Bulk Energy Storage Increases United States Electricity System Emissions

• Published in: Environmental science & technology 2015-03, Vol.49 (5), p.3203-3210
• Main Authors: Hittinger, Eric S, Azevedo, Inês M. L
• Format: Article
• Language: English
• Subjects: Air Pollutants - analysis; Carbon; Carbon Dioxide - analysis; Electricity; Electricity generation; Emissions control; Energy storage; Environmental science; Models, Economic; Nitric Oxide - analysis; Sulfur Dioxide - analysis; United States
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es505027p

Bulk energy storage is generally considered an important contributor for the transition toward a more flexible and sustainable electricity system. Although economically valuable, storage is not fundamentally a “green” technology, leading to reductions in emissions. We model the economic and emissions effects of bulk energy storage providing an energy arbitrage service. We calculate the profits under two scenarios (perfect and imperfect information about future electricity prices), and estimate the effect of bulk storage on net emissions of CO2, SO2, and NO x for 20 eGRID subregions in the United States. We find that net system CO2 emissions resulting from storage operation are nontrivial when compared to the emissions from electricity generation, ranging from 104 to 407 kg/MWh of delivered energy depending on location, storage operation mode, and assumptions regarding carbon intensity. Net NO x emissions range from −0.16 (i.e., producing net savings) to 0.49 kg/MWh, and are generally small when compared to average generation-related emissions. Net SO2 emissions from storage operation range from −0.01 to 1.7 kg/MWh, depending on location and storage operation mode.