Solar PV

The case for PV solar panels on your home:

PV solar panels produce electricity which you can either use yourself or export to the national grid.

In 2011 you could get 40p for every Kwh you produced from solar panels fitted to your home.
In 2018 it's 4p for every Kwh you produce and a further 5p for every Kwh you export to the grid.
These payments are referred to as FIT (Feed In Tariffs).

At first glance you'd think it's hardly worth getting them fitted nowadays.
However:

• PV solar panels have come down in price hugely
• If you can use a lot of the electricity you generate then your bills will be reduced significantly
• If you have a small pot of money languishing in a building society somewhere that you are using to generate a small income from (interest) then the investment is better off on your roof
• PV solar panels (that you own) can increase the value of your property

 Our example:

We had 10 x 0.295 kwh panels fitted. So, on a sunny day they can produce 2.95 kwh.
It's estimated that in a year we would produce 2579 kwh.

2579 X 4p =  £103
It is deemed that we would export 50% of this to the grid and use 50% ourselves.
The equipment installed can't actually measure what is being used or exported, the FIT is based on the the assumption that we would export 50%, and the FIT payment to us is based on this.
So 1/2 of 2579 X 5p = £65.

A total income through FIT of £168 per year. Not a huge amount - but the key point is:
Any of the electricity we use, of that we are producing during the day, is free to us. So the electricity used to do the washing, or heating water etc etc during the day when we are producing electricity from our panels costs us nothing.
It is assumed we would make a saving of £144 in the year.
I personally think it will be much higher, as we are totally electric - water heating, space heating etc is all using electricity. I think the figure will turn out to be nearer £160+

The system cost £6050 to fit.
In a year the panels create £144 + £168 = £312.
If I keep the £6050 in the building society I'm lucky if I can get 2% on the investment.
By investing the money in solar PV I'm effectively getting a minimum of 5.1% .

It is as they say a 'no brainer'.
Additionally, the panels will increase the value of the house.
It also feels quite nice to be producing and using electricity that is less polluting in the long run.

Further details:

• Our system was fitted  by EON. The cost stated above includes everything - fitting of panels, erecting scaffolding, providing all monitoring equipment etc
• We chose an expensive system with higher output panels and a long life inverter. You can get a similar but cheaper system for around £4300. 
• The system we bought is particularly good if a shadow falls on any of the panels - in simple systems if you get a shadow on one panel the whole array will not produce any electricity. We have a cheeky telegraph pole that casts a shadow on the roof for part of the day.
• Our inverter is said to have a life of 20 years - cheaper ones only 5 years
•  Using the electricity you produce is the key to getting maximum value from the panels - could you heat a hot tub, charge your electric car?
• The system we have - Solar Edge - comes with a smart phone 'app' that tells you how much electricity you are producing, how much of it you are using and also shows your total electricity consumption - all in a nice little graph. It shows all this for each day, or week, or month or the year. Great for 'technogeeks' like me. In the screen shot below you can see that as it was a cloudy day we were only producing 300w and using 3.14 kw from the grid.

• Very soon it will be worthwhile getting batteries to go with a PV array. This will mean being able to store electricity produced during the day and then using it to run appliances at night time or when there is no light. Lithium Titanite is on the way. These are very safe (unlike lithium ion), can charge very quickly and have a cycle life of 3000-5000 times. When the prices come down, battery storage for PV will be viable.