The paper's overall preferred approach is the bunching estimator (small negative), not the 2SLS which they show is non-robust; among the 4 coded IV cells, Spec.1 (-0.102) is the lead specification they report first. || 'For the first specification, the estimated elasticity is -0.102. However, for specification 2, the elasticity is instead positive... the 2SLS estimates are not robust to changes to the set of controls or to the sample definition' (p.9, abstract p.1)
Lanot, G., & Vesterberg, M. (2021): "The price elasticity of electricity demand when marginal incentives are very large." Energy Economics, 104, 105604.