Sustainable Transit at Altitude

At 7,891 feet above sea level, Aspen, Colorado – popularly known as “Ski County USA” – receives heavy snowfall and attracts thousands of visitors each winter. But with world-class ski slopes comes a challenge: traffic congestion and limited parking threaten both the visitor experience and the pristine environment that makes Aspen so iconic.

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To reduce emissions and limit the number of cars on the road, the City of Aspen and the Roaring Fork Transportation Authority (RFTA) provide free, year-round bus service between Aspen and Snowmass Village, as well as regional routes that connect communities between Aspen and Glenwood Springs. Their 42-bus fleet currently includes eight battery-electric buses powered by ABB E-mobility charging technology, ensuring that public transit operates reliably throughout the valley.

A Depot Solution Built for the Slopes

Operating electric buses at Aspen’s high-altitude, mountainous terrain is no small feat. The Ruby Park Transit Center in downtown Aspen—the main transit hub for RFTA services—required charging infrastructure capable of supporting high-frequency service, particularly during the busy winter months when weather conditions are most extreme. RFTA chose ABB E-mobility technology for its proven reliability in challenging environments and its flexibility in catering to both overnight depot charging and rapid opportunity charging.

RFTA’s zero-emission bus service became operational in 2019 with the electrification of the RFTA-owned Aspen Maintenance Facility and the deployment of eight battery-electric buses. Here, four HVC150 power cabinets power eight CCS1 outlets, delivering up to 150 kW to buses charging sequentially overnight. In 2026, the charging capacity will increase by four more CCS1 outlets, bringing the total charging capacity to 12.

Opportunity Charging that Meets Regional Demands

The success of the first electric buses led to a funded charging infrastructure expansion by the City of Aspen, RFTA, and a Colorado Department of Transportation (CDOT) Faster Grant. In the Spring of 2025, a 450 kW Stemmann pantograph was installed at Ruby Park Transit Center to provide fast charging between trips. This investment directly addresses one of the primary challenges of battery-electric buses on RFTA’s long regional routes—range—particularly for routes that extend over 60 miles one way.

With pantograph opportunity charging in place, electric buses can reliably meet the demands of all-day service without needing to return to the maintenance facility for charging. Today, RFTA’s electric buses serve the Snowmass Village to Aspen routes and run valley-wide on RFTA’s Bus Rapid Transit route between Aspen and Glenwood Springs. Looking ahead, RFTA will install a second 450 kW Stemmann pantograph in West Glenwood Springs to further support electric bus operations between Glenwood Springs and Aspen.

ABB E-mobility Infrastructure at a Glance

Aspen Maintenance Facility: Four HVC150 depot units powering eight CCS1 outlets for overnight charging.
Ruby Park Transit Center: One 450 kW Stemmann pantograph for opportunity charging.
Glenwood Maintenance Center: Four HVC150 depot units powering four CCS1 outlets.

2026 Expansion

Four more CCS1 outlets at Aspen Maintenance Facility
One 450 kW Stemmann pantograph for opportunity charging at West Glenwood Transit Center
Four more CCS1 outlets at Glenwood Maintenance Center

Keeping Aspen Winters White

With 11 more battery-electric buses arriving in 2026, RFTA is making strides towards its Climate Action Plan and the goal to reduce fossil fuels by 50% by 2030 and 90% by 2050.

For Aspen, protecting winter means protecting its economy, environment, and identity. Groups like Protect Our Winters (POW) champion these efforts, recognizing that every ton of CO₂ avoided helps keep ski seasons operational for generations to come. With ABB E-mobility’s charging infrastructure, RFTA sets a new standard for electrifying public transit at altitude without compromise.