Solar power is a renewable and an infinite energy source that creates no harmful greenhouse gas emissions. As long as the sun continues to shine, energy will be released. It can be a major player in confronting the climate emergency. However, it’s not new and there remain issues to be resolved.
Solar energy was used by humans centuries ago to light fires by reflecting the sun’s rays off shiny objects. The Egyptian God Ra was the patron of the sun, heaven, kingship, power, and light. Later, in 3rd century BC, the Greeks and Romans harnessed solar power with mirrors to light torches for religious ceremonies and the sun emblem is a major feature in many cultures.
In 1839 and at the age of just 19, French physicist Edmond Becquerel discovered the photovoltaic (PV) effect while experimenting with a cell made of metal electrodes in a conducting solution. He noted that the cell produced more electricity when it was exposed to light – it was a photovoltaic cell.
In 1954 PV technology was born when Daryl Chapin, Calvin Fuller and Gerald Pearson developed the silicon PV cell at Bell Labs in 1954. It was the first solar cell capable of absorbing and converting enough of the sun’s energy into power to run everyday electrical equipment.
Today satellites, spacecraft orbiting Earth, are powered by solar energy. The construction industry was not so quick to adopt solar. If every new house built in the UK in the last twenty years had solar panels fitted just think how much electric we would save!
Solar Panels: are they the future?
Solar panels convert sunlight into electrical energy through PV panels. This energy can be used to generate electricity or can be stored in batteries or thermal storage. Once installed, solar panels produce energy to help run and heat your home. They are your own mini power station.
When the sun shines onto a solar panel, energy from the sunlight is absorbed by the PV cells in the panel. This energy creates electrical charges that move in response to an internal electrical field in the cell, causing electricity to flow. Therefore, natural daylight is absorbed by an intricate system of PV cells, this is passed to an inverter and converted to usable power and distributed around the home for use.
The heart of a PV system is the inverter; essentially this does all the hard work. Your home runs off AC power BUT your panels are producing DC power, so it is the job of the inverter to convert the generated power (DC) into usable power (AC).
A problem with shade? Use Optimisers!
If your panels are likely to be partly in the shade you may need to fit an ‘optimiser’ on each panel to ensure full electricity production.
For a single roof installation a traditional ‘string’ inverter would be installed. If shading is an issue then you need to consider adding optimisers to the system.
With a two roof installation requires a ‘dual tracker’ inverter. This allows each roof to work independently. For example, with some panels installed on a south-facing roof and other on a west-facing roof, the panels on one roof wouldn’t work as efficiently when the panels on the other roof are in natural daylight. Choosing a dual tracker inverter would allow each roof to work independently.
If you use three or more roofs then the shading issues are multiplied. If one roof is in daylight and another is in shade, the panels would only work to the strength of the weakest panel, even if with a traditional string inverter (or dual tracker inverter). So to ensure all panels are working to their maximum output, you need to use ‘optimisers’ or ‘micro inverters’.
Once the DC power has reached the inverter, it is converted into usable AC electricity. The usable AC electricity is then passed via a PV cable into the main fuse box (consumer unit) for distribution around the home e.g. to power the washing machine, lights, TV etc.
Exporting Surplus Electricity
With any domestic PV system, there will be times when the electricity you generate is more than you can use or store. The surplus will be exported to the grid to be used by somebody else. If you want to be paid for exporting, you need to make sure you’re getting a Smart Export Guarantee (SEG) from an electricity provider. If you applied before April 2019, you were able to claim export payments at an Ofgem ‘Feed-in Tariff’. If not, you need to find an energy company that will pay you a goof SEG for this surplus and have the correct smart meter.
As with any industrial product there is an environmental impact associated with PV panels. The main areas of potential concern are:
- The energy required to manufacture them.
- Toxic and other potentially harmful materials used or created during manufacture.
- What happens to them at the end of their lifetime?
It’s important to keep these issues in context. All electronic equipment leads to similar concerns. Whereas many electrical goods are only in use for a few years, most PV panels are expected to last for much longer. Furthermore, PV panels are used to replace other sources of electricity such as coal, oil and gas that usually have a much greater environmental impact. Generating about 3,000 kWh from solar panels instead of from a gas-fired power station will save about 1.2 tonnes of carbon dioxide emissions.
The main component of most PV modules is silicon. This isn’t intrinsically harmful, but the manufacturing process can involve chemicals that need to be carefully controlled and regulated to prevent environmental damage. Even in the UK their carbon footprint can be paid back in the first six years of their operation. If you live somewhere sunnier, this can go down to as little as 1.5 years, a fraction to the expected life of 30 years.
Solar panels are made from materials, which are either recyclable or reusable and in the UK every solar panel company must join the ‘Producer Compliance Scheme’, which ensures panels are collected and recycled properly. While this may require further regulation, with the industry growing, improvements should be expected.
The mining of materials such as cobalt and lithium used in some systems also raises concerns regarding their negative environmental impact, the amount of energy consumed in their production, long term viability and in places, weak workers’ rights. For solar energy to be become more widespread and acceptable alternatives to these will need to be found and regulations enforced.
As technology presently stands, batteries hold the key to unlocking the full potential of renewable energy as any extra energy generated during sunny periods can be captured and stored within these batteries for future use. This also ensures a continuous power supply all year round.
How safe are lithium batteries?
The good news is that solar lithium battery fires are not usually caused by solar batteries and that the risk can be largely mitigated if not prevented entirely through the correct installation of a good quality battery. As with any lithium-ion battery, a solar battery could potentially cause a fire if it overheats. But the top brands have strict quality control and are very quick to do a recall if something is found to go wrong, which is incredibly rare. Only buy a reputable, top quality battery.
It is vital to remember that with all forms of energy production (consider the dangers posed by oil, petrol, gas and coal!) there are potential downsides.
But as it has been calculated that the amount of sunlight that strikes the earth’s surface in an hour and a half is enough to handle the entire world’s energy consumption for a full year then surely the world has to make full use of the power of the sun and its potential role in renewable energy and the fight against climate change.
What’s the cost?
Prices vary depending on how many panels and batteries you install and what type and quality they are. Many panels are made in China but you can get excellent quality panels made in Spain and Italy.For a decent quality, ten panels, solar/battery set up expect to pay around £9-10,000. This should supply you with decent amounts of hot water, run a proportion of your electrical equipment and in sunny weather you’ll be able to earn money by supplying electric back to the National Grid. In the UK you can expect one kilowatt (kW) of panels to generate between 800 and 1,000 kilowatt-hours (kWh) of electricity per year. So a well-sited domestic system of about 3.5kW peak output could produce around 3,000 to 3,500 kWh per year.
My own experience
My electric boiler came from a Scottish company, EHC, and were fitted, along with the solar panels and battery, by a local company CME, all running on renewable energy. When there is light it heats our water, supports our energy uses and feeds back into the national grid. I can also control and view what is happening with an app on my laptop, phone and smart meter.
There are many firms offering solar panel packages and obviously good research is recommended to find the best quality arrangement, which suits your requirements. Make sure they are affiliated to MCS (Microgeneration Certification Scheme), RECC (Renewable Energy Consumer Code) and an electrical governing body.
Some helpful links
Solar Energy UK, an industry trade association.
Solar Service Solutions, a Hampshire based firm.
PS: It is reported that the painter J.W.M. Turner’s last words were: “The Sun is God …”.
JWM Turner. Detail The Fighting Temeraire – National Gallery.
Ed: West England Bylines does not support any particular organisation or company. We do however give space to those who promote progressive and sustainable goals.