The idea of the East Bronx Healthcare Microgrid was born out of special pressure on the crucial hospital system.
During storms and power outages, the four hospitals must remain open not only to serve existing patients, but also those transferred from evacuated hospitals in Manhattan and other New York City boroughs.
Further, the medical facilities house $700 million in biological research that could be lost during extended power outages. This includes advanced research into cancer treatment, cardiovascular disease, aging, transplantation surgery and children’s health.
That’s why a $34 million microgrid is being considered for the East Bronx medical facilities as part of the NY Prize, a state competition to incentivize microgrids.
The hospital system is no stranger to crippling weather. Superstorm Sandy knocked out area power lines for 56 hours. Two and a half years prior, high winds and storms caused power outages for 15 hours. When the power goes out, the East Bronx facilities must limit their services because their only electricity source becomes single-purpose emergency generators.
The East Bronx Healthcare Microgrid would help ensure electricity for the hospitals, which assist about 10 percent of the Bronx population—over 137,000 patients annually – of which half live below the poverty line.
Healthcare microgrid to serve 30 buildings
As described in a feasibility study submitted to the NY Prize, the microgrid would serve 30 buildings located across four campuses:
- Montefiore Medical Center’s Jack D. Weiler Hospital
- Albert Einstein College of Medicine (acquired by Montefiore in 2015)
- Jacobi Medical Center
- Calvary Hospital
The microgrid would operate in islanded mode—independent of the main grid—during a utility power outage. As an added bonus, it would maintain the ability to sell excess electricity to the grid during normal operations. This could provide a revenue stream in excess of $13 million annually to the microgrid owners.
To serve the combined 21-MW peak demand from the facilities, the microgrid proposal integrates several distributed energy resources, including five 4.6-MW natural gas-fired combined heat and power (CHP) units, battery systems for energy storage, steam turbine generators, and heat recovery steam generators. In addition, two 2 MW diesel generators would provide black start (emergency start up) capability. Calvary Hospital, due to its distance from the other two hospitals, would have its own 1 MW CHP microturbine combined with 1 MW of solar photovoltaics. The design also incorporates existing steam generation plants at the four facilities.
The microgrid would satisfy the facilities’ electrical demands. If one of the microgrid’s turbines fail, another can generate excess capacity. During normal operations any excess capacity could be exported to the grid. In addition, the microgrid would provide heating, cooling and hot water to the facilities by way of a thermal byproduct of its electrical production.
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Because of the mission-critical patient care and research conducted at the medical facilities, the CHP engines are limited in size to 20 percent of microgrid peak load. To make the system redundant, the design offers smaller but more CHP engines, rather than larger but fewer engines. Emergency redundancy is also built into the system via black-start diesel engines. These engines are sized to support the microgrid should one of its primary CHP engines fail.
The system configuration sends microgrid generated power into the distribution system of local utility Consolidated Edison, which then redistributes it to the microgrid customers. If the main grid fails, ConEd will automatically isolate and island the microgrid from the rest of their system, allowing it to operate grid-independent for as long as required. Upon restoration of grid power, ConEd would revert the system back to normal grid operation.
Private developer to own microgrid
The proposal calls for ConEd to install and retain ownership of the microgrid transmission infrastructure, including interconnection to the main power grid. The microgrid design proposes that easements be granted for ConEd to install and operate the interconnections between the microgrid and the utility’s underground network, and also to control the distribution of microgrid power.
A project developer would build, own, operate and maintain the healthcare microgrid. Several developers already have expressed interest in the project, and one will be selected should the project move forward to stages two and three of the NY Prize, according to the feasibility study.
The developer would assume ownership of the microgrid, and enter into individual power purchase agreements (PPAs) with the hospitals. Each PPA would consist of three components: energy charge per kWh; demand charge per kW per day; and minimum take or pay per kWh to ensure debt service for initial capital outlays by the developer.
The project partners are Gotham Energy 360, Van Zelm Engineers, and Environmental Engineering Solutions, according to the NY Prize website.
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