Measuring the Costs and Economic, Social, and Environmental Benefits of Nationwide Geothermal Heat Pump Deployment: A Progress Report on the Geological Impacts

Abstract

The use of geothermal heat pump systems (GHPs) in the United States is marginal, despite their high efficiency and minimal greenhouse gas emissions. To evaluate the consequences of broader deployment of GHPs we are conducting a national costbenefit analysis for 30 metropolitan regions. The strategy we are following is to collect relevant historical data where such systems have been installed. However, since many areas do not have an adequate record to conduct such an analysis, we are also collecting the necessary physical data for each region and modeling, using standard software packages, loop designs based on that data, as a means to estimate costs and benefits. In this report we summarize the data collection process, and provide preliminary results regarding the extent and nature of data variability and its impact on design and, implicitly, costs. According to the U.S. Energy Information Administration (EIA), geothermal heat pumps (GHPs), also known as groundsource heat pumps and GeoExchange®, are the most efficient means for heating and cooling buildings, compared to standard heating systems that burn fuel or use electricity. This fact is significant because buildings annually account for almost half (48 percent) of the energy consumption and greenhouse gas (GHG) emissions in the United States. In addition, residential, commercial, and industrial building operations consume 76 percent of total U.S. electricity generation. In 2006, weather-related energy use, in the form of heating, cooling, and ventilation (HVAC) of residential and commercial buildings, accounted for more than 40 percent of all delivered energy use1. These statistics make it clear why the building sector is an area in which important reductions in energy consumption and GHG emissions could have significant economic and environmental impacts if GHPs were utilized for HVAC purposes.