Chelsea DeArmond jokes that her business, which sells vintage vacuum tubes to musicians and audiophiles, specializes in "trailing edge technology."

But the East Sider who is part of St. Paul 350, a grassroots group committed to ending fossil fuel pollution, said she gets pretty amped about the eco-friendly technology that the capital city and its development arm are contemplating for the former Hillcrest Golf Club redevelopment.

"I'm very excited about several aspects of Hillcrest," DeArmond said. "The biggest is that the Port Authority and the city are committed to making it carbon net zero. It would be the only one in the country."

Tasked with transforming 112 acres of polluted old golf course into a bustling new neighborhood boasting 1,000 jobs and 1,000 units of housing, officials insist they can make it carbon neutral as well. Combining rooftop solar arrays, a geothermal heating and cooling network, energy-efficiency and electric vehicle charging stations, planners at the St. Paul Port Authority envision something quite unique: This site at the city's northeast corner would be the nation's first made-from-scratch, carbon-neutral, mixed-use development.

Monte Hilleman, a senior vice president at the Port Authority responsible for redeveloping brownfield properties, said the plan is decidedly "aspirational." But he also said that 18 months of studying the necessary components to become carbon neutral has shown "none of them seem to be dead ends."

Offering a combination of financial incentives that could help pay for cutting-edge technology in seven to 10 years instead of 20 to 25, Hilleman said Hillcrest would be able to attract the kinds of businesses that thrive on being green. Any financial package would likely require a combination of philanthropy, federal, state and local funding — including bonding, or borrowing, authority — that will need to be determined as the site's master plan gets finalized by next spring.

Most of all, Hilleman said, creating a green Hillcrest will take a commitment by leaders to make it happen.

Removing the footprint

What does it mean to be carbon neutral?

Everything that produces carbon dioxide — from driving your car to heating your home — makes up your carbon footprint. "Carbon neutral" means cutting net carbon output to next to nothing and offsetting what remains through alternative production.

Tony Poole, business agent for Steamfitters Pipefitters 455 — which owned Hillcrest before the Port Authority bought it — said the union recently converted its 100,000-square-foot training center from standard air conditioning to an enclosed system that uses groundwater to chill coolant.

"It's free air conditioning," he said of the system that saves $26,000 a year and will pay for itself in less than eight years. A similar geothermal system could work for Hillcrest, he said.

"Obviously, they would have to do some studies," Poole said. "But what we did here is going to take off."

Russ Stark, St. Paul's chief resilience officer, said Hillcrest's carbon neutral goals are ambitious but doable.

"There have been carbon-neutral buildings, both here and abroad. But it's a little more limited when talking about larger development areas," Stark said. "It's an exciting proposition to really push forward to this place where we all realize we're going to have to get to."

Building design — from energy efficiency to how they are heated and cooled — makes a huge impact, Stark said. In St. Paul, building energy use accounts for 60% of greenhouse gas emissions. Building an entire development to be carbon neutral won't be cheap, he said, but it would put a dent in the city's carbon footprint

Key to getting it built will be reducing businesses' upfront costs, Stark said, adding that the public sector "has a part to play in this" with tools such as federal infrastructure aid, federal and state grants and state bonding. When asked about the city's role, Stark said: "I think we are really interested in trying to make this happen and pulling the tools together. We cannot do it all, but maybe be a part of the solution."

St. Paul's ambitions are part of a growing trend around the world, as cities from Amsterdam to Yokohama are forging plans to become carbon neutral. Many of those look anywhere from 10 to 30 years into the future. According to the Carbon Neutral Cities Alliance, which highlights 22 urban plans at its website, a number have begun designing districts that combine engineering, transportation and alternative energy — such as river or solar power — as pilot projects or first steps in getting there.

Glasgow, Scotland, is working with the University of Strathclyde to create a climate-neutral area within the Glasgow City Innovation District. Between 2006 and 2018, the city cut emissions by 37%.

In Helsinki, Finland, officials are transforming Kalasatama, a brownfield district, into a "smart & clean" neighborhood. The area, now home to 3,000 people, will by 2035 house 25,000 residents and host 10,000 jobs.

Rachel Finazzo Doll lives a couple of blocks from the Hillcrest site. The board member for Greater East Side St. Paul district council and the Hillcrest Community Advisory Committee said transforming Hillcrest into a model eco-friendly redevelopment "makes us a model for these kinds of things. Ultimately, [Hillcrest] being carbon neutral is a great role."

In a way, though, having manufacturing jobs and housing on the same site is a throwback to the days when St. Paul neighborhoods grew up around major employers like 3M and Whirlpool. Having residents walk to work is another green idea she supports. Her family is a single-car household.

"I think [carbon neutral] generates interest in the East Side of St. Paul, which is a really important thing," Finazzo Doll said.