Thursday, 23 January 2014

Solar - how did that happen?

In November 2013 my father got solar panels - I think mainly due to disappointing savings and ever-increasing energy costs he thought it would be a good investment.  It took a fair bit of and is still taking a fair bit of convincing to get the missus on board with it but I think she is beginning to see the light too - interest rates as low as they currently are mean money in the bank is becoming devalued whereas in a few years time solar will be making us money (hopefully).

December 2013
We saw various suppliers in December and quickly decided we liked Tom Mastin's company The Renewable Shop. They are based in Darley Dale (not more than half a mile from my mum and dad's house!).  The cool thing about solar is you pretty much have to shop local - Amazon don't get a look in with this!   We liked Tom's company for a number of reasons - good price, thorough job of checking that the installation would work and they came across as nice people to work with.

http://www.therenewableshop.com/


How much would/should it generate/return on investment etc?

A good site to use to get an idea of likely generation is to go to
Photovoltaic Geographical Information System - Interactive Maps
at http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php


Solar radiation database used: PVGIS-CMSAF

Nominal power of the PV system: 3.8 kW (crystalline silicon)
Estimated losses due to temperature and low irradiance: 11.7% (using local ambient temperature)
Estimated loss due to angular reflectance effects: 3.4%
Other losses (cables, inverter etc.): 5.0%
Combined PV system losses: 19.0%

Fixed system: inclination=40°, orientation=-65°
MonthEdEmHdHm
Jan2.7986.40.8626.6
Feb4.911371.5042.1
Mar8.782722.7384.6
Apr12.303683.94118
May14.104364.58142
Jun14.404324.76143
Jul13.704264.57142
Aug11.703633.87120
Sep9.322803.0190.3
Oct5.751781.8156.2
Nov3.471041.0732.1
Dec2.4274.90.7523.2
Yearly average8.652632.7985.0
Total for year31601020
Ed: Average daily electricity production from the given system (kWh)
Em: Average monthly electricity production from the given system (kWh)
Hd: Average daily sum of global irradiation per square meter received by the modules of the given system (kWh/m2)
Hm: Average sum of global irradiation per square meter received by the modules of the given system (kWh/m2)

According to 
http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php

So in theory our ESE facing roof should generate 3160 kilowatt hours of electricity per annum.   
We're signing up to the Feed in Tarriff where we get paid to generate PV electricity which  means we will be paid 14.9p for every kilowatt hour we produce (called the FIT rate) and an additional 4.9p for half of the power we produce (called the FIT export rate)  - the assumption being that we will use half the electricty we generate).

So in the first year we should get
3160 x 14.9p + 
1580 x 4.9p meaning a cheque of about £548.
We will also be expected to use about half of the electricity which is seen as a benefit of about £189 so the saving in year one is about £733

So that's on the bad side £730 odd quid in year one.  However, the important thing to note about FIT is that it's not metered going back into the grid if your system is 4K or less, SO you can use 100% of the power you use!  Which means if we're clever and switch on stuff when the sun doth shine we will do even better.

Another reason I've done it is that it's ecologically good, and it gives me a better understanding of climate and seasons just as doing the allotment does. 





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