Tank-building company finds clean energy niche ← Related Article Visit The Boston Globe Share on Twitter Share on Facebook Comment on this Scroll to top of page Jonathan Wiggs/Globe Staff A steel water tank is fabricated as part of a project at Middleborough-based Mass Tank. Jonathan Wiggs/Globe Staff Mass Tank recently signed a deal to partner with Goldwind to make turbine towers. Tom Pozzi worked on a steel tank. Jonathan Wiggs/Globe Staff The company will make 20-story towers that support wind turbine blades. Above, Ed Costello of Mass Tank at work.