Selected Cost Considerations for Geothermal District Heating in Existing SingleFamily

In the past, district heating (geothermal or conventionally fueled) has not been widely applied to the single-family residential sector. Low-heat load density is the commonly cited reason for this. Although it's true that load density in these areas is much lower than for downtown business districts, other frequently overlooked factors may compensate for load density. In particular, costs for distribution system installation can be substantially lower in some residential areas due to a variety of factors. This reduced development cost may partially compensate for the reduced revenue resulting from low-load density. This report examines cost associated with the overall design of the system (direct or indirect system design), distribution piping installation, and customer branch lines. It concludes with a comparison of the costs for system development and the revenue from an example residential area. Distribution system installation costs were reviewed based on the use of double line (supply and return), preinsulated ductile iron piping. This material is currently the most widely used product for new distribution projects. Actual construction cost data was used along with cost calculations to disaggregate gross costs ($/lf) into 11 individual areas for lines in the 3 " to 12 " range. Each o