Sainsbury's said the Devon-based store will use 50% less energy from the national grid and produce 40% less carbon dioxide than a normal store.
Cutting its annual electricity bill by one third, it boasts 38 different energy-saving measures including a biomass boiler burning wood chips to provide heating, LED lights and solar-powered fans.
Sainsbury's planted 400 trees to compensate for the 200 used in the store's timber frame and construction of the site was environmentally friendly with 90% of the building waste being recycled.
Neil Sachdev, commercial director at Sainsbury's, said the store was a "leader in sustainable construction", adding: "We've been keen to experiment with a number of energy-saving measures here, from sun pipes, which provide amazing natural light, to using a timber frame rather than steel, which consumes less energy in its production, but looks good too."
In addition to the store, Sainsbury's unveiled a greener delivery lorry, which is powered by the gas produced from rotting rubbish such as waste food, garden waste and newspapers dumped in landfill.
The lorry made its first daily drop-off at the new Dartmouth store in a 300-mile round trip from the firm's depot in Bristol.
Sainsbury's is the first UK supermarket to deliver food using the green fuel technology.