By LESLIE KWOH
Soon after the earth shook under Japan last March, NRG Energy Inc. felt aftershocks halfway around the world.
When the earthquake triggered a meltdown at the Fukushima Daiichi power plant, the independent power producer was building two nuclear reactors in Texas. Amid regulatory uncertainty in the U.S., the ambitious multibillion-dollar project was halted.
Now, Chief Executive David Crane faces the task of moving Princeton, N.J.-based NRG forward without nuclear energy, one of the primary drivers of its growth. The company has shifted focus to its solar and natural-gas businesses, he says. And solar, in particular, is a bright spot: In December, Warren Buffett's MidAmerican Energy Holdings purchased a 49% stake in one of NRG's Arizona solar plants.
The changes come as Mr. Crane is guiding the wholesale producer's expansion into retail power, with three acquisitions since 2009: Reliant Energy, Green Mountain Energy and Energy Plus Holdings. The company is also rolling out an electric-vehicle charging network in Dallas and Houston in a bid to capture a slice of the urban trend toward more eco-friendly cars.
Mr. Crane, 53 years old, spoke with The Wall Street Journal about the company's post-nuclear future and whether the world is a safer place after the Fukushima disaster. Edited excerpts: