Current affairs do sometimes fall out rather sweetly. About halfway through this not-notably-happy year for humanity, two electrically powered heavier-than-air flying-machines made memorable appearances, stimulating some of our more excitable commentators to herald the dawn of renewably powered aviation just when renewably powered motoring seemed to be enjoying a revival.

The first of the two events pictured and reported in the media was the flight of a jetliner-span car-weight sailplane-like aircraft with 12 000 wing-mounted solar cells, four electric motors, and storage batteries for nocturnal continuation on course. Days after the first take-off of the machine the pilot embarked on a 26h flip over Switzerland without, as he said afterwards, ‘using a drop of fuel and without causing any pollution’, and soon another (but pilotless) sailplane-like aircraft (of UK design), also solar-powered, broke an endurance record over the USA.

The organisers of the Swiss enterprise spoke of a plan to circle the earth in two years’ time. The Anglo-American people reportedly hoped that their machine ‘would be recognised as ‘the world’s first truly eternal plane’. Some observers thought the prospects for ‘solar aviation’ boundless. Others reflected on the persistent inadequacy of batteries for automobile propulsion, and on the formidable development required to give commercial carrying capacity to solar aircraft.

Pessimists should temper their doubts.

During last century’s energy crises there were many radical proposals for lifestyle reform to match the changing circumstances. While some innovative spirits looked to alternative energy sources for example, more nostalgic souls contemplated return to muscle power, as extracted from horses and oxen, and even men. Pedestrianism was advocated, in one guise or another. And, for the first time, aeroplanes were flown that were propelled by airscrews driven by pilots’ pedal power. The sea channel that separates England and France was crossed by an American pedalplane in 1979, sadly to less social acclaim than the Frenchman, Blériot, received for the first channel crossing by an aeroplane – engine-driven – in 1909. However, for a time, there was talk of a new popular sport, aerial cycling.

Electrically propelled aircraft were of course discussed, as were electrically propelled cars, and the problems of ‘refuelling’ infrastructure. The question of recharging battery-powered aeroplanes might seem to have been answered by photovoltaics, but there is another way, as has been shown very recently. Nokia, the mobile phone people, have revealed to their customers a portable pedal-driven charger which they can use to keep their phones going while they themselves are on the hoof, or otherwise on the move.

The next step, surely, is to equip every electric car with at least one pedal charger: and then every electric aeroplane.

Was it not Luigi Galvani, the Italian obstetrician-cum-physiologist (1737-98), who originally demonstrated connection between electrical and muscular power?

Sunny prospects for rising generation

I draw welcome refreshment from the continued ability of the Solar System to produce surprises, in spite of ancient indications to the contrary.* Sadly for me, however, one of the surprises is that direct use of solar energy is the least successful of the various renewable energy pursuits. Particularly saddening is the experience of a country such as Spain, which has been in the forefront of efforts to exploit its substantial solar energy resource but has been forced by economic circumstances to reduce its national investment in this as in other renewable resources.

Anecdote has it that the Spanish authorities have had to probe the oversatisfactory statistics of the nation’s solar power generation at night. The unexpected bounty has been found due to contributions from wind turbine generators which have been registered as ‘solar’ to qualify for the higher subsidies. Which is not to say that any solar electricity has been undervalued in Spain. Interestingly, Spanish operators have found their solar thermal converters to be more productive than their solar cell arrays.

Although the solar installations are the lowest-ranking of the world’s renewable electric power producers, they are still highly esteemed by the cognoscenti for the long term. I found it encouraging to be told that the International Energy Agency this year predicted a 22% share of worldwide output for solar plants in 2050 – a bit too long-term though that may be for me, perhaps.