The future of solar power

The overview on the applications of solar photovoltaic systems (December 31) promises an extremely bright future for solar power. A word of warning so as not to fall into the same trap as that posed by adverts for solar water heating systems.

Adverts used to claim that a solar water heater saved “80 per cent of your electricity needs” while in reality it saved 80 per cent of that proportion of electricity spent on heating only or, in other words, about 15 per cent of the total electricity bill. Many times “adorned-truths” could backfire on the whole promotion concept.

Long-term studies carried out by myself on a number of systems installed at the Institute for Energy Technology of the University of Malta and elsewhere showed that stationary grid-connected systems would produce 1,300 kWh per annum. It is important to point out that this output is only valid for grid-connected systems. A stand-alone system that charges batteries would produce some 40 per cent less power due to the inefficiencies connected with charging and discharging batteries.

The fact still remains that we cannot be biased towards fossil fuelled electricity throughout, since every unit of electricity produced from solar energy saves an equivalent of three to four units of input oil energy and an astonishing 850g of carbon dioxide. In other words, a 1 kWp system would save 1.1 tonnes of carbon dioxide per annum and this is not to be underestimated. timesofmalta