This weekend's Live Earth concerts are to have solar-powered websites to keep in with the environmental message. The web hosting company chosen to power the sites, Affordable Internet Services Online (AISO) offers a 100-percent solar-powered web hosting facility in Romoland, California.

The concerts are to be held on 7 July in Shanghai, Tokyo, London, New York and other cities. Organisers of the Live Earth event say the concert venues will be carbon neutral, with electricity to power musicians' amplifiers and microphones coming from renewable energy sources.

AISO has been using the renewable energy of the sun to power its data centre since 2001, said Phil Nail, chief technology officer for the 10-year-old company.

AISO will operate two Live Earth sites, one for the concert and the other to track pledges. Live Earth is not seeking financial donations but asks people to pledge to adopt a carbon-neutral lifestyle.

The company installed 14 IBM BladeCenter servers powered by AMD Opteron dual-core processors to host the sites. Each of the servers uses about 142 watts of electricity, which Nail considers more energy efficient than average. Low-end servers, including blades, run at an average of 218 watts and midrange servers at an average of 638 watts, according to figures from a 2007 Lawrence Berkeley National Laboratory study.

Because these are the first Live Earth concerts, organisers have no idea how much traffic to expect at the websites, he said. The concert will be televised and viewers will be invited to make pledges on the AISO-hosted pledge sites. Later, the names of those who pledged will appear on TV.

Other web hosting companies advertise themselves as "green," Nail said, but they often simply buy carbon offsets rather than actually improve their own energy efficiency. Affordable Internet also has installed solar tubes, shafts that run from the roof of a building to the ceiling in a room, to light the data centre's interior. It also irrigates a rooftop garden with recycled water from the data centre's cooling system.

Affordable Internet, with 15,000 customers, has attracted prospective customers from as far away as the UK to host their websites because they are seeking out carbon-neutral hosting services.