- LEED Gold CERTIFIED
- Energy Star rating of 77
- Demand response system
- Headquarters of one of the largest and most successful hotel chains in the world
- 900,000 square feet
- Earned $51,000 in 2011 from demand response
Founded in 1927, Marriott International is one of the largest and most successful hotel chains in the world. Its 3,150 properties extend across the United States and into 68 other countries and territories, putting annual revenue in the tens of billions each year. Marriott’s quest to extend its portfolio of green properties included the first LEED CERTIFIED hotel in the United States. Its International Headquarters, certified LEED Gold, located in Bethesda, Maryland, was built in 1977 and offers 900,000 square feet of space for the hundreds of Marriott associates who work there.
“Over the last 20 years, the system functioned exactly like it was supposed to and has been extremely reliable. Marriott, like most businesses in this economic climate, is always looking for new initiatives to save money and energy. Once we found out about CALMAC’s technology, it was an easy decision with a great payback," said Pete Carrino, manager of plant operations at Marriott International Headquarters.
In 1992, Marriott began making energy efficiency upgrades to the headquarters after receiving an energy grant from PEPCO, the local electric utility company. One of the improvements targeted the building’s outdated cooling system. Today the cooling system continues to operate but is controlled as a demand response system.
The sheer size of the facility made maintaining occupant comfort levels a costly task. The electricity load required to cool an office building with nearly one million sq. ft. of space is quite large. As is the case with most office buildings, much of the energy use is during the day, when demand on the electric grid is high. Marriott’s cooling system was drawing energy during the most expensive time of day. But the challenge for Marriott executives is one many building owners and managers face – how to reduce energy consumption and cooling costs while maintaining occupant comfort. Key areas of focus included enrollment in demand response energy reduction and electricity incentive programs.
Marriott enlisted the help of CALMAC, a leader in energy storage systems, to help provide a solution for the building’s cooling needs. In 1992, Marriott installed CALMAC’s IceBank® energy storage tanks to decrease energy use during peak demand hours, when the cost of electricity was more expensive. The tanks produced ice during off-peak, night hours and used it to cool the building the next day.
Later, in 2007, Marriott officials implemented the CALMAC tanks as a demand response system at the suggestion of its manager of plant operations and maintenance. This allowed the building to shift its electricity consumption in response to price signals from the utility provider or when the electric grid became stressed with more demand than supply. By burning ice during select times, Marriott shifted its energy demand without sacrificing the comfort of the occupants inside the building.
“Over the last 20 years, the system functioned exactly like it was supposed to and has been extremely reliable,” said Pete Carrino, manager of plant operations at Marriott International Headquarters. “Marriott, like most businesses in this economic climate, is always looking for new initiatives to save money and energy. Once we found out about CALMAC’s technology, it was an easy decision with a great payback.”
Prior to deregulation in the PJM electric market, when electricity was more expensive during peak daylight hours and less expensive at night, CALMAC’s IceBank thermal energy storage tanks allowed Marriott to shed electric loads when they were most costly. When Maryland passed electric deregulation legislation in 1999, eliminating the electric energy price differential between on peak and off-peak times, CALMAC’s storage tanks were idle until Marriott officials decided to use them as a demand response strategy.
“We burn ice at strategic times throughout the day when it’s beneficial to shift the electricity load. Without CALMAC, we wouldn’t be able to do this and take advantage of the demand response program to the extent that we are now,” said Pete Carrino, manager of plant operations.
In 2007, they elected to enroll in both mandatory and voluntary electricity load shedding with PJM Interconnection, the regional electricity provider. Marriott responded to explicit requests to shut off power when PJM needed it most. To compensate, Marriott transferred its cooling needs to its energy storage plant, which used stored energy. The stored energy was ice made at night and stored in the tanks, which was then used to cool the building when called upon. Even though the building operators responded to requests to reduce demand to help the grid, building temperatures remained consistent and occupants remained comfortable during a demand response.
Marriot’s ability to shed peak electric loads by tapping stored energy instead of relying on standby generators when the electricity grid was stressed prompted PJM Interconnection to offer incentives to Marriott based on the amount of electrical load shed. Building operators were able to time-shift, or store excess nighttime energy in the form of ice, for use at peak times. The mutually beneficial relationship removed some of the burden from PJM’s grid. As a result, PJM has compensated Marriott more than $200,000 in incentives for its efforts over the last four years.
“We burn ice at strategic times throughout the day when it’s beneficial to shift the electricity load,” Carrino said. “Without CALMAC, we wouldn’t be able to do this and take advantage of the demand response program to the extent that we are now.”
The facility ultimately earned the second-highest LEED rating possible: Gold. The building has also received an Energy Star rating of 77 for the past three years and consistently ranks in the top 25th percentile in the U.S. for energy efficiency when compared to buildings of similar size, age and purpose.
Overall, CALMAC IceBank thermal energy storage tanks have proven to be an effective and relatively inexpensive way to not only cool Marriott International Headquarters, but also a flexible investment for the future. The hotel giant continues to make additional returns on an installation that occurred two decades ago, which was paid off shortly thereafter, way before deregulation took effect. So even as technology and rate structures change and incentive programs are modified, Marriot reaps large benefits.
“A building without energy storage is a building that isn’t prepared for the future,” said CALMAC Chief Executive Officer Mark MacCracken. “Marriott’s International Headquarters is a testament to that. They installed the ice tanks and were able to take advantage of the changes in the electric markets, namely demand response.”
Despite challenging times during deregulation, changes in electricity regulations and new incentive programs are breathing new life into energy storage. “In 2011 we’ve earned another $51,000 from demand response,” Carrino said. “That’s what CALMAC’s ice system has done for us.”
Running today’s commercial buildings can be a costly expense for business owners and property managers. A cooling system that can be used for demand response is a relatively small investment when the result is years of savings on utility bills and incentive programs from power distributors. In order to optimize energy storage use at buildings, various strategies and pricing options from utility providers must be compared. Time of use rates may still be a more cost-effective option in many electricity markets. Off-peak energy is typically half the cost of on-peak energy and incentive programs vary from region to region.