We propose a priority-pricing scheme for zonal access to the electric
power grid that is uniform across all buses in a zone. The Independent
System Operator (ISO) charges bulk power traders a per unit ex ante transmission
access fee. The zonal access fee serves as an access insurance premium
that entitles a bulk power trader to either physical injection of one unit
of energy or a compensation payment. The access fee per MWh depends on
the injection zone and a self-selected strike price that serves as an insurance
\deductible" that determines the scheduling priority of the insured transaction
and the compensation level in case of curtailment. Inter-zonal transactions
are charged (or credited) with an additional ex post congestion fee equal
to the differences in zonal spot prices. The compensation for curtailed
transactions equals the difference between the realized zonal spot price
and the selected strike price (deductible level). The ISO manages congestion
so as to minimize net compensation payments and thus, curtailment probabilities
increase with strike price and for any particular strike price may vary
from bus to bus. We calculate the rational expectations
equilibrium for three-, four- and six-node systems and demonstrate
that the efficiency losses of the proposed second best scheme relative
to the efficient dispatch solutions are modest.