11 Jul Shaped by sunlight
The world of renewable energy development is filled with all sorts of scientific equations and technological hurdles. Thankfully, as time passes, we are beginning to understand the science better – particularly in terms of solar power – and the hurdles are being overcome when it comes to finding technical solutions.
One ‘equation’ where much has been accomplished over the years, is in figuring out how to cope with the supply of sunlight – the key factor in the photovoltaic (PV) process of converting radiation into electricity. After all, the supply of the Sun’s radiation determines the extent to which we must design and construct our applications of renewable energy. Thus, the underlying principle of this equation is that solar power systems are supply-driven.
Supply-driven infrastructure for electricity is different from the present demand-driven infrastructure of diesel-powered electricity. When it comes to fossil fuels like diesel, we build our power systems based on the demand for energy from customers. But in the case of solar power, we need to design the delivery of electricity based on the supply of the Sun’s energy. The ‘supply versus demand equation’ is the core of where our efforts are going.
The installation of solar power systems is shaped and defined by available sunlight: the radiation, or insolation factor. So to capture the maximum amount of sunshine, solar PV panels are commonly fixed to rooftops, and angled in such a way as to attract as much of the light as possible. The more space that’s available, the more PV panels can be mounted to capture the sunshine. Whenever the sun is shining, the PV panels should be positioned to the best advantage.
As a result of the supply principle, we are constrained by the characteristics of sunshine. That includes the total number of hours each day that the sun is shining, and how continuous the sun does shine without being blocked out by clouds. Faced with these scientific parameters, investment in the technology has grown markedly over recent years.
Among the breakthroughs, solar PV systems have expanded from straightforward rooftop-mounted installations to more complex arrangements. Installations are now found anywhere there is room to fit the panels and in varying methods of applications. For example, solar cell technology is being applied to the transport sector where we have seen in recent times the first solar-powered vessel and plane conduct historic journeys. Solar PV is also found in space energizing main power systems, and in cars providing auxiliary power. The advances keep coming.
On buildings, solar cells have been utilised in new ways. Bus stop shelters and car park coverings are being adorned with PV panels. Rooftop arrays have been developed to automatically adjust and track the radiation as the sun moves across the sky. And the walls of buildings are even accommodating the power systems to take advantage of available space.
Smaller applications of PV panels are becoming more common. Many homes and gardens feature solar-powered lighting and stand-alone devices have integrated with modern facilities like ATMs, pay-stations, traffic signs and signals, and emergency telephones. In remote areas too, solar cells are providing energy to rural cooking systems and water pumps.
While our own applications of solar cells are beginning to broaden on Rarotonga, we will have the advantage of learning from the development of new technology and how it can benefit and enhance our power needs. Issued in the Cook Islands Herald on 11 July 2012.