Con Ed And First Student Bring Solar Microgrid To New York – CleanTechnica

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Con Ed (Con Edison) is the utility company that services most of New York City and surrounding communities. Looking into its crystal ball, it sees the need to charge about 10,000 electric school buses a decade from now. While those buses seldom travel very far each school day, servicing 10,000 of them could put a substantial strain on the Con Ed electrical grid. First Student, one of the largest school bus operators in New York City, also sees a large increase in the number of electric school buses in its fleet coming, and is concerned that those buses may not have enough charge in their batteries to perform their duties as required.

Recently, Con Ed and First Student started a trial program that will use solar panels to supply some of the electricity needed for those electric school buses. Assuming each bus has at least a 100 kWh battery, that translates to 1 GW of storage for the fleet. That’s a lot of storage capacity that can be used to support a dedicated microgrid for those electric school buses. The economic advantages are self-evident. Con Ed would not have to build new generating capacity and transmission infrastructure to support the bus fleet, and the buses could provide grid stabilization services to Con Ed. The result? Everybody wins, especially the students who do not have to breathe in a miasma of diesel fumes every day as they travel back and forth to school.

The joint Con Ed/First Student $9 million pilot project in Brooklyn is starting small. According to Canary Media, there are four battery electric school buses that are part of the trial, with 12 more expected by the start of next school year. Today there is a 500 kilowatt solar array and a 2 megawatt-hour battery onsite, as well as solar panels on some of the buses themselves. Con Ed expects the combination of onsite clean power and smart charging will help keep grid stress and costs in check at EV charging depots across New York City and surrounding communities.

A Microgrid Grows In Brooklyn

All the assets at the site in eastern Brooklyn — buses, solar panels, and batteries — can modulate when they pull power from the grid, as well as send power back to the grid when the utility needs it. “We really think what we’re learning with these buses is something we can scale up, not just with school buses but with any fleet in our territory,” Roy Rada, Con Ed’s manager of EV demonstration projects, told Canary Media. ​“We think school buses are a first mover.” They are an ideal target for vehicle-to-grid services, Rada explained, because they operate on daily schedules that are set well in advance and seldom vary. In addition, during most hours of the day, they are parked and plugged in, especially in the summer.

That means bus operators like First Student can pick and choose when to charge the buses to avoid putting strain on the electrical grid. They can also opt to discharge extra power stored in the batteries of those buses during hot summer evening hours when New York City electricity demand tends to peak. Similar electric bus V2G projects are being launched in multiple states, including California, Colorado, Illinois, Maryland, and Massachusetts. Con Edison forecasts that grid demand from electric buses, trucks, and other commercial vehicles will add up to more than 100 megawatts by 2030, Rada said. Being able to control when those vehicles charge, or tap their spare capacity to relieve grid stresses, could be quite valuable.

Beyond system-wide impacts, individual charging depots can add megawatts of new electric load concentrated in discrete pockets of an already congested urban grid. In fact, local grid congestion initially led First Student to start searching for onsite power resources that could replace electricity from Con Ed, said Kevin Matthews, First Student’s head of electrification. “We’re looking at a depot that has its own challenges, and Con Ed has its own challenges getting electricity to us.” With the new pilot project, ​“we’ve figured out a way to resolve that.” Solar and batteries at the site were an obvious first step, Matthews said.

First Student Embraces Solar Panels

First Student is adding a novel twist — solar panels on top of the school buses themselves. At 4 kilowatts of capacity per bus on six of its buses, those panels won’t provide that much of a boost, Matthews said. Yet they do represent an interesting experiment in how to deliver extra solar power not just to bus batteries but — through the bidirectional chargers — to the microgrid at the bus depot. All these systems will be integrated with Con Edison’s grid operations via software, he said.

First Student and the utility haven’t yet picked which combination of software they will use to manage onsite charging and grid requirement. There are several companies that provide those software services. All those technologies do add costs compared with simply plugging into the Con Ed grid and calling it a day. But as the number of electric school buses grows from a few dozen today to thousands ten years from now, microgrids that are supported by the batteries in electric bus fleets will become more cost-effective, Matthews said.

He added that First Student is working with dozens of school districts across the country that have received federal electric-school bus grants and rebates and is using other techniques to cut the cost of EV charging systems. One example is the ​“trenchless” system used at the Brooklyn bus depot, which encases power conduits in hardened above-ground structures to avoid digging trenches in concrete and asphalt. That approach, which First Student developed and which has been mirrored by other companies, reduces construction expenses by about 30 percent compared with a trenched deployment. It also allows the company to reconfigure its power cabling layout in the future at much lower expense.

Managing Grid Demand

Utilities and EV fleet charging developers are eager to find ways to bring down the cost of integrating electric vehicles into their grids. Already, the fast growing demand for charging power is overwhelming available grid capacity in California, which has the country’s most aggressive vehicle electrification mandates. Similar issues are cropping up in New York City. New York state is not far behind California in its EV ambitions, with school buses a particular target. State law requires all school buses sold in New York to be zero-emissions by 2027 and calls for a complete conversion to zero-emissions school buses by 2035.

Con Ed offers incentives to reduce the cost of connecting medium- and heavy-duty EV charging hubs to the grid through a pilot program that is expected to expand into a full-scale program in the coming years, Rada said. It also offers special charging rates to customers who charge during times when grid demand is low and avoid charging when it’s high. But the sheer scale of the EV charging load coming onto the Con Ed grid will take a variety of strategies to manage, he said.

A significant portion of the costs that utilities incur on their grids results from upgrading them to deliver power during the relatively rare number of hours per year when electricity demand peaks. Utilities pass on those upgrade costs to their customers at large. If investing in solar, batteries, smart EV charging, and microgrid controls can reduce the need for some of those grid upgrades, that could be a win not just for EV charging hubs but for utility customers as a whole, Matthews said. The primary goal of this pilot project is to determine ​“what avoided cost the utility will have on the customer side of the microgrid,” he said, ​“and what avoided cost the fleet operator will have by being able to assist the utility.”