Solar matrix

There is an interesting article on viable alternatives to fossil fuels in Energy Bulletin. Borrowed from a do-your-math blog, this one sees the blogger, a physicist making some calculations to arrive at the answer.

For his matrix he chooses a few important characteristics - abundance (of the fuel), technical difficulty (in producing energy), intermittency, demonstrated (is it ready for use), electricity, heat, transport, acceptance, backyard (can it be deployed in our backyard), efficiency. Yes, cost is missing! But as he later explains, the lowest scoring ones are the costliest.

Except for abundance aspect where fossil fuels fail, there is no comparison with fossil fuels that tower over the alternatives in every other aspect. But abundance, and repurcussion, such as climate change, are two major aspects.

The best alternatives turn out to be soalr PV and solar thermal. Covering only 0.5% of land area with 15% efficient PV panels provides the annual energy needs of our society, qualifying solar PV as abundant. It’s not terribly difficult to produce; silicon is the most abundant element in Earth’s crust, and PV panels are being produced globally at 25 GW peak capacity per year.

As to solar thermal, it achieves comparable efficiency to PV, but uses more land area, generating electricity from concentrated solar thermal energy automatically fits in the abundant category—though somewhat more regionally constrained. It’s relatively low-tech: shiny curved mirrors tracking on (often) one axis, heating oil or other fluid to run a plain-old heat engine. Intermittency can be mitigated by storing thermal energy, perhaps even for a few days. Because a standard heat-engine follows, fossil fuels can supplement in lean times using the same back-end.

Finally, as the writer notes, the other controlled option is to deliberately adjust our lives to require fewer resources, preferably abandoning the growth paradigm at the same time. 'Can we manage a calm, orderly exit from the building? In either case, the first step is to agree that the building is in trouble. Techno-optimism keeps us from even agreeing on that.'

Check out the calculations for more.