Early in 2021, a mansion in Biscayne Bay, Miami Beach, marketed as a solar-powered home, sold for $1525 million. The 112 solar panels on the roof generate enough power to operate the house for weeks or even months completely off-grid.
Some climate change theorists ask the question: does that make the house green? So much of what goes into a house—concrete, imported furnishings (in this case, marble), forged steel, etc.—requires energy, which puts carbon into the atmosphere.
Buildings expel two types of energy: operational energy (energy used for air conditioning and light) and embodied energy (energy used to build).
“There’s no denying that homes of this size and complexity contain lots of embodied energy,” Max Strang, the Miami Beach residence designer, told Architectural Digest. He hopes the building’s solar panels will produce enough excess energy to reduce embodied energy. “To not try to offset embodied energy would just be sitting idly by.”
Michael Green, another Vancouver-based architect, says, “If we’re going to hold warming to 1.5 degrees Celsius—or anything close to that—we’re going to have to deal with embodied energy right now.”
Green attempts to use as little embodied energy as possible on his projects. Recently, he rejected a mansion contract and chose to renovate a 1912 craftsman-style house in Vancouver. “The first green thing we did was to not tear down the house. Reusing what you’ve got is a big part of sustainability,” he says. He chose wood as the primary structural material to enlarge the back of the house. Unlike steel and concrete, wood is created “using the power of the sun,” he says. “I’d rather use photosynthesis than photovoltaics,” he adds.
LEED, a leading green building certification system, doesn’t factor embodied energy into the equation; to some, this presents a problem. Apps exist that calculate embodied energy, such as Tally (from the Philadelphia architecture firm Kieran Timberlake), but many criticize these calculations as inaccurate.
Membership in Carbon Leadership Forum, an organization of architects and engineers committed to reducing embodied energy, shows growth from 400 to 6,500 in the last two years. Kate Simonen, the founder of the forum, says, “Architects are finally seeing the urgency and starting to act.”
Among climate change theorists, some builders cite embodied energy as a significant contributor to carbon emissions. Some of those factions continue to reduce overall construction energy costs.