@techreport{KalkuhlFranksGruneretal.2023,
  type      = {Working Paper},
  author    = {Kalkuhl, Matthias and Franks, Max and Gruner, Friedemann and Lessmann, Kai and Edenhofer, Ottmar},
  title     = {Pigou's Advice and Sisyphus' Warning},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  number    = {62},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-57588},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-575882},
  pages     = {66},
  year      = {2023},
  abstract  = {Carbon dioxide removal from the atmosphere is becoming an important option to achieve net zero climate targets. This paper develops a welfare and public economics perspective on optimal policies for carbon removal and storage in non-permanent sinks like forests, soil, oceans, wood products or chemical products. We derive a new metric for the valuation of non-permanent carbon storage, the social cost of carbon removal (SCC-R), which embeds also the conventional social cost of carbon emissions. We show that the contribution of CDR is to create new carbon sinks that should be used to reduce transition costs, even if the stored carbon is released to the atmosphere eventually. Importantly, CDR does not raise the ambition of optimal temperature levels unless initial atmospheric carbon stocks are excessively high. For high initial atmospheric carbon stocks, CDR allows to reduce the optimal temperature below initial levels. Finally, we characterize three different policy regimes that ensure an optimal deployment of carbon removal: downstream carbon pricing, upstream carbon pricing, and carbon storage pricing. The policy regimes differ in their informational and institutional requirements regarding monitoring, liability and financing.},
  language  = {en}
}
@techreport{FranksKalkuhlLessmann2022,
  type      = {Working Paper},
  author    = {Franks, Max and Kalkuhl, Matthias and Lessmann, Kai},
  title     = {Optimal Pricing for Carbon Dioxide Removal Under Inter-Regional Leakage},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  number    = {43},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-53808},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-538080},
  pages     = {12},
  year      = {2022},
  abstract  = {Carbon dioxide removal (CDR) moves atmospheric carbon to geological or land-based sinks. In a first-best setting, the optimal use of CDR is achieved by a removal subsidy that equals the optimal carbon tax and marginal damages. We derive second-best subsidies for CDR when no global carbon price exists but a national government implements a unilateral climate policy. We find that the optimal carbon tax differs from an optimal CDR subsidy because of carbon leakage, terms-of-trade and fossil resource rent dynamics. First, the optimal removal subsidy tends to be larger than the carbon tax because of lower supply-side leakage on fossil resource markets. Second, terms-of-trade effects exacerbate this wedge for net resource exporters, implying even larger removal subsidies. Third, the optimal removal subsidy may fall below the carbon tax for resource-poor countries when marginal environmental damages are small.},
  language  = {en}
}
@techreport{LessmannGrunerKalkuhletal.2024,
  type      = {Working Paper},
  author    = {Lessmann, Kai and Gruner, Friedemann and Kalkuhl, Matthias and Edenhofer, Ottmar},
  title     = {Emissions Trading with Clean-up Certificates},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  number    = {79},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-64136},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-641368},
  pages     = {35},
  year      = {2024},
  abstract  = {We analyze how conventional emissions trading schemes (ETS) can be modified by introducing "clean-up certificates" to allow for a phase of net-negative emissions. Clean-up certificates bundle the permission to emit CO2 with the obligation for its removal. We show that demand for such certificates is determined by cost-saving technological progress, the discount rate and the length of the compliance period. Introducing extra clean-up certificates into an existing ETS reduces near-term carbon prices and mitigation efforts. In contrast, substituting ETS allowances with clean-up certificates reduces cumulative emissions without depressing carbon prices or mitigation in the near term. We calibrate our model to the EU ETS and identify reforms where simultaneously (i) ambition levels rise, (ii) climate damages fall, (iii) revenues from carbon prices rise and (iv) carbon prices and aggregate mitigation cost fall. For reducing climate damages, roughly half of the issued clean-up certificates should replace conventional ETS allowances. In the context of the EU ETS, a European Carbon Central Bank could manage the implementation of cleanup certificates and could serve as an enforcement mechanism.},
  language  = {en}
}