PG&E collaborates on University of California Davis campus home that's the ultimate in energy savings
By David Kligman
Located among student and faculty housing at the edge of the University of California, Davis, campus is a newly built, fully furnished two-story house that many would love to call home.
Yes, there's a modern kitchen, two bedrooms and all the conveniences of new construction. But this is no ordinary house because it was built entirely to maximize energy efficiency.
The Honda Smart Home uses less than half the energy of a similar sized new home for heating, cooling and lighting. It even comes with a Honda Fit electric vehicle that's parked in the garage.
"This is an awesome home," said Paul Klavins of the California Energy Commission as he inspected an energy-efficient ceiling fan. "You have to think of this as an investment. You're reducing your carbon footprint but you're also saving money."
Zero net energy buildings use only as much energy as they create. But this nearly 2,000-square-foot home actually generates more energy than it uses—a surplus of 2.6 megawatt hours of electricity. And it's three times more water efficient than a typical U.S. home.
Construction began in 2013 and was completed in March.
PG&E, Honda, UC Davis project partners
The utility is a longtime partner on the project, working closely with Honda and the university to monitor the home, how it performs and how it interacts with the electric grid.
This project is helping PG&E evolve the grid and energy efficiency programs that could support new technologies like the ones in the Honda Smart Home.
Today (May 1), PG&E hosted an open house at the new home to explain the features. Visitors from the State of California, the California Energy Commission and others put on disposable shoe coverings to walk throughout the house and talk to the people who designed the lighting and other features.
"In order to create value, we knew we couldn't do this alone," said Michael Koenig, who oversaw the project for Honda. "And that's why we're partnering with the university and PG&E."
So what makes this home so efficient? Where to start?
- The home is driven by its Home Energy Management System, which is housed in the garage to monitor and optimize electrical consumption throughout the home. Residents can remotely monitor and adjust all aspects of energy use in real time
- Alongside the system is a 10-kWh battery with the same lithium-ion cells as the Fit. The battery stores energy collected by the rooftop solar system for nighttime use
- The home's windows were positioned to maximize natural light, keeping the home naturally cool in the summer and warm in the winter. Windows open and close, and shading extends and retracts automatically to moderate temperature and provide natural ventilation
- LED lighting throughout the home is five times more energy efficient than conventional lighting. And the lighting modifies the color temperature depending on the time of day
- Buried deep in the back yard are eight 20-foot boreholes that allow a geothermal heat pump to harness heat from the earth and wastewater to heat and cool the home's floors and ceilings throughout the year
- A 9.5-kilowatt solar photovoltaic system mounted on the roof generates more energy than the home and Fit consume in a year. These solar panels provide all the energy for heating, cooling, ventilation, lighting, hot water and the home's appliances
- The electric vehicle can fully recharge in two hours directly from sunlight when the solar panels are generating electricity at full capacity
- Nothing goes to waste. Shower water is reused to warm the house and then used for landscape irrigation
Construction also energy efficient
Even the concrete slab that supports the home was constructed with energy efficiency in mind. Producing cement involves heating it to more than 1,000 degrees Celsius, which requires energy and a chemical reaction that produces carbon dioxide. The construction team replaced half the cement with a substance that occurs naturally in the earth from volcanic ash deposits and requires less heating.
For PG&E, this home represents what's possible for energy efficiency. Peter Turnbull, principal for PG&E's Zero Net Energy program, calls it a "living laboratory."
"Our role is a pretty elaborate evaluation of the system's performance," he said. "Do we want to promote these technologies going forward? Probably, but we really need definitive performance information on them. That's the point of the monitoring."
The home is in the UC Davis West Village, the largest planned zero net energy community in the United States. The goal of the community is to demonstrate that zero net energy is practical on a large scale.
Now that the home is built, UC Davis will soon select a faculty member or graduate student to lease the house for a year beginning this fall. Then the calculations of energy savings will begin.