NBER Working Papers · 2026 · Susanna B. Berkouwer、Joshua T. Dean
中文摘要
信贷约束和其他需求扭曲在低收入环境中普遍存在。一个清洁技术采纳模型表明,需求扭曲可以增加绿色补贴的福利收益。这一效应通过两个渠道产生:使边际采纳者转向具有更高私人和社会收益的选择,以及提高需求弹性。为检验这一点,我们在肯尼亚对 2,134 名木炭使用者交叉随机分配针对售价 84 美元的电磁炉的购买价格补贴、使用补贴以及无息贷款。75% 的使用补贴对采纳和使用均产生精确的零效应。然而,购买价格补贴带来了可观的福利收益。信贷约束使补贴的有效性提高 35%–73%,每一美元补贴带来的可观测福利收益最高可达 10–12 美元。这一需求扭曲还将减排的补贴成本降低 41%,降至每吨二氧化碳当量 12 美元。其作用机制正是理论中识别的两个渠道:信贷约束使边际采纳者的正外部性提高 19%、燃料节约提高 30%,并使每次边际采纳的补贴成本降低 29%。在没有需求扭曲的反事实情形下,减排成本升至每吨二氧化碳当量 137 美元。需求扭曲较大的环境可能为气候变化减缓融资提供许多具有成本效益的机会。
Abstract
Credit constraints and other demand distortions are pervasive in lower-income contexts. A model of clean technology adoption shows that demand distortions can increase the welfare gains from green subsidies. This arises through two channels: shifting the marginal adopter toward higher private and social benefits, and increasing demand elasticity. We test this by cross-randomizing purchase price subsidies, usage subsidies, and access to an interest-free loan for a US$84 induction stove among 2,134 charcoal users in Kenya. Usage subsidies of 75% have a precise zero effect on adoption and usage. Purchase price subsidies, however, generate large welfare gains. Credit constraints raise the subsidy’s efficacy by 35%–73%, up to US$10–US$12 in observable welfare gain per subsidy dollar. This demand distortion also lowers the subsidy cost of abatement by 41%, to US$12 per tCO2e. This operates through the two channels identified in the theory: credit constraints raise the marginal adopter’s positive externality by 19% and fuel savings by 30%, and lower the subsidy cost per marginal adoption by 29%. In a counterfactual without demand distortions, the abatement cost rises to US$137 per tCO2e. Contexts with large demand distortions could offer many cost-effective opportunities for climate change mitigation financing.