Effects of Electric Utilities on a Zero Energy Building (ZEB). NICOLAS BABCOCK (Colorado State University Fort Collins, CO 80523) PAUL TORCELLINI (National Renewable Energy Laboratory, Golden, CO, 89401)

Buildings consume approximately forty percent of U.S. source energy. However, design technologies, materials, and control systems allow for construction of commercial buildings that consume significantly less energy than minimum code-compliant buildings of identical size. The Office of Energy Efficiency and Renewable Energy (EERE) has set goals for ZEB's to enter the market place no later than 2025. Once built, however, source energy use and site energy costs are regulated largely by the electric utility. This study explores how a high-performance building (HPB) can reach ZEB status with respect to source energy, site energy, energy cost and emissions by varying the generating capacity of the building's photovoltaic (PV) array. Utility rate calculations for energy costs were processed using three tariff structures: a Small Power General Service Tariff (GS), a Time of Use Tariff (TOU), and a Real-Time Pricing Tariff (RTP). A net metering rider was applied to each tariff to explore the cost benefit of exporting energy to the grid. Further, an attempt was made to calculate a variable source-to-site conversion factor (SSCF) that considers time of day, time of year, base load, peak load, generating capacity, and source energy. A variable SSCF is needed to better calculate source energy use and source environmental impacts. Proprietary concerns from surveyed utilities made this exploration largely unsuccessful, however. Evidence suggests a general service tariff with a net-metering rider that pays an equivalent rate for on-site generation is most favorable from a ZEB cost viewpoint. Current rate structures, however, do not provide financial incentives for incorporating energy efficient design into buildings.

Innovation Diffusion Modeling; Tests and Application to the Renewable Energy Sector. ZACHARY BRATUN-GLENNON (University of Virginia Charlottesville, VA 22904) DOUGLAS ARENT (National Renewable Energy Laboratory, Golden, CO, 89401)

The field of innovation diffusion modeling has proved the ability to accurately predict the adoption of a new consumer good. This science has been applied, in large part, only to consumer durable goods that do not encompass the unique characteristics of renewable energy technologies. For this reason, this study applied diffusion models to the renewable energy market. The Bass Model, Generalized Bass Model, and Nonuniform Influence Model were selected and applied, along with a new combination of the last two, to historical market data for testing. Photovoltaic technology was used, as representative of current renewable energy technologies, for generating a model that sufficiently predicted adoption of this product sector. Because of PV's several uses, three market sectors were determined and comparisons were drawn between each sector and another technology with more historical data. While conventional models were found to adequately predicted consumer good applications, they over-predicted the diffusion of PV. The Nonuniform Influence Model was used to adapt the models for accurate renewable energy diffusion forecasting.