Solar PV

How Does Solar PV Work?

Solar PV cells are made from layers of semi-conducting material, usually silicon.

When light shines on the material, electrons are knocked loose, creating a flow of electricity. The cells don’t need direct sunlight to work, they can work on a cloudy day. However, the stronger the sunshine, the more electricity generated.

Solar PV cells are grouped into modules, and modules are usually grouped into solar arrays. Modules and arrays come in a variety of shapes and sizes.

Most PV systems are made up of panels that fit on top of your roof, but you can also install on the ground, or fit solar tiles.

The electricity generated is direct current (DC), whereas the electricity you use for household appliances is alternating current (AC). An inverter is installed along with the system to convert DC electricity to AC.

What Are The Benefits To Having Solar PV Installed?

  • Cut your electricity bills

  • Reduce your carbon footprint

  • Receive payments for extra electricity you generate

Is Solar PV Right For Me?

Space is a key consideration as is roof angle and the direction it faces. Ideally you want a south facing roof with a pitch at an angle of 30 or 40 degrees.

East or west facing roofs can still be considered but North facing roofs are not recommended.

Also worth noting that are nearby buildings, chimneys or trees that shade your roof will have a negative impact on the performance of your system.

Planning permission is not usually required as Solar is classed as a permitted development but you should always check with your local authority before installing in case there are any local limits or restrictions.

Export Payments

With any domestic PV system, there will be times when the electricity you generate is more than you can use or store, so the surplus will be exported to the grid to be used by somebody else.

The old Feed-in Tariff closed for applications in March 2019 and has since been replaced by the Smart Export Guarantee. While not as generous as the Feed-in Tariff it is still a worthwhile scheme and does provide some financial support for electricity that you generate and export back to the grid.

Battery Storage

 Energy storage works well with the idea of the ‘smart home’. Many smart storage systems allow you to keep track of your energy use online and charge the batteries with low rate electricity from the grid if you’re on a tariff that is cheaper at certain times of day, such as Economy 7.

 

If you have a renewable electricity generation system in your house, such as solar PV, then you will inevitably generate more electricity than you need at times of high supply and low demand, with any surplus exported back into the grid. At the moment, many people are paid for this through the Smart Export Guarantee system. 

If you have an existing small solar PV system, with little excess to go into a battery or other storage options, it’s not likely to make financial or practical sense. New build homes integrating small PV systems into their designs are also unlikely to benefit.

On the other hand, if you install a good number of panels onto your roof and there’s generally no-one around during the day using the electricity generated, it might be worth considering your storage options.

Power Purchase Agreement for Solar PV & Battery Storage

A Power Purchase Agreement (PPA) is a long term agreement is a contract between an owner and a purchaser that allows you to secure revenue for a installation or scheme.

In this case it allows for the Free installation of a Solar PV system and Battery Storage that is paid back over an agreed amount of time from the electricity generated by the Solar PV.

Key Points:

  • The standard agreement is for 10 years.

  • The customer will pay a rate of 11p-14p per kWh (depending on geographical location) for any electricity used from the Solar array or battery and this rate will increase yearly by 2%

  • There will be a standing charge of 24p per day

  • The system will be remotely monitored and serviced and maintained free of charge for the term of the contract

  • The contract can be bought out by the customer at anytime and this is done on a sliding scale of value depending on how long is left on the contract

  • The contract can be migrated to a new homeowner in the event of a house sale or the current owner can buy out the contract as above.