Reliability for Critical Research and Life Support
Several reports and market surveys have documented the need for reliable energy for hospitals and healthcare facilities. Last year the American Hospital Associations reported that there are currently 900 fewer hospitals in the US than there were in 1980, so there is increasing demand for new or improved facilities. Healthcare tends to be counter-cyclical to the economy, i.e. business in these markets is relatively recession-resistant because it is based on pure need and tends not to be speculative like the office market.
IDEA notes that many colleges and universities have similar drivers for enhanced reliability. Many colleges and universities perform critical research in laboratory space on campus and may provide heating, cooling and power to an adjacent health care facility or teaching hospital. On-campus cogeneration and highly reliable district cooling systems, some with thermal storage, have proven invaluable for supporting and preserving critical research and critical care facilities.
The IDEA survey has identified 675 MW in college and university markets doing critical research based on average campus CHP system in census.
Greening the Campus
Sustainable or greening campus movements across the country, particularly in the Northeast and perhaps California, are driving a trend toward clean CHP projects as a way to promote sustainability and reducing the ecological footprint of campus energy systems.
College and university markets have significant pressures from students to practice sustainable design and utilize greener technologies on campuses across the country. Princeton, MIT, Rutgers, UNC Chapel Hill and the New Jersey Higher Education Partnership for Sustainability are exemplary, but there are other promising college and university examples spread across the country such as Oberlin College in Ohio. Private colleges and universities in these areas are a promising market due to both environmental pressures and a stable economic outlook.
Communities sometimes raise objections to CHP projects without understanding the clean energy/clean environment attributes of CHP. To reduce resistance to CHP projects, CHP proponents can educate the appropriate decision makers (e.g., the Mayor's office, air quality board, student environmental groups, zoning boards) about the environmental benefits of CHP.
For example, a proposed power plant at the University of Wisconsin-Madison drew criticism from students and faculty, reported the Badger Herald. Student groups stressed that energy conservation and environmental impact concerns should come before new generation plans. Proponents of CHP could have explained to these groups that efficient CHP plants could in fact have a positive effect for the environment, especially if the new plant offset coal-fired central generation. Experts could have worked with the Wisconsin Department of Natural Resources to make sure electrical and thermal efficiencies were fully understood and given appropriate credit.
Frequently, large campuses centralize heating and cooling and have large electrical loads. Many options are available for satisfying this electrical, heating, and cooling demand. A common way is to size a boiler for the entire campus's heating load. Oil, natural gas, or coal is usually the fuel of choice for large boilers. Large facilities may be able to negotiate attractive fuel contracts that lower heating costs and may choose to oversize the boiler, enabling the use of excess steam to power a steam turbine for electrical generation or a steam-driven chiller. This cheap, on-site secondary power source (steam) may make the generation of electricity or cooling less expensive than conventional methods such as purchasing from the grid and using conventional electric chillers.
Three examples of this type of situation are at the University of North Carolina-Chapel Hill, University of Texas-Austin, and Cornell University. In each case, the universities have large boilers making steam for a variety of uses. Each campus ties the boilers to a steam turbine and the campus's heating system. The steam turbine generates electricity for campus use, reducing the dependency on the local grid and saving operating dollars for the campus. This cheap electricity also may be used to operate electric chillers for cooling, further reducing cooling costs. The remainder of the steam is used for heating of domestic water and all of the campus's office, classroom, and dormitory spaces. Steam generated by the boilers also may be used by steam-driven chillers for cooling campus living space.
The University of Iowa is consuming oat hulls--a form of biomass--to diversify its energy feedstock portfolio.
Downtown Utilities Realizing Value of CHP
Addressing the need for distributed energy systems to interconnect to the electric utility grid, and to obtain supplemental and back-up power, is critical to the success of CHP projects. Including multiple, dispersed generating and CHP units throughout the grid is a relatively new concept one that has to be incorporated into the existing technical, regulatory, and institutional framework.
In dense urban centers, like Philadelphia and New York City, urban-scale CHP is delivering local sources of power generation and valuable steam supplies to offset other electricity requirements and reduce emissions. In Manhattan, for instance, Con Edison Steam Business Unit is currently re-powering the East River Plant to add 140 MW of CHP capacity in the world's largest district steam system. Con Ed provides steam service to over 1800 buildings, including over 750,000 tons of steam-driven air conditioning in customer buildings, that displaces over 500 MW of peak electrical demand downtown.
Veolia Energy N.A. in Philadelphia operates the award-winning 170 MW Grays Ferry Cogeneration Facility and provides utility district steam service to over 400 buildings downtown, including industrial facilities, hospitals, universities, commercial offices, hotels, and large residential facilities. Since Grays Ferry began operations in 1998, Trigen has reduced annual emissions by over 74% (from 2,880 tonnes to 898 tons in 1998) while fuel efficiency has doubled. Its combined cycle plant and heat-recovery steam generator (HRSG) thermal recovery capabilities closely match with the steam demand of the steam system.
While the US utility sector has been deeply challenged in the aftermath of the Enron scandal, there is renewed interest in capital assets and infrastructure with traditional business profiles, solid investment returns and general revenue stability. Downtown district energy systems generally provide highly reliable service (99.999 is commonplace); have sizable market share under long-term service agreements and often have the advantages of scale to optimize efficiency and manage risks through fuel flexibility. In fact, IDEA member companies have reported combined customer growth averaging more than 2 million m2 of space annually each year since 1990.
Many downtown steam systems are evaluating adding power generation to achieve emissions reductions and to produce local power in response to issues like congestion pricing; grid support and consumer demands for highly reliable power. In fact, NStar in Massachusetts elected to increase CHP output at a district energy facility serving the steam, chilled water and power requirements of the densely loaded Longwood Medical Area as an alternative to an expensive urban substation in the distribution grid. There is growing recognition that diverse, distributed generating assets are preferable in terms of energy security as well.
Campus Load Growth
According to findings from a recent census for DOE, CHP systems on US campuses currently provide over 967 MW of generation, with another 675 MW in planning, consideration or construction. A university campus is an ideal application for CHP because thermal loads (heating and air conditioning) match well with power requirements and existing district energy piping systems already aggregate thermal requirements.
IDEA found that the average campus CHP system was 15 MW in size and the median system was 7.4 MW, with a wide range, from 0.18 to 85 MW installed on campuses. In the US, with over 160 institutions in the US DOE census, IDEA identified 43 million lb/h (20 tonnes/h) of 150 psig steam installed heating capacity, coupled to 4.5 million linear feet (1400 km) of piping networks. Campus district cooling systems total 900,000 tonnes of cooling capacity, coupled with 1.7 million linear feet (500km) of chilled water distribution networks. Campus cooling systems often use steam-driven chillers and are reporting substantial growth due to campus building construction.
Colleges and universities are installing CHP in response to campus load growth and a shift toward year-round operations and the growth of attendant air conditioning loads. There is potential for 472662 MW of added CHP capacity identified by the IDEA, based on average campus CHP system in its recent census, complemented by significant and steady growth in district cooling project expansion.
Airports Addressing NOx/Ozone Nonattainment
Airports are often in NOx nonattainment areas and face significant emissions pressure from both regulators and the community. With large space conditioning and electrical load with long hours of operation, airports are often well suited to add CHP to their District Energy systems.
The IDEA survey has identified 120-600 MW in airports. The Dallas-Ft. Worth (DFW) International, e.g., is investing $126 million in modernizing their District Energy plant and is evaluating development of a 120 MW CHP facility that might include plasma technology to utilize community solid waste as a fuel source. CHP at DFW International would reduce emissions in all categories, creating emissions credits to allow for further economic growth.
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