Green WebHost is an UK company that started providing environmental guided hosting in 2003. They were, according to them, the first ISP in UK that took this issue seriously.
Their datacenter is located in California, east of Los Angeles, and uses 120 solar panels which generate all the electricity they need to power the servers and their offices, becoming the first and only solar-powered hosting company in the UK.
One of their plans for the near future is to build the first "Solar Powered Data-centre" in Europe. This data-centre is expected to be built in Portugal. They are currently looking for Investors or Internet companies wishing to help.