Parkland USA is pilot-testing a new thermal energy storage system to go with its "Electric Charging Destination Of The Future" (image courtesy of Parkland).

New Energy Storage In-A-Can To Balance EV Charging At Convenience Stores

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The match-making between convenience stores and EV fast charging stations may seem obvious, but there is a glitch. The electricity needed for EV fast charging can mess with peak demand, potentially hiking utility bills for the stores. Various solutions are emerging, and one of them deploys the energy storage potential of the cans, bottles, and whatnot packed into convenience store refrigerator cases.

EV Charging & Peak Demand: We Told You So!

The peak demand charge issue has been festering for a while now. In April of 2021 the Energy Department’s National Renewable Energy Laboratory published a study in the journal Advances in Applied Energy warning of just such a thing.

“As electric vehicle penetration increases, charging is expected to have a significant impact on the grid. Electric vehicle charging stations will greatly affect a building site’s power demand, especially with the onset of fast charging with power levels as high as 350 kW per charger,” the research team observed.

Shifting a building’s demand load can provide a partial or complete solution. However, the team assessed the body the research at the time and noted a significant knowledge gap.

“…many papers explore how building loads, which account for over 70% of the electricity consumption in the United States, can be shifted or shaved to improve grid operation; however, this strongly depends on the load at the building meter, which could change significantly with the addition of DC fast charging,” they observed.

In their study, the team assessed the impact of EV fast charging on peak demand at a big box grocery store, such as a Walmart Supercenter or Kroger Marketplace. They did not mince words.

“We find that an electric vehicle station has the potential to dwarf a big box building’s power demand if behind the same meter, increasing monthly peak power demand at the site by over 250%,” they said.

“Cold-climate areas paired with rate structures incorporating high demand charges are most susceptible for significant changes to the annual electricity bill, with increases as high as 88%,” they added.


Despite the pain at the meter, the researchers pointed out that big box stores are a natural fit for public EV charging stations. Some shoppers are already accustomed to filling up their cars at gas stations in big box complexes, so filling up an EV is a natural step. Big box stores are also beginning to attract EV charging stakeholders like Electrify America, EVgo, ChargePoint, and Tesla.

The researchers also note that the peak demand charge problem can’t be left to solve itself, because public charging stations play a key role in the mobility electrification movement. Public charging stations are necessary for long distance travel, and they also enable renters and others without home charging stations to own an EV.

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The Energy Storage In-A-Can Solution

Though the NREL research team found a significant difference in peak demand charges, they also found that, for big box stores, the addition of EV fast charging stations makes “comparatively little” difference in monthly electricity use.

That finding suggests that big box stores could add energy storage, on-site solar energy, or other features to accommodate EV fast charging without incurring high demand charges from the grid.

That’s all well and good for deep-pocketed big box retailers with a huge electricity footprint. The addition of fast charging stations to big box stores is a drop in a bucket, according to the NREL researchers. Smaller convenience stores need a more economical solution.

That’s the market tackled by the Colorado startup Maplewell Energy, which emailed CleanTechnica last week to draw our attention to its solution.

If you’re familiar with the use of ice to shift electricity demand in buildings, the Mapewell system will sound familiar. In an ice-based storage system, the basic idea is to make ice at night, when both demand and rates are lower. More wind-sourced electricity is also generally available on the grid at night. The ice-fed system then goes to work during the daytime, cooling the building through its HVAC system.

Maplewell applied a similar idea to the refrigerator cases in convenience stores, deploying their proprietary “JANiiT” demand management platform.

The diversified fuel and convenience store operator Parkland USA lent two of its locations, in Denver and Salt Lake City, to pilot the system.

“Using on-site refrigerators and HVAC as energy storage, the pilot was successful in dynamically balancing the buildings’ energy use and reducing peak usage,” Maplewell reported in a press release last week. “The technology used, known as thermal energy storage (TES) in refrigeration, precools canned and bottled beverages prior to an energy peak, optimizing and balancing loads as needed.”

Maplewell reported a 25% reduction in peak energy usage for a convenience store in the pilot test. The company also anticipates that the savings could go up to 42% with additional energy storage.

Apparently JANiiT is catching on. The company notes that JANiiT can aggregate energy use among buildings in a campus, in addition to managing energy in an individual building.

Energy Storage, Convenience Stores, & EV Charging

As for Parkland’s interest in the energy storage system, that’s interesting because Parkland is known as a fossil fuel retailer as well as a convenience store operator. Nevertheless, they have seen the energy transition writing on the wall.

“As EV fast charging becomes a part of our business and retailers, predictive energy management makes perfect sense for our stores,” said Jeff Bush, who is Parkland USA’s VP of Retail. “Maplewell’s software allows us to manage energy efficiently and reduce our demand charges.”

In February of 2022, Parkland Corporation also announced that plans to host the “Electric Charging Destination of the Future” and “set a new standard for electric vehicle charging and customer experience.”

Parkland kicked off the venture with a design competition administered by the EV stakeholder organization Electric Autonomy Canada. The award-winning Scotland-based architect James Silvester came away with the winning design, complete with a rooftop solar array.

Everything Is Coming Up ESG

The anti-ESG set has been blowing a lot of hot air over businesses that align with environmental, social, and governance principles. However, they are running out of oxygen, and not just on account of their inability to explain what they actually mean by “woke.”

For all their ranting, the world is moving on. Maplewell, for example, seems to be getting quite a bit of mileage out of its cans-and-bottles system. Last month, JANiiT nailed down the top slot in the “Internet of Things” category, in the Product Awards program hosted by the organization Products That Count.

If that rings a bell, you may be thinking of Products That Count founder and investor SC Moatti, known for her work at Facebook and Nokia. Moatti, who has an actual engineering degree from Stanford and not a fake one, is a founding partner of the Silicon Valley venture capital firm Mighty Capital.

Mighty Capital has been focusing on sustainable product management it is a co-sponsor of the awards program with the firm Capgemini, which has developed an AI-driven system for rooting out illegal offroading in the Mojave desert.

For that matter, Parkland is not the only legacy travel center operator on board with EV charging. Travel Centers of America and Pilot have also committed their combined 700 locations to the EV charging cause.

UPDATE: We reached out to Maplewell with a few follow-up questions, and the company replied as follows:

1. Can you describe the energy storage element in detail for us?

As noted by NREL, EV fast charging adds significant peak beyond the building load. As part of Maplewell’s solution, batteries are added behind the meter to add demand flexibility in a repeatable manner and peak shave to avoid peak demand charges. Maplewell’s Energy Management System, JANiiT, is battery, DER, and resource agnostic. JANiiT’s optimization engine is built to optimize electricity import/export across the utility meter and level peak loads.

2. Is Maplewell pilot testing JANiiT at any buildings with on-site solar?

Yes, Maplewell is piloting 3 sites with a combination of onsite solar and behind-the-meter batteries. JANiiT maximizes self-consumption of the onsite solar with the battery while dispatching during peak events.

3. Are the next two pilot locations with Parkland different from the first two — if so, how?

Yes, the next two locations feature onsite solar with a different demand profile. One is an office with an attached warehouse. The second is a light industrial environment with pumps and storage tanks.

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Image: Award-winning EV charging station courtesy of Parkland.

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Tina Casey

Tina specializes in advanced energy technology, military sustainability, emerging materials, biofuels, ESG and related policy and political matters. Views expressed are her own. Follow her on LinkedIn, Threads, or Bluesky.

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