Energy managers are tasked with identifying energy savings opportunities and promoting energy independence. Energy-efficient (EE) and renewable-energy (RE) technology demonstrations enable energy managers to evaluate new energy technologies and adopt those that appear most effective. This study examined whether energy technology demonstrations increased energy managers' acceptance of innovative EE and RE technologies by tapping into the Diffusion of Innovation Theory (DOI) and the Technology Acceptance Model (TAM). In-depth interviews were conducted with 36 energy managers at Department of Defense (DoD) installations, federal facilities, and land-grant universities to determine their acceptance of innovative energy technologies as a result of participating in energy technology demonstration(s) at their respective DoD installation, federal facility or land-grant university. Results showed that interviewees understood participation in energy technology demonstrations could be difficult but were furthering the adoption of innovative EE and RE technologies. Over a third of the participants reported that participation in these demonstrations had resulted in adoption of a new technology at their facility, which suggests the demonstrations assist the diffusion of innovation process. However, interviews highlighted several adopter-level and system-level issues that need to be addressed so energy managers can adopt more of these technologies. These issues included maintenance manpower and expertise deficits due to lack of funding for maintenance for new technologies; outdated and restrictive regulations from electric utility companies that limit implementation of energy-saving technologies; and employees' hesitation to adopt innovative technologies when doing so could jeopardize career advancement, a problem mentioned by some of those working at federal facilities, but not those employed by state-level land-grant universities. The policy implications for this study's results call for increasing funding for to train maintenance staff in operating and repairing new technologies, creation of federal renewable portfolio standards (RPS) mandates, establishing a federal demonstration program, and exposing energy managers to more educational opportunities, conferences, and social media as a way of increasing awareness among energy managers of energy-efficient options and the perceived effectiveness of these options among energy managers nationwide. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]