Solar & Battery Storage For Charging Electric Trucks Lead The Way Toward A Blended Grid

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There was a time not so long ago when if you needed electricity, you called your local utility company and they would build the infrastructure necessary to supply it. If that meant building a new generating station, new transmission lines, or new substations, well, that’s what they would do. The secret sauce that makes investor-owned utilities work is that, in exchange for being granted a monopoly, they are guaranteed a fixed rate of return on their investments. The more stuff they build, the more money they make. That model has worked reasonably well for generations, but as more electric trucks go into service, they cannot wait three to five years for the new infrastructure to materialize. That’s when solar and battery storage become part of the equation, says Canary Media.

But adding solar panels and large-scale energy storage batteries throws a curveball into the traditional relationship between utility companies and their customers. Now those customers are in a position to send some electricity back to the grid when asked and to avoid drawing power from the grid when time of use tariffs make it most expensive. The result is a blended grid with some generation and storage capacity at the margins. That change requires rethinking the relationship between utilities and their customers.

The vast majority of the goods that enter the Unites States each year arrive at ports on the west coast, especially those in southern California. Diesel engines unload the containers, move them around inside the port, and haul them to distribution centers inland, where they are sorted and put on other diesel trucks to be distributed across the country. The problem is, there are so many diesel engines involved in the process that air around the ports and the highways leading inland is hazardous to human health, It is not always about carbon dioxide emissions. Diesel engines spew large quantities of nitrogen oxides and fine particulates matter into the air, pollutants that are associated with a myriad of human health risks. The push for more electric trucks is driven as much by a desire not to poison people as it is by not wanting to contribute to global heating

Charging Electric Trucks Is a Challenge

California is strongly encouraging replacing diesel trucks with battery-electric models, but fleet operators are finding their local utility companies are unable to supply the electricity they need when they need it at prices they can afford. Most utilities add so-called demand charges that bill customers for the cost of upgrading the distribution system so there will be sufficient electricity available to meet the highest possible demand, even it if only lasts for a few minutes a day or only once a month. Those demand charges can double or triple the cost of electricity, making the transition to electric vehicles economically unsound. Trucking companies in California are finding it is faster and cheaper to build to build their own microgrids with solar panels and battery storage than to wait for grid upgrades and pay those demand charges.

There is a downside, however. Trucking depots in urban areas may not have enough land available to install all the solar panels they need to charge their electric trucks. The result is some are using methane-powered generators to power their battery storage units. That will make some readers frown, but there are still benefits. Although far from ideal, it represents a step in the right direction and does allow the trucks to operate on electrons instead of molecules.

Whether methane-fired microgrids fit with California’s carbon reduction and air quality regulations is far from clear, said Tim Victor, associate director of eMobility at Scale Microgrid Solutions. His company is building a microgrid for Quality Custom Distribution in La Puente, California, that will combine 1.45 megawatts of rooftop and carport solar with 3 megawatt-hours of battery storage to cover most charging needs, as well as power needs for the site’s refrigerated warehouses. Scale also included a 1.5-megawatt methane-fired backup generator that will only operate during grid emergencies. The project is ​“supposed to save them money in the first year,” Victor said, and will also allow the site to charge more of the 30 Volvo electric trucks it’s deploying than its current grid connection would allow.

California regulators have made some allowances for on-site generators to run during grid emergencies, despite the state’s stringent local air-quality mandates. But it’s less clear how regulators will deal with newly built projects that plan to rely regularly on running methane fired generators, he said. “I’ve heard both sides of the equation from customers,” said Victor. ​“Some say, ​‘All we care about is getting the trucks on the road.’ Others say, ​‘If we care about our sustainability goals, we can’t just replace diesel with natural gas.’” Companies choosing the methane-fueled on-site power option contend that they offer a better alternative to leaving truck charging sites in grid limbo, which will result in years-long delays in replacing diesel trucks with battery-powered trucks.

The largest truck charging hub in California is the Prologis and Performance Team warehouse on Denker Avenue near the ports of Los Angeles and Long Beach, which combines 6 megawatts of methane-powered generators and 18 megawatt-hours of batteries to charge the 96 electric trucks that use that facility. The microgrid allowed it to open in May of 2024, several years before the Los Angeles Department of Water and Power could expand the grid to serve its needs. And the benefits go beyond speed. ​

“I’m looking at numbers that are very attractive compared to getting service from a utility,” said Henrik Holland, global head of Prologis Mobility, the subsidiary that installs and manages EV charging for its customers. “It makes a lot of sense to put generation and storage at the grid edge. We’ve been talking about it for 20 years, how the energy system is going to change from centralized to distributed, and be more bidirectional, EVs are the use case for this stuff. You’re dealing with very peaky loads, with time-of-use issues, with resiliency issues, because these trucks can’t be stranded when the grid goes out.”

Controlling Costs Is Key

Resiliency, along with charging costs, was a motivation behind freight operator NFI Industries’ decision to install a 1 megawatt solar array and 7 megawatt-hours of batteries at its Ontario, California, warehouse. That microgrid, set to be turned on later this year, will help supplement grid power for the 50 Volvo and Daimler electric big rigs that will be charging at the site. NFI was lucky enough to have ample capacity from Southern California Edison’s grid for its Ontario site, said Jim O’Leary, the company’s vice president of fleet services. But it wanted to make sure that it could keep charging trucks in the event of grid outages, he said.

That source of backup power can also shave costs during normal operations. High voltage chargers for electric trucks can trigger expensive demand charges. A microgrid can help keep those spikes in check and avoid those fees. The Ontario microgrid can also help NFI avoid paying the high time-of-use rates that California utilities impose during afternoon and evening hours when the state’s grid is under maximum stress, O’Leary said. Similar concerns about utility power costs have led a growing number of EV charging sites to install batteries to cushion their peak demands on the grid.

A question that cannot be answered fully at the moment is how utilities will choose to work with charging hubs for electric trucks that want to supply their own on-site power. Pacific Gas & Electric and Southern California Edison are developing programs that will allow large customers to use more power at times when grid capacity is available, in exchange for agreeing to throttle power use when capacity is strained. As long as flexible interconnection customers stay within the agreed limits on how much power they draw from the grid, it doesn’t really matter whether they do it by curtailing their charging loads or using their own on-site solar, batteries, or generators, said Alex Portilla, PG&E’s director of grid edge innovation.

Victor of Scale Microgrids agreed that ​“flexible interconnection is a huge path forward. It’s a way for a utility to get access to a certain amount of energy consumption and still meet the needs of that customer. The way I always pitched this when we started having conversations with utilities is to make sure they understand our goal is not to never come to you for more power, but to make it easier for you to plan this out,” he said. Outside of a handful of projects under the ongoing flexible interconnection pilot programs, ​“that conversation hasn’t progressed past the theoretical, but it seems to be generally welcomed.”

What’s needed, said O’Leary at NFI, is clear direction from California utility regulators on how to standardize these kinds of cooperative approaches, to provide fleet operators like NFI more certainty in their planning. “The most important thing from the fleet perspective, when we’re deciding when, where, and how we’re doing these projects, is to look at the total cost of ownership. We have to know how much it’s going to cost us to run that fleet,” he said. ​“The sooner the fleets have that information, the clearer our decisions can be and the clearer our conversations with customers.” Clarity is precisely what is needed for all business decisions and is precisely what is lacking at the federal level at the moment.