Amtrak is running ahead of schedule. The Washington, D.C.-based national train giant is one of the first transit systems to plan a community microgrid so that it can keep its operations running during power outages.
In the aftermath of the 2012 Superstorm Sandy, half of Sunnyside Yard had to rely on portable backup generators for a month due to a damaged transmission line. And in July 2006, about 25,000 customers in the Yard’s Long Island City border lost power for more than five days due to wind-related equipment failures.
Independently owned, the proposed $31.3 million microgrid would secure critical transportation services via 17.2 MW of energy generation and 4 MWh of storage. Operation, maintenance, and fuel costs would total $7.2 million yearly, with annual revenue streams of $10 million, primarily through the sale of electricity to Amtrak and Consolidated Edison.
Planned for Amtrak’s Sunnyside Yard in Queens and Penn Station in Manhattan, the microgrid also will include a nearby college and high school. In addition, it could provide emergency power to a public housing complex, gas stations, and a grocery store in the Sunnyside area of New York City.
Madison Square Garden, also at Penn Station, and public housing and new developments near Sunnyside Yard will be considered for inclusion in Phase II of the project.
The project proposes five new distributed energy resources: a 6-MW combined heat and power (CHP) unit; two natural gas reciprocating generators (at 3 MW and 8 MW); a 200-kW solar photovoltaic (PV) array; a 1 MW zinc air battery storage unit.
The CHP will be located at Penn Station; the remaining new assets will be based at two different locations at Sunnyside Yard. Around 2,000 feet of new natural gas line will be necessary to provide the proposed generators with an adequate fuel supply.
Mirogrid’s inner workings
The microgrid will produce on-site power in both grid-connected and island (non-grid) mode.
The CHP unit is sized to meet Penn Station’s entire electric load. In grid-connected mode, the CHP plant will operate continuously, selling electricity to Con Edison under a long-term power purchase agreement and selling co-generated steam to Penn Station. In island mode, the CHP plant will sell power directly to Penn Station. Two existing standby diesel generators at Penn Station will also be included in the microgrid, but will only operate as needed in island mode.
Amtrak will purchase electricity from the 3 MW natural-gas generator at its maintenance and support facilities at Sunnyside Yard. These facilities are critical to emergency evacuation operations, and as such are important to the health, safety, and welfare of the community’s residents.
The 8-MW natural gas reciprocating generator, 200-kW solar PV array, and battery storage will support Amtrak’s traction systems, mainly passenger trains in grid mode. The natural gas generator could only be sized to partially supply the traction loads in island mode, so may just support the full electric demands at LaGuardia College and Middle College High School at that time. The 8 MW generator will be supported by the solar array and battery storage unit which can provide temporary back-up power if the generator fails and must be restarted.
The proposed CHP unit, natural gas generators, battery storage unit, and existing diesel generators will be equipped with black start (emergency startup) capabilities. A microgrid control system such as the Siemens SICAM PAS or equivalent would continuously monitor and direct the microgrid in both grid-connected and island modes, according to the project feasibility study filed with the New York State Research and Development Authority (NYSERDA).
In island mode, the controller will optimize the generators, solar arrays and battery, automatically shedding non-critical loads as needed to maintain a stable and reliable power flow. It will also constantly monitor the status of the larger grid and will re-connect when conditions have stabilized. In grid-connected mode, the controller will optimize the use of available assets to reduce energy costs when possible.
Management and control system network data will be fully encrypted when stored or transmitted to protect the microgrid from cyber intrusion and disruption.
The microgrid power management system also includes highly accurate solar forecasting to smooth the natural spikes in the daily PV output by optimally integrating the PV and battery systems. The solar array would operate at maximum capacity during the high electricity demand summer months to comply with the Con Edison Demand Management incentive program. This NYC program will also finance around 60 percent of the capital cost of the battery storage unit.
How the microgrid makes money
Since neither Con Edison nor Amtrak wish to assume ownership or operating costs, the team proposes that a special purpose vehicle (SPV) owns and operates the distributed energy resources and microgrid equipment. The SPV will receive all revenues associated with the microgrid operation but in turn will bear the capital and operating costs.
The microgrid will have several sources of revenue:
- Electricity sales to Con Edison
- Electricity sales to Amtrak (at 90 percent of the local industrial electricity rate)
- Thermal energy sales to Penn Station
- Demand response payments from the battery storage units.
In normal grid mode, the solar PV array will sell electricity to Con Edison under a long-term PPA. It will not qualify for net metering as the SPV does not own a metered facility in the area. In island mode, SPV shareholders will also receive limited revenues from electricity sales to the college and high school.
Finally, the project team notes that unless the CHP unit or battery storage unit can be expanded, the microgrid most likely will not participate in NYISO ancillary service markets. This is because it could not reliably meet minimum capacity requirements.
The project is one of 83 projects that won funds for a feasibility study during Phase 1 of the NY Prize, a state-sponsored competition to encourage microgrid development.
The project partners include Booz Allen Hamilton, Con Edison, Viridity Energy, Verde Advisory, Amtrak, and New York City.
Track microgrid projects by subscribing to the free Microgrid Knowledge newsletter.