Denmark—and this was a while ago—was named one of the most energy-efficient countries in the world.
The example that comes to mind about how they do user-producer interactions is actually from the wind industry. The textbook case of wind development was that technology developers worked very closely with agricultural co-ops and there was consistent feedback on how to improve the technology over time, so that's the key example I'm thinking of.
That's the type of thing I think can work well in the building retrofit energy-efficiency space, because there are a whole bunch of small problems, such as how to measure a building really accurately so that we can manufacture panels off-site. People have already come forward with “Well, we're going to use drones to do that.” Getting that type of consistent feedback between the users with the problems and the potential solution providers is, I think, a good innovation strategy.