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Durango’s electric school bus is like a huge battery on wheels

Vehicle-to-grid technology will save District 9-R on fuel and maintenance
Dominic May, energy resource program architect with La Plata Electric Association, checks the charging levels for Durango School District 9-R’s electric-powered school bus at the bus barn. (Jerry McBride/Durango Herald)

Durango School District 9-R acquired an electric school bus that is the first of its kind to be implemented in Colorado and among the first in the nation, according to La Plata Electric Association.

The bus, which emits zero fuel emissions, is battery powered and can discharge kilowatts back into a power grid when done with its route. It is expected to save the school district thousands of dollars in maintenance costs annually.

It hit the streets for its first official route Tuesday afternoon.

Superintendent Karen Cheser said the district anticipates saving about $5,000 a year on fuel costs alone. But fuel isn’t the only cost-savings the 81-seat electric bus will bring to the school district.

The electric bus will save the school district money by requiring less maintenance and will reduce potential impacts to children’s health linked to diesel fuel emissions such as asthma attacks, respiratory illness and cancer by eliminating those emissions entirely while shrinking the school district’s carbon footprint.

The bus’s route covers about 75 miles daily and includes Escalante Middle School, Florida Mesa Elementary and Florida Road, although it could also be used for field trips, sports events and other such activities.

A school bus typically travels about 20,000 miles per year. Eventually, that travel is going to require vehicle maintenance. With an electric bus, there are myriad common problems that are missing from the equation (and the budget).

Because the bus lacks a diesel motor, there is no need for 20 quarts of oil every 5,000 miles or so; no fuel filters that need to be periodically replaced; no multispeed transmission.

Community members were introduced to Durango School District 9-R's new electric-powered school bus last month. The 81-seat bus can discharge kilowatts back into a power grid when done with its route. (Jerry McBride/Durango Herald)

The electric bus’s 155-kWh lithium ion battery has a projected life span of 20 to 23 years, or 25,000 to 50,000 dispatches. It charges best at around 80% charged and 30% charged – charging or discharging it at the far ends of that scale can be damaging to the battery.

“The worst-case scenario is it doesn’t discharge at the speed we think it does or it has a glitch, but it isn’t going to burn or blow up or anything like that,” said Dominic May, LPEA energy resource program architect. “It’s quite safe.”

The electric bus is rated with a travel range of 200 miles on one charge, although weather conditions can affect its real operational distance. In conditions such as what Durango has experienced through much of December, with rain, freezing temperatures and snow aplenty, the bus has a range of 110 to 120 miles.

Because the bus lacks a diesel engine, the battery is the primary source of heat. The bus can be preheated by turning it on while it is still plugged in, but electric vehicles in especially cold climates can expend up to 30% more of their charge than in moderate conditions.

The bus can charge to 100% power over about three hours and is planned to discharge back into the grid over two hours.

Durango School District 9-R was one of just eight grant recipients out of 38 applicants.

Dominic May, energy resource program architect with La Plata Electric Association, checks on the charging levels on a Durango School District 9-R electric-powered school bus at the school bus barn. (Jerry McBride/Durango Herald)

The school district was awarded $328,803, which it applied for jointly with LPEA, for the electric bus plus accompanying charging infrastructure.

LPEA is also contributing an extra $120,000 to cover electric charging infrastructure and bus costs.

The grant was funded through the Regional Air Quality Council ALT Fuels Colorado program, which strives to improve Colorado’s air quality by removing barriers to alternative fuel vehicles, including fully electric and renewable natural gas fleet vehicles.

The vehicle-to-grid technology behind the school district’s electric bus

The new bus isn’t your typical electric vehicle; instead, it has bi-chargable technology, according to representatives of LPEA.

Bi-chargable vehicle technology is that which cannot only intake kilowatts but can also discharge them back into a power grid using vehicle-to-grid (V2G) technology provided by Nuvve Holding Corp. That V2G technology allows vehicles such as the school district’s new electric bus to match power demand with available supply by returning power to the grid or adjusting its charging rate.

LPEA CEO Jessica Matlock called the implementation of vehicle-to-grid technology in the school bus “monumental” for Southwest Colorado and the United States.

Matlock said she spoke with the Department of Energy’s deputy secretary of the environment over the phone to brief her about LPEA’s and Durango School District’s electric bus project. She even hinted that the electric association might partner with the school district on more electric buses in the future.

Durango School District 9-R has a new electric-powered school bus. The 81-seat bus looks like others in the fleet, but a sign on its side announces the bus’s electric capabilities. (Jerry McBride/Durango Herald)

Matlock described the electric bus as a “battery” for the electric association. When fully charged, the bus can discharge enough electricity to power 30 homes for up to two hours.

“When we come back and plug it in, it’s going into our battery and we’re saving money,” Matlock said.

The plan is to charge the bus during hours that power is inexpensive and to discharge remaining power after routes during high power usage time periods, feeding energy back into LPEA’s power banks. Matlock described the process as a “win-win situation for all of us.”

May said the electric bus can discharge 60 kilowatts – the average single-family home typically draws only about 2 kilowatts when running.

“The idea is we basically tow 9-R,” he said.

Durango School District 9-R’s new electric bus hit the road for an official route on Tuesday afternoon. (Jerry McBride/Durango Herald)

When LPEA is about to peak in energy consumption, it will contact 9-R and ask it to dispatch the electric bus. May said this action plan will shave off Tri-State Generation and Transmission costs “significantly” while reducing the electric association’s carbon footprint.

This bi-chargable technology allows the school district to purchase power at notably cheap rates. May said LPEA’s rate to the district for fueling the electric bus is only about 2 cents per kilowatt hour because the bus will charge only during off-peak power consumption hours.

May said he hopes the project emphasizes that more advanced charging technology is worth the costs and efforts, and that it helps punctuate the potential of vehicle-to-grid bi-directional charging technologies.

“At any rate, I think this is a really exciting pilot for that,” he said.

LPEA is the first in the state to try out this technology with school buses and said it is among the first in the nation.

On Dec. 16, LPEA and the school district successfully initiated the second ever discharge – at least in the Four Corners, May said – from a vehicle back into the power grid. The first test had been conducted just five days earlier. May assured the test was safe and absolutely explosion-free, although he did lament the lack of oscillating science-fiction sound effects.

cburney@durangoherald.com

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