03 Jul 2014
The UK may have experienced one of the warmest Junes on record, according to initial statistics from the Met Office National Climate Information Centre. It is therefore unsurprising that the UK’s use and generation of renewable energy has increased this year, as reported by The Independent, Green Peace’s Energy Desk and Edie Energy. The Guardian also reported that the UK’s sunny weather boosted solar power generation, providing an estimated 7.8% of the UK’s electricity in daylight hours of solstice. Additionally this year the Solar Trade association (STA) has estimated that the capacity of solar generated from homes, building and solar farms has risen from 2.7GW in July 2013 to 4.7GW (the equivalent of 3 new nuclear power reactors) in June 2014.
At the weekend I was out with a friend, who spotted a solar panel on a roof; it was force of habit that I corrected her, what she pointed at was actually a solar water heating system. So what is the difference and how can you tell?
What is a solar PV panel?
Solar photovoltaic (PV) panels capture the suns energy to produce electricity using cells comprised primarily of silicon semiconductors; photo meaning ‘light’ and voltaic meaning ‘electricity’. These cells, arranged in layers on a panel, convert sunlight directly into electricity. This arrangement looks like the panel is made up of squares. When sunlight shines on the cell an electric field is created: the stronger the sunshine the more electricity is produced. The solar panels may be roof mounted on a frame, ground mounted or even incorporated into solar tiles as show in the picture above. The generation power of a PV panel is measured in kilowatts peak (kWp), it’s the rate at which it generates energy at peak performance in full direct sunlight during the summer. Although the technology is relatively easy to understand, the economics of solar PV are complicated, involving cost, output and quality control.
What is a solar water heating system?
A solar water heating system is a type of solar panel used for heating water. It is called a collector and like a solar PV panel can be roof mounted. Solar heat is collected and used to heat up water which is stored in a hot water cylinder. Water is the best means of storing energy. The water that passes through the wall mounted tubes is not the water that pours out the tap, these pipes are separated in the cylinder and in the heating system. The hot water can also be run through pipes under the floor, creating radiating heat, improving the thermal comfort of a space.
There are two types of solar water heating panels:
- Evacuated tubes: these are more distinctive as you can see the tubes which make up the panel, through which the water passes (photo 1).
- Flat plate collectors: these can be fixed on the roof tiles or integrated into the roof. This can give a neater look – similar to Velux windows – and saves money on other roofing materials (photo 2).
Evacuated-tube collectors have a higher efficiency than flat-plate collectors, so they may be a good option if you only have a small area of space. The most important aspect of choosing a solar thermal system is the use of the heat in the summertime.
Using solar power to generate electricity or to heat water is beneficial because it is a renewable source, unlike fossil fuels such as coal, oil and gas which are finite resources that will eventually run out. Electricity or heat generated from sunlight can be used all around your home or business; it doesn’t produce harmful greenhouse gas emissions such as carbon dioxide (CO2) and there is no impact on the environment. Utility bills will also be reduced as installing the renewable initiatives will reduce your reliance on mains power. Your roof can become a valuable asset, generating electricity and heat for your property at little running cost. In fact, as fossil fuel prices increase, solar will become more commonplace, as people take advantage of generating their own energy at less cost.
Installing solar panels in your home or business:
Solar panels for electricity or a solar water heating system can be mounted on sloping and flat roofs, ideally south facing (can also be east/west). Solar panels can be expensive to install, although prices have halved in the last two years. BHESCo offers a Pay As You Save model whereby we can install an initiative in your home or business for no upfront cost. You buy the electricity or heat generated by the system we install for a discounted tariff. This saves you money immediately, helping you to transition to your own energy generation once the agreement is paid off. Find out more about BHESCO’s Pay As You Save model. You can also find out more about the benefits, costs, savings and maintenance of solar PV panels on the energy saving trust website.
Finally let’s face up to those myths about solar PV and solar thermal panels!
Myth: Solar panels don’t work when it’s cloudy
Incorrect! Solar PV and solar water heating systems don’t need direct sunlight to generate electricity or heat, then can still generate in cloudy or overcast weather. Cloudy weather reduces the generating capacity of solar PV by approximately 50%, in comparison to direct sunlight. However this is still a valid, and most importantly renewable, way of generating electricity. Not convinced? Germany is the world’s leading solar power producer producing half of their electricity demand from solar power in June 2014 and they have a comparable climate to the UK. If they can do it so can we!
Myth: Panels mounted on my roof will cause damage.
Incorrect! Panels attach to rails which fix onto brackets. On a tiled roof, these pass under the tiles and fix to the rafters in the roof. This method of mounting solar panels is very secure and provides distribution of the load. Some tiles will need to be removed in order to attach the brackets but the installer will replace these after the bracket has been attached. Depending on the tile shape and size, it may be necessary to make a small groove in the overlaying tile. Panels can be mounted on most roofs regardless of type. Make sure you completely understand the works that the installer intends to undertake.
Myth: I won’t be able to insure my house with panels on the roof
Incorrect! As a general rule insurers will include solar PV and solar thermal panels in overall home insurance. Here is what Aviva and Churchill say:
Aviva: ‘Our home insurance will automatically cover solar panels as part of its standard buildings policy. Customers just need make sure they include the value of the Solar Panels in the overall sum insured’.
Churchill: ‘You do not need to tell us if you have or are having Solar panels fitted to your property. Loss of, or damage to solar panels would be covered under the Buildings section of our Home Insurance policy so it is important that you ensure that the Buildings sums insured is adequate to include the replacement cost of such items’.
Myth: I need to get planning permission to install panels
Incorrect! In most cases planning permission is not needed as PV and solar thermal panels are silent in operation and visually. However if you live in a listed building, or within a conservation area, you should check with your local council.
Myth: Having solar solar panels on house will reduce its value.
Incorrect! As the panels are generating energy for free, reducing energy bills of the property, this will not decrease the value of your home. Moreover the value today of the energy generated over the life of the panels, can be quantified and incorporated in the value of the property. If an income is received from the Feed In Tariff (FIT), the new homeowner could receive an income.
Another myth? Let us know and we’ll tell you if it’s true or not!
If you have any questions about solar panels, solar thermal, renewable energy generation or the Pay As You Save model please get in touch with us to find out more.