KB Homes is one of the largest and most recognized homebuilders in the U.S. and has built over 650k quality homes in its more than 60-year history.

Now, in partnership with the US Dept. of Energy, KB Homes is now taking “green home construction and sustainability technology” to an entirely new level; as a model for the entire building industry.

With a $6.65 million Dept. of Energy (DOE) grant, microgrid design and engineering support from Schneider Electric, and strong collaboration with SCE to ensure a smooth transition between grid and off-grid electricity, these innovative homes are now available to the public.

A Neighborhood of (Green) Power Brokers
By Todd Woody/LA Times

At first glance, Durango at Shadow Mountain looks like just another cookie-cutter subdivision of new homes sprawling across an arid valley in the Riverside County town of Menifee.

Walk into a $577,990 model home on Hopscotch Drive, though, and the possible future of low-carbon, climate-resilient housing comes into view behind the stucco and faux-stone façade.

In the garage, a sleek, white battery attached to one wall stores electricity generated by the 16 solar panels on the roof. 

Next to the battery is an electric vehicle charger, and some homeowners can tap their car’s battery to supply energy to the house — an experiment to transform EVs into mobile power plants.

A high-efficiency electric heat pump water heater is tucked into one corner of the garage, and a heat pump that warms and cools the house sits next to the backyard patio.

The open-plan kitchen in the 2,906-square-foot, 4-bedroom home features an induction stove that consumes less electricity than a conventional electric model and emits none of the harmful pollutants of a gas one.

According to builder KB Home, these appliances will reduce energy consumption by up to 40% compared with a conventional home.

The 78 homes under construction at Durango are connected to form a microgrid, a self-contained system that can operate independently of California’s power grid if it fails. That’s an increasingly likely occurrence as climate-driven wildfires, heat waves, and storms trigger blackouts.

An additional 141 homes being built in an adjacent subdivision, Oak Shade at Shadow Mountain, will be connected to a second microgrid that can also tap solar energy and batteries to keep electricity flowing during blackouts.

The two developments will share a 2.3-megawatt-hour “community battery” to provide additional power during an outage. In energy jargon, Durango and Oak Shade can be “islanded” from the power grid — an archipelago of light if the desert goes dark.

“In California, when there are fires, you’re threatened with power loss,” said Dan Bridleman, Sr. VP for Sustainability, Tech, and strategic sourcing at KB Homes. “We felt like there was an affordable way to build resiliency, not only at the house level but also into the community.”

So far, KB Home executives say, about 50 houses have been sold, and the first owners are expected to move in early next year. The company said that with prices ranging  from $482,000 to $578,000, the houses are attracting young families priced out of coastal cities.

The solar energy company SunPower Corp., utility SCE, automaker Kia Corp., UC Irvine, Schneider Electric, and the U.S. Energy Dept. are collaborating with KB Home on the project​.

The federal government has provided $6.65 million to develop and test first-of-its-kind microgrid technology and determine whether the Menifee microgrid could serve as a model for future housing developments.

Over the next four years, a team at SunPower and researchers at UC Irvine will gather data and monitor the microgrids’ performance.

“We want to see how we can improve resilience for the homeowner,” said Ram Narayanamurthy, the manager of the Emerging Technologies Program at the U.S. Dept of Energy. “Electrification will drive carbon footprint reduction as the California grid gets increasingly decarbonized.”

Microgrids offer a way to decarbonize suburban sprawl. 

They can also “increase electricity grid reliability, play a role in mitigating wildfire risk [and] help make communities more resilient,” said Terrie Prosper, a spokesperson for the CPUC, the state energy regulator.

While other Menifee residents are subject to rising electricity and natural gas prices, Durango and Oak Shade owners will become power brokers.

They’ll be able to sell excess electricity generated by their solar panels and stored in their home batteries to SoCal Edison. Collectively, the homes in the microgrids can act as virtual power plants, supplying electricity to help keep the grid stable during surges in demand, such as during heat waves.

Each home’s battery is a 13-kilowatt-hour SunVault model from SunPower, which also supplies rooftop solar panels.

The heat pumps and smart thermostats are Wi-Fi-enabled, allowing a home’s appliances, batteries, and solar array to be coordinated to maximize energy production and reduce costs.

For instance, the 219 heat pump water heaters in Durango and Oak Shade can be transformed into “thermal batteries.” In the middle of the day, excess electricity generated by a home’s solar array heats water for use later when the sun isn’t shining, and utility rates rise.

That can reduce the need to fire up natural gas power plants to meet nighttime demand.

SunPower’s technology manages the energy system for homeowners, enabling the homes to engage in energy arbitrage while their inhabitants are at work or sleeping. When the resident’s utility rates surge, the house can draw on the solar electricity stored in the battery.

All homes are prewired for EV chargers, and about 20% of buyers have them installed during construction, said Matt Brost, a SunPower vice president.

“During the high solar production hours of the day, when homes often aren’t using much electricity, we believe the solar systems will more than sufficiently charge both the batteries in the homes and the community battery,” Brost said.

At the edge of the development, Scott Hansen, VP of forward planning for KB Home’s Inland Empire division, pointed out a patch of dirt where the community battery will be installed on a fenced-in platform.

The battery, about the size of a shipping container, will typically be charged by the grid, drawing solar electricity from the surrounding houses only when needed.

At the Durango model home, Hansen gestured at the 5.6-kilowatt rooftop solar array. It’s about half the wattage — and cost — of a solar system typically needed to power a similar-size conventionally constructed home.

That’s because houses in Durango and Oak Shade are being built to the Energy Department’s Zero Energy Ready Home standard, which requires a building to be so well-insulated and sealed that a renewable energy system can offset most or all of its energy use.

This smart panel controls every circuit in the home, balancing the electrical loads generated by appliances and allowing the homeowner to choose which ones to power in a blackout.

Green labels indicate circuits powered by the home battery in an outage, including the lights, outlets (keeping the Wi-Fi on), refrigerator, and microwave.

High-voltage appliances such as the stove and heat pumps are labeled in gray and would remain offline until the community battery kicks in and provides an extra 6 kilowatt-hours of electricity per house.

Once the community battery comes online, Brost said, “it will effectively power the whole home, but the homeowner is not going to be able to run everything simultaneously or charge a car, so they will have to choose what they want to run.”

Some homeowners will have one more option during a blackout: Using their car to charge their house.

Five houses in Durango and five in Oak Shade are being installed with bidirectional chargers made by Spanish company Wallbox that can transfer electricity from an electric vehicle battery to the house, said Scott Samuelsen, a professor of mechanical, aerospace, and environmental engineering at UC Irvine, which will design and manage the experiment.

Samuelsen said it’s enough to keep a home powered for hours or even days during a blackout and the kind of thing he expects “to be an integral attribute of an electric vehicle in the future.”