MOAPA, Nev. — Roads often follow rivers, taking advantage of the level ground created by water. But here in the desert of south central Nevada, the road and the river grew together. Only the river does not carry water. At the edge of Interstate 15, a crackling river of electrons provides power not just to Nevada’s homes, mines and casinos, but to parts of California as well.

For years, many of those electrons were generated by coal, a fuel now largely abandoned here thanks to both economics and legislative decree. Now an increasing percentage of them are coming from renewable sources — geothermal, solar and wind. This makes them all the more salable now that California, the biggest energy market in the West, severely restricts the purchase of electricity associated with excessive greenhouse gases.

This has not escaped the attention of Warren E. Buffett, the country’s premier investor. Through his companies, he has in recent years acquired two major utilities, NV Energy and PacifiCorp Energy, which are poised to take advantage of the energy market recently expanded by California.

Thanks in part to the transmission lines alongside Interstate 15, Mr. Buffett’s company, Berkshire Hathaway, and its subsidiary Berkshire Hathaway Energy stand to make steady, predictable profits in an energy market undergoing transformations.