An electric tugboat docks in San Diego

The nation's first zero-emissions, all-electric tugboat called eWolf has arrived in the Port of San Diego.

Why it matters: A major environmental milestone for the maritime industry, this vessel is part of city and state efforts to reduce greenhouse gas emissions and improve air quality for local residents.

Zoom in: The eWolf, which will guide and tow cargo ships, will be powered by a shoreside charging station that uses a mix of solar and electric-grid energy.

• The charging station is set to be complete in April, and the tugboat is expected to start running later this spring, according to Crowley, the logistics, marine and energy solutions company that built the vessel.

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