ConEd's hybrid service model for large microgrid could become standard
The utility worked on a giant multi-use real estate project to deliver power the way developers wanted.
It's not quite Burger King, but Consolidated Edison wants customers to have it their way. And driven by new technologies, economic development, and policies from the state, large projects in New York City may have increasing control over their electricity needs.
Take Hudson Yards, the giant multi-use development in New York City that is the largest private real estate project in the United States. Under development for years, it will ultimately include more than 18 million square feet of commercial and residential space, including 4,000 residences.
The project is being designed from the ground up to be efficient, connected and cutting edge. Last month its first commercial office building received a LEED Platinum certification from the United States Green Building Council, a reflection of its sustainability. Consolidated Edison has helped developer Related Cos. to power its buildings through unique service connection architectures to facilitate a microgrid.
The utility is doing things a bit differently than it normally would, accommodating requests from Related that specify where the power is delivered. It's a "hybrid" structure that has eliminated some complicated equipment and will quicken and simplify reconnecting to the grid when Hudson Yards moves out of island mode.
Energy needs central
Tom McAndrews, section manager of Consolidated Edison's Energy Services group, said the utility developed a unique design that utilized "microgrid breakers" that are actually upstream of the utility's service.
“These microgrid breakers allow the customer to isolate and reconnect to the utility service seamlessly while a new means of communications allows the utility to continuously monitor our transformation equipment even when the customer is isolated," McAndrews said.
The development is utilizing cogeneration, gas-fired combined heat and power, along with diesel, as well as taking service from Consolidated Edison. The 13.2 MW cogen plant on the campus and another 1.2 MW of gas-fired microturbines at 10 Hudson Yards, the new office space, generate electricity and thermal energy. There are also about 15 MW of diesel generation on site, and the development's utility connections.
While Hudson Yards will not supply all of its own power, project developers say the onsite power-generation will have the "capacity to keep basic building services, residences and restaurant refrigerators running."
All of this is indicative of how energy needs are now central to planning large projects, and how developers are pushing efficiency and reliability in an effort to attract more high-tech customers. While microgrid developments are often used to achieve those aims, for Consolidated Edison, the inventive part of this project was on the grid-powered side.
"We came up with a new and different service design to make this all possible," ConEd spokesman Allan Drury said. "Our people think it could be the future standard for microgrids."
A new kind of architecture
New York's Reforming the Energy Vision process has placed emphasis on customer choice as a means to energy innovation. In this instance, Consolidated Edison largely let Hudson Yards call the shots and the result is a hybrid approach to electricity service that is generating interest.
Consolidated Edison brings six 13 kV lines up to the property line, which then go through customer-owned microgrid breakers, and then into the utility transformers “that steps it down to a usable voltage for the customer," McAndrews said.
The microgrid breaker design is new to ConEd and potentially unique, said McAndrews. "We've never used that design before," he said. Their use was the result of a "mutual agreement regarding the system's design." The breakers put the step-down infrastructure and communications inside Hudson Yard's islanded grid.
“What they can do is seamlessly go from grid-connect to independent mode, and transition back to the grid, without having to come down," McAndrews said. “We dance back and forth. That's the unique design.”
And now that Hudson Yards has paved the way, other large multi-use projects could utilize similar arrangements.
"Since the design of this, there have been several other locations interested in a similar design," McAndrews said. "This is an atypical design for us .... but this is what they asked for to meet their specific needs and we worked with them to accommodate it."
That's probably not something the utility would have done, two decades past, McAndrews conceded.
Regional remote net metering
Typically, ConEd would supply a large customer with 13 kV service and they would take it from there. But in this case, the utility provides that service to the microgrid breakers, which are customer-owned, and then to utility-owned and maintained transformers to bring the voltage down to a usable level.
The design helps to reduce the necessary equipment. A high-tension substation would be the typical design, but high tension service "involves a lot more equipment" and the microgrid breakers are simpler, working to isolate circuit breakers.
McAndrews called the microgrid breakers "kind of like a hybrid of a full high tension design."
Damian Sciano, Consolidated Edison's director of distribution planning, said serving customers with a 13kV feeder is "unusual and specific to a very large customers.
"We typically deliver the 13 kv feeders right to a single part of the premise as opposed to distributing within a very large property or development," Sciano said. "But in this case, Related asked us to work with them on this microgrid design. ... In accommodating the design, we gave them what they wanted, which was a combination of the [high tension service] but also the transformation assets at the five different locations on the property."
All of this is enabled by an "offset tariff," ConEdison offers to Related.
"Traditionally, you would have to put a generator behind each building," McAndrews said. "If four or five buildings wanted cogen, you'd have to put one in each of those buildings. But now they can put the 13 MW in one place and export it ... It's sort of like regional remote net metering.
Hudson Yards will export power from one building, which ConEd will record, and then the utility will remove that volume from meters at other buildings.
"We're permitting that at this location through a tariff provision known as the 'Offset Tariff,'" McAndrews said. "Traditionally, CHP is not a remote net-metering technology."
CHP is the big microgrid resource in Manhattan
But combined heat and power projects are the big microgrid resource in Manhattan, where real estate constraints and rooftop space mean the economics of solar are more challenging. CHP requires a smaller footprint while helping Hudson Yards attract tenants looking for a high degree of reliability.
10 Hudson Yards is headquarters to several large retail brands, along with Crescent Capital Group, Ardea Partners, Chain Bridge Asset Management and Intercept Pharmaceuticals.
"In this case, the majority of the property is commercial office space," McAndrews said. "If you're looking to court high-tech tenants, you want to promote resiliency and redundancy and backup power, and the ability to seamlessly transfer. That is definitely a selling point. There's also the economics point."
Most distributed generation customers with CHP are breaking even on the electricity, relative to simply taking utility power. "But the thermal side is where they make their gravy," McAndrews said. "If you have a 12 month thermal load, whether it's heating or hot water or even cooling ... then it seems to make economics sense."
Across Consolidated Edison's service territory in New York City's five boroughs and Westchester County, there are more than 18,000 solar projects that produce about 183 MW. CHP has far fewer installations, at 285, but provides roughly the same power, 178 MW.
More CHP projects utilizing Consolidated Edison's new microgrid breaker scheme could be in the works. "We are seeing more generation go behind the meter," McAndrews said. "There's no question that REV and the New York state goals are helping everyone think differently about how to make this happen."
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