BUILDING TECHNOLOGIES PROGRAM Hospitals Discover Advantages to Using CHP Systems Combined heat and power systems—also known as cogeneration systems— use a heat engine or power station to simultaneously generate both electricity and heat. They convert Hospitals are ideal candidates for combined heat and power (CHP) systems. Because hospitals function 365 days a year, 24/7, they require round-the-clock energy. Combined waste heat from electrical systems enable hospitals to reduce energy costs, improve environmental performance, and generation into energy increase energy reliability. Resources saved are often redirected to improve patient care. that can be used for heating and cooling. More than 200 • Lower, more predictable energy bills: Total system energy efficiency is improved hospitals nationwide operate when power is produced onsite through a CHP system. Annual operations and maintenance savings can average more than $400,0003 for a 2 MW gas turbine 1 CHP systems. system. By enabling hospitals to supply their own power, CHP systems also provide The number of hospitals using CHP systems a hedge against the rising cost of electricity. has grown steadily2 in recent years. • Increased revenue potential: In some states, CHP can create an additional revenue Hospitals using cogeneration are taking stream by allowing hospitals to sell surplus electricity back to their utilities. A advantage of favorable utility rate structures hospital’s ability to do this depends on the net metering and rate policies of its utility. and hedging against rising electricity prices. Typically, “selling back” during off-peak hours is not profitable for a hospital, but, Because cogeneration uses waste heat to given the right circumstances, it can be a revenue generator during peak hours. produce thermal energy for heating and cooling, hospitals that use CHP systems are CHP systems often can be installed for less cost upfront than renewable energy more energy efficient. Reduced emissions options—such as photovoltaic systems—of a similar scale. When matched to suitable lessen their impact on the environment as loads, some CHP systems can provide a simple payback in the five- to 10-year range, 4 well. This fact sheet has been developed by depending on system size and energy costs. the U.S. Department of Energy’s Hospital Energy Alliance to assist hospitals in planning, designing, and constructing Shown here are natural gas and electricity energy-efficient, cost-effective combined National Average prices needed to achieve three-, five-, and heat and power systems. (13) 10 yrs 10-year simple paybacks for a 2 MW CHP Financial Advantages system. At an electricity price of 13 cents/ 5 yrs kWh, a five-year simple payback can be CHP often can offer financial advantages achieved when natural gas prices are less over power purchased from a local utility 3 yrs than $11.25/mcf. or produced by other energy systems. 20 This analysis assumes a construction cost of $2,000 Those advantages follow. per kilowatt. See http://www.eia.doe.gov/cneaf/ 15 electricity/epm/table5_6_a.html for average retail 15 electricity price data by region and state. 1. Midwest CHP Application Center and Oak Ridge National 14 Laboratory. http://www.chpcentermw.org/06-01_application.html. 10 2. Report on National Center for Energy Management and Building 13 Technologies Task 15, 2005. 12 3. 2 MW CHP operating at 10k Btu/kWh for 8,322 hrs/yr with 5 5 MMBtu/hr recoverable, capital cost of $2,000/kW, O&M cost of 11 $0.011/kWh, and given U.S. average gas prices of $9.78/MMBtu 10 0 and electricity prices of 10.12 cents/kWh. (See graph at right.) Natural Gas Prices ($/mcf) 9 4. Given average system of 2 MW with $1,500–$2,000/kW installed Electricity Prices (cents/kWh) cost, and national U.S. energy prices. (See graph at right.) 2 CHP FACT SHEET More Reliable Case Study Emergency Power NewYork-Presbyterian Hospital Hospitals must perform critical, life- saving functions even when a widespread New York, New York • Completed in 2009 disaster interrupts their supply of natural gas and electricity from the utility grid. Details CHP systems can be designed to maintain critical life-support systems, operate • The CHP plant has a gas turbine drive, independently of the grid during a 7,500 kW electric generator, and a emergencies, and be capable of black heat recovery boiler with duct firing. start (the ability to come online without • The onsite system operates in a relying on external energy sources). synchronous parallel configuration with Because they are already up and running, the utility grid; supplemental electric CHP systems can offer a more seamless, energy is provided by Consolidated reliable power alternative than traditional Edison under normal operating emergency generators. During the New conditions. York City blackout of 2003, half of the 58 metropolitan hospitals had failures in • Installation was simplified because the their backup power generators.5 CHP system was designed to fit into the systems, however, are not automatically existing boiler plant location. configured for backup capability; • The hospital takes advantage of hospitals must ensure that the systems Consolidated Edison’s rate structure have automatic transfer capability and that promotes use of clean that output can be matched with demand. cogeneration. NewYork-Presbyterian Hospital/Weill Cornell Medical Center determined that major Environmental Benefits Expected Results operational and cost benefits would result from installing a CHP system in its existing CHP systems have a higher whole- • Will save the hospital approximately boiler plant. The hospital took advantage system efficiency than systems that split $5 million per year. of state and utility incentives to construct a heating and power generation because cost-effective and environmentally friendly cogeneration captures waste heat from • Will generate 100 percent of the electricity generation and uses it to hospital’s base electrical load and system. generate steam for heating and cooling. two-thirds of its peak electrical load. • Will reduce CO produced by 67,000 With less fuel consumed, greenhouse • Will reduce the hospital’s purchased 2 gases (such as carbon dioxide) and air power by 80 percent. tons annually. pollutants (like nitrogen oxides and sulfur • Will provide a 100 percent redundant dioxides) are reduced; for a 5 MW CHP • Will increase firm steam capacity by power source for inpatient areas. plant, emissions generally are reduced by 23 percent. more than 25,000 tons per year (see chart at right). CHP Systems Decrease Harmful Emissions By using cleaner feedstocks, such as some forms of biogas and biomass, CHP Conventional Combined systems can in some cases produce fewer Generation Heat & Power 5 MW Natural Gas emissions than those utilizing traditional Combustion Turbine fuels. These environmental benefits Power Station Fuel should be quantified and factored into Power Plant 30 98 Units Fuel Units the total cost of the CHP system. For an Electricity EFFICIENCY: Combined example of how to perform this type of 31% 154 Units Fuel Heat & Power 100 Units Fuel CHP analysis, see Practice Greenhealth’s EFFICIENCY: 56 Units Fuel 80% energy impact calculator at http:// 45 Heat Heat practicegreenhealth.org/tools-resources/ Boiler Fuel Units Boiler Steam energy-impact-calculator. OVERALL OVERALL 5. From Energy and Environmental Analysis, Inc., for the EFFICIENCY 75% EFFICIENCY U.S. Department of Energy Oak Ridge National Laboratory, 49% June 2004. Source: EPA Conventional Generation vs. CHP Report, http://www.epa.gov/chp/basic/environmental.html. CHP FACT SHEET 3 Important Factors Case Study to Consider Dell Children’s Medical Center of Central Texas CHP systems are not for every hospital. Their cost-effectiveness needs to be Austin, Texas • Completed in 2007 evaluated on a case-by-case basis. In determining a CHP system’s viability, Details there are several important considerations: • A 4.3 MW gas-fired turbine was installed in a new 35,000-square-foot • Incentives and rate structures: Many utility plant. utilities are implementing “friendly • Construction cost was $18 million. tariffs” that facilitate CHP. Some utilities charge hospitals a standby • Two independent electrical feeders rate, so that the utility can provide provide a backup for the onsite the infrastructure to support all of a generation. hospital system’s load in the event that • An emergency generator (for black the cogeneration plant should fail. start capability) provides another Interconnection agreements, siting backup for life-safety systems. issues, and permits all should be discussed with the partnering utility. Local and national incentives— Results including direct financial grants, tax • The system generates all of the incentives, and low-interest loans— hospital’s electricity. should be determined. See the U.S. Department of Energy’s Database of • The plant is 75 percent more efficient State Incentives for Renewables and than coal-fired power plants. Efficiency:www.dsireusa.org/library/ • Waste heat from the gas turbine is used includes/techno.cfm?EE=1&RE=1. to produce steam and chilled water • Black start capability: Hospital CHP used directly by the hospital. systems should be configured for black • Enhanced quality of power ensures start, or the ability to come online smooth, continuous operation of without relying on the electric grid. clinical equipment. This involves extra equipment, such as a battery pack, but enables hospitals • Excess electricity is exported to the to operate effectively during times utility grid. of crisis. • The hospital experienced gross savings • Prime mover type: Designers must of $6.8 million in construction costs choose equipment that best fits the and reinvested $5.8 million in hospital’s thermal and electrical loads additional energy conservation and power quality requirements. measures. • The project earned 10 points in LEED Dell Children’s Medical Center of Central EA1 efficiency credit. Texas is a 509,000-square-foot, 176-bed • The CHP system and reduced energy hospital built in 2007.