Photovoltaic Energy

One of the most talkedabout sources of renewable, sustainable and clean energy is solar power, but what exactly goes into the process of producing electricity this way? Firstly, solar energy can be used for heating as well as generating electricity, and the technology used for the latter revolves around the photovoltaic process by which solar rays captured on devices such as solar panels are converted into electric power with the use of semiconductor materials such as silicon.

The concept was originally developed by Canadian inventor George Cove, who created the world’s first solar electric generation equipment over a century ago – almost 50 years before Bell Labs produced the first industrial prototype. By the 1990s, the technology was ready for commercialisation, and got a major boost from the first large-scale installation in a Japanese brownfield in 1994.

Since those early days, when expensive solar panels limited the potential of the technology, it has really taken off, with the economies of scale reached reducing prices by 90% within little more than a decade, though costs have again spiralled during the latest bout of inflation. For all that – and the hundreds of thousands of panels that have been installed on the ground, on rooftops and even as part of solar farms – solar energy still supplies little more than 2% of global electricity demand. ›

HOW IT WORKS

The essence of solar power generation is the conversion of light into electricity, a process by which solar panels – or rather, the solar cells they are made up of – catch the sunlight that hits the earth’s surface and feed this energy into an electric grid, be it a localised one or the greater power grid. Though they operate best at an oblique angle, solar panels can be mounted on the ground, fitted to a wall or attached to a flat or sloping roof, as is often the case. They can be fixed in one position or follow the sun with a ‘solar tracker’ for optimal productive hours. Solar energy is therefore a renewable and sustainable energy source that is free of CO2 and other harmful emissions, though the latter does occur in the manufacture and installation of its main elements, including the solar panels themselves. The main material used as the semiconductor, silicon, is abundant and cheap to produce, though others, such as silver and polysilicon are more costly.

Production is highly scalable and in recent years new advances in the technology and equipment that underly solar power have greatly improved output and efficiency. However, certain problems remain, not least of which are the environmental cost of the infrastructure and the fact that the solar panels – which have a useful lifespan of 10-30 years, cannot be recycled. Though the energy generation itself is clean and renewable, solar power as a whole does come at a cost. ›

CHALLENGES

These and other factors explain why, for all its almost limitless potential, solar power has lagged in third place among renewable energy sources, behind hydroelectric and even wind power. The latter seems so much more cumbersome and has many of its own shortcomings – not least of which are the unsightly ‘wind farms’ themselves, but even so it outperforms solar in both investment/ funding and output.

One problem solar power shared with Aeolic (wind) is the irregularity of production – basically, electricity is produced when there is sunlight/ wind and nothing is created when there isn’t. This compares very unfavourably with conventional power stations, which produce as much or as little as we want, and if need be, 24 hours per day. It creates a massive supply, storage and distribution headache for electricity companies that they have not had to deal with before. ›

Up to now, power storage has been a problem for renewable energy

New home battery systems are becoming ever more efficient Solar panels on rooftops – the best way to use an otherwise dead space

The above explains why solar power has so far enjoyed limited growth, given its enormous potential, and why it is still not that much of a large-scale form of electricity supply, and more of a localised source, based upon the installation of solar panels on the roofs of individual homes and buildings, which feeds into a local grid powering the electricity needs of the home, office or warehouse. Any overproduction is sold into the grid, but so far this has been resisted by energy companies.

FUTURE POTENTIAL

In 2019, global solar power production was 665 gigawatts (GW), a fraction of what is possible, yet some core problems will have to be resolved before this renewable energy can truly take off and be produced on the kind of scale it deserves. That said, there is nothing wrong with the model, which sees local production in homes and buildings being stored in ever more efficient batteries and used to satisfy local needs, with the remainder fed to the grid.

In fact, the trend to create solar farms on acres of open land, let alone prime agricultural resources, is a dangerous practice that harks back to an antiquated

TOP 10 PV COUNTRIES IN 2019 (MW)

Installed and Total Solar Power Capacity in 2019 (MW)

Data: IEA-PVPS Snapshot of Global PV Markets 2020 report, April 2020

industrial revolution way of thinking. Put simply, it is not environmentally friendly – which is the whole purpose of solar energy – wasting precious land when there are so many rooftops available on which to place solar panels, out of sight and better positioned to feed into the grid.

New battery storage and power distribution systems will have to be developed, but more localised production reduces costs and energy loss in transport, while new research is also opening up other, more cost-effective and/or efficient forms of producing solar-powered electricity. At the moment, they include thin-film PV, which uses a new semiconducting material, perovskite, and the advent of more attractive solar rooftiles that are lighter and more flexible than roof panels. ›

It would be a waste to cover nature and valuable agricultural land in glass panels

LOCAL IMPLICATIONS

The majority of engineering production not surprisingly takes place in China, with much of the technology coming out of places such as the USA and Germany, where the relatively sunny city of Freiburg leads the way in research, investment and production on a continent where countries such as Spain have such a huge natural advantage that it shouldn’t take long before Andalucía, and indeed the province of Málaga, become major European producers of solar power.

If successful, this could spark a valuable tech sector at the heart of the Costa del Sol. e