Renewable energy (RE) policies are widely used to decarbonize power generation and implemented at various governance levels. We use an analytically tractable two-level model to study the effects of overlapping RE policies from the federal and state governments. We find that there are contrasting incentives for states to support RE deployment, depending on whether the federal government implements a feed-in tariff (FIT) or an auction system. Under federal FIT, states that bear a greater burden in financing the federal policy under-subsidize RE in order to reduce nationwide RE deployment and thereby lower their costs. Under federal auction, states that bear a greater burden to finance federal policy over-subsidize RE to drive down the quota price, and thereby also their costs. In an application to Germany, we illustrate that the recent shift from FIT to auctions increases incentives for state governments to support RE in the demand-intensive south, while decreasing them in the wind-abundant north.

可再生能源 (RE) 政策被广泛用于发电脱碳，并在各个治理层面实施。我们使用一个易于分析的两级模型来研究联邦政府和州政府重叠的可再生能源政策的影响。我们发现，各州支持可再生能源部署的动机不同，这取决于联邦政府是实施上网电价 (FIT) 还是拍卖系统。在联邦 FIT 下，在联邦政策融资方面承担更大负担的州对可再生能源补贴不足，以减少全国可再生能源的部署，从而降低其成本。在联邦拍卖下，承担更大负担以资助联邦政策的州过度补贴可再生能源以压低配额价格，从而压低其成本。在申请德国时，