An energy audit sought by the City of Missoula last spring has continued to advance and now carries recommendations that could cut hundreds of tons of carbon dioxide from city operations while netting future energy savings.

Doing so may require a varying degree of investment and take several years to pay off, but pursuing the recommendations would bring the city closer to its climate goals.

“There's lots of different moving parts and pieces, and some have different motivating factors,” said Reid Prison, a program manager with McKinstry. “But really, it's about building that base and adding in those bigger goals. The city has some aggressive and aspirational climate and emission goals, so we're looking at those.”

The city contracted McKinstry last March to complete an energy audit on several key facilities. The work has advanced to the point of a potential Energy Services Performance Contract, something permitted by the state Legislature.

The contract, if adopted by the City Council at some point in the future, would divert a percentage of the money the city now pays to NorthWestern Energy and invest it instead into energy upgrades.

Tim Tolman, director of McKinstry's technical and consulting services for the Inland Northwest, said it's one way the city can begin to move the dial as it looks to cut its CO2 emissions and reduce its carbon footprint.

“It's a financial delivery method for Missoula that takes the money it's presently giving to the utility, through its utility bills, and uses that money instead to pay for a project,” Tolman said. “That's money you can do other things with.”

An electric vehicle charges in a downtown Missoula parking garage. (Martin Kidston/Missoula Current file)
An electric vehicle charges in a downtown Missoula parking garage. (Martin Kidston/Missoula Current file)

Over the past year, McKinstry analyzed nine city buildings, three parking garages, outdoor field lighting and 28 city parks. Doing so consumed more than 3,300 man hours, not including time invested by city staff.

Last July, the results netted what Prison described as a “rough order of magnitude,” or estimated cost and savings based on different scenarios. That has now advanced to a pre-final list of recommendations and priorities which includes 150 line items.

In a presentation to the city's Energy and Climate Team this week, Prison cited several package examples, one of which would cut 555 metric tons of CO2 from city operations, or the equivalent of 455 acres of trees. It would cost $3.1 million to implement but require no down payment. The pay-back period would be less than 18 years.

The second package example would cut annual emissions by 751 metric tons, or 616 acres of trees. The cost of implementing that turn-key package stands at $6.2 million and would require a down payment of $1.8 million. The pay-back calculation comes to 29.6 years.

Prison said the Legislature has capped the pay-back period for an Energy Services Performance Contract to 20 years.

“But the city can chose to infuse capital and buy that down,” he said, citing the $1.8 million down payment. “If we think in simple proportions, that's about one-third of the total $6 million cost.”

The two packages were provided as samples, and Prison presented more specific figures that resulted from scoping meetings with city officials. That effort suggested a $5.5 million total budget for a turn-key project across a number of city departments including aquatics, fire, parking, the art museum, city shops and parks.

The scoping package would require a $1.5 million down payment and would cut the city's carbon emissions by 698 metric tons, or an equivalent of 573 acres of trees. The city's aquatic facilities, shops and fire represent the most costly portions of the package – each at more than $1 million – but would curb city emissions by more than 450 metric tons when combined.

Prison said improvements to Splash, for example, could replace the boiler plant with “heat pump water heaters.” Doing so would take advantage of the season in which the water facility operates.

“We've got warm ambient air temperatures, and we're using these heat pumps to take that heat in the ambient air and drive that into the water and the pool features,” he said. “It takes the place of the natural gas boilers. It's unique because of the season.”

Upgrading the city's aquatics facilities with more efficient heating and cooling systems could shave hundreds of tons of Co2 from Missoula's carbon output. (City of Missoula)
Upgrading the city's aquatics facilities with more efficient heating and cooling systems could shave hundreds of tons of Co2 from Missoula's carbon output. (City of Missoula)

The city's maintenance garage could also be a target for more efficient upgrades, including its large system of exhaust fans. The system is needed to vent the shop from toxic fumes resulting from vehicles, welding and grinding, and draw in fresh air.

But that air needs to be heated in the winter and cooled in the summer, consuming even more energy. Prison said a more efficient system can both evacuate air from inside the shop while also controlling the temperature.

“We have heat recovery systems that use the inside air and transfer it with the outside air as we're bringing in fresh ventilation, and it works both ways,” he said. “In the winter, the warm inside air will preheat the cold outside air and in the summer, the relatively cool inside air will cool off the hot outside air as we're bringing in that ventilation.”

Tolman and Prison both said the proposed project is nearing a point of decision making. Whatever the city goes with, McKinstry will contract out the work to qualified subs.

The City Council will have to approve of the project and Tolman said the work would be guaranteed.

“If we give the city a $3 million price tag for all this work and it comes in at $3.2 million, that $200,000 problem is not the city's problem – it's ours,” Tolman said. “We have a guaranteed maximum price. It's a turn-key way of doing things.”