Specialization, diversification and environmental technology life-cycle

The article analyzes whether and to what extent regional related and unrelated variety matter for the development of green technology, and whether their influence differs over the technology life cycle. Using patent and socioeconomic data on a thirty-year (1980–2009) panel of US states, we find that unrelated variety is a positive predictor of green innovative activities. When unpacked over the life cycle, unrelated variety is the main driver of green technology development in the early stages, while related variety becomes more prominent as the technology enters into maturity.