PV shading thoughts.

If you are thinking of having a solar PV system installed in 2010 to take advantage of the last chances of getting a lump sum grant before the Feed In Tariff starts in April, the first thing to do is look for a good location to install it.

Traditionally for domestic Solar PV installations, a pitched roof is the ideal location, being up high and out of the way from most obstructions... Looking at your roof, are you able to check off that it faces somewhere between South East through South to South West?

If yes, you need to see how much open roof space there is available. Solar PV takes up much more space than Solar Thermal systems. Think about 8 square metres per kWp for system size. Once you have ascertained you've got space, look for possible problems from shading. Gabled windows and chimney stacks are probable issues and you will have to consider the array can never be shaded at any point in the day by close structures as array output could drop and cause loading on some of the shaded cells.

Looking further away from your house, are there any trees close by or right next to the house which you know will shade the array at certain times of the day? Trees further away from the PV array could have an impact, for example, a wooded area on the other side of the road may not block the sun during the summer, but may be in shade all winter due to low sun angle in these colder months.

For the PV array, shading issues at best will simply mean less production of electricity at certain times of the day/ year, or at worst will cause overheating in some of the cells as they try to carry electrical current from the other modules. If damage occurred, your warranty would be invalid.

Freestanding Array

We recently commisioned this 3.96kWp array near Totnes.

As you can see, its an ideal solution for people who have some spare space outside, but limited on southerly facing roof area.

This 3.96kWp is the maximum economical size that can be installed onto a single phase mains supply, and keeping under 4kWp it should also attract the maximum pay back under the new Feed In Tariff.

Obviously, this 22 module array is possibly quite large for most gardens, but illustrates another method of installation available. Systems like this can start at just 6 modules to provide a 1kWp system.

See www.chrisrudge.co.uk for more information and a cost guide.

From Huge to Tiny!

Today we completed a lovely little system providing power to an unusual off grid installation in the centre of a popular Dorset seaside town.

Using a 130Wp PV module and 240Ah of batteries, this system provides enough power for lights and 12v & 230v power for a weekend retreat.

As it has proved to be either expensive or difficult to bring in power and mains water for this location, the owner has opted for Off Grid living during holidays and breaks.

The main system has been running all summer, providing power and lights, and has worked beyond expectations.

Dartmoor Off Grid

We have been commencing an installation of a large off grid system in Dartmoor on the high moor. With temperatures in the winter plunging to -17C on occasion and a wild variation of weather conditions that are always prevalent on the Moor, this dwelling needs as much backup and self suffiency as possible. There is no mains electricity or water available, so we are taking part in implementing a complete infrastructure for the customer.
From Solar PV through control electronics, backup generator and house wiring, we will be providing a complete self reliant system for the customer.

The picture here shows the partly completed array being installed.

More to be posted on this project as systems are installed.

Off Grid in Dorset

We completed the installation of a Solar PV off gid system in Dorset last week.
Assisted by the customer, this installation was a joy to work on, being mounted on a house of cedar in such a tranquil (but remote) location.
The PV modules are capable of charging the 1500Ah battery bank at almost 30amps in bright sunlight if required.
Power usage is low, with low energy lamps and a few low wattage appliances.

The system will be upgraded soon with a larger sine inverter to run a possible larger range of appliances.

Mounting system

We use almost exclusively the K2 roof mounting system for our solar PV installations. I thought I'd take a few pictures on an installation this week to let you see a close up of how it works. So many people ask how the system gets put on the roof!

You can see the horizontal rail against the Redland tiles on the left. On the right you can see the PV module being clamped down by a corrosion proof alloy bracket and stainless bolt & fitting.

This system has worked well for us, is guaranteed 10 years for corrosion and structure integrity.


On the left you'll see the complete 1.44kWp array. This system will generate over 1300kWh of power for our customer every 12 months wich under the new Feed In Tariff scheme commencing next April, will earn them at least £598, and maybe more depending on the electricity deal they have!

For the more fiscally minded, if you have a grant supported system similar to this size installed this year, financial payback time will get reduced from 16 years to 8 years.. Cool!

Feed In Tariff rates announced

The proposed Feed In Tariff rates have been announced this week by the Government and I've just had more details published by the Renewable Energy Association.

Right at the moment is the best time ever to get a Renewable Energy system installed! You will benefit from both the Microgeneration grant now, then reap the rewards of anything up to 40p a unit payback from next April!

As an example. I have just completed a quote for a 3.24kWp system, which after the current grant has been taken off will cost the customer £14,500. Then every year will earn the customer £1017 in Feed In Tariff!
And of course thats before taking into account all that FREE renewable power available for use in the house.

We are now just realising why Solar Power is so popular in Germany and other European countries.

Go to www.chrisrudge.co.uk to check on more updates as they occur