already described, solid-state lighting may offer benefits to other subgroups of optoelectronics. One is vertical-cavity surface-emitting lasers, or VCSELs, which have the potential to run the fiber-optic backbone of the Internet and perform medical and scientific research.

Energy Savings

Dr. Ginsberg reviewed the energy-saving potential of solid-state lighting. Total energy consumption in the United States in 1998 was almost 95 quadrillion BTUs, or quads. About a third of this energy, or 35.6 quads, was used to generate the electricity used in all commercial, industrial, and residential applications, including lighting. Across all sectors the national primary energy consumption dedicated to lighting is approximately 6.3 quads, or nearly 18 percent of the total electricity used in buildings. The commercial sector uses 54 percent of this, followed by the residential (26 percent) and industrial (14 percent) sectors. Lighting is also a key contributor to peak electricity demand and increases the internal heat load of buildings. For each of the four sectors BTS has targeted those with biggest electricity consumption—primarily residential incandescent and commercial incandescent and fluorescent lighting—as the key areas where solid state will have to be competitive to achieve significant energy savings.

BTS had also estimated how much of the 6.3 quads of energy used for lighting might be replaced. The study considered three scenarios: (1) the base case; (2) a case in which technology breakthroughs are achieved by limited investment and innovation but the cost of manufacturing remains high; and (3) a case in which investment achieves not only technical breakthroughs but also dramatic price reductions to about 50 cents per kilolumen of light.

Dr. Ginsberg presented a bar chart reflecting this analysis (See Figure 1). The first set of the three bars showed the reduction in quads of energy for use by lighting in 2020, which ranged from 0.15 quads for the base case to 2.6 quads for the price-breakthrough case. The second set of bars showed cumulative energy savings achieved between now and 2020, with the potential under the price-break-through scenario to save nearly 14 quads of electricity, the equivalent of $93 billion in the United States.

A Roadmap for Lighting

DOE recently sponsored five meetings to develop an interest in white light from solid-state lighting sources. In accordance with DOE’s Vision 2020 roadmap, which was developed with industry, these meetings drew on key stake-holders from industry, academia, and the national labs. The invited experts, some of whom were attending the current symposium, identified the technical barriers that needed to be addressed. At the same time they concluded that there are no



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