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How solar panels work

Let’s face it, the UK isn’t a Mediterranean country – so can we realistically get enough electricity from sunshine to power our homes? You might be surprised at how efficient solar panels can be, especially in rainy Britain. Here’s a look at how solar panels work.

Let’s face it, the UK isn’t a Mediterranean country – so can we realistically get enough electricity from sunshine to power our homes? You might be surprised at how efficient solar panels can be, especially in rainy Britain. Here’s a look at how solar panels work.

Peter Earl
From the Energy team
minute read
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Posted 30 SEPTEMBER 2020

How do solar panels work?

In its simplest form, a solar panel sits on the roof of your home and draws energy from the sun. It then turns that energy into electricity, which can be used to power your home.

Solar panels are made of photovoltaic cells (PV) that are sandwiched between a semi-conducting material, such as silicon. When sunlight hits the solar panels, the PV cells absorb the light and convert it into direct current (DC) electricity. This is then passed through an inverter box that converts it into alternating current (AC) electricity. The electricity collected can then be funnelled to the National Grid or used to power your home.

Does it need to be sunny for solar panels to work?

Not necessarily. If there’s enough daylight for you to see, there’s enough light for solar panels to work. This means that even on cold and cloudy days, your solar panels will be able to generate electricity.

It makes sense that the stronger the sunlight, the more efficient your solar panels will be. That’s why they’re able to produce more electricity in summer. But it’s the light from the sun that makes the solar panels work – not heat. In fact, extreme heat or cold can actually make them less efficient.

Here in the UK, we don’t usually experience extreme temperatures, but we can expect an average of eight hours of light a day throughout the year. So, we’re pretty well set up for solar power.

How efficient are solar panels?

Solar panel efficiency depends on a number of factors. If you want to install solar panels, you’ll need to consider:

  • Which direction your roof faces A south-facing roof will have more access to direct sunlight.
  • The amount of shade covering your roof For example, because of surrounding trees.
  • Roof space Your roof needs to be big enough to accommodate the right size and number of panels for your energy needs.
  • Roof angle To get the most out of the sunlight hours, it’s recommended that your roof has an inclination of between 22 and 75 degrees. You might want to consider adjustable panels that can be altered with the seasonal changes.
  • The type of PV cells Different types can produce more or less energy, depending on their size, thickness and purity. The purer types are generally more efficient, so tend to cost more.

Facts about solar panels

  • Solar energy is the most abundant source of energy on the planet.
  • China leads the way in global solar energy with a whopping 200 gigawatt (GW) capacity.
  • There are over 1 million PV systems installed throughout the UK.
  • According to government figures for the first three months of 2020, solar energy combined with wind energy accounted for a record 32.2% of electricity generation.
  • Residential solar panels are now more than 50% cheaper than they were in 2011.
  • During the government’s Feed-in-Tariff, which ran from April 2010 to March 2019, there were more than 850,000 PV installations.
  • In January 2020, the Feed-in-Tariff was replaced by the Smart Export Guarantee (SEG). The new government scheme ensures that customers using renewable energy sources will be guaranteed a payment from suppliers for each unit of electricity they sell to the grid.

How much do solar panels cost?

An average three-bedroom family home with a roof capacity of around 20 square metres will need at least 3 kilowatt (kW) of energy. So, the cost of installing solar panels roughly works out at around £5,000 to £6,000.

It’s worth noting that although the initial outlay is still relatively high, it’s around half of what you would have paid 10 years ago in 2010.


What are the advantages of solar panels?

  • A clean, green and abundant source of renewable energy
  • Could help save money on your electricity bills
  • A lower carbon footprint
  • Solar panels are silent – no noise pollution
  • Earn money by selling unused energy back to the grid
  • The Smart Export Guarantee ensures you’ll get payment
  • Extremely low maintenance

What are the disadvantages of solar panels?

  • Initial cost of installation can be expensive
  • Efficiency is dependent on the weather
  • You need a fair amount of roof space
  • Not all roofs are suitable for solar panels

If you’re interested in learning more about solar panels and the potential savings you could make, take a look at our Guide to solar panels for the home.

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