This paper is authored by REsurety’s Sarah Sofia and Johns Hopkins University’s Yury Dvorkin. Read the abstract and download the full paper below.
Abstract
Carbon accounting frameworks guide policy and decision-making around investments in renewable energy, making them critical to understand in the context of real-world grid operations. In the absence of empirical work assessing the effects of intra-regional congestion on carbon emissions, ongoing policy design assumes that transmission congestion within grid boundaries can be ignored. In this work, we aim to test this assumption by quantifying the frequency and severity of intra-regional congestion and its impacts on carbon emissions and prominent carbon accounting frameworks. This analysis is done in both PJM and ERCOT using nodal locational marginal emissions data. Through several case studies, we find that load that is 100% hourly-matched through load-shifting will often result in significant net operational emissions, and sometimes even increase net emissions relative to annual-matching. This work demonstrates that, in the absence of robust transmission expansion, grid-region boundaries are insufficient to ensure hourly-matching is effective. Impacts of intra-regional transmission congestion are shown to be vital components of effective carbon accounting frameworks, calling into question frequently made assumptions ignoring intra-regional congestion in studies and policy proposals.
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