Overview and purpose
Solar panels capture the sun’s energy and convert it into electricity that can be used in a dwelling. By installing solar panels, the property can hence generate its own renewable energy. The key components of a solar panel system include:
- the panels themselves
- a controller
- a battery bank
- an inverter
- a meter
It is important to distinguish between two main types:
- solar thermal panels that are used for heating purposes
- photovoltaic panels that produce electricity
Solar thermal panels or solar collectors are devices that are mounted on the property’s roof to absorb the sun’s heat and use it to heat up water, stored in a cylinder. The liquid flowing through the panels is a mix of water and antifreeze. The main purposes of this technology are space and water heating, with the two main types being flat-plat collectors and evacuated (or vacuum) tube collectors.
Photovoltaic systems are the most commonly used solar panel systems in Britain and are the focus of this resource paper. A solar photovoltaic panel consists of many cells made from layers of semi-conducting material, most commonly silicon. When light shines on this material, a flow of electricity is created. The cells do not need direct sunlight to work and can even operate on cloudy days. However, the stronger the sunshine, the more electricity generated.
Key points to consider
Space is a key consideration. The average photovoltaic system size is around 3.5kWp (meaning ‘kilowatts peak’), and this will typically take up around 20m2 of roof area. An unshaded, south facing roof is ideal for maximum electrical output. East or west facing roofs could still be considered, but north facing roofs are not recommended. A system facing east or west will yield around 15-20% less energy than one facing directly south.
Any nearby buildings, trees or chimneys could shade the roof and have a negative impact on the performance of the system. Finding an unshaded spot is best, however sometimes shading is unavoidable. Some solar photovoltaic systems can minimise the impact of shading using ‘optimisers’. If the property does not accommodate shading, the use of optimisers is not necessary or beneficial, other than the increased monitoring opportunities they offer – they will not generate more energy.
Grid-connected systems make use of the local utility grid to ensure the property is never without electricity. If the domestic solar panel system generates more electricity than the household requires in a day, this surplus energy can be exported back and sold to the national grid.
Stand-alone photovoltaic systems are not connected to the grid, but instead charge a solar battery system. These batteries store the electricity generated by the panels. To operate the appliances, the stored electricity from these batteries will be used. Stand-alone systems are used in areas that cannot be connected to a grid, and are typically more expensive than grid-connected systems.
There are four main factors affecting solar panel efficiency:
- location, angle, and direction – the solar panel is required to be located and angled so that the solar cells can capture the maximum amount of sunlight
- roof suitability – the roof needs to be strong enough to support the weight of the solar system
- size of the solar panel system – the larger the solar panel system, the more electricity is generated
- maintenance – proper solar panel maintenance maximises the lifespan of the system
The practical implications for planning officers and applicants
Solar photovoltaic panels are considered ‘permitted development’ and often do not require planning permission. However, exceptions apply and it is best to check with the local authority for guidance and to check if planning permission is required in certain instances. Examples of such instances are if the property is within a listed building, conservation area or national park. If a property owner wishes to install a solar panel on the roof of the property, building regulations will normally apply. The ability of the existing roof to carry the load (weight) of the panel will need to be checked and proven. Some strengthening work may be needed.
Building regulations also apply to other aspects of the work such as electrical installation. It is advisable to contact an installer who can provide the necessary advice, preferably one who belongs to the Competent Person Scheme. Learn more about the Competent Person Scheme on the government website.
If a person is planning to install a solar photovoltaic system in the dwelling, it must be registered with the Distribution Network Operator. The Distribution Network Operator is the company responsible for bringing electricity to the dwelling. Usually, the installer will register the device for the property owner.
The UK Government has advice on how to register your new energy device in England, Scotland and Wales. Access the full government planning guidance for renewable technologies in England.
Relevant Craven local plan policies and guidance
Policies ENV3: Good Design, ENV9: Renewable and Low Carbon Energy