Balloon power isn’t just a load of hot air

For those who dislike the sight of wind turbines on the horizon, would a spectacular hot-air balloon farm be more acceptable?

Ian Edmonds, an environmental consultant with Solartran in Brisbane, Australia, has designed a giant engine with a balloon as its “piston”. A greenhouse traps solar energy, providing hot air to fill the balloon. As the balloon rises, it pulls a tether, which turns a generator on the ground. Once the balloon has reached 3 kilometres, air is released through its vent and it loses buoyancy. This means less energy is needed to pull the balloon back down again, resulting in a net power gain “It is like a huge two-stroke engine, with a capacity of 45 million litres, a stroke of 3 kilometres, and a frequency of one revolution per hour,” says Edmonds.



For roughly the same cost as wind power, Edmonds has calculated that a large 44-metre-diameter recreational balloon could generate 50 kilowatts, enough to supply energy to about 10 homes. Doubling the diameter of the balloon would increase power production tenfold, substantially reducing costs, he says.

New Scientist