Daylighting, Dimming, and the Electricity Crisis in California

Dimming controls for electric lighting have been one of the mainstays of the effort to use daylighting to reduce annual lighting energy consumption. The coincidence of daylighting with electric utility peak demand makes daylighting controls an effective strategy for reducing commercial building peak electric loads. During times of energy shortage, there is a greatly increased need to reduce electricity use during peak periods, both to ease the burden on electricity providers and to control the operating costs of buildings. The paper presents a typical commercial building electric demand profile during summer, and shows how daylighting-linked lighting controls and load shedding techniques can reduce lighting at precisely those times when electricity is most expensive. We look at the importance of dimming for increasing the reliability of the electricity grid in California and other states, as well as examine the potential cost-effectiveness of widespread use of daylighting to save energy and reduce monthly electricity bills.