Subsidies for close substitutes: Aggregate demand for residential solar electricity
研究了美国住宅太阳能补贴对电网电力需求的影响，发现补贴每增加1千瓦时太阳能发电仅替代0.5千瓦时电网用电，2018年减排成本为每吨二氧化碳332美元。
Subsidies promoting residential solar systems are intended to reduce carbon emissions by lowering demand for electricity from the grid. The ability of these subsidies to reduce grid demand hinges on how close, on aggregate, the two sources of electricity are to perfect substitutes. To test the efficacy of these policies, we form a tractable model of national residential electricity demand that identifies the aggregate substitutability between residential systems and electricity drawn from the grid. When estimated on the United States, we find that while the two are close to perfect substitutes, the degree to which substitutability is imperfect has material implications for policy. Subsidies inducing one kWh of residential solar electricity demand displace only 0.5 kWh of grid consumption. As an emissions reduction policy, subsidies had national abatement costs of $332 per MTCO 2 in 2018.