After the oil shocks of the 1970s, several European countries recognized that they simply could not afford to continue importing most of their energy and then wasting a large percentage of it. Denmark and other Scandinavian countries undertook a massive effort to replace their centralized electric generating plants and individual building heating systems with community-wide district energy systems. Today more than sixty percent of Danish households are connected to district energy networks supplied by combined heat and power plants and other low cost heat sources, many using local renewable resources such as wood chips, straw, and large solar thermal arrays.
In early 2006 Eco Grid, a non-profit organization, was formed to analyze the potential energy and economic benefits of a biomass-fired, district CHP/heating and cooling system for the City of Hudson, New York. Funding for the study was provided by a grant from NYSERDA. District heating systems are typically installed as part of the infrastructure of a new development; however, so our challenge was to see if this technology could be retrofitted into an existing city-scape. The Eco Grid staff performed the data collection and integration function for the project and utilized several groups of technical experts to provide analysis, design and review of the system.
Example of biomass cogeneration can utilize up to 98% of thermal energy according to manufacturer's literature. Turboden is a Pratt & Witney Power Systems Company.
Our proposed design for a Hudson CHP/heating and cooling system could consist of several major elements: a biomass-fired co-generation plant with fuel from wood residues; a low-temperature, hot water, district heating network to deliver thermal energy to Hudson customers; connection to buildings and conversion of existing systems to efficiently use hot water for heating. We also evaluated the potential use of geothermal heat pumps, solar thermal collectors and long term underground heat storage as other components of the system. Our hope was to create a plan for a system that would provide low pollution heat and electrical power for the City of Hudson in a manner that would be cost competitive with existing methods. As you can see in Resources below by reading the final report (Dec. 2010), there are conditions under which these objectives would be met, and an investment would be justified. However, the investors would also have to make a wager on the future prices of natural gas and electricity which this system's output would be competing with. Even if no investor steps forward with the vision (and capital) needed to implement this project, we feel the effort expended to characterize the energy demand and usage patterns of Hudson and potential methods of satisfying that demand will have been well worth the effort we put into doing this research, as it will serve Hudson in future considerations and hopefully show others an opportunity.
Michel O'Hara is the Director of Research for Eco-Grid, a Hudson-based non-profit that provides the technical, outreach and management leadership for the development of a renewable-energy system in Hudson, New York. He is also an energy consultant and founder of the Hudson 10% Challenge. He can best be reached by email.