thin-film solar modules – a more flexible solution

I’ve been hearing that the costs of solar installations are coming down, making the take-up easier and faster, but I haven’t spent the time to research exactly why this is happening, presumably world-wide. So now’s the time to do so. I thought I’d start with something I heard recently on a podcast about revolutionary thin solar cells…

Thin-film solar cells have been around for a while now, and they’re described well here. They’re only one micron thick, compared to traditional 350 microns-thick silicon-wafer cells, and they utilise superconductor materials, usually silicon-based, which are highly efficient absorbers of solar energy. However, according to Wikipedia, this new technology isn’t doing so well in the market-place, with only about 7% of market share, and not rising, though with crystalline silicon being replaced more and more by other materials (such as cadmium telluride, copper indium gallium selenide and amorphous silicon) there’s still hope for its future.

This technology was first utilised on a small scale in pocket calculators quite some time ago but it has been difficult to scale it up to the level of large-scale solar panels. There are problems with both stability and toxicity – cadmium for example is a poison that can accumulate in the food chain like mercury. It doesn’t look like it’s this or any other technological development that’s reducing costs or increasing efficiency, though of course they may do in the future, with graphene looking like a promising material.

So let’s return to the question of why solar has suddenly become much cheaper and is apparently set to get cheaper still. Large manufacturing investment and economies of scale seem to be a large part of the story. This means that the costs of solar modules now make up less than half of the total cost of what Ramez Naam calls ‘complete solar deployments at the utility scale’, and these other costs are also coming down as the industry ‘scales’. His article in Renew Economy from August last year makes projections based on the idea that ‘doubling of cumulative capacity tends to reduce prices by a predictable rate’, though he’s also prepared to heavily qualify such projections based on a multitude of possibly limiting factors. If all goes well, solar electricity costs will become less than half the cost of new coal or natural gas in a generation – without factoring in the climate costs of continuing fossil fuel usage. The extraordinary rise in solar energy usage in China, set to continue well into the future, bolsters the prediction, and India is also keen to incease usage, despite problems with domestic manufacturing and trade rules. Most panels are being imported from China and the USA, while domestic production struggles.

It’s interesting that solar and other renewable technologies are now being spruiked as mainstream by mainstream and even conservative sources, such as Fortune and oilprice.com. Fortune’s article also usefully points out how the cost of different power sources to the consumer is heavily dependent on government policies relating to fossil fuels and their alternatives, as well as to the natural assets of particular regions. Even so, it’s clear that the cost of fossil-fuel based electricity is rising everywhere while wind and solar electricity costs are falling, creating an increasingly clear-cut scenario for governments worldwide to deal with. Some governments are obviously facing it more squarely than others.

US residential solar costs. Beyond 2013, these are estimates, but already out of date it seems