moving towards more energy self-sufficient homes.
BY BILL HENSLEY
IT WAS A CANDLELIGHT DINNER, but the candles were not for aesthetics. Our home was without electrical power. Our neighborhood was without power. In fact, a large part of Northern California was without power. This was in the Fall of 2019 when Pacific Gas & Electric, the power utility for Northern California, preemptively shut off power to minimize fire risk in a major wind event hitting many parts of the region. In our still calm Marin County neighborhood, we could see the feint flicker of candlelight in some houses, flashlights in others, darkness in most.
On evening two of the blackout, we felt adventurous enough to take a drive just to see how dark the area was. Traffic was understandably light, as the more sensible residents were staying home. We stuck mostly to side streets, where flashlights, candles and occasionally a generator-powered room or two were visible. But when we drove through one of the area’s more upscale neighborhoods, we were struck by something we’d not previously seen in our evening adventure: abundant bright lights. It wasn’t as if every home was a blaze of light, but one or two houses on each block looked unaffected by the outage.
The night was still and quiet, as the anticipated winds were still to the north. There could have been gas generators at work, but we couldn’t hear them. Were we seeing the promise of the home battery system in full display? Given the neighborhood we were driving through, these home batteries were most likely connected to rooftop solar panels. This was evening two of the power outage, so it was unlikely that a home battery would still be providing power like that.
California leads the way
The CEO of Pacific Gas & Electric announced at a California Public Utilities Commission meeting that same Fall of 2019 that the state will likely see similar blackouts for another 10 years. This is while the company makes efforts to reduce the chances of future wildfires through tree trimming and deploying technologies to limit shutoffs to smaller parts of the power grid when fire dangers are at their highest. Clearly, this is not an enviable leadership position for those of us in the Golden State; any outage affecting hundreds of thousands of households and businesses is exceptionally disruptive and expensive. The design-build community should hear this as a wake-up call for us to consider how our projects interact with the electrical grid.
battery or generator?
If it is truly for emergencies, then a logical question is, “am I better off with a battery backup or a generator?” In that comparison, the return on investment will tip in favor of the generator. Generator options are available between $3,000 and $5,000 that can power a typical U.S. home.
Modern interior with white Sofa on hardwood floor decorated with potted plant.
Larger homes will likely need to invest more to power the whole home. A home backup battery costs $6,000 or more before installation costs to power a small to mid-sized home, and larger homes may require multiple batteries to support the entire home. With installation, the cost of battery backup starts at around $10,000 and can easily scale up depending on the home’s needs. For both generator and battery back-up, the presence and use of power-hungry devices and systems such as a central air conditioning unit, electric water heater or swimming pool pump can place large requirements on the emergency power, creating a cost-benefit trade-off. In emergencies we make trade-offs, so the key is for the homeowner to know what absolutely needs to be powered on. In the California power outages, much of the loss was related to spoilage of frozen or refrigerated food.
future-ready
Let’s take this as an opportunity to look more broadly at what it means to be more self-sufficient in the power that feeds our homes, not just to make it through power outages. Self-sufficiency means producing power, and unless we have a mini geothermal or hydro-electric plant on the property — no, probably not — then rooftop solar panels are the energy producers of choice. Self-sufficiency also means having an energy-smart home, and we’re all taking this into consideration when we design and build, right?
We’ll start with the biggest energy use — heating. The U.S. Department of Energy estimates that over four out of every ten dollars U.S. homes spend on energy goes toward heating. Thus, it makes sense that home design includes passive or active solar heating systems. The main difference between the two is that passive solar heating systems gather energy through well-placed windows that favor the winter sun, trapping and circulating heat naturally, while active solar heating uses collectors, pumps, tanks, and other mechanisms to distribute captured heat. In each case of course, the home must be well insulated to deliver the full benefit.
Beyond heating, much of what we expect in the modern home plugs into an electric source, especially if we are also intent on reducing the burning of fossil fuels. The emerging sweet spot matches energy-saving design (to reduce the overall energy need), with photovoltaic solar panels (to capture the sun’s energy) and a home battery (to store the energy). Any one of these three components by itself will help, but all three together begin to define the future-ready home.
As we trend toward electric vehicles, this places an additional burden on the energy-sufficient home. Beyond the 240-Volt EV charger, the electric stove, pool system and central air conditioning can also place overly large requirements on batteries. To be clear, energy planning and management is essential. Those making the jump toward energy sufficiency become a part of the distributed energy resources (DERs) populating the electrical grid. Think of DERs as behind-the-meter generation and energy storage devices, including solar panels, wind turbines, inverters and batteries, and other sources that enable the home to push energy back onto the grid.
California has become the first state to make solar mandatory for new houses. Beginning in 2020, newly constructed homes must have solar panels. As the price of solar panels continues to fall, they are becoming a more viable option for homeowners. There are now multiple players competing in the home battery market as well, including Tesla, LG, sonnen, RoseWater Energy and others. Tesla is well known for its electric cars, and its Powerwall battery with displays in the big-box home stores that brought the home battery into the mainstream. The LG CHEM RESU battery is one of the better-known options for solar-plus-storage systems in Europe and Australia and is reasonably new to the U.S. market. The sonnen eco and ecoLinx products are made from German engineering combined with American ingenuity by sonnen, Inc. and is available in the U.S. through the company’s installer network.
sonnen takes the clean energy concept further with its Virtual Power Plants, turning neighborhoods of decentralized batteries into controllable power grid assets for sustainable living. The sonnen ecoLinx20 battery integrates with leading home automation control systems. The company’s Virtual Power Plant software links sonnen systems together in a network of decentralized and renewable energy sources. The result is residential batteries that act as storage assets on the grid in addition to powering the individual homes.
sonnen has announced or begun four projects in the U.S. leveraging the Virtual Power Plant: The groundbreaking Soleil Lofts in Herriman, Utah is a 600 unit all-electric apartment community developed by The Wasatch Group, with 5 MW solar and 12.6 MWh energy storage, with a first of its kind residential Virtual Power Plant that is operated by the local utility, Rocky Mountain Power. Hunters Point on Florida’s west coast is a gated community of 720 LEED Zero Energy certified homes developed by Pearl Homes with 7.2 MW solar and 9 MWh of energy storage.
Wildwood of Marengo is a suburban Chicago development of 28 single-family, certified energy positive passive homes, with 168 kW solar and 560 kWh energy storage. The development is led by Evolutionary Home Builders partnering with healthy home building expert and Passive House Certified Builder Brandon Weiss. “This groundbreaking community development is taking root in the Chicago area where the homes must flourish on the merits of their design and affordability,” stated Adam Weinstein, National Manager of Consumer Products at sonnen, Inc. “Driving this tipping point for the next stage of passive home building is a key reason we are so appreciative of our relationship with Brandon Weiss.”
Each Wildwood of Marengo home is built pursuant to the world’s most rigorous energy-efficiency standards, with design certified by Passive House Institute United States in Chicago to maximize energy gains and minimize energy losses.
Each residence uses smart home technology with solar to produce, store and intelligently manage the home’s power without sacrificing the occupants’ comfort. During high-electrical-cost periods of the day, the homes are capable of becoming independent of the utility grid to avoid the use of carbon-intensive peak power and minimize stress on the grid.
The most ambitious project will be Jasper in Arizona’s Prescott Valley, developed by Mandalay Homes. The master-planned development will total 2,900 single-family energy-efficient homes with 11.6 MW solar and 23MW energy storage. The footprint of stored sunlight energy will be on a scale not yet seen in residential energy storage for a single planned community.
All of Soleil Loft’s apartments will be linked together using sonnen’s robust software to form a “hive” of systems, which sonnen brands as a “sonnen Virtual Power Plant.” The hive of clean energy storage systems have the capability to dynamically interact with the needs of the electricity grid on a day-by-day basis to increase grid efficiency and lower operating costs. The Soleil Lofts VPP will be managed by the local utility, Rocky Mountain Power, and seeks to flatten the energy demand curve of the community, minimize grid stress, and improve renewable integration while also providing residents with access to clean and reliable backup power.
“Self-consuming locally harvested sunlight energy, while collaborating with your neighbors and with the grid to create a clean energy community, represents a transformational design concept for the U.S. homebuilding industry,” said Christoph Ostermann, Global CEO and Founder of sonnen. “All communities represent an evolution in residential construction in the United States and will forever alter how American builders, utilities, and regulators view distributed renewable energy The most ambitious project will be Jasper in Arizona’s Prescott Valley, developed by Mandalay Homes. The master-planned development will total 2,900 single-family energy-efficient homes with 11.6 MW solar and 23MW energy storage. The footprint of stored sunlight energy will be on a scale not yet seen in residential energy storage for a single planned community.
All of Soleil Loft’s apartments will be linked together using sonnen’s robust software to form a “hive” of systems, which sonnen brands as a “sonnen Virtual Power Plant.” The hive of clean energy storage systems have the capability to dynamically interact with the needs of the electricity grid on a day-by-day basis to increase grid efficiency and lower operating costs. The Soleil Lofts VPP will be managed by the local utility, Rocky Mountain Power, and seeks to flatten the energy demand curve of the community, minimize grid stress, and improve renewable integration while also providing residents with access to clean and reliable backup power.
“Self-consuming locally harvested sunlight energy, while collaborating with your neighbors and with the grid to create a clean energy community, represents a transformational design concept for the U.S. homebuilding industry,” said Christoph Ostermann, Global CEO and Founder of sonnen. “All communities represent an evolution in residential construction in the United States and will forever alter how American builders, utilities, and regulators view distributed renewable energy resources on the grid and what it means to ‘build green!’”
meanwhile— back in marin
Pulling up to our darkened home, I couldn’t help but think what the south-facing roof line would look like supporting an array of solar panels, and how logical it would be to store that energy in a home battery. We parked in the driveway, turned on our flashlights and made our way inside.
