Australia's merciless sunshine is about to be harnessed to produce massive amounts of renewable energy. As part of the process, the tallest man-made structure built, a one-kilometre-tall solar-thermal tower, will rise from the red desert in the south-west of New South Wales.

Plans for a one-kilometre tall "Solar Tower" that would provide clean energy for up to 200,000 homes have been approved by the Australian government. But some environmental campaigners are questioning the practical benefits of the scheme.

Looking somewhat like a huge, upturned golf tee, it would be the highest man-made structure on earth. It would also provide electricity to as many as 200,000 homes. If built, a proposed 200-megawatt "solar chimney" for rural Australia would become the most daring application yet of a quirky form of generating alternative, renewable electricity.