|Year||BAU (TWh)||Scenario 1 (TWh)||Scenario 2 (TWh)|
NOTE: BAU = business as usual; TWh = terawatt-hours.
maximum rated wattages (see Chapter 2), these standards are only expected to substantially impact general illumination in the residential sector starting in 2014 (see Chapter 2 for the detail on EISA standards for general illumination). It is assumed that residential illumination services will be provided with the maximum allowed wattage while providing the same level of illumination. As a result, this scenario provides an estimate of the technical potential energy savings that can be anticipated as a result of EISA implementation.17 Under this scenario, lighting technologies (whether CFLs or LEDs) would replace standard incandescent lighting starting in 2014, leading to residential electricity use of 112 TWh in 2020. Savings are estimated at 514 TWh between 2012 and 2020 (or an average of 57 TWh per year).
A more aggressive scenario was also developed in which LED lamp efficacy would continue to evolve according to projections in DOE’s Solid-State Lighting Research and Development: Manufacturing Roadmap (DOE, 2011), shown in Table 6.4. The values in the table were depreciated by 24 percent to take account of the higher operating temperature. DOE does not report projections for overall lamp efficacies—only packaged device efficacies. Thus, a package-to-lamp efficacy ratio of 42 percent is assumed— which reflects the ratio between 2010 package efficacies and the efficacy for LED lamps reported in the DOE 2010 market characterization. Under this aggressive scenario, cumulative savings from 2012 to 2020 could reach 939 TWh (an average of 103 TWh savings per year).
Potential Energy Savings for the Commercial Sector
Baseline assumptions for average efficacy, power, usage, and lamp counts in the commercial sector are shown in Table 6.5 for each technology.
TABLE 6.4 Projections for LED Package Efficacies Used in the Committee’s “Aggressive Scenario”
NOTE: Projections are taken from DOE (2011, p. 24) and are for device temperatures of 25° C.
Using similar scenarios as those used to estimate residential sector savings, commercial lighting use would grow from roughly 347 TWh in 2010 to 406 TWh in 2020 in the base case. The base case does not account for the impact of EISA 2007. The committee estimates that the EISA 2007 standards will save 60 TWh between 2012 and 2020. A more aggressive scenario was also developed in which LED package efficacy would continue to improve according to the projections in Table 6.4, again depreciated to take account of the operating temperature. Under this aggressive scenario, widespread adoption of LEDs could lead to cumulative savings from 2012 to 2020 of 771 TWh (an average of 86 TWh savings annually) (see Table 6.6).
The Residential Energy Consumption Survey (RECS), the Commercial Energy Consumption Survey (CEBCS),18 and the Manufacturing Energy Consumption Survey (MECS) have been the primary sources of data for estimating the nation’s lighting energy use. These surveys were designed to be nationally representative of U.S. residential, commercial, and manufacturing building energy use and expenditures, and are administered by the Energy Information Administration (EIA). Since the late seventies, CBECS and RECS surveys have been conducted every 4 years. MECS was developed in the mid-1980s and has been conducted once every 4 years on average since its inception.
While RECS data are available for 2009, the most recent CBECS data available are from the 2003 edition of the Survey. EIA reports, “the 2007 data did not yield valid estimates of building counts, energy characteristics, consumption, and expenditures.”19,20 These data collection errors have since
17 Technical potential does not take into account different rates of adoption to technology turnover; it assumes the baseline technology is replaced by the efficient one overnight.
18 CBECS includes all buildings in which at least half of the floor space is used for a purpose that is not residential, industrial, or agricultural. Thus, it includes also schools, correctional institutions, and buildings used for religious worship, in additional to “commercial” buildings.
20 EIA reports that because of the use of “a cheaper but experimental survey frame and sampling method by EIA’s prime contractor, design errors in the construction of the method and selection of common building types, and an inability to monitor and manage its use in a production survey environment.” Available at http://www.eia.gov/emeu/cbecs/. Accessed May 24, 2011.