While the use of solar cells is become increasingly widespread, the silicon technology used in many types is becoming obsolete. JP Casey looks at concentrated solar power, micro-trackers and perovskite compounds as innovations that could potentially improve solar efficiency.
On the one hand, the future of solar power is bright. Greater demand for solar cells has slashed installation prices and encouraged manufacturers to develop ever more efficient technologies, and governments to pass increasingly pro-solar legislation. However, raising the efficiency of solar cells often means a parallel increase in price, and with the technology now so widespread, seemingly minor technological improvements could have significant economic consequences on the global solar industry.
With conventional silicon-based solar cells reaching the limits of their efficiency, the solar industry is looking towards new technologies to improve solar cell performance, from the exciting but unpredictable perovskite compounds to concentrated solar photovoltaic solutions.
Solar is booming but efficiency is lagging behind
The last decade has seen a boom in solar energy, with global solar photovoltaic (PV) energy consumption leaping from below 50TWh in 2010 to over 300TWh in 2016, according to BP. Countries such as China and Germany are leading the way with solar investments, the former installing more solar capacity in 2017 than the rest of the world combined, and the latter relying on solar for 7% of its annual energy needs in 2016.
Meanwhile, the US has introduced legislation to further its solar industry, a clear government commitment to the renewable energy source. The solar Investment Tax Credit (ITC), which introduced a 30% tax break for solar systems installed on residential properties, has contributed to an astonishing growth of 8,600% in the US solar industry, since its enacting in 2006. These three regions – Asia Pacific, Europe and Eurasia, and North America – have been largely responsible for the shift, contributing 318TWh of the 2016 global solar PV consumption of 333TWh.
However, this incredible growth has been in spite of solar technology itself remaining relatively inefficient, with cells using crystalline silicon only being 22.3% energy efficient, according to the Fraunhofer Institute, a leading European research organisation. Crystalline silicon is the most commonly-used material in the construction of solar cells, so improving their efficiency could have knock-on effects on the profitability and effectiveness of the solar industry as a whole, although this could be challenging; a Fraunhofer experiment to improve the efficiency of crystalline silicon cells only yielded an improvement of 0.7% over the duration of 2016.
Some of the world’s largest companies are investing heavily in improving solar efficiency, with Spectrolab, a subsidiary of Boeing, producing the world’s first terrestrial 40% efficiency solar cell, many of these solutions are too specialised for everyday use; the majority of Spectrolab’s cells, for instance, are used in solar facilities in space. However, Spectrolab’s record-breaking panel takes advantage of a process known as concentrated solar photovoltaic (CPV), the principles of which can be applied to smaller cells to improve efficiency across the industry.