  We propose an operating envelopes (OEs) aware energy community market
mechanism that dynamically charges/rewards its members based on two-part
pricing. The OEs are imposed exogenously by a regulated distribution system
operator (DSO) on the energy community's revenue meter and is subject to a
generalized net energy metering (NEM) tariff design. By formulating the
interaction of the community operator and its members as a Stackelberg game, we
show that the proposed two-part pricing achieves a Nash equilibrium and
maximizes the community's social welfare in a decentralized fashion while
ensuring that the community's operation abides by the OEs. The market mechanism
conforms with the cost-causation principle and guarantees community members a
surplus level no less than their maximum surplus when they autonomously face
the DSO. The dynamic and uniform community price is a monotonically decreasing
function of the community's aggregate renewable generation. We also analyze the
impact of exogenous parameters such as NEM rates and OEs on the value of
joining the community. Lastly, through numerical studies, we showcase the
community's welfare, and pricing, and compare its members' surplus to customers
under the DSO's regime.
