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About Solar PV

Why Go Solar?

Solar PV energy is clean and renewable. It not only lowers the cost of your electricity bills, but also reduces negative impact on the environment.

PV technology has many benefits. It’s a quiet, clean source of energy, is reliable, requires minimal maintenance, and lasts for decades. It’s not only competitive with other sources of energy in terms of costs, but directly contributes to reduction in greenhouse gases. In addition, the government feed-in tariffs reward you financially for producing green energy!

Read more about feed-in tariffs here.

Photovoltaics have become an increasingly attractive option for a variety of small and large scale uses. They are in use from outer space to the polar ice caps, and are a desirable source of electricity in rural areas and developing countries. Although PV is still a small part of the world’s energy, more and more businesses and homeowners are turning to PV systems to supplement their conventional power utility.

How do Photovoltaics Work?

Photovoltaics (PV) are solar cells that convert sunlight directly into electricity. Semiconducting materials such as silicon produce an electric current when exposed to sunlight. Metal contacts on the top and bottom of the PV cell allow the current to be drawn off for external use. Rows of PV cells are combined to make a solar panel.

Despite the cloudy weather, Solar PV is incredibly effective in the UK climate. Solar panels rely on intensity of light as opposed to direct sunlight, so even if it is overcast, your panels will still produce electricity. In fact, PV modules work more effectively in cooler temperatures, meaning a bright February day could produce as much energy as in the height of summer.

Roof Suitability

  • Location: Your roof must not be shaded by objects like trees or buildings.
  • Orientation: Solar energy works on all roofs, but is most effective on those facing south, southeast and south-west.
  • Inclination: Solar products are suitable for pitched, flat and curved roofs, although the optimal roof angle is 30 – 40 degrees for the UK.
  • Available area: The more surface area available, the greater the power potential! For a grid-connected system the minimum required area is approximately 10m2. In some cases where suitable roof area is not available, you can install a solar energy system on garages and outhouses or on a frame located close to the property.
  • Planning permission: Solar roofs do not usually require planning permission unless the building is listed or in a conservation area. However you should always call your council to check on local policy.


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  • What are the benefits of a solar PV system?

    Solar Photovoltaic energy is clean and renewable, meaning it not only lowers the cost of your electricity bills but reduces negative impact on the environment. Solar panels give you a long term source of free energy with minimal maintenance and no CO₂ emissions.

  • How much energy will I save?

    The average home uses around 4400kWh of electricity per year and a typical domestic PV system between 1.5 & 4 kWp could generate 1,200-3,400 kWh per year. This means that a domestic installation of 4Kwp could save you £150 in bills annually plus the money you could make from the feed in tariff, amounting to over £600 in total.

  • What is the Feed-in Tariff (FIT)?
    Feed-In Tariffs are a government-proposed scheme that pays people for creating their own energy. They were introduced to help increase the level of renewable energy in the UK.

    Read more about feed-in tariffs here.

  • How long will my solar PV system last?

    Alternergy stock only quality PV panels with warranties of 20+ years. The panels feature no moving parts meaning there is no reason why they shouldn’t last 30 years. Being a new technology, it is difficult to gauge the lifespan of a solar panel, although some are 40+ years old and still generating electricity! The system itself needs little maintenance although the inverter may need replacing after 10 years.

  • Is there any maintenance required with a solar PV system?

    Solar PV systems require minimal maintenance as the panels are mounted on an angle and designed to wash clean when it rains. There are no moving parts and the modules and mounting are designed to last decades, but the inverter may need replacing after 10 years.

  • How long will it take to install a PV system?

    It depends on the size of the system, but a small residential installation may only take 1-2 days. Larger or commercialised installations could take a couple of weeks.

  • Do I need planning permission?

    No. You don’t need planning permission unless the sight is listed or located in a place of outstanding natural beauty. However, it’s best to contact your local council first to check the local regulations. There may also be different regulations for commercial buildings.

  • Do solar panels work on cloudy days or in the winter?

    Yes! Solar panels rely on intensity of light as opposed to direct sunlight, so even if the weather is overcast, your panel will still produce energy. In fact, PV panels work better in cooler temperatures, meaning a clear winter’s day can produce as much energy as in the height of summer.

  • Will my PV system produce hot water?

    No. A solar PV module uses energy from sunlight to directly generate electricity. A Solar Thermal System, on the other hand, provides hot water for households using warmth from the sun. However, the electricity generated from a PV system can be used to power an immersion heater.

  • How do Watts (W) differ from Watt hours (Wh)?
    A Watt is a unit of power that measures the rate of energy transfer. Watt hours relate to the amount of energy transferred by a source over one hour. For example, 1kWh is the amount of energy produced/used by a 1kW source over the course of an hour.

    Solar electricity systems are given a rating in kilowatts peak (kWp). This is effectively the rate at which it generates energy at peak performance, for example at noon on a sunny day. The amount of electricity created by a PV system over the course of a year is measured in kWh.

  • What happens if my solar panels are covered in snow or leaves?

    If the light to your solar panels is blocked by leaves or snow, this will greatly reduce the performance of the PV module. We advise to clear debris from your panels when the weather begins to improve.