A lot of work has been done on net zero energy homes and on streamlining the energy consumption of industrial-scale utility and manufacturing plants. There has been less attention to the mid-sized buildings that comprise the bulk of city life.
In The CO2 Abatement Potential Of California’s Mid-Sized Commercial Buildings, researchers from the U.S. Department of Energy Lawrence Berkeley National Laboratory studied the potential energy and emissions reductions possible by bringing New Energy (NE) and Energy Efficiency (EE) methods and technologies to Main Street.
The study looks at a cross section of buildings in California that consume from 100 kilowatts (about 25 houses) to 5 megawatts (a small suburb) of power. It estimates such buildings use roughly a third of the energy consumed by California’s commercial sector.
A building with that level of energy consumption constitutes a microgrid that serves a variety of purposes including (1) electricity for lighting, office equipment; etc., (2) cooling via (a) electricity-powered compression, (b) heat-activated absorption cooling, (c) natural gas chillers, (d) waste heat or (e) solar heat, (3) refrigeration via standard equipment or absorption cooling, (4) hot-water and space-heating via recovered heat from other generation or by natural gas, and (5) natural gas for cooking. ::continue::
Such a microgrid can integrate with the grid power supplied to the building a variety of New Energy and Energy Efficiency options, including especially (1) natural gas-fired engines, (2) gas turbines, microturbines, and fuel cells, (3) solar photovoltaics (PV) and solar heating systems, (4) conventional batteries, flow batteries, and storage of heat, (5) heat exchangers used with solar thermal or recovered heat, (6) natural gas chillers, and (7) heat-driven absorption chillers.
The Lawrence Berkeley Lab researchers drew on Distributed Energy Resources Customer Adoption Model (DER-CAM), a powerful new tool that integrates the spectrum of a microgrid’s needs and potential supplies to determine which options best serve the goals of cutting back the use of energy and reducing the building’s greenhouse gas emissions (GhGs).
The most noteworthy conclusion is that much heat is available for recapture and reuse, enough to meet a third of the state’s goal for combined heat and power (CHP) (set by the California Air Resources Board (CARB) for 2020 at 4 megawatts). Buildings in the hot inland areas of the state may offer the biggest opportunities for energy savings and GhG reductions.
This post is based on The CO2 Abatement Potential Of California’s Mid-Sized Commercial Buildings by Michael Stadler, Chris Marnay, Gonçalo Cardoso, Tim Lipman, Olivier Mégel, Srirupa Ganguly, Afzal Siddiqui, and Judy Lai (January 25, 2010, Lawrence Berkeley National Laboratory)