Confronting the Carbon Pricing Gap: Second-Best Climate Policy
面对有效率碳定价所遭遇的政治阻力，气候政策转而诉诸替代性工具，而这些工具伴随着可接受性带来的福利成本与财政成本。为评估这些成本，本研究考察了将固定碳税与对无碳发电及储能的补贴相结合的次优政策。借助一个包含化石能源与清洁能源以及碳预算的能源转型程式化动态模型，我们表明：碳税越低，碳定价缺口越大，满足碳预算所需的补贴规模也越大。可能需要清洁资本的过度积累，以挤出化石燃料。对欧洲能源市场的校准显示，可接受性成本最高可达福利的2.6%，且预算缺口相当于电力消费现值的56%。这表明，依靠绿色补贴推动能源转型可能并不明智。
英文原文
Faced with political opposition to efficient carbon pricing, climate policy resorts to alternative instruments, which come with welfare and fiscal costs of acceptability. To assess these costs, this study examines second-best policies combining a constant carbon tax with subsidies to carbon-free electricity generation and storage. Using a stylized dynamic model of the energy transition featuring fossil and clean energy sources and a carbon budget, we show that the lower the carbon tax, the greater the carbon pricing gap, and the larger the subsidies required to meet the carbon budget. Overaccumulation of clean capital may be needed to crowd out fossil fuels. Calibration to the European energy market reveals costs of acceptability up to 2.6% of welfare and a budget shortfall equivalent to 56% of the present value of electricity consumption. This suggests that relying on green subsidies for the energy transition may be unwise.