Lighting and Electrical Demand

Lighting and Electrical Demand

There are good reasons why we should curb our energy appetites, but where does lighting fit into the Canadian energy consumption picture? Residential and commercial buildings consume about 36% of all the energy consumed in Canada (Figure 1) [4]. And lighting is responsible for about 30% of all energy consumed in commercial buildings (Figure 2) [5]. The cost of lighting Canadian commercial buildings is very high, perhaps as high as $2 billion annually, equivalent to the total output of eight 1000 MW power stations. Yet the technology exists to cost-effectively reduce lighting energy consumption significantly, while maintaining, or even improving, lighting quality. Clearly, lighting is an appropriate target for energy conservation efforts.

Figure 1. Canadian energy consumption by sector

Figure 2. Typical Canadian commercial building energy consumption by end-use

New Energy Guidelines

Origins of the guidelines

Two energy guidelines are discussed in this paper: the ASHRAE/IES 90.1 Standard[6] and the Canadian Code for Energy Efficiency in New Buildings. The evolution of these guidelines began in 1975 with the publication of ASHRAE 90[7], in response to the energy crisis of the early 1970s. It contained recommendations, by consensus of experts, for the construction of energy efficient buildings. In 1978 the document Measures for Energy Conservation in New Buildings[8] was published in Canada. This document was based on ASHRAE 90 but with more emphasis on the economics of energy efficient design. However, neither of these documents contained much about lighting, and neither achieved widespread adoption into building codes; Measures for Energy Conservation in New Buildings was adopted only by the province of Québec. In 1989, the IES (Illuminating Engineering Society) joined ASHRAE (American Society of Heating, Refrigeration and Air Conditioning Engineers) in producing ASHRAE/IES 90.1. This standard updated the recommendations of ASHRAE 90 and, as one might expect, given the co-authorship of IES, contained a whole chapter on energy efficient lighting. An update to ASHRAE/IES 90.1 is expected in 1993.

Work on the Canadian Code for Energy Efficiency in New Buildings began in 1990. Following public review, the new Canadian code will be published in 1995 as a companion document to the National Building Code of Canada. It will then be passed on to the provinces and municipalities for consideration and adoption into local building codes, a process that could take up to two years. A number of provinces and municipalities have already adopted ASHRAE/ IES 90.1 into their building codes, among them, the city of Vancouver, and the province of Ontario.

Although the lighting part of the new Canadian code will be largely based on the ASHRAE/IES 90.1 standard, there will be significant differences. Since the Canadian energy code is still a "work-in-progress," the rest of this chapter describes the ASHRAE/IES 90.1 standard.