A net zero energy (NZE) building or installation produces as much energy as it uses over the course of a year. The Fort Carson Army base in Colorado Springs, Colorado is a flagship in the Army's Net Zero Initiative, under which the entire base is aiming to achieve net zero energy (NZE), water and waste by the year 2020.
To help the Army and Fort Carson achieve their NZE goals, GSA partnered with them to conduct the Fort Carson Energy Research Project. The research team tested and analyzed strategies to minimize energy use, including both improving building systems and influencing occupant behavior. The researchers targeted strategies with the highest return on investment over the lifecycle of the buildings studied.
The Fort Carson project targeted six different Army building types and four areas of opportunity for the buildings to achieve energy efficiency breakthroughs. Three of these opportunities – thermal envelope optimization, daylighting and lighting system performance, and retrofit optimization – involved improving building systems and the fourth targeted the impact of building occupant behavior on energy performance. The first three studies were conducted by NREL, while the latter was conducted by PNNL.
As a whole, this research project demonstrated effective ways in which not only Fort Carson, but Federal agencies and other building owners and operators can drive down their energy use and thereby save money and achieve ambitious energy and climate change goals. The following research questions were addressed:
- How can thermal envelope construction be optimized for lifecycle energy savings?
- How well are the daylighting and lighting systems performing now, and how can their performance be maximized?
- What sets of efficiency solutions are available at optimal energy lifecycle cost for common retrofits?
- Which occupant behaviors have the greatest potential to reduce energy use in buildings, and what approaches can motivate and maintain these behaviors?
Findings of each of the four studies are summarized below. Links to the full studies can be downloaded by clicking on each banner.
This study incorporated actual performance and cost data into energy models to compare a variety of wall, roof, and window envelope assemblies in five Fort Carson building types. A net present value (NPV) analysis was applied to determine the most cost-effective solutions over 30-year building lifecycles. The research team also studied opportunities to save energy during troop deployments. Research findings included:
- Envelope optimization in new buildings at Fort Carson can yield savings up to 25% over the code baseline with NPV up to $350,000 and simple payback as low as seven years.
- Results vary widely by building type; e.g., envelope improvements are a key component of NZE design for buildings with large heating loads, but may be less helpful for buildings that are dominated by equipment loads.
- Thermal zoning and ventilation setback when troops are deployed can yield energy savings up to 23%.
This research evaluated lighting and daylighting performance and opportunities for Fort Carson buildings to provide superior lighting with minimal energy use. The researchers observed occupancy, lighting, and daylighting patterns at four building types, modeling alternative solutions and identifying recommendations for improvement. Research findings included:
- Fort Carson is using up to 50% less lighting energy than buildings meeting minimum energy code requirements.
- The base has further opportunities to optimize lighting quality and efficiency while reducing consumption to levels 90% lower than required by code.
The research team used an office building on the base that had been renovated from a former barracks as the basis for a study to identify lifecycle-cost-effective pathways to achieve energy reduction performance up to NZE as part of a retrofit project. NREL sought to demonstrate the feasibility of NZE retrofit planning primarily using open source on-line modeling tools. Research findings included:
- Fort Carson office building retrofits have a clear, low-risk investment path of bundled energy technology solutions from lowest life-cycle cost to NZE.
- Publicly available open source tools can be used to identify much of this roadmap of bundled energy technology solutions.
This research tested the potential of the Army’s Building Energy Monitor (BEM) program to motivate building occupants to employ energy-saving behaviors. Based on surveys and interviews with occupants, the research team designed a three-month intervention at five buildings to test a model of change that integrates policy (“Rules”), identification of people in specific roles as linchpins (“Roles”), and a variety of behavior change methods (“Tools”). Research findings included:
- Occupants increased energy-saving behaviors as part of the intervention, leading to energy reductions of 2% or more in one building. Success rates varied across the five buildings.
- Having an engaged BEM, with reinforcement from leadership, helped drive behavior change.
- Occupant behavior can be influenced as part of a well-structured effort that includes considering the institutional context, targeting specific and relevant behaviors, providing social reinforcement, measuring results, and incorporating feedback.