  This letter proposes a market-clearing-based locational marginal carbon
emission (LMCE) metric to assess the marginal carbon emission effect of nodal
load demand. Unlike the prevalent carbon emission flow (CEF) method that relies
on a hypothetical power-flow tracking process, the proposed LMCE metric depends
on a novel sensitivity analysis of market-clearing results, capable of
revealing both energy-dependent and network-dependent impacts on emissions.
Additionally, we introduce a locational average carbon emission (LACE) metric,
derived from LMCE, to effectively measure the general emission effect. It
offers insights into demand-side carbon emission effects, such as a negative
LMCE and LACE indicating emission reduction even as load increases. It can also
prevent excessive demand-side emission allocations. Overall, the proposed
method provides a clear perspective for the ongoing decarbonization policies.
