Solar Energy: Definition, Advantages and disadvantages

solar energy

Using renewable energy instead of fossil fuels is key to sustainable development. Solar energy is becoming increasingly popular across the UK with more than one million households already relying on solar power. In this article, we’ll look at some solar energy pros and cons and some solar energy facts.


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How does solar energy work?

Solar energy is a renewable energy which is inexhaustible and obtained from the electromagnetic radiation from the sun. It generates electricity and heat in a manner which is entirely sustainable and free.

Is solar energy renewable? Solar energy does not produce air pollution or greenhouse gases. The main environmental impact of solar energy is the use of land and potential loss of habitat in the case of large solar energy farms.

How is solar energy produced?

Solar energy can be obtained from panels and mirrors:

  • Photovoltaic cells: convert solar light directly into electricity due to the so-called “photoelectric effect” through which certain materials are able to absorb photons and free electrons, generating an electrical current.
  • Solar thermal collectors: use panels or mirrors to absorb and concentrate the sun’s heat, transfer it to a liquid and conduct it through tubes for its use in buildings and facilities or also for the production of electricity.

This energy can also be used in a passive way by using bioclimatic architectural techniques.

Types of solar energy

There are three types of solar energy:

  1. Photovoltaic solar energy: used to produce electricity;
  2. Solar thermal energy: used to heat water;
  3. Passive solar energy: which directly takes advantage of sunlight.

Photovoltaic solar energy

solar panels uk

Photovoltaic solar energy provides light which is converted into electricity using photovoltaic solar panels. These photovoltaic solar panels are made up of groups of cells or solar cells which transform light (photons) into electric energy (electrons).

Solar photovoltaic energy consists of directly obtaining electricity from solar radiation. This can be obtained thanks to the installation of photovoltaic solar panels, which are made up of silicon cells that transform light and heat from the sun into electric energy. These solar panels can be installed domestically on buildings and homes, as well as on a larger scale at larger facilities.

  • Types of photovoltaic installations:
  • Solar panels for self-supply;
  • Photovoltaic production plants.

Photovoltaic solar panels do not produce heat, and therefore cannot be used for solar energy storage. Nevertheless, the excess production of photovoltaic solar energy can be transferred to the consumption grid, and it is known as excess photovoltaic production. Thanks to photovoltaic panels, energy self-supply has become more democratic, meaning that each person’s home can produce its own electricity for its own consumption and reduce their electricity bill. Solar energy is the best way to be self-sufficient when it comes to energy production.

Solar thermal energy

solar thermal energy

Solar thermal energy, also known as thermosolar power, uses the sun’s energy to produce heat, which is then used as an energy source at the domestic level (to heat up one’s house, cook or for personal hygiene) as well as at an industrial level, transforming this energy into mechanical energy and from this obtaining electrical energy.

Solar thermal energy provides heat using mirrors so that the sun’s rays can be concentrated into a receptor and reach temperatures of up to 1000°C. The heat is then used to warm up a liquid which generates vapour and moves a turbine which produces electricity. Solar thermal collectors use panels or mirrors to absorb and concentrate solar heat, transfer it to a liquid and conduct it through tubes for its use in buildings or facilities or also for the production of solar thermoelectric energy.

There are three types of solar thermal energy:

  1. Low temperature solar thermal energy: low temperature collectors generate temperatures of up to 65ºC;
  2. Medium temperature solar thermal energy: medium temperature collectors can reach temperatures of up to 300ºC;
  3. High temperature solar thermal energy: high temperature collectors generate temperatures over 500ºC.

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Passive solar energy?

Photovoltaic solar energy and solar thermal energy use different technology to capture and process the sun’s energy. This is known as active solar energy. However, solar energy can also be used in a passive way, meaning without needing any type of mechanism to collect and use it. This is the oldest method to take advantage of solar radiation.

The objective is to maximise the existing properties of one’s home:

  • Positioning it in the best place;
  • Ensuring the building is best oriented;
  • Insulating the home;
  • Using the best roofing;
  • Using protections.

In this way passive solar energy is obtained principally using bioclimatic architecture: a principle of designing buildings where, through the use of different materials and orientations, the energy captured throughout the day is used to keep the building warm at night and to avoid excessive heat during the hours of most sunlight during the day, and therefore reducing the need to illuminate, heat or cool down the building.

What is solar energy used for?

There are many uses of solar energy. The most common uses are:

  • Generate electricity;
  • Heat water;
  • Produce “solar cold” and heating;
  • Water crops;
  • Illuminate exterior areas;
  • Solar cars and other inventions.

How much energy does a solar panel produce?In average UK weather conditions, you can expect one kilowatt of panels to generate between 700 and 900 units (kilowatt-hours, kWh) of electricity per year. Where you live in the UK is a factor – Cornwall receives 30% more solar energy than northern Scotland, for example.

Advantages of solar energy and disadvantages of solar energy

The need for solar energy to be the future is clearer day by day. While it is clear there are many benefits of solar energy, it is important to know the pros and cons of solar energy before embarking on any installation.

Solar energy: pros and cons
What are the advantages of solar energy? What are the disadvantages of solar energy?
  • 100% inexhaustible energy, which is renewable and free;
  • No toxic or polluting emissions into the air;
  • Reduces the use of fossil fuels;
  • Increasingly competitive energy source;
  • Reduces the need to rely on the electricity grid or natural gas;
  • Subsidies for self-supply;
  • Key measure against climate change;
  • Generates wealth and local employment.
  • Intermittent energy;
  • High initial investment;
  • Location of the home.

Solar energy in the UK

Renewable energy (solar, wind, biomass, hydro) overtook fossil fuels at the end of 2020 as the main source of energy in the UK. Latest figures show that renewable energy accounts for around 43% and fossil fuels 38% of UK energy sources.

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Solar power is the third most generated renewable energy in the UK, after wind and biomass, and it is estimated that around 900,000 homes have solar panels in the UK. As a nation, the UK has a combined capacity of 13.26 GW of solar PV power, although the rate at which homes generate electricity depends on the location. Because the south of England generally has more days of sunlight every year, homes with solar panels installed will normally generate more electricity than those located in the rest of the UK.

Figure published by the UK government in its Digest of UK Energy Statistics (DUKES) show just how much solar energy has grown in the UK in the past decade. In 2011, solar PV energy made up just 1% of the UK’s renewable energy mix. By 2020, that had increased to 28%.

  • Solar energy UK: Facts
  • Installing solar energy storage batteries in just 4.4 million homes would provide enough flexibility to completely flatten spikes in electricity demand.
  • One million rooftops in the UK feature some sort of solar panel or solar technology.
  • Trebling the UK’s solar energy capacity by 2030 could cut total UK carbon emissions by 21.2 million tonnes per year as fossil fuels are replaced with cleaner power.

Source: Solar Energy UK.

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