In a warm world of increasingly extreme weather events, homeowners are turning to backup batteries for relief and peace of mind. But the backup only lasts so long and there is a bigger problem when playing: the aging power grid.

Enter a virtual power plant managed through a cloud-based system. This is a fertile market for many companies as consumers seek higher reliability, especially in areas prone to high temperatures and storms.

Based in Austin, Texas, Basic Power Supply is a virtual power plant and hardware company that provides battery backups for homeowners. The startup manages batteries, which actually controls the power supply in and out.

“We install batteries on our customers’ homes. When the grid is up and running, we use these batteries to support the grid,” said Zach Dell, CEO of the base. “When the grid goes off, our customers receive these batteries to back up their homes. We can also save our customers on a 10% to 20% monthly electricity bill.”

Unlike Tesla and Enphase, Base does not sell home backup batteries. Instead, it rents the battery to the homeowner, providing hardware, software, installation, operation and power. Essentially, it is a battery-based energy company.

“We own and operate it,” Dell said. "We handle all maintenance. We take care of the system as we do."

This control allows the basic operating method of the battery, especially accessing cheaper power and passing the saved power to the consumer. When demand is low, it is basically usually at night, charging from the grid battery. When demand peaks (summer evenings and winter mornings), the base sells power supplies, draining batteries to support the grid.

For an upfront fee of $595, then about $19 per month, homeowners can use the reliable power provided by the base. The electricity is generated from a variety of sources, including wind, solar, natural gas and coal. According to the company, about half of customers have solar power, which makes them more cost-effective and allows them to sell the power back to base.

A company spokesperson said Base compensated customers for the electricity sold by the power supply, which is a real-time wholesale energy price of 3 cents per kilowatt-hour. Repurchase rates may vary depending on market conditions and other factors.

Base is now serving Lennar, one of the largest home builders in the United States, which is also an investor. The base installs batteries during construction of approximately 20 Lennar blackout communities in Texas.

Stuart Miller, chairman and co-CEO of Lennar, said it was more than just making money.

“This is, can we improve the overall figure of the housing construction business as it tries to solve the stress and problems of the market?” he said. “Utilities and electricity are part of that.”

Base raised a total of $268 million from investors including Lennar, Thrive Capital, Valor Equity Partners, Lightspeed Venture Partners and Andreesen Horowitz.

Base recently announced its first utility partnership near San Antonio. Dell said the company hopes to expand outside Texas soon. However, the battery is made in China, Dell said he hopes to see the impact of tariffs.

- CNBC producer Lisa Rizzolo contributed to the work.