Aspen’s transformers, like the one that serves the 800 block of East Cooper Avenue, play an important role in delivering electricity that could help reduce greenhouse gas emissions. But limited space in the downtown core can make it difficult to upsize or add transformers to meet new demand.
No one ever claimed electrification would be easy, but moving away from gas power has long been seen as a key element in the city of Aspen’s goal to reach net-zero emissions by 2050.
As the city, the state and international building codes all embrace cutting greenhouse gas emissions, it has become common for contractors, including Jimmy Terui of TE Builders, to request larger electrical services on residential projects. On a recent remodel of a residence in downtown Aspen, Terui and his team calculated that they would need an additional 200 amps, for a total of 400 amps of electricity to power electric heat and appliances.
“We were going to go all-electric,” Terui said.
The plans were approved by the city’s engineering department, but the electric utilities department said the increase in electric service wasn’t feasible.
“Unfortunately, that block only has one transformer in it and it feeds everything in that block,” Ron Christian, electric superintendent with the city of Aspen, wrote in an email obtained by Aspen Journalism. “There is no room in it for more cables and no option to upsize it either.”
The city of Aspen serves as the electric utility for about 3,100 residential and commercial customers in the downtown core and surrounding neighborhoods. The utility has more than 250 transformers, and this one, which serves the 800 block of East Cooper Avenue, simply didn’t have enough space. There was no room on the property to add a new one, so Terui and his team had to backtrack.
“We had to go back and redesign our whole mechanical system,” Terui said. “We had to go back to two [gas] boilers. It was a complete redesign.”
Terui’s project is indicative of several challenges the city and communities across the country face in the effort to reduce building emissions by using electricity from renewable sources, rather than using gas, to heat homes. Even when there is a will to go electric, the way is not always clear.
Increased demand, limited space
Buildings account for 57% of Aspen’s greenhouse gas emissions, so the construction industry is of particular importance as the city works toward its emissions-reductions goals.
The current building codes in the city of Aspen were adopted in January 2023 and are based on the 2021 International Codes, a group of widely adopted and comprehensive model building codes that are updated every three years. The city made adjustments in areas dealing with energy conservation and carbon emissions reductions and aimed to incentivize all-electric buildings. Aspen requires higher insulation values and limits the percentage of glass on the exterior of buildings in an effort to reduce energy loss and make buildings more efficient. The city also set limits on exterior energy use, such as snowmelt, which isn’t required by the international codes.
In the work leading up to the adoption of the new requirements, city staff noted some of the challenges that were likely to arise.
“This increased electric demand may necessitate additional on-site transformers for existing construction with tight site constraints,” reads a September 2022 memo to Aspen City Council from the community development department. “Staff is collaborating with our utility providers, and both have said that their grids can meet the increased electric load demand but there may be challenges in keeping the grid efficient, in finding renewable energy to purchase to meet the increased load, and in maintaining affordability and equity for customers.”
City staff say there is not a shortage of electricity or storage for the power.
“The utility — we don’t see supply of electricity as a limiting factor,” said Erin Loughlin Molliconi, field operations manager for Aspen’s utility.
The utility is working to understand how to right-size transformers as demand for electricity continues to grow.
“We’re in the middle of a study right now to analyze what a fully electrified customer base would look like, to see if there’s circuit level improvements that we should be looking at,” Loughlin Molliconi said.
On average, she said, the city utility will upsize or add a transformer to meet a larger load request about three to five times per year.
As older buildings are renovated, there is often a call for more electricity even when they are not going to all-electric systems.
“It’s pretty common even for projects that aren’t trying to do electric heating and cooling but just because of their large loads with new construction that they have to upsize transformers,” said Bonnie Muhigirwa, chief building official for the city of Aspen.
In many cases, because of luxury amenities such as home oxygenation and theater-quality audio/visual systems, the amount of electricity required to power a home can double, triple or more after a remodel.
Although a 200-amp electrical service used to be fairly typical, Terui said he rarely has projects requiring under 400 amps now, and he has worked on residential projects that need up to 1,200-amp electrical service.
“Most projects we do require additional service and a lot of times an additional transformer,” said Jack Wheeler, owner of the general contracting firm The Home Group and the construction management firm Concept One Group, and former capital asset director for the city of Aspen.
Also, there often isn’t physical space to accommodate that extra infrastructure on crowded city blocks.
Transformers sit on pads measuring 5-feet square or 7-feet square. Often, they are on easements that the city acquires through the development process. Those easements require a 10-foot clearance to access the front, where there is a door, and 3 feet of clearance on the sides and back.
No infrastructure is allowed in the public right of way, which includes alleys.
“In our downtown core, where buildings are built lot line to lot line and there’s very little space, a lot of times it looks like the only solution is to have transformers in the right of way,” Muhigirwa said.
With changing code requirements and a world moving toward more electric power, Wheeler said the codes around infrastructure need a second look and creative thinking.
“Moving to electrification by ordinance is tricky because the technology hasn’t caught up yet,” Wheeler said. “It takes time for manufacturing to catch up to our vision. In that time, we need to be creatively having the conversation about how to solve the issue that’s outside the bounds of how we’ve always done it.”
In the case of infrastructure upgrades for which there is currently no space, Wheeler said the city could, for example, convert some two-way alleys to one-way, freeing up room for transformers, or it could look into subgrade vaults to house more infrastructure.
“There needs to be a new conversation,” Wheeler said.
When Aspen City Council passed the current building code, it also directed staff to create a new electrification task force to study how to move toward cleaner power, including a close look at the infrastructure that will be needed to support it.
Muhigirwa said that group has, to this point, been an internal working group of city staff from the building, utilities and engineering departments. She said the task force is looking at whether there could be flexibility around the use of the public right of way, but she also noted that those areas are meant to be clear of private property and used for safe passage.
City of Aspen staff, including chief building official Bonnie Muhigirwa and utilities field operations manager Erin Loughlin Molliconi, are looking into how to move toward cleaner power. When buildings move away from gas-powered appliances and heating systems, the demand for electricity — and the infrastructure that provides that power — increases.
Who pays the cost?
When Terui’s team requested an upgrade in electrical service at a downtown Aspen residence, he knew it would be expensive.
“It’s a unique transformer where we’re located. It serves maybe five residences,” Terui said. “It was going to be costly.”
New transformers range in cost depending on size, with the smallest running about $5,000 and the largest costing upward of $60,000. Justin Forman, director of utilities for the city of Aspen, said his department tries to keep a couple of each size in stock, because it can take up to two years for a new transformer to be delivered, thanks to delays in shipping.
The development that requests increased electrical service pays the full cost if a new transformer is needed. Forman said it is the industry standard for development to pay for upgrades to infrastructure, as well as a fee for expanded electrical service called the Electric Community Investment fee.
“ECI fees are designed and collected to ensure that development pays its own way when increasing the size of a service or connecting a new service to our electric system,” Forman said. “Without those fees, costs of expanding and maintaining our electric system for these new and larger customer service would fall on existing rate payers.”
But Wheeler points out that the additional costs for infrastructure that benefits the entire system can push people to stick to gas-powered systems that emit more greenhouse gasses.
“It shouldn’t be that the first guy pays,” Wheeler said. “It’s a disincentive.”
The city of Aspen has tried to incentivize electrification, and Muhigirwa said the task force is thinking hard about “making sure that the city regulations aren’t what’s getting in the way of people doing what they want to reduce their climate impact.”
At the time of the building code adoption, the city wasn’t ready to require electrification and has spent the past year in discussion about how to ensure that city requirements align with state and federal laws. The California city of Berkeley attempted to ban new natural gas hookups in 2019, but a federal appeals court found that legislation was preempted by the Energy Policy and Conservation Act of 1975, a federal law that gives the U.S. Department of Energy the power to set energy conservation standards for appliances.
For now, there are some incentives around electrification, but it’s not clear they are working.
Projects that are designed all-electric are eligible for expedited permit review. Muhigirwa is aware of two affordable-housing projects and one single-family home that are aiming for the voluntary all-electric path. She said there may be more projects soon, since the design process is often lengthy.
There are also rebates available through the Community Office for Resource Efficiency and state and federal programs designed to incentivize electric power.
The current building code requires what city staff call “sensible, feasible, electric-ready provisions,” including wiring for the replacement of gas stoves and clothes dryers. It does not go as far as more recent state requirements that call for making heating and cooling systems electric-ready as well.
Muhigirwa said a trial version of such a requirement led to vastly oversized electrical systems in Aspen’s unique home market.
“We felt like it was wasteful to have the electric-ready requirements for the types of homes we see,” she said. “It makes sense for smaller, typical American homes that have gas furnaces.”
To design an electric heating system that will be used in new construction is simpler than trying to replace gas boilers because the two systems can rely on different methods of heating and cooling the space. The most efficient way to heat and cool a house with electricity is through a heat pump, which requires a fundamentally different duct system than gas boilers.
In Aspen’s luxury-home market, replacing gas boilers with electric ones — which, as Muhigirwa notes, are “a really inefficient use of electric heat” — requires a huge service load.
A large, high-end home with extra amenities has “a larger electric capacity before you even get to heating and cooling,” Muhigirwa said. “Then once you add in those loads, if you have any snowmelt, pools, spas, it just exponentially raises the electricity that those homes will need to be all-electric.”
In Aspen’s luxury homes, there are opportunities to use highly efficient materials that are newer to the market and more expensive, regardless of the home’s power source.
“It’s a two-sided coin for where there’s opportunities and why there are unique challenges,” she said. “We have definitely seen that we can’t just copy regulations from other places that don’t have our same climate zone and don’t have our same luxury-home market.”
As electrification is still a rather new endeavor in the city, and because it’s difficult to replicate systems that work elsewhere, Wheeler said Aspen will have to be imaginative and innovative, at least until technology catches up with the city’s climate goals.
“I really appreciate what staff at the city and council do; they need to be forward-thinking,” Wheeler said. “But there needs to be an avenue for creative conversations that aren’t based on how we’ve done things in the past.”
