Solar PV

What are solar panels?
Solar panel electricity systems, also known as solar photovoltaics (PV), capture the sun's

energy using photovoltaic cells. These cells don't need direct sunlight to work – they can still generate some electricity on a cloudy day. The cells convert the sunlight into electricity, which can be used to run household appliances and lighting.

The benefits of solar electricity

Cut your electricity bills. Sunlight is free, so once you've paid for the initial installation, your electricity costs will be reduced.
Get paid for the electricity you generate. The UK government’s Feed inTariff scheme pays you for the electricity you generate, even if you use it.
Sell electricity back to the grid. If your system is producing more electricity than you need, you can sell the surplus back to the grid through the Feed-in Tariff scheme.
Cut your carbon footprint. Solar electricity is green renewable energy and doesn't release any harmful carbon dioxide or other pollutants. A typical home solar PV system could save nearly two tonnes of carbon per year.

How do solar panels (PV) cells work?

PV cells are made from layers of semi-conducting material, usually silicon. When light shines on the cell it creates an electric field across the layers. The stronger the sunshine, the more electricity is produced. Groups of cells are mounted together in panels or modules that can either be mounted on your roof or on the ground.

The power of a PV cell is measured in kilowatts peak (kWp). That's the rate at which it generates energy at peak performance in full direct sunlight during the summer. PV cells come in a variety of shapes and sizes. Most PV systems are made up of panels that fit on top of an existing roof, but you can also fit solar tiles.

A well-designed installation generating 4kWp should generate up to 86% of the total electricity consumption for the average UK household [based on Ofgem figures].

Tesla Powerwall
The Tesla Powerwall is an outdoor rated, wall mounted Lithium-ion battery system designed for storing electricity from residential solar PV panels for powering your home in the evening.

Automated, compact, simple to install and requiring no maintenance, the Powerwall enables you to maximise self-consumption of solar power generation.

Features:

6.4kWh energy storage capacity
100% depth of discharge
Integrated thermal control system
Integrated battery management system
DC-DC converter enabling safe and efficient connection to compatible solar inverters.

Benefits of installing a Powerwall

Increase self-consumption - The Powerwall can store surplus solar PV energy, not used at the time it is generated, so you can use that energy later when the sun is not shining.
Protect against future increases in energy costs by using your own generated power.
Load shifting - The battery can provide financial savings to its owner by charging during low rate periods when demand for electricity is lower and discharging during more expensive rate periods when electricity demand is higher.
Back-up power – Assures power in the event of an outage.
The Tesla Powerwall must be installed by a Tesla Energy Certified Installer.

More Information:

Batteries are designed to capture surplus electricity generated by your solar PV system allow you to store solar electricity for use later in the day.

Batteries can help you use more of the electricity generated by your PV system, saving you money on your electricity bill.

Your solar PV system
The solar PV system on your roof will generate electricity during the day that you can use in your home. Without a means of storing that solar electricity, any surplus energy that you don’t use is ‘exported’ to the local electricity grid. During times when the panels are no longer generating (or not generating enough for your needs), you need to buy electricity from your electricity supplier.

Solar PV plus storage
“Energy storage” lets you store the surplus solar electricity, instead of exporting it. Battery storage lets you use more of your solar PV system’s output (in the jargon, it ‘increases ‘self-consumption’). This reduces the amount of grid electricity you need to buy, saving you money on your electricity bill.

During the day :

The solar PV system generates solar electricity
The battery storage system will check if all the generation is being used to power your lights and appliances
If you’re not using all the electricity that the solar PV system is generating, then the system will ensure that any surplus energy is used to charge the battery
Once the battery is fully charged, if there is still more solar electricity being generated, this will be exported to the grid (or in some systems, will be diverted to other uses e.g. to an immersion heater) In the evening or at time of low solar generation:
The solar PV panels have a reduced or zero output
The battery system can discharge the stored electricity, providing you with renewable-generated electricity at no additional cost
Once the battery is discharged, if you need to use more electricity, you buy it from your electricity supplier