Abstract: | Abstract. This paper models some reductions in output that may follow the opening of electricity markets to competition. Specifically, we show that vertical separation of electricity generation, transmission and distribution could reduce welfare compared to the previous system of vertically integrated monopoly, if grid owners can act as monopolistic retailers or, alternatively, set access prices that maximize merchandizing surplus. Moreover, we show that a rule of non‐discriminatory pricing would not remedy any of these problems. Hence, to secure the efficiency gains of deregulation, the re‐regulation of the remaining monopolistic core – the electric grid – cannot rely on simple rules like cost‐based non‐discriminatory pricing. |