Neckarsonne – Heidelberg’s Big Solar Catamaran

The solar ship Neckarsonne on the Neckar in Heidelberg with the old bridge behind

Heidelberg is one of Germany’s most romantic cities: the castle ruins, the old bridge, the river Neckar. And since 2004 visitors can see it all from the water without any engine noise, on board the Neckarsonne (“Neckar sun”).

The Neckarsonne is a solar catamaran and one of the largest of its kind, with room for up to 110 passengers. Its long, flat roof carries 77 solar modules that charge the batteries. Thanks to that storage, the boat can operate in sunshine, rain and twilight. It glides along the river quietly and without emissions.

Passengers on board the Neckarsonne in front of Heidelberg's old town. Photo: Photographs by Radosław Drożdżewski (User:Zwiadowca21) / Wikimedia Commons, CC BY-SA 4.0

The usual trip is a round of about 50 minutes, starting at the landing stage near the Old Bridge (Alte Brücke), with commentary in German and English. Boat and landing stage are wheelchair-accessible, and the boat can be chartered for company or private parties.

The long, flat solar roof covers almost the whole boat. Photo: Photographs by Radosław Drożdżewski (User:Zwiadowca21) / Wikimedia Commons, CC BY-SA 4.0

The Neckarsonne belongs to a growing family of solar passenger boats on European rivers and lakes. You will find its relatives on our site: the MobiCat on Lake Biel, the Serpentine Solar Shuttle in London, the Alstersonne in Hamburg and Prague’s Elektronemo. If you ride the Neckar cycle route on your solar e-bike, it is a perfect break.

Technical data

Type	Solar catamaran, passenger boat
In service	Since 2004, Heidelberg (Germany)
Capacity	Up to 110 passengers
Solar	77 solar modules charging the batteries
Operation	Sunshine, rain and twilight; ~50-minute round trips from the Old Bridge
Access	Wheelchair-accessible boat and landing stage