Last week, Honda unveiled its net zero energy "Smart Home" on the University of California Davis campus. The company says the building, which includes a charging facility for a Honda Fit EV and is intended to demonstrate Honda's vision for zero-carbon living and personal mobility, will on average generate more electricity from on-site renewable energy than it receives from the local utility.
UC Davis describes the project as: “A Honda-developed home energy management system and an energy-efficient design that will allow the occupants to use less than half of the energy of a similarly sized new home in the Davis area for heating, cooling and lighting. The home is also claimed to be three times more water-efficient than a typical US home.” The home is expected to generate a surplus of 2.6 mWh of electricity over the course of the year while a comparable home will use roughly 13.3 mWh. The offset is nearly 13,100 pounds of CO2 per year, which increases to 23,500 pounds a year if you take transportation fuel into account.
“With the Honda Smart Home, we’ve developed technologies and design solutions to address two primary sources of greenhouse gas emissions — homes and cars,” said Steve Center, VP of the Environmental Business Development Office of American Honda Motor Co. Inc.
Honda broke ground on the home in April and went on to incorporate a host of key features, including:
A 9.5-kW solar photovoltaic system on its roof, which generates enough power not just for the home but also for charging a Honda Fit EV. The home can operate independent of the City's power grid, if necessary.
The home's Honda Fit EV has been modified to accept power directly from the home's solar panels or the stationary battery. Most solar panels convert energy into AC but electric car batteries mostly use DC. The home supplies the car directly with DC, thereby eliminating energy loss during conversion.
A 10-kWh battery energy storage system (using lithium-ion cells — the same as the Fit EV) allows stored solar energy to be used at night, when energy demand is typically high and electric vehicles are usually charged.
The building is managed by Honda's Home Energy Management System (HEMS), which monitors and controls the home's energy loads, the Fit EV and the energy storage system. It manages the building's demands and communicates with the homeowner as well as the utility company to optimize consumption and generation — reducing consumption and supplying energy back to the power grid when feasible.
“Honda’s HEMS is also capable of improving grid reliability by automatically responding to demand response signals and providing other grid services. If the electricity grid is overloaded, for example, the Smart Home is capable of shedding its load and even supplying power back to the grid. This type of smart grid connectivity will enable the mass deployment of electric vehicles and renewable energy without sacrificing grid reliability,” says UC Davis.
In most homes, heating and cooling systems consume a significant amount of energy. Below the Honda home's yard is a geothermal heat pump that recovers heat from the earth and the home's wastewater, while a radiant heating and cooling system has been installed in the floors and ceilings, which have more potential to be efficient than a forced-air system.
Concrete is a huge emitter of CO2 in construction, largely due to emissions during the production of cement. The Honda home was built using a combination of concrete and pozzolan, a volcanic ash, thereby reducing the use of concrete by half. In addition, a technique called post-tension was used to compress and strengthen the concrete, requiring less material.
Passive design helps to maximize the home's efficiency — i.e. it considers the local weather conditions and the sun's direction to optimize heating and cooling of the home.
According to UC Davis, the LED lighting used throughout the home is five times more energy-efficient than conventional lighting. As Honda explains in a video: “Mimicking the natural shifts in daylight that occur from morning to night, the lighting design allows occupants to select lighting scenes that complement occupants’ circadian rhythms and support nighttime vision.”
The Honda home is thrice as water-efficient as a typical US home. Dual-flush toilets with WaterSense certification; low-flow faucets in the sinks and showers; a high-efficiency washing machine and dishwasher; climate-specific garden plants and greywater recycling contribute to savings.
Construction materials were chosen with care, avoiding those that emit volatile compounds and contribute to indoor air pollution. The house features FSC-certified lumber and 96 percent of the construction waste associated with the project, including drywall, brick, plastics and lumber, was recycled.
UC Davis says that in addition to showcasing Honda's vision, the home “will function as a living laboratory where the company, along with researchers from UC Davis and Pacific Gas and Electric (PG&E), will evaluate new technologies and business opportunities at the intersection of housing, transportation, energy and the environment.” The University's West Village is the largest planned zero net energy housing development in the US.
According to the official video, “Honda envisions a zero-carbon future with electric vehicles powered by renewable energy. We are demonstrating a pathway for the full integration of electric vehicles into our home.”
“What we are trying to do is develop a technology pathway to meet California's goal of having zero net energy homes,” Center says. “But we are also trying to exceed that by including transportation in the solution.”
More details on the Honda project at UC Davis are available on the company's website.
Honda experimented with extensive demo testing of a smart home in Saitama, Japan in 2012, with the ultimate goal of reducing CO2 emissions by 50 percent. The home includes solar panels, rechargeable home battery units and Honda's Smart Home System amongst other features.
Another motor company that’s venturing into home energy optimization is Ford: Last year, the automaker launched MyEnergi Lifestyle, a strategic collaboration with Whirlpool, SunPower, Eaton and Nest that shows how a typical home can significantly reduce its carbon footprint by integrating solar power with time-flexible vehicle charging and home appliance usage to achieve an energy-efficient lifestyle.