In this paper, we review activity by the large petroleum majors in the renewables sector. Oil companies have traditionally invested in other energy sectors (e.g., coal, nuclear) but in recent years the trend has been to concentrate on the petroleum sector. The low price of oil throughout the last decade of the 20th century limited the scope for speculative investments outside the core oil and gas business. Most majors sold off other ventures, although there were some notable long term investors in solar. As we enter the new century certain major oil and gas companies are once again investing in alternative energy to become broader ‘energy’ companies. This trend is the result of greater awareness of future energy demand, greater pressure and incentives to reduce emissions in their own operations, and the promotion of social responsibility and other general sustainability issues.