It looks like Royal Dutch Shell is backing away from its pledges to invest in a wide array of renewable energy projects. A Shell executive told the U.K. Guardian on Tuesday that it is cutting its spending on solar, wind and hydrogen power, and will concentrate instead on biofuels and cleaner ways to use the fossil fuels that make up its core business. That would include finding ways to capture and store the carbon emissions from Shell projects around the world.  "Wind and solar are interesting [but] we may continue to struggle with other investment opportunities in the portfolio even with big subsidies in many markets," Linda Cook, Shell's executive director of gas and power, was quoted as saying. "We do not expect material investment [in wind and solar] going forward."  Shell says it has spent $1.7 billion on "alternative energy" over the past five years, but that compared to a 2008 overall capital budget of about $32 billion, the Times of London reported.  The news marks a pretty big turnaround for a company that was saying as recently as October that it planned to quadruple its spending on renewable energy, though it didn't specify at that time how it would split that investment between solar and wind power and various biofuel and carbon capture projects (see Shell Boosts Renewable Energy Spending).  Some of the company's decisions over the past years appear to counter its green claims. The company sold the bulk of its solar business to Germany's Solar World in 2006 and in December 2007 sold off its rural India and Sri Lanka solar businesses (see Shell Sheds Solar). The company said it would instead concentrate on developing thin-film solar technologies. How that research will stand up in light of this week's announcement remains to be seen. Shell also backed out of its investment in the massive London Array wind power project in April (see Masdar Bets on Massive Offshore Wind Park). The company still retains ownership of about 1.1 gigawatts of wind power capacity around the world.  Shell's biofuel investments will continue, Cook told the Guardian. That includes a recent decision to expand its stake in biofuel catalyst company Codexis and link it in a research project with cellulosic ethanol maker Iogen Energy to shorten the time it will take to shift Iogen's demonstration-level production to commercial-scale production.