You might have seen my solar installation on the other thread, but here it is again :
That comprises 16 panels rated at 250W each, for a total capacity of 4kW.
I live in the South West of the Uk. Torbay in Devon to be precise.
Ideally the panels should face south to get the most exposure time, but ours face west.
This is not too much of a problem as for much of the year, the sun spends more time in that quadrant of the sky. Also, we live by the coast, which is about 1.5 miles from the other side of the photo above. This causes local weather like mist that can hide the sun for a few hours every day in the mornings.
So west facing is better than east, and we have no facility for south facing anyway.
Apparently these panels do not need direct sunlight to work, but I think that is largely marketing, as until the sun gets quite high and shines on the panels directly, we only get a dribble of power. This can be monitored using the supplying companies "portal". The solar generation meter and inverter are wifi enabled and talks to a remote server.
Here's a typical portal shot :
The top row shows live figures, probably self explanatory. They don't match the graph because I have selected yesterdays output graph to illustrate the daily power "curve".
As you can see, the maximum figure generated yesterday was 3240 W at around 13:40 GMT+1
It was a good day yesterday. Total generated was 20.1kW. Not every day is this good, but as the seasons change it should wax and wane. Some days we generate less than 1kW total.
Anyhoo, that's the basic set up. I've been trying to find the relevant technical papers but my partner "files" things 
My interest is in the mining opportunity here.
We had these panels fitted around Jan 8th. There is not much sun at that time of year. However, we got a payment from our energy supplier at the end of March. This is the end of the financial quarter and we received £190 for our generated power.
That might not seem a lot for nearly 3 months, but they only pay us for half of what we generate. Which means we actually generated £380 over less than a quarter, and at the worst season for generation.
We don't have an export meter (most private installations don't). So the power company pay us half the generated amount, regardless of our usage. There is a small govt. subsidy too, per unit generated.
So, being anxious to get "Good Value for Money" I thought that I could run miners right up to the full capacity of the panels and not have to pay power.
It doesn't quite work out like that. I have to use creative accounting.
Power costs 0.11 per kW
Miner (S5) uses 590W costing £1.56 per day
Miner generates around 0.015 or £2.28
I put to one side the money for the power used. Over a quarter this would amount to £140.40.
When we get our feed in payment, we get maybe another £190, possibly more.
So the miner has actually generated 205.20 and cost nothing to run plus we have been paid for the pleasure. We also have only used less than half the possible generating capacity. As long as we generate enough on average to cover a miners monthly consumption, we don't pay any power costs. Of course it gets dark. We will still get an electricity bill for that. But most of it is gravy.
You start to ROI in 3 months on an S5 costing £300, as long as BTC prices stay above $240.
It can be scaled to more than one miner. We are essentially getting free electricity, being paid for half of it AND free mining. No limits other than generating capacity. Mining is more affordable under these circumstances. However, even free power can't bring some hardware back to economic life.
Please feel free to point out glaring logical errors in my math or thinking. IS it too good to be true ?
[edit] Changed "I pay the power bill from the miner" to "I put to one side the money for the power used"
[edit 2] I ought to point out that if bitcoin prices drop so that the miners don't make any profit, this essentially becomes a crypto related piggy bank. I put what I would have spent on power away for later use. But my partner likes to see the miners paying their way power wise so that's how I think about it. Plus it's good to keep an eye on the profit/power cost relationship.
