Three-quarters of the electric buses in the City of Edmonton fleet are in the shop for repairs, but they may be there for a while.

Proterra, the manufacturer of electric vehicle parts that the city relies on, filed for bankruptcy 11 in August.

“We have faced various market and macroeconomic headwinds that have impacted our ability to efficiently scale,” CEO Gareth Joyce said.

Edmonton’s public transit system currently has 60 electric buses, according to the City of Edmonton’s website, which says the city “remains highly committed to reducing greenhouse gas emissions, providing more sustainable transportation and improving the rider experience.”