Here’s a great idea — build office buildings that use zero energy. Sound impossible? Hardly. It’s already becoming a reality (of course, not as fast as we would like).
Zero energy building (ZEB), or net zero energy building, means a building consumes zero net energy and emits zero carbon annually.
The Department of Energy, the American Society of Heating, Refrigerating and Air-Conditioning (ASHRAE), the American Institute of Architects and the National Renewable Energy Lab are taking tangible steps to achieve this goal. The US Department of Energy launched the Net-Zero Energy Commercial Building Initiative in August 2008.
Chris Gaul, a contributor to this blog and engineer at the NREL, sent along an email about the NREL’s recent success with ZEB.
“NREL’s 220,000 square foot “net zero energy” office building is on line with part of its solar panels operational. The graph below is revealing. At the 4 PM starting time the building is occupied and using less than 200 kilowatts. People go home and during the night power demand drops to less than 150 kilowatts (kW).
“As people arrive at work in the morning demand increases to 225 kW, as expected. Then demand plummets to less than -50 kW. An error? No. The sun came up. The rooftop solar panels are generating more electricity than the building needs. Power is flowing to the grid and the power meter is running backwards. As daylight ends solar power decreases and the building draws power from the grid at night.
“The trick to net zero energy buildings is to make enough power during the day to balance what is drawn from the grid at night. NREL is installing more solar (photovoltaic, or PV) panels to achieve this energy balance.”
It’ll be interesting to see how far this can go, and how soon we can start seeing more buildings built to use zero energy.
Zero Energy graph from NREL
