Install for one or more city-owned/school buildings one of the following efficiency measures:

Install for one or more city-owned/school buildings one of the following efficiency measures:

Best Practice of this action

Rating Guideline

	Geothermal systems should meet a minimum coefficient of performance of 3.3 for closed loop systems.
	Use a waste heat stream to heat one or more buildings; create a district energy system/microgrid for several buildings (using waste wood, geothermal energy, gas turbine, fuel cell); harvest rainwater.
	Integrate solar thermal or other renewable production into a combined heat & power system; use the constant temperature of drinking water pipes in a geothermal system.

Resources

Geothermal heating systems can increase greenhouse gas emissions by 40% over high-efficiency natural gas furnaces due the higher CO2 emissions from the typical coal-fired electricity in Minnesota that runs the geothermal pump. Thus a geothermal system replacement should be analyzed for CO2 emissions, which can be lowered by purchasing renewably generated electricity from sources like wind.
District energy describes a system that produces and distributes one or more of heating, cooling, and electricity for buildings in a neighborhood-scale distribution network. Various ownership and operating models are available for locating generation close to the load being served. This improves the net efficiency of fuels, lowers costs, improves reliability and resiliency, and reduces emissions. The most popular and mature technology uses gas turbines to co-generate heat and power (CHP), utilizing waste heat to drive absorption chillers for cooling. Once the grid is set up, users can incorporate renewables like solar or wind. See the in-depth report Minnesota Microgrids: Barriers, Opportunities, and Pathways Toward Energy Assurance (Microgrid Institute: 2013), which takes an in-depth look at regulatory barriers to and opportunities for microgrid development to enhance energy assurance in the state of Minnesota, with recommendations to address barriers and identify pathways to facilitate microgrid development.
The Combined Heat and Power Action Plan (October 2015) synthesizes MN Department of Commerce findings to inform clear and achievable recommendations that could help lead to potential CHP implementation in Minnesota.
A 2005 microturbine installation at the Hennepin County Home School (Minnetonka) resulted in annual utility savings of $8,000.
For actions and resources related to renewable energy generation/distribution, and combined heat and power, see GreenStep best practices #26 (Renewable Energy) and #29.8 (Resilience).
See the Minnesota intergency report Advancing Safe and Sustainable Water Reuse in Minnesota (Minnesota Department of Health, 2018) for benefits, examples, and recommendations. For information on planning and implementation, see the Stormwater Reuse Guide (Metropolitan Council, 2011).