than assuming everything gets exported. You can also adjust things like whether you are home during the day, which makes quite a difference to the outcome.

I’m still trying to sense check how accurate it is in practice, especially compared to real world setups. If anyone here already has panels or a similar system, would be really interested to hear how close these kinds of estimates usually get.

If anyone wants to try it, just search “plug solar hub calculator” and it should come up.

QrizB

.. unless panels faced to south west and hope for as much coverage of 16-19 period as possible.

My roof faces ~210 degrees (a bit west of south, but not fully SW) produces about a kilowatt (40% of nominal capacity) at 1800 BST and about 250 watts (10%) at 1900 BST on a sunny early-April afternoon.

lohr500

https://forums.moneysavingexpert.com/discussion/comment/81965535#Comment_81965535

Got it!! Thanks.
I hadn't considered the impact if trying to run off a limited solar or other off-grid input.

tim_p

https://forums.moneysavingexpert.com/discussion/comment/81965898#Comment_81965898

this sounds a bit familiar!

(Or am I mistaken?)

TroubledTarts

https://forums.moneysavingexpert.com/discussion/comment/81965898#Comment_81965898

Sadly it's double what our 2 450w panels would produce and we would use it came out at £140 when the real world is £70-80 because it is a little bias on the estimated self consumption.

But of course the calculator will be biased as they are trying to sell kits to those that don't know any better and trying to say it's a 3-4 year payback.

TroubledTarts

https://forums.moneysavingexpert.com/discussion/comment/81965963#Comment_81965963

You are not mistaken

always_learning22

https://forums.moneysavingexpert.com/discussion/comment/81965990#Comment_81965990

not surprised there , is your with or without battery ?

TroubledTarts

https://forums.moneysavingexpert.com/discussion/comment/81965998#Comment_81965998

So to be clear we track our solar generation through battery to the minute so we know what we produce. We also know our home habits and base load so we know exactly what we produce and would use and be able to use. If we maxed the year out (difficult to do with holidays, time away and working away we might be able to get to £100 payback a year) but that's unrealistic so that website amount of £140 is ridiculous.

We haven't got a micro inverter yet as we ponder our next steps in solar/battery generation and connecting to the house/grid