GREEN RANKING FOR 2009
Ranking: 2
Worth: £26bn
Green investment: Renewable fuel

Microsoft founder Bill Gates stepped down from the software giant last year to devote his time and money to philanthropy. He has given away much of his wealth in recent years to the Bill & Melinda Gates Foundation, which has $29.7 billion to spend on favoured causes. More than half of Gates’s wealth is outside Microsoft now. He has also invested in ventures through his Cascade Investments operation, including a holding in Pacific Ethanol, a fuel company.More recently he invested in Sapphire Energy, a Californian company that intends to make motor fuel from algae. Algae are the renewable-fuel industry’s great green hope because they are rich in oil and can grow in a range of conditions. Many companies are betting they can create fuels or other chemicals cheaper than existing feedstocks. In all, Gates is worth about £26 billion.