A model of technological breakthrough in the renewable energy sector

Models with induced technological change in the energy sector often predict a gradual expansion of renewable energies, and a substantial share of fossil fuels remaining in the energy mix through the end of our century. However, there are historical examples where new products or technologies expanded rapidly and achieved a high output in a relatively short period of time. This paper explores the possibility of a 'technological breakthrough' in the renewable energy sector, using a partial equilibrium model of energy generation with endogenous R&D. Our results indicate, that due to increasing returns-to-scale, a multiplicity of equilibria can arise. In the model, two stable states can coexist, one characterized by a lower and one by higher supply of renewable energy. The transition from the low-output to the high-output equilibrium is characterized by a discontinuous rise in R&D activity and capacity investments in the renewable energy sector. The transition can be triggered by a rise in world energy demand, by a drop in the supply of fossil fuels, or by policy intervention. Under market conditions, the transition occurs later than in the social optimum. Hence, we identify a market failure related to path-dependence and technological lock-in, that can justify a strong policy intervention initially. Paradoxically, well-intended energy-saving policies can actually lead to higher emissions, as they reduce the incentives to invest in renewable energies by having a cushioning effect on the energy price. Hence, these policies should be supplemented by other instruments that restore the incentives to invest in renewable energies. Finally, we discuss the influence of monopoly power in the market for innovations. We show that market power can alleviate the problem of technological lock-in, but creates a new market failure that reduces static efficiency.