The cost of solar panels is coming down and “solar farms” are on the edge of becoming economic without government support.I f you are a land owner, you might be offered £750 to £1400 per acre in rent for 25 years, plus an RPI escalator, to cover a hundred acres or so with solar panels. That is pension fund stuff. However, is it environmentally sustainable and does it matter anyway?
It is almost certainly true that the energy put into making all the solar panels so far manufactured will not be recovered in the productive life of those panels. If the energy put into manufacture, packaging, transport by sea (most are made in China), in road transport, in mounting on frameworks, in making the frameworks (all the same actions over again), and maintenance, and decommissioning, … All of a sudden, it does not seem possible that “PV”, photovoltaics, or just “solar panels”, could possibly be genuinely environmentally sustainable.
There is at least some research which gives a useful guide. Much of that research suggests an energy payback period, on the panels themselves, of 2 to 10 years. The US Department of Energy quotes in one of its published documents several pieces of research from all over the world where researchers of some academic standing looked at the question and showed a wide range of results but they were all presented by the Department as positive. The summary of research indicated that crystalline modules were significantly better than a few years ago and their efficiency would improve still more. The conclusions were also that thin-film technology was currently more efficient than crystalline and would continue to keep its lead over crystallines. Further, as new technologies develop, this is very likely to increase efficiencies again. For example, the sun emits a much wider range of energy wavelengths than just the visible spectrum. New panel technologies will collect infrared and ultra violet and maybe wider.
Nevertheless, reading between the lines, most of the quoted research appeared to be limited to the energy cost of manufacture of the panels themselves. There was limited or no indication that the total energy cost of a working installation had been taken into account. One of the bits of research even admitted that they had not even included the thin frame that surrounds the panel before putting into its packaging. So, there is some doubt about whether the research figures cover all the energy costs, not just of manufacture, but also of packaging, shipping, land transport, installation, site infrastructure, site works, supporting frame construction, commissioning, maintenance, cleaning and failures.
DOES PAY-BACK MATTER?
Maybe not. It depends on where you sit. If it makes money for everyone involved; maybe that is good enough? Only the taxpayer might not agree. One thing “renewable” (but not necessarily sustainable) might be seen to deliver is less reliance in future on imported oil, gas and electricity. (Yes, we import significant amounts of electricity from France.) There is another plus. Whatever the energy cost, it is paid for at today’s cost. The energy produced over the life of the installation pays back at tomorrow’s energy values; it is an investment in tomorrow.
What it comes down to is, as usual, money. If a detailed financial study says it makes cash, then read the small print, cover the “what ifs” over the next 25 years and go ahead. However, tone down the environmental benefit; you might be on thin film, sorry, ice.