Going off-grid?

Renewable Energy for Your GO Logic Home: Why the Grid is Your Friend

The core of every GO Logic building is a Passive House building shell that requires an astonishingly small amount of energy to support the healthiest, most comfortable indoor environment. Even in a northern climate like that of our home state of Maine, a modest array of photovoltaic (PV) panels can supply all the energy needed to attain net-zero performance. For that reason many of our clients inquire about living completely off the grid, which is indeed a feasible option for any GO Logic house. But after a thorough energy analysis—a standard part of our design process—we most often recommend instead a renewable (or renewable-ready) energy system tied to the power grid.

Here's why:  

Pulling the Plug Doesn’t Make You Energy Independent

The PV panels on a net-zero GO Logic house produce as much energy as the house will consume over the course of a year. The problem here in Maine is that energy supply and energy demand don’t align, either by time of day or time of year. The sun shines during the daytime, but we need electricity for heating, cooling, cooking, and lighting after sundown too. Shorter winter days yield half the energy produced at the height of summer.

Off-grid systems address this mismatch with banks of batteries that store surplus power for later use. But battery storage is only a partial solution. In addition to the environmental cost of producing batteries, a PV-plus-battery system sufficient to cover a house’s year-round energy needs would be prohibitively large and expensive. For that reason, off-grid homes typically use gas appliances for major loads—heating, hot water, and cooking—along with a gas generator topping off the batteries to ensure consistent power for lighting, refrigeration, a water pump, and plug loads. As a result, the typical off-grid house consumes a considerable amount of non-renewable energy, generating more carbon emissions than an equivalent all-electric house that’s tied to the grid.

The Grid is Your Battery

When a grid-tied house needs more electricity than its PV array is producing, it seamlessly draws power from the grid (when the reverse is true, it sends power back to the grid, winding the electrical meter backward and helping power neighboring houses). This avoids not only the cost of batteries, but also the need to house, monitor, maintain, and eventually replace them.

Equally important, it radically reduces the burning of fossil fuel on site, a crucial step toward the necessary goal of a carbon-neutral society. Grid power isn’t perfectly clean—power companies still burn coal, oil, and natural gas in their powerplants—but the mix is shifting in the right direction. In 2021, renewables represented an impressive 72 percent of Maine’s electric power. A propane appliance will always burn propane, degrading the atmosphere as well as indoor air quality, but grid power becomes more renewable with every community solar project, wind farm, or biomass plant that comes online. The climate-friendly house of the future is—and must be—all electric.

Passive House Performance Makes Backup Power Simple

The grid itself is vulnerable to climate change as well, of course, with more frequent and intense storms leading to more frequent power outages. In this regard, the advantages of going off-grid are less compelling than they might seem. Our grid-connected projects often include a backup system to ride through the occasional power outage, usually a gas generator (battery backup systems like Tesla’s Powerwall are far more expensive and can’t handle heavy loads like space heating).

Off-grid houses can shrug off downed powerlines, but they must run generators on a regular basis, while grid-connected houses tap theirs only in emergencies. In this, too, Passive House energy efficiency plays a crucial role, by reducing the size and cost of the backup system required and making the building itself more resilient to power loss. Even with no backup power at all, a GO Logic house will remain relatively comfortable for days after a mid-winter outage. If equipped with a wood stove (another source of carbon-neutral heat), it will stay toasty until the line crews arrive, no matter how long that takes.

Choose a System to Suit Your Site

Remote sites tend to favor an off-grid energy system, due to the high cost of stringing powerlines (the high cost of building a long driveway, on the other hand, may be unavoidable, and must also be factored in). For sites with reasonable access to a powerline, which includes most of those we see, the nod goes to making a grid connection. A grid-tied renewable energy system costs less, operates autonomously in the background, generates less CO2 from day one, and will actually improve its carbon performance as the grid itself shifts more and more toward renewables.