The objective of this demonstration was to provide a credible, independent, third party evaluation of the performance, economics, and environmental impacts of the Ener-Core Powerstation™ (FP250) technology in a landfill gas (LFG) energy recovery application at a U.S. Department of Defense (DoD) site. Ener-Core Power, Inc. was formerly known as Flex Power Generation, Inc. The evaluation was designed to provide sufficient data to allow end-users, purchasers, and others to determine the feasibility of the technology at DoD sites and other applications. Success factors that were validated during this demonstration include energy production, emissions, and emission reductions compared to alternative systems, economics, and operability, including reliability and availability.
The FP250 is a unique power plant that is able to generate electric power using low energy content gas or vapor while emitting low levels of atmospheric pollutants. The FP250 integrates a modified conventional micro-turbine (Ingersoll Rand MT250, now manufactured by FlexEnergy Energy Systems) of proven design with a proprietary gradual thermal oxidizer in place of the conventional turbine’s combustor. Gradual oxidation is the 1- to 2-second conversion of a dilute fuel air mixture to heat energy, carbon dioxide (CO2), and water. Compared to traditional combustion processes, which occur in milliseconds, the Ener-Core oxidation process is more gradual. The FP250 is able to operate using low heating value fuel sources (theoretically as low as 15 British thermal units [BTU]/standard cubic feet [scf]) that would not support operation of conventional gas turbines or reciprocating engines, which require a minimum fuel heating value of 300-500 BTU/scf.
Key outcomes from the demonstration at Fort Benning, Georgia, include:
Installation managers should understand that the FP250, like other turbine-based technologies, requires a steady fuel supply with minimum total energy content of about 3.4 million (MM)BTU/hour (higher heating value). That is, the FP250 is only capable of operating near 100 percent of rated capacity and has little or no turn-down capability. In addition, the FP250 does not tolerate excessive thermal cycling. As with larger frame size industrial gas turbines, continuous 24/7 operation is recommended and the number of restarts over the system lifetime should be minimized to avoid excessive maintenance. It is important that a sufficient, continuous fuel supply be verified during site selection. It is also important to verify the reliability of the grid interconnect (if any) at candidate sites.
The FP250 is undergoing minor modifications to improve reliability and operability. These modifications include:
Ener-Core has conducted testing and/or engineering evaluations for each of these modifications at their engineering development facility and maintains that these modifications will allow the system to operate unattended with high reliability (>90%) and minimal unplanned downtime. The performance of these modifications was not verified during this demonstration.
Due to the system’s low emissions, minimal noise, and small footprint, Southern does not expect permitting or other site approvals to present a significant obstacle to implementation at most sites. For this demonstration, permitting and required approvals required minimal effort.