Dispatchable Energy Assets: Key Components in Microgrids
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DEPARTMENTS | MICROGRIDS + DISTRICT ENERGY |||||||||||||||||||||||||||||||||||||||||| Dispatchable energy assets: key components in microgrids Scott Yappen, Director of Business Development, Foley Power Systems Inc. ith the evolution and growth ing of nearly $200 million for CHP-centric ƥQLHRCDUDKNOHMFLTKSHOKDDMDQFXQDRHK- of microgrids, a wide variety of projects at hospitals and wastewater ience and microgrid projects, “CHP not Wdispatchable distributed ener- utilities. Funding prerequisites, such as only provides the dispatchable capacity to gy resources are now in place island blackstart capability and operation allow a facility such as a hospital to oper- in numerous applications. Combined of critical facility loads for one or more ate as normal without grid power, but the heat and power and other on-site energy weeks without utility grid power or liquid energy cost savings associated with the sources are key microgrid components fuel transportation, are aligned well with "'/OK@MSOQNUHCDSGDONRHSHUDB@RGƦNV that deliver 24/7 resiliency and availabil- M@STQ@KF@R ƥQDC"'/ that enables development of the project.” ity, and also maximize energy cost savings Existing communications, microgrid and revenue. ECONOMIC DISPATCH controls and information technologies 2HFMHƥB@MSR@UHMFR@MCNQQDUDMTD not only make integration and dispatch of IMPROVING ENERGY RESILIENCE can be extracted by displacing utility grid multiple generation sources feasible but Improving resilience is the principal power consumption. For example, highly also allow for layering of energy storage – driver for microgrid development. Utility ETDK DƧBHDMSRHLOKDNQBNLAHMDC BXBKD both electric and thermal. Where electric grid interruptions and natural disasters generation plants provide not only resil- and thermal loads justify the deployment have caused “energy resilience” to be- ience but also attractive ROI opportuni- of CHP, the opportunities for cost savings BNLDƥQLKXDMSQDMBGDCHMSGDKDWHBNM ties. Peak shaving, or temporarily displac- RHFMHƥB@MSKXHMBQD@RD SGDQDAXHLOQNUHMF The lessons of Superstorm Sandy and ing grid power during a few peak hours, the likelihood of project development. hurricanes Katrina, Irma and others have can avoid costly capacity and transmis- Utilizing this approach, campuses prompted activity at the federal level to sion charges that amount to savings of such as Princeton University have devel- push critical facilities like hospitals to $100,000-$200,000 per megawatt in NODCGHFGKXDƤDBSHUDGXAQHCLHBQNFQHC provide more power. some locations. Another opportunity exists resources, integrating CHP, gas and diesel According to Don Allik, former direc- to reduce high locational marginal pricing reciprocating engine generators, energy tor of facilities for the University of Mary- when kilowatt-hour cost elevates due to storage, solar photovoltaic technology, land Upper Chesapeake Medical Center utility grid supply and demand imbalance. demand management and more. (UCMC) in Bel Air, Md., “The only economi- This can occur during summer heat waves, Princeton’s microgrid assets include cal way to do that is through CHP, because winter freezes, central power plant in- a 15 MW CHP plant powered by a gas to install additional emergency capacity to terruptions, etc. Several other ancillary turbine with heat recovery to generate have that asset sitting there just in case is services revenue streams also exist in vari- steam, along with a chilled-water plant ultimately very expensive. With CHP pow- ous locations, and dispatching of on-site and thermal storage. At the university’s ering our daily operations, we can save generators can enable monetization of this High-Performance Computing Research money and have that additional capacity.” energy savings and revenue. Center, a CHP plant with a 1.9 MW recip- The implementation of CHP provides rocating engine generator and absorp- the opportunity to develop a highly ef- SHNMBGHKKDQB@MADƦDWHAKXCHRO@SBGDC ƥBHDMS@MCQDKH@AKDLHBQNFQHC (ML@MX “THE ENERGY COST SAVINGS ASSOCIATED 27-acre solar PV farm produces an addi- states like Massachusetts, New York and WITH THE CHP PLANT PROVIDE THE tional 5.4 MW to supplement power from New Jersey, government-sponsored ener- POSITIVE CASH FLOW THAT ENABLES the grid. The center also operates other gy programs foster the use of microgrids DEVELOPMENT OF THE [MICROGRID] energy assets including numerous emer- and CHP as the key component of clean, PROJECT.” gency generators that are dispatched dur- DƧBHDMS@MCBNRS DƤDBSHUDQDRHKHDMBD %NQ ing grid outages. example, the New Jersey Energy Resil- Utilizing its microgrid resources, ience Bank opened a program after Su- According to Gearoid Foley, president Princeton University can operate in island perstorm Sandy that has approved fund- of Integrated CHP Systems Corp., whose mode during emergencies or remain con- © 2018 International District Energy Association. ALL RIGHTS RESERVED. District Energy / Fourth Quarter 2018 57 MICROGRIDS + DISTRICT ENERGY |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| nected to the grid in order to hedge its lize absorption chillers to lower power itself’ rather than sit idle while waiting for power purchases based on real-time pric- demands by displacing electric chillers. At a rare emergency,” Borer says. es in the wholesale market. The Princeton the University of Maryland Upper Chesa- He adds, “By combining the gas en- energy team uses an economic dispatch peake Medical Center, waste heat from a gine with an absorption chiller, I can get system, combining analysis and real-time Caterpillar 2 MW generator set is utilized 1.9 MW of power and 600 tons of cool- data to determine which assets to use for to produce hot water as well as steam ing. It’s an ideal combination for the data SGDADRSDBNMNLHBADMDƥS in a heat recovery steam generator. The center.” “We look at what it costs to make the system can direct steam into absorption Multifamily residential buildings of- next kilowatt-hour, and then we look at chillers to create chilled water for air con- ten utilize CHP as a component of their the price of power from the grid. Anytime ditioning. microgrid. These plants provide winter the grid price is higher than our marginal “The byproducts of a CHP system heating, domestic hot water and summer cost to make kilowatt-hours, we dispatch L@JDHSLNQDDƧBHDMSSG@MSQ@CHSHNM@K cooling as components of the output, en- the equipment,” says Ted Borer, energy electricity,” says UCMC’s Allik. “Com- abling the buildings to be fully functional plant manager for Princeton University. bined heat and power at the hospital without the electric grid. Commercial, in- “Based on the status of the regional QTMR@SODQBDMSSNODQBDMSDƧ- dustrial, institutional, municipal and other PJM electric grid, and the real-time price, ciency (lower heating value [LHV]), much RDFLDMSRG@UD@KRNADMDƥSDCEQNLSGHR our program analyzes all the variables – GHFGDQSG@MSGDBNLAHMDCDƧBHDMBXNE for decades. including weather conditions – and tells the utility grid and boilers. Also, carbon SGDE@BHKHSHDRRS@ƤVG@SDPTHOLDMSSGDX DLHRRHNMRBNLHMFEQNL@"'/OK@MSƥQ- FUTURE GROWTH OF MICROGRIDS AND should be running and when,” adds Eric ing natural gas are much lower than with DISPATCH Wachtman, chief engineer for Princeton’s other utility options.” The deployment of microgrids is cogeneration plant. Data centers that have large thermal growing. Pro-microgrid policies and incen- needs to maintain space temperatures tives in many states are fostering future THE “H” IN CHP VHSGHMRDQUDQQNNLKHLHSRADMDƥSEQNL project design and development – through, When it comes to general building cooling-only CHP, which, through the use for example, Massachusetts’ Community design, ambient-driven HVAC loads force NESGDQL@KKX@BSHU@SDCBGHKKDQRSNNƤRDS Microgrid Program, New Jersey’s Town a designer to size equipment to meet the electric demand for conventional chillers, Center DER microgrid program and New peak operating load even though this B@MANNRSSGDDƤDBSHUDDMDQFXNTSOTS York state’s NY Prize. Whatever the objec- load only occurs a minimal amount of the substantially. In regions like the Mid- tives of the microgrid design, the deploy- time. For microgrids this problem is even Atlantic, a CHP plant with modern high- ment of dispatchable generation including greater, as the investment in equipment DƧBHDMBXQDBHOQNB@SHMFDMFHMDRODQ- "'/B@MRHFMHƥB@MSKXDMG@MBDNODQ@SHMF B@MADRHFMHƥB@MSKXGHFGDQ 4SHKHY@SHNMNE cent to 45 percent or more LHV) and ab- economics and thereby enable the devel- thermal energy storage allows designers sorption chillers can be economically dis- opment of more microgrids with resultant SNƦ@SSDMSGDCDL@MCBTQUD@MCTRD patched for approximately 20 percent to HMBQD@RDCDMDQFXQDRHKHDMBD DMDQFXDƧ- lower-capacity systems to meet the same 25 percent more hours against wholesale ciency and security. load needs. This can help optimize costs market prices than a simple-cycle plant, by spending less on equipment that @MC@RHFMHƥB@MSQDRHKHDMBD@CU@MS@FDHR works longer hours. gained by incorporating the chiller. Scott Yappen is the Microgrid designs that incorporate Princeton University has deployed director of business CHP and thermal storage provide an a CHP plant for cooling the Ivy League development for Foley DUDMFQD@SDQKDUDKNEDƧBHDMBX BNRSNO- school’s High-Performance Computing Power Systems Inc., a timization and resilience. Combined heat Research Center. The CHP plant consists Caterpillar dealer in and power in conjunction with chilled- NE@ODQBDMSDKDBSQHBDƧBHDMS+'5 New