Warren Buffett is a busy man, and never more so than during Berkshire Hathaway's annual meetings, sometimes called the Woodstock of capitalism, which attract thousands of people each year to Omaha, Nebraska.

But Buffett found time during this year's gathering to sit down for an hour with Chuanfu Wang, the chairman and CEO of BYD, the Chinese company that makes cars, batteries, electronics and solar power equipment.

And why not? Berkshire's MidAmerican Energy Holdings unit bought a 10% stake in BYD for about $230 million in September, 2008. Today, it's worth nearly $2 billion.

That's a nifty return, even by Buffett's standards.

"BYD is really running on all cylinders," says Li Lu, a BYD investor and money manager who brought the company to the attention of Berkshire vice chairman Charles Munger several years ago. Munger took the idea to Buffett and to MidAmerican chairman David Sokol, who now sits on BYD's board.

I wrote a FORTUNE cover story about BYD in 2009, met with Mr. Wang in Shenzhen and late had the pleasure of meeting Li Lu. He's a fascinating guy -- participated in the Tiananmen Square uprising in 1989, then fled China, earned business and law degrees at Columbia University and for the past 13 has run an investment firm called Himalaya Capital. He's been an informal adviser to BYD and traveled to Omaha with Mr. Wang. Li Lu now lives and works in Pasadena, Ca., where we met last week.

The most important thing to know about BYD -- the letters are the initials of the company's Chinese name, but they have come to stand for Build Your Dreams–is that the company has enormous ambitions. It aims to be not only the world's biggest carmaker, but a leader in cheap solar power and utility-scale battery storage as well. Mr. Wang, the founder and chairmen, has said that he believes that the automobile and energy industries are on the verge of a major transformation. Buffett, Munger and Sokol all told me that they were really impressed with Mr. Wang–not a bad trio of endorsements.

BYD's been in the news lately for three reasons. In March, the company announced a joint venture to develop electric cars in China with Mercedes. The idea is to combine Mercedes' design excellence with BYD's technological savvy, particularly with respect to batteries, and the Chinese firm's access to its home market. "Daimler's know-how in electric vehicle architecture and BYD's excellence in battery technology and e-drive systems are a perfect match," Mercedes chief Dieter Zetsche said at the time.

Last month, BYD announced that it will open its North American headquarters in a downtown neighborhood of Los Angeles. Mr. Wang was joined by California Gov. Schwarzenegger and LA Mayor Villaraigosa at the ceremony and, interestingly, the company said it would put more than its electric cars on display -- it will showcase "solar panels, energy storage systems and advanced LED lighting products" as well.