Locational marginal emission rates calculation considering reserve requirements

As new policies are adopted to transition toward emission-free electricity, effective metrics are needed to accurately quantify emissions. Locational Marginal Emission Rates (LMERs) effectively capture the change in emissions associated with a change in demand. This paper introduces a computationally efficient LMER calculation algorithm that considers reserve requirements and network constraints in the economic dispatch model. Unlike locational marginal prices (LMPs), which can be directly derived from shadow prices expressed in $/MWh, calculating LMERs requires identifying marginal units that adjust their outputs in response to infinitesimal changes in system parameters. The LMER calculation algorithms also compute the incremental output changes of these marginal units and utilize these output changes, combined with the respective emission rates to compute LMERs accurately. However, the inclusion of reserve requirements, which are essential in modern electricity markets to address the uncertainties introduced by contingencies and significant intermittent generation, complicates identification of marginal units and calculation of their corresponding output changes in response to the locational demand changes. Thus calculating LMERs become increasingly complex. The proposed algorithm for the calculation of LMERs considering the reserve requirement systematically identifies marginal units and their corresponding output changes to calculate LMERs. This algorithm has been tested on both a four-bus system and a synthetic Texas Test System to show its efficiency and validate its accuracy. Furthermore, this algorithm is examined with different levels of reserve requirements and hence analyzes the impact of reserve requirements on marginal units and LMERs.