NRG Energy and Princeton HealthCare System Partner to Power New University Medical Center of Princeton at Plainsboro

Tue Dec 29, 11:59 AM

Princeton HealthCare System (PHCS) has contracted with NRG Thermal, a subsidiary of Princeton-based NRG Energy, Inc., to provide power services by means of its Combined Heat and Power Plus (CHP Plus) program to University Medical Center of Princeton at Plainsboro (UMCPP), the acute care hospital of PHCS being built on 50 acres at One Plainsboro Road, Plainsboro.  No other facilities on the 160-acre Plainsboro Health Campus will be served under the 13-year contractual agreement between NRG and PHCS. The CHP Plus Program was created and will be implemented only for the purpose of operating the health care services of UMCPP.

The CHP Plus Program integrates conventional, proven energy sources and leverages them with leading efficiency and environmental technologies consisting of the following:

CHP, also known as co-generation, that will provide electricity and heating/cooling; a small photo-voltaic solar facility for generating electricity; a Central Utility Plant (CUP); and a Chilled Water Thermal Energy Storage System (TES). All the elements of the CHP Plus system and their respective equipment will be monitored and controlled through a state-of-the-art digital computer control system to provide operations optimized for both energy and cost efficiency.

The CHP Plus Program is the key element of UMCPP’s carbon abatement initiative, which has been lauded by the NJ Board of Public Utilities and PSE&G.  Approximately, 18.1 million pounds of carbon per year is being eliminated from the atmosphere, the equivalent to removing 1,555 cars from the road annually. The on-site CHP facility is especially beneficial for a hospital, as it will provide enhanced reliability and 100 percent redundancy for its power needs. Generally hospitals have two sources of power: the local utility and limited power from emergency generators in case of grid failure. UMCPP will have access to power generated by CHP as the primary source; this power will be backed up fully by the local utility power, and finally, a limited power to crucial areas of the hospital will be available from emergency generators.

 The decision to go forward with this technology was made by PHCS after NRG completed a feasibility study.  The NRG feasibility study demonstrated that CHP offers substantial economic and operational benefits for UMCPP. CHP/co-generation, is the ultimate energy re-cycling, or the production of two kinds of energy, usually electricity and heating/cooling, from a single source of fuel, in this case natural gas. Co-generation can replace the traditional method of supplying energy from multiple sources, i.e., purchasing electricity from the power grid and burning natural gas or oil separately in a furnace to produce heat or steam. The environmental reasons for going in this direction are compelling. Compared to traditional electric generation, a CHP system is up to twice as efficient. Traditional electric generation generally coverts about 31 percent of the energy it uses to produce electricity, thus wasting two thirds of the energy in the original fuel. CHP puts up to 80 percent of the energy in the original fuel to productive use. Rejected energy from electric generation in the United States is equal to all of the oil imported each year.  Specifically, high-temperature, high-pressure steam from a boiler and super heater first passes through a turbine to produce power. It then exhausts at a temperature and pressure suitable for heating purposes, instead of being expanded in the turbine to the lowest possible pressure and then discharged to the condenser, which would result in losing energy remaining in the steam. Steam discharged from the turbine at the medium pressure in cogeneration can provide large amounts of lower-temperature energy for such applications as heating buildings. The CHP facility cools through chilled water distribution by means of a chilled water storage system (see below).

The noise produced by the CHP at UMCPP will never exceed the level of noise produced by other UMCPP facilities. The CHP also will produce lower overall emissions than those from the boiler plant originally slated to serve the hospital. Noxious emissions will be lowered by 30 to 50 percent, thanks to CHP and the efficiency of the gas turbine.

 The following equipment will be installed within the CHP building: gas turbine generator, heat recovery steam generator, steam absorption, air conditioning, gas compressor, electrical switchgear, and electrical interconnection.

The Central Utility Plant is another component of the hospital’s power service. The CUP will contain boilers, chillers, backup emergency generators, and other plant equipment. The CHP component of the energy center will be housed in an addition to the CUP building, sharing a common wall.

A small Photo-Voltaic Solar Installation for generating electricity to be sold to the hospital will probably be constructed in the northeast parking lot, the employee parking area. The solar facility, consisting of 15 panels approximately 30 feet by 30 feet, will generate approximately two percent of the Medical Center’s electricity needs, thus producing energy equivalent to what would be needed to power 30 average-sized single family homes. The solar panels will be on columns rising from the employee parking area, thus not interfering with parking or any element of the building’s design. The solar panels would feed electric power into the  hospital’s 480-volt distribution system. The columns are expected to incorporate electric recharging stations serving electric powered vehicles that would be used throughout the Plainsboro Health Campus.

The Chilled Water Storage is a thermal energy storage tank system that removes thousands of kilowatt hours of demand from the power grid during the peak-demand time. A chilled water storage system cools water at night using off-peak electricity and then stores the water in a huge tank. The water is distributed to customers during the day at a reduced cost. Chilled water storage reduces regional peak electric demands, improves air quality, provides greater rate stability, increases cooling capacity, and provides high overall system reliability. Specifically, the storage tank on the hospital site will remove thousands of kilowatt hours of demand from the power grid, as well as will shield the environment from the pollution that would have been generated by producing the same thousands of kilowatt hours.  The Thermal Energy Storage system consists of a chilled water storage tank, interconnecting piping and automated valves, and two chilled water distribution pumps.