Solar Photovoltaics (PV)

What is it?

Solar PV technology uses solar panels to capture sunlight and convert it into electrical energy.  The technology can be employed on both an industrial and local scale.  Industrial projects such as solar farms are the most productive method for harnessing the power of the sun.  These tend to be built on old farmland and use the greatest coverage of solar panels to maximise energy production.  Solar PV can also be employed on a smaller scale, via retrofitting panels to the roofs of existing buildings or by including them in the planning and construction of new projects.  Solar PV offers a flexible method of harnessing renewable energy, and it is commonly used alongside other technologies, such as onshore wind farms and on top of EV charging stations.

How does it work?

Solar PV technology works by converting sunlight into electricity through solar cells, which make up the surface of a solar panel.  The cells are made from thin layers of a ‘semiconductor’ material (commonly silicon) between layers of glass.  Once the sunlight passes through these layers, a direct electrical current (DC) is generated, this then passes through an inverter, which converts it to a 240V alternating current (AC) which can then be used in your home or put into the national grid.  

How do solar panels work? (Credit: Student Energy)

What are the advantages of solar PV?

  • Accessibility – As previously mentioned, individuals can purchase solar PV technology and use it on a micro-scale.

  • Cost Effective – Solar PV is significantly cheaper to both purchase and maintain in comparison with other renewable energy sources.  This also adds to its accessibility to individual buyers.

  • Operation and Maintenance - There are no moving parts, so solar panels require infrequent servicing and there is a significantly lower chance of the system breaking when compared to other technologies which use equipment such as wind turbines.

  • Noise Pollution – Solar PV is completely silent so it can easily be employed in urban centres and on rooftops without disturbing the local population.

What are the disadvantages of solar PV?

  • Climate – Solar PV relies on sunlight to generate electricity, so its output is significantly reduced when there is thick cloud cover and during periods of darkness.  Therefore, it remains a seasonal technology in the UK as its output in the summer is significantly more than in the winter, meaning it cannot be relied upon as a constant source of energy.

  • Efficiency - Solar panels efficiency levels are relatively low (between 14%-25%). This has an impact on land use, as you need to use a wider area to achieve the same output in comparison to technologies such as onshore wind.

  • Fragility – Solar PV panels can be easily damaged, so despite a high degree of reliability, it is still common for them to break.

Current energy production?

 In Q1 of 2022 Solar PV accounted for 2.4% of the total electrical energy produced in the UK.  However, across the full year in 2021, solar PV accounted for 4.3% of the total energy produced.  This shows the impact that weather can have on its total output.

Where are the solar PV farms located?  

In 2020 there were just under 500 Solar Farms in the UK.  As you can see from the illustration, most large solar farms are located in the South of England.  This is supported by the colour coding which represents solar irradiance which is the power per unit area produced by the sun in the form of electromagnetic radiation.  As you can see, the general trend is for this to increase as you travel from North to South. It is also important to remember that there are also thousands of solar panels fitted to people’s homes across the country which are contributing energy to the national grid, but they are not represented on the illustration.

Solar PV Farms in the UK - Current solar farms compared to interpolated average hourly GHI Wh/m2 (Credit: REPD, 2015)

Key Projects in the industry

Future projects and development of solar PV

The future development of solar PV farms in the UK has been and will remain a source of controversy.  Solar PV is an essential tool for helping reach net zero targets; however, its land use and lack of efficiency in our climate remains a big issue.  As our population increases and outside events impact both our energy, and food security, solar PV is pushed into greater conflict with agricultural demand.  Other renewable technologies such as onshore wind allow for a better compromise with agriculture as livestock can still graze in fields where turbines have been built.  For this reason, solar PV farms remain a contentious issue, and global pressures will have a direct impact on their future development.

In contrast, small-scale, rooftop solar PV is growing in popularity.  New sustainable housing initiatives are also in place to ensure that solar panel use is considered when producing new-build properties.  These small-scale projects will be key to the future of solar PV, and they offer an ideal starting place for a service leaver, veterans and spouses/partners who are interested in working in the solar PV industry.

Solar PV (Credit: Fully Charged Show) - A useful insight into the solar panel installation process, and provides a ‘day in the life of’ example for a solar panel fitting technician.