Solar District #1

Net zero energy is possible, even in Seattle.

  • Connected to the grid, where excess power is stored
  • One meter measures energy sold to Seattle City Light, one measures energy purchased

To be certified as a Living Building, the Bullitt Center must annually produce as much electricity as it uses. To achieve this goal, the Bullitt Center has 575 solar panels on the roof, creating a large array to generate electricity.

The panels are sensitive to the amount of daylight they receive, meaning that production values are closely related to solar intensity and sky conditions. In the summer, the Bullitt Center will produce vastly more electricity than it uses, and in the winter it will produce less.

In order to “store” the summer’s surplus, the Bullitt Center uses Seattle’s electrical grid, pushing electricity onto the grid in the summer months when production is high (and when Seattle’s demand is at its highest). The building then takes electricity from the grid in the winter months when production is low. To achieve its “net zero energy” goal, the summer production surplus must meet or exceed the winter production deficit.

Two electricity meters live in the core of the Bullitt Center, carefully monitored by Seattle City Light and the Bullitt Center building engineer. One spins clockwise for the amount of energy the Bullitt Center is pulling from the grid, the other spins counter-clockwise and counts how much energy the Bullitt Center is pushing back onto the grid.

 Next building feature: Building Neurology – Building Management System