Speak EV - Electric Car Forums banner

21 - 25 of 25 Posts

·
Registered
Joined
·
170 Posts
I can't understand that. A bad year isn't that much different to a good year.
Hah... you don't live where I am living. :) A bad year can be dull an dark, very thick clouds all through the summer, with very few clear days and temperatures not higher that 15-17C. A very good year, like two years ago, can be very clear and sunny almost every day for three months and temperatures around or even over 30C several times. While I know you don't need clear and sunny days for producing electricity, the clearer and the sunnier it is, the better it is also. So yes, there are some good years and some bad years, and during such short payback period, you don't need more than one or two bad years to ruin that calculation, since it is based on average weather and what statistically is expected, not the extremes. On the other hand, one or two extremely good years would of course balance that, or make it much better, especially if the bad years never come during that period.

Never the less, my point was that you never know, you make a long term investment based on the assumption that the weather will be a certain type, following statistical data. Reality may be different, so if that is critical to anyone, then solar panels may not be the best investments one can make in ones future economy planning.

Increasing consumption would ensure that you have more chance of using your own power and help guarantee the return. I was lucky in getting the early FIT, so mine are already paid for and into profit.
I will have no problems using up almost all of my self produced electricity, at least 8-9 months of the year as it is. My house is pretty large, not using any fossil fuel, have electric heating, plus one EV and a PHEV today, which are charged every day so I am consuming quite some power most of the year. During high summer I will be producing most of it during the working hours, will not need heating and the cars are out. Coming home around 5 pm, and while normally during summer we have good sun a fair bit more and is not getting dark before 10-11pm, also getting light again around 2am, it will not be enough for charging two cars, so I have to buy at least part of the power. Some times (not unusual) we also need to heat the house during the night, especially during "bad" summers. If I would get a high capacity EV to replace my PHEV with, then I would need to use even more electricity from the grid.

Anyway, I hope I am wrong about this, but I think not, so for me it is more about "giving back" than making profit, but of course, if I can make profit in 8-10 years, and I am still alive then that's even better. Right now, I am a newbie, my solar panels being in operation only since the beginning of this year, but I am an engineer, so I am not totally lost in the subject, but also not overly optimistic. In this respect, regarding the financial investments, I think it is better to be a bit pessimistic than optimistic. It is a big investment for most people, so i my opinion, it is better to have a pragmatic approach, not to be overly optimistic when one decides for going solar.
 

·
Registered
Joined
·
1,844 Posts
Discussion Starter #22
Even the worse Solar system has a payback inside 20 years so is "profitable".
 

·
Registered
Joined
·
170 Posts
Even the worse Solar system has a payback inside 20 years so is "profitable".
Yes, assuming no major parts break down, or that all failed parts are covered by warranty. Besides, 20 years is a pretty long term investment, so investing the same amount in something else may give better profit during the same period. Also, the total lifespan of solar installations is calculated to be maximum 25 years, after that it is expected that every part of it must be replaced, so calculating with 20 years is in my opinion totally wrong if economy and profit is the only aspect.
 

·
Registered
Joined
·
179 Posts
You shouldn't ever look at solar as a long term investment unless you know the cost of electricity saved, and the unit price of electricity would out pace inflation.

£8000 in 1999 would be nigh on £14k now at 2.8% averaged inflation. Do doing the simple calculation at the start makes no sense.

You buy solar because you want to help not just your pocket, but our reliance on fossil fuels and expensive grid infrastructure.

There's obviously a lot more to it than that, but looking at payback time is a fools game IMO. :)
 

·
Registered
Joined
·
116 Posts
The point is this: until recently there was a financial incentive to install solar PV with the Feed In Tariff giving you an income for every kWh generated regardless of how much you use or export. That no longer exists.

At the time of my installation the FIT was around 4.14p/kWh with a further 5.03p/kWh for the deemed 50% export. This increases with RPI every year so is inflation proof. My 3.42kWp array cost £4150. At the predicted rate of generation of 3250 kWh/year that's a little over 19 years to break even; before considering any savings from reducing my import from the grid.

Assuming that a similar sized array would cost a similar amount today, and assuming 50% export at the current highest market rate of 5.5p/kWh, it would take 46 years to break even.

Where I save the full cost of each unit I am able to self-consume (because I still get paid the deemed export), you would be reducing your export income by using the energy yourself. So you save around 7p per kWh to my 12.5p. I estimate that I use up to 2000kWh of what I generate each year.

So, real world figures: my combined income and bill savings total £466 per year. If installed today it would total £318. My installation is guaranteed for 10 years (the panels themselves for 20) and I am projected to break even inside 9 years. Today's installation would be looking at 13 years - nearly 50% longer.

Essentially I took a gamble that my solar panels would last at least 9 years. Any less and I would be out of pocket; any more and I would have saved some money. If they last for 20 years then I will have saved around £5000.

If installed today, after 10 years you would still be £1000 out of pocket. After 20 years the maximum potential saving is £2225. That seems like a much bigger gamble.

Obviously there are factors other than money, and there are different calculations depending on the way you actually use the energy. However, it is really important to actually do the sums and make an informed choice based on accurate information. If you wanted to spend £4000 and weren't worried about any return on investment then there are probably better things for helping the environment.
 
21 - 25 of 25 Posts
Top