Facts - Solar Panel FAQ

Do I need planning permission to put solar panels on my roof?
In most cases no, but it is best to inform you local authority of your intentions.

If you live in a building or area that has any special listing or planning control you will probably need to obtain permission.

How many panels do I need?
You’ll need roughly one square meter of collector area per person in the household. And each meter of panel area will require between 30 and 60 litres of tank volume.

Can I put the panels anywhere on my roof?
For maximum efficiency, solar panels should be mounted on a south-facing roof at 30 degree angle to the horizontal (up to 65 degrees will still work in the UK) and away from the shadows of trees, buildings or chimneys.

Can I simply connect my new solar system up to my existing boiler?
This is only possible if your boiler is one of the few that can accept pre-heated water.

Check with the manufacturer before buying a new boiler. In most cases you’ll need a separate water tank.

Buying a new efficient boiler could save you up to a third of your annual fuel bill.

And don’t forget your hot water tank. You can cut heat loss from the tank by up to 75 per cent by fitting a thick insulating jacket,which can pay for itself in just six months.

Reducing the temperature of stored hot water will also reduce wasted energy and save you money, setting the cylinder thermostat at 60 degrees should be hot enough.

Is solar power more expensive?
Solar power is clean energy, but it comes at a price, and payback periods are long, especially for photovolatics which can take up to 50 years to pay for themselves.

Help is at hand however.

The Low Carbon Buildings Project, the government’s grant programme for renewable energy systems, offers grants of £400 on solar water heating systems, which cost £2-3K.

You can get a grant for up to 50 per cent of a photovoltaic system (including installation) which cost £6K and more.

To be eligible for a grant you’ll need to buy a system approved by the government and use an accredited installer.

You’ll also need to undertake a number of energy efficiency measures at your home first - you’ll find details at www.lowcarbonbuildings.org.uk.

What about wind power?
Solar power isn’t the only way to generate your own energy; another option is a wind turbine.

Already growing in popularity, turbines are now being actively promoted by the government.

In March 2006 Chancellor Gordon Brown announced £50 million of new money for micro-generation technologies, and the government also wants planning laws relaxed to make installation easier. 

A recently passed Bill will also make it easier for householders who produce electricity from microgeneration technologies at home to sell unused power back to their supplier.

A small domestic wind turbine can provide up to 33 per cent of an average home’s electricity needs and can pay for itself in as little as seven or eight years - much quicker than solar.

Two rooftop wind turbines are undergoing trials in the UK.

We’ve got our name on the waiting list for a Windsave turbine developed by a Glaswegian entrepreneur and will feature it as soon as we get our hands on it.

We are also keeping an eye on the Swift turbine produced by another Scottish company Renewable Devices.

What do the following terms mean?
Passive Solar
Capturing the sun’s energy passively - for example, through large south facing windows - and holding on to it by minimising heat loss through unwanted leaks

Active Solar
Using a collector, for example a solar panel, to capture the sun’s energy and use it to heat water or convert it to electricity

Solar water heating
Water is pumped through a solar panel and heated by solar energy, the heated water then flows through a heat exchanger, warming the water in your hot water cylinder

Evacuated tubes
A type of solar water heating panel. Evacuated glass tubes collect the sun’s energy and heat water running through a container at the top of the tubes. Water does not flow through the glass tubes.

Photovoltaics, PV
PV cells are thin layers of semi-conducting material (usually silicon), electrical charges are generated when the silicon is exposed to light which can be conducted away as direct current, multiple cells are connected together (usually behind glass) to form a panel

Solar Tiles
Use the same technology as photovoltaic cells, but are smaller and narrower than large PV panels and look like roof tiles.

Pressurised system
Water is pumped through the solar panel and heated, this heated water flows through a heat exchanger warming the water stored in your hot water cylinder ready for use. These systems typically use antifreeze.

Drainback system
When the pump switches off, the water inside the solar panel will drain back into a small drain back bottle. This protects the system against damage due to boiling and freezing, without the use of antifreeze.

Monocrystalline silicon cells
The most efficient and expensive cell, cut from single crystals of silicon produces a system which can harness around 15 per cent of the sun’s energy that falls on it.

Multicrystalline silicon cells
Made from silicon cut into wafers, slightly less efficient than monocrystalline cells but also slightly cheaper.

source: Which

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