Big Oil Follows Silicon Valley into Backing Green Energy Firms

Major oil companies are joining Silicon Valley in backing energy-technology start-ups, a signal that that those with the deepest pockets in the industry are casting around for a new strategy.

From Royal Dutch Shell Plc to Total SA and Exxon Mobil Corp., the biggest investor-owned oil companies are dribbling money into ventures probing the edge of energy technologies. The investments go beyond wind and solar power into projects that improve electricity grids and brew new fuels from renewable resources.

While the money involved is small—a fraction of the $7.5 billion that venture capital and private equity injected into the ...