Princeton HealthCare System

To remain one of the most advanced healthcare institutions in the nation, Princeton HealthCare System needed a new facility. However, renovating and expanding the existing 93-year-old facility — with obsolete infrastructure and located in a densely developed residential neighborhood — was not a viable option.

The Opportunity

To meet and exceed the hospital board's and administration's standards for state-of-the-art patient care, efficiency and environmental sustainability, a new $522 million, 636,000-square-foot facility known as University Medical Center of Princeton at Plainsboro, was conceived, designed and built over a period of seven years between 2005-2012. Its features include 231 private patient rooms, 21st century technology and high-tech robotics — all evidence-based components that improve quality of care and productivity.

However, this ambitious approach required a reliable and continuous energy supply. The originally proposed solution, a conventional central utility plant for heating and cooling, fell short in terms of helping UMCPP reduce its environmental impact and operating costs — definitely not as forward-thinking as the facility it would power. UMCPP needed an efficient (in terms of cost and logistics) solution that would allow it to stay focused on its primary mission of providing exceptional healthcare.

The Challenge

Clearway Energy had a better idea – a combined heat and power plant, known as a CHP, which provides highly reliable electricity, steam and chilled water. The new facility is completely energy self-sufficient, with the lowest net energy consumption and highest reliability available for a healthcare facility of this size. Clearway Energy designed, built, and financed the facility, and now owns, operates and maintains it under a long-term contract. In other words, UMCPP is able to focus on its mission while Clearway Energy continues to do what it does best — provide a best-in-class power solution.

Clearway Energy's state of the art energy solution includes a 4.6 MW natural-gas turbine matched to a supplemental-fired heat recovery steam generator, three 24,000-lb/hr. low-emission steam boilers, three 1,000-ton electric chillers, a 700-ton steam absorption chiller, three 2 MW emergency backup generators and a 1 million gallon thermal energy storage (TES) system for off-peak chilled water production, which flattens its thermal and energy demand profiles and provides substantial energy savings.

The clean natural gas-fueled turbine generator, which is backed up by three emergency generators, has a compressor system to boost its pressure and another system to manage its parasitic load. This generator can also supply all of the hospital's essential power needs. In turn, heat from the turbine exhaust is captured to provide thermal energy to the building — steam for heating and sterilization, and chilled water for air conditioning. If necessary, the hospital's electricity load can also be supplied from the grid via two parallel feeders, either of which can supply the hospital's entire load as a contingency. If more power is generated by the turbine than what the hospital needs, the additional power can be sold back to the grid operator.

All components are monitored and cycled by a sophisticated control system, which features proprietary economic dispatch software. This software can read and anticipate energy price volatility, then schedules CHP equipment accordingly to minimize the cost of energy production. Because CHP can co-generate electricity, it can avoid buying off the grid during peak hours and can help schedule power sales back to the regional grid operator, PJM.

The Solution

From start to finish, the CHP solution was designed to meet UMCPP's specific requirements. With capital and technical expertise, Clearway Energy facilitated both the construction of the CHP project and its operation. The plant itself represents a significant step beyond conventional thinking; most hospitals are powered only from the main utility grid, with backup generators for crucial areas. Here, additional systems provide a high degree of reliability with infrastructure designed to accommodate future growth.

By combining efficient power sources with intelligent control systems, CHP takes energy efficiency to a new level. It's estimated that the UMCPP plant will pay for itself within five years, with annual savings of hundreds of thousands of dollars. Environmentally, it eliminates 18.1 million pounds of annual carbon emissions.

The CHP solution defines a new standard for hospitals and healthcare facilities looking to improve reliability, sustainability and operational efficiency.

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