In early November 2019, parts of the UK saw a month’s worth of rain fall in just 24 hours. One person died and hundreds more faced the misery and hardship of flooded homes and ruined possessions.
From devastating floods, to horrific forest fires and melting ice, the entire world is facing the effects of rising temperatures. In its annual emissions gap report, the UN Environment Programme shows that carbon emissions globally have increased by 1.5% per year in the last decade. This is putting the Earth on course to experience a temperature rise of 3.2o C by the end of the 21st Century, way higher than the 1.5oC increase that the Intergovernmental Panel on Climate Change warned would have hugely damaging effects on human, plant and animal life across the planet.
In the face of rising awareness and concern about the effects of climate change, it’s unsurprising that the UK’s use and generation of renewable energy is on the increase. In the third quarter of 2019, renewable sources of energy in the UK generated more electricity than fossil fuels for the first time.
There is still plenty of scope to increase energy generation from renewable resources. Solar power is the option most frequently used on domestic buildings, so in this article, we set out to clarify some of the misconceptions that people may have about solar power, starting with the difference between a solar PV panel and a solar water heating system.
What is a Solar PV Panel?
Solar PV roof mounted panel
Solar photovoltaic (PV) panels capture the sun’s 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. The panel looks like it is made up of squares.
When sunlight shines on a cell, an electric field is created: the stronger the sunshine the more electricity is produced.
Solar panels may be roof mounted on a frame, ground mounted or even incorporated into solar tiles as shown in the picture below.
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.
Solar roof tile
What is a Solar Water Heating System?
A solar water heating system (also known as solar thermal) uses a type of solar panel called a collector. It looks different to a solar PV panel but, like a solar PV panel, it can be roof mounted.
Heat from the sun is used by the collector to heat up water which is then stored in a hot water cylinder. Water is a very efficient way of storing energy. A conventional boiler or immersion heater can be used to make the water hotter or to heat water when solar energy is unavailable.
The water that passes through the collector’s tubes is not the water that comes out of the tap, the water from the collector is kept in separated pipes in the cylinder and in the heating system.
Hot water from the collector can also be run through pipes under the floor, creating radiating heat, improving the temperature and 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.
Photo 1: Evacuated tube collector
Photo 2: Flat plate collector
Solar PVT - a two-in-one solution
Photovoltaic thermal (PVT) unit
Solar photovoltaic thermal (PVT) is still not common in the UK but it has great potential when used in appropriate situations. Its use looks set to grow, particularly on commercial buildings which have a year round need for large amounts of hot water.
PVT is a hybrid photovoltaic (PV) and thermal unit which generates both electricity and hot water. In the UK, air or water is usually used to cool the PV panels within the unit, improving the efficiency of its electricity generation. The warmed air or water is then used to contribute to a hot water supply and/or a building’s heating system.
The Benefits of Solar Power
Using solar power to generate electricity or to heat water is beneficial in a number of ways. Solar power doesn’t generate harmful climate changing gases such as carbon dioxide and it is a renewable resource, unlike fossil fuels such as coal, oil and gas which will eventually run out. You will see a reduction in your utility bills as installing solar systems decreases your reliance on power bought from utility companies.
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 (but can also be east/west facing).
The initial outlay involved in installing solar panels can put people off. Although prices have reduced significantly as the systems have become more common place, a typical installation can cost between £5000 and £8000.
To help overcome this initial hurdle, BHESCo offers a Pay As You Save financing model whereby we can install a solar system in your home or business for no upfront cost. You buy the electricity or heat generated by the system we install from us for a tariff that is less than you would pay from a utility company. This saves you money immediately, while paying off the cost of the installation over time. It helps 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 read more about the benefits, costs, savings and maintenance of solar PV panels on the energy saving trust website.
So, let’s face up to those myths about solar PV and solar thermal panels!
MYTH: Solar panels don’t work when it’s cloudy or cold
False. Solar PV and solar water heating systems don’t need direct sunlight to generate electricity or heat, they can still generate in cloudy or cold weather. In fact they are more effective in cooler temperatures. Cloudy weather reduces the generating capacity of solar PV by approximately 50%, in comparison to direct sunlight. However they still remain a valid, and most importantly, renewable way of generating electricity. Not convinced? Germany is the world’s leading producer of solar power and it has a comparable climate to the UK.
MYTH: Panels mounted on my roof will cause damage.
False. 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.
Solar panels can actually benefit the portion of the roof they cover by protecting and preserving it. In the unlikely event that the roof the panels are sitting on is damaged and needs to be repaired, the panels can be removed easily since they aren’t directly attached to the roof; they are just mounted on top of it.
Make sure your roof is free of damage before installing solar panels and that you completely understand the works that the installer intends to undertake before going ahead.
MYTH: I Need to get Planning Permission to Install Panels
False. In most cases planning permission is not needed as solar PV and water heating panels normally fall under ‘permitted development’. However, it is always best to check with your local council before going ahead, especially if you live in a listed building, or within a conservation area.
MYTH: Having solar panels on my house will reduce its value
False. As the panels are generating energy for free, reducing energy bills in 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 into the value of the property. If payments are received from the former Feed In Tariff (FIT) or the new arrangements in place for after January 2020, the new homeowner could receive an income.
MYTH: Solar panels require a lot of maintenance
False. Solar panels are constructed to withstand harsh weather and, with no moving parts, should last for around 25 years with no or very little maintenance. In the UK it is not usually necessary to clean panels, but in some scenarios, such as becoming covered in bird droppings, it can improve performance if panels are cleaned once or twice a year.
MYTH: My installation won't make any difference to climate change
False. The more people who have solar panels, the bigger the impact on the UK’s carbon emissions. As the number of people generating energy from solar increases, the more we reduce our CO2 emissions from burning coal or gas. Any electricity you don’t use yourself can be fed into the grid and reduces emissions from energy used by others.
Myth: Solar power is not economically viable
It depends. The government incentive to encourage people to install solar panels, known as the Feed In Tariff, has now ended and this has prompted people to question whether solar is still an economically viable option.
The government is introducing a Smart Export Guarantee in January 2020, which will require most suppliers to offer at least some payment for your exported electricity. Some suppliers are already offering payment ahead of the deadline.
The economic viability of solar panels depends on a number of variables:
- Where you live in the UK. If you live in London or the South East, your panels can perform more efficiently due to higher levels of sunlight.
- The initial cost of your system.
- The amount of electricity your system can generate.
- The location of your solar panels. South facing, unshaded panels generate the most electricity.
- How much of the electricity generated you are able to use as opposed to exporting it to the grid.
- The level of payment you can receive for your exported electricity.
The Energy Saving Trust details the likely costs, savings and payback times of typical solar panel installations in different areas of the UK both with and without the Smart Export Guarantee payment.
MYTH: Solar power is just for domestic buildings
False. Solar power works well for businesses and community buildings such as schools. In fact this type of property may have more roof space or land where they can install solar panels.
Solar PVT can be particularly suitable for businesses.
MYTH: I have to sell any excess energy I generate to the grid
False. Often the installation of a battery that stores energy generated from your solar panels enables you to make better use of the electricity you generate. Rather than exporting energy that is not used, it can be stored for later use.
The average cost of buying electricity in the UK is around 17p per kWhr. Early indications are that payments under the Smart Export Guarantee will be around 5.5p per kWhr. Based on these figures, it makes economic sense to use as much of the electricity you generate for your own needs rather than exporting it to the grid.
See our case study about a domestic solar power and battery storage installation for more information.
MYTH: I need a smart meter if I have solar panels
Maybe. If you currently have solar panels installed on your property then you are under no obligation to have a smart meter. If, however, you are thinking of installing solar panels and want to take advantage of the new Smart Export Guarantee payment, you will need to have a smart meter installed.
Under the old Feed-in Tariff scheme, households weren’t paid accurately for the electricity they exported to the grid. Payments were based on an estimate which assumed that everyone was exporting 50% of their solar-generated electricity – even if the true figure was much more or less than this.
By using smart meters, the new Smart Export Guarantee payments will be fairer and more accurate. Most smart meters record your energy exports every half an hour.
Have you heard other statements about solar power that you are not sure about? Let us know in the comments section below and we’ll tell you if they’re 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.