Solutions were sought for analysis and demonstrations of integrated district energy systems (also called “Thermal Microgrids”) to simultaneously serve variable heating and cooling loads across a group of co-located buildings. Solutions should have sought to eliminate or significantly reduce on-site fuel-fired heating systems through electrification, optimization of thermal load management, and leverage economy of scale through aggregation of thermal loads from groups of closely-sited buildings.

Implementing demonstrations of thermal microgrids requires significant planning and coordination with host sites. To minimize project risk and allow sufficient time for project teams to access information and coordinate with potential demonstration sites, these projects will be conducted in two phases. Phase 1 will consist of feasibility studies to validate proposed solutions with site data and energy models. Following Phase 1, projects that show technical and economic viability will be invited to submit proposals for Phase 2 demonstrations.

Pre-proposals were requested for Phase 1 only. The pre-proposals should have followed the general instructions provided on the ESTCP website and should have considered the following information:

• In the Technology Description section, proposers should provide information on their design approach and technologies under consideration (energy storage, water/ground/air-source heat pumps, heat recovery chillers, thermal energy loop, etc.). Information on design and engineering tools and processes, potential distributed energy resources, control strategies, revenue streams and cost savings, as well as an operations and maintenance approach should be discussed.
• In the Technical Approach section, the proposed approach for designing and modeling the system’s cost and performance should be described. No demonstration plan will be required for Phase 1 efforts. Discussion on technical risks and maturity should refer to issues associated with a potential future Phase 2 demonstration.
• In the Expected Benefits section, a qualitative and semi-quantitative description of the energy and water savings, utility cost savings and greenhouse gas reductions should be included.
• Project costs should be estimated for conducting a feasibility study at a single military installation in Phase 1.
• The Technology Transfer section should discuss activities to engage with key stakeholders involved with energy project development for military installations to facilitate information exchange and explore collaboration for a potential Phase 2 demonstration.

Funded projects will appear below as project overviews are posted to the website.

The Executive Order released on December 8, 2021, on Catalyzing Clean Energy Industries and Jobs Through Federal Sustainability, has set a goal for the federal government to achieve a carbon pollution-free electricity sector by 2035 and net-zero emissions economy-wide by no later than 2050. As part of this goal, agencies are required to prioritize improvements in energy efficiency and reduction in greenhouse gas emissions to achieve net-zero emission buildings. Looking at solutions for groups of buildings rather than building-by-building, the DoD can realize benefits through optimized system design for networked thermal loads, reduced overall installation costs through economies of scale, and greater greenhouse gas reduction through electrification of building and water heating systems.

The DoD owns nearly 300,000 buildings across its 500 installations, accounting for nearly 33% of the DoD’s total energy use. Most installations include areas with high building density along with areas of open space. Most buildings on military installations have electrical and natural gas service to power and fuel building electrical and thermal loads; however, there are some examples of district steam systems, central combined heat and power, and smaller central chiller plants that serve small groups of buildings. These examples of district systems are not considered thermal microgrids because they are designed with centralized energy generation with one-way energy delivery, whereas a thermal microgrids use the district system(s) as a thermal sink and source and integrate distributed energy sources (air/water/ground-source heat pumps, energy storage, waste heat recovery) located throughout the network.

To meet the aggressive greenhouse gas (GHG) emissions reduction targets outlined in Executive Order 14057, the DoD needs to find solutions that make step-change improvements to energy efficiency and to the way buildings are heated, cooled, and powered. It is likely that solutions that generate significant reductions in energy use and GHG emissions will come at a higher cost; however, it is expected that these solutions will generate sufficient cost savings to justify the investment.