Solar Panels, how much energy do they realistically produce?

ProTofik

I'm trying to calculate if it's worth for me to invest in solar panels. I am about to finish paying off my HP car which is £200 a month. I'm not planning to change it for another 5 years or so, and my next one will hopefully be EV. My electricity bill right now is £60 a month but I'm sure it will go up at some point. I think I could afford to pay for the install on a 0% credit card and pay it off £300-350 a month.

I live on my own in 3 bed semi in N. Ireland and I work from home. I have changed oil heating to gas combi boiler last year so it's all brand new and efficient.

I monitor my electricity usage so I know that on average day I use 7-8kWh. If I'm doing laundry/batch cooking/baking etc I would use 11-12kWh. My average is 215kWh per month throughout the year.

My house has a funny shape, one side of my roof is longer than the other. The longer side, East facing is 45 degrees steep whereas West side is standard at around 30 degrees I guess. 

My base load when I'm working, using tv, and so on is at around 300-400W. My base load when everything is off at night is 145W. I was also thinking that if I had solar panels, I could get electric heaters in the winter into my bedroom/office/living room, connect them to my house automation system, and have them automatically switch on/off with my central heating if I'm overproducing enough electricity to run them. Of course that wouldn't be enough to heat up the entire house, but should bring down my gas usage a bit.

How much worth of solar panels would usually fit on an average 3 bed semi house's roof? How much power does it realistically produce? Is it worth getting if I my roof is East and West facing?

Petriix

East/West in NI is likely around 700Wh per kWp. A 6kWp array will likely average about 4,200kWh per year. You'll likely use about a third of that and export two thirds. At the current price cap you'll save around £400 per year off your bills and earn an additional £140 in SEG payments.

A 6kWp array used to cost about £5k which would roughly take 9 and a quarter years to break even at today's prices. However, installation prices have jumped by about 30-40%. With the projected electricity price rises you're likely still looking at a little under 10 years to break even.

With your low usage, batteries are definitely not worth while today. Next year, who knows... 

[Deleted User]

There are various tools that you can use to calculate solar output. A number use Google Earth:

https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html

xeny

East and West facing give a much longer but lower peaked production profile through the day. As panels have got cheaper that approach has become more attractive.

The flaw in your plan is that panels produce hugely less energy in the winter than the summer, so as you don't have a huge roof (I'd _guess_ you'd get a 3-4KW peak output system on one side)  you're unlikely to get enough in the winter to do anything meaningful with electric heaters.