Blast from the Past

Seattle Steam's silo and building in downtown Seattle. Photo by Chris Landry

Imagine an efficient system of centralized heating powered by renewable energy using underground pipes to heat water and air for multiple buildings. Sergius Orata developed just such a system. Is Sergius Orata a new experimental energy start-up from Scandinavia? Actually, he was a hydraulic engineer who did the bulk of his work about 2000 years ago in ancient Rome. Sergius is credited with significant innovation in centralized heating, specifically systems designed to heat Roman baths. That’s how old the idea of district energy is.

So Sergius would feel right at home in the discussions about large scale energy efficiency, and especially recently proposed federal legislation sponsored by Rep. Betty McCollum (D-Minn), along with Sens. Al Franken (D-Minn) and Kit Bond (R-Mo). Their proposal, the Thermal Renewable Energy and Efficiency Act,would add incentives to promote the development of combined heat and power (CHP) and district energy.

Think about the building you are sitting in right now. More than likely the building has centralized heating and cooling but it also likely gets its electricity from another source. What CHP does is combine all the heating and energy needs and takes care of them from one place and with one fuel, like natural gas. District energy solutions do the same thing as CHP, but for more than one building, such as downtowns, neighborhoods, or university campuses.

What makes this energy solution appealing is that with the right fuel source, like ground source heat, district energy is a sustainable energy solution for cities looking to make an impact on carbon emissions. Seattle Steam has set the example locally by bringing a biomass boiler online late last year. The boiler produces steam using waste wood from local sources, resulting in a reduction of carbon emissions by 45,000 tonnes annually.

In Portland, two projects using district energy at the neighborhood scale have been proposed and studied. Sunnyside Energy would use ground source heat to service a local school campus and the surrounding neighborhood as well. And in the North Pearl Neighborhood, the City of Portland has found district energy to be a viable solution for potential new growth there. These projects could benefit from passage of this legislation.

Rep. McCollum’s bill expands the renewable energy tax credit to the production of thermal energy, benefiting most district energy producers and encouraging new projects. The bill also expands tax exempt bonding for capital costs associated with thermal energy, and it expands the Department of Energy's Energy Sustainability and Efficiency grant program so it can more fully support large scale thermal projects.