The cost savings from using RMES instead of transmission lines. Darker red indicates higher costs for RMES relative to stationary storage or transmission lines, while darker grey represents higher savings. As AEF increases, RMES becomes less economic compared to both stationary storage and transmission lines. As distance travelled between regions increases, RMES becomes less economic compared to stationary storage. At low AEFs, RMES becomes more economic than transmission lines as distance increases because the per-km increase in RMES shipment cost is lower than the per-km increase in transmission capital expenditure. This relationship is reversed as event frequency increases. Generally, RMES is economic as a replacement for stationary capacity at all distances when AEF is under 1% and economic as a replacement for transmission when distances between regions exceed 1,500 km.
