Clean innovation, heterogeneous financing costs, and the optimal climate policy mix
研究发现，最优气候政策组合除了碳税和清洁研发补贴外，还应包括直接降低清洁技术融资成本的补贴，且内生融资经验效应要求短期内碳价提高39%以加速融资成本趋同。
Access to finance is a major barrier to clean innovation. We incorporate a financial sector in a directed technological change model, where research firms working on different technologies raise funding from financial intermediaries at potentially different costs. We show that, in addition to a rising carbon tax and a generous but short-lived clean research subsidy, optimal climate policies include a clean finance subsidy directly aimed at reducing the financing cost differential across technologies. The presence of an endogenous financing experience effect induces stronger mitigation efforts in the short-term to accelerate the convergence of heterogeneous financing costs. This is achieved primarily through a carbon price premium of 39% in 2025, relative to a case with no financing costs.