One example of these "new utilities" is Recurrent Energy, a private San Francisco-based solar company that has large-scale solar projects in California and Ontario, Canada. CEO Arno Harris thinks of his company and its peers as traditional electric operations, despite producing a non-traditional type of power.
"We develop power plants first and foremost," said Harris. "Look at all the different power industries and you'll find developers that do essentially what we do—find land, find connections and market power."
Traditional utility companies, including NextEra, the largest producer of wind and solar power in the U.S., are also diversifying their power bases. NextEra gets 56 percent of its energy from wind, 22 percent from natural gas, 15 percent from nuclear, 4 percent from oil and 3 percent from solar. Five years ago, gas accounted for 37 percent of its power, while wind made up 41 percent and solar less than 1 percent.
Many people think of solar companies that cater to the small-scale commercial and residential markets, including SolarCity and Sungevity, as solar panel sellers and not utility companies. SolarCity now has sales representatives in Home Depot and Best Buy locations, allowing residential customers to shop for a solar rooftop or backyard project just like they would a home improvement or electronics product. But in effect, they operate more like utilities, allowing their customers to lease the solar projects on their property. Any excess power that's created from a project is fed back into the neighborhood electric grid, and the user may then be given a discount on their electrical bill.
The fact that end user is generating power—rather than getting it from a utility company—is a major change.
"As you move to solar, the traditional utilities model is breaking down," said Paul Coster, an alternative energy analyst with JPMorgan. "There's potential for one or more of these companies to emerge as a national utility."
People who have solar panels on their roofs still depend on their local utility to supply electricity when solar power runs low, but there could come a time when people disconnect from the power grid all together, Aggarwal said.
At some point, energy-storage batteries will be able to store enough power to keep homes running when the sun isn't shining—it's no coincidence that Elon Musk is founder of both Tesla Motors and SolarCity, two companies that are already working together on ways to store solar power in lithium-ion battery units inside Tesla electric vehicles. When that happens, individual homeowners will have the power to become utilities themselves, Aggarwal said.