Estimations of cost and CO2 emissions for smart grids using a linear programing approach

A smart grid is an electricity network that uses digital technology to monitor and manage the transport of electricity from all generation sources to meet the varying electricity demands of end users. In this paper, the smart grid is defined as the electric power system consistent with the BASE or BLUE scenarios in the Energy Technology Perspectives 2010 with the large scale renewable integration and the capability of demand response. Quantitative estimations of the cost and the CO₂ emissions are made using a linear programing approach for the BASE and BLUE smart grids in the US. Among the BASE smart grids, a smart grid where a high penetration of renewables is considered is more expensive than the BASE scenario. The increased cost was due to expensive renewables. Another smart grid where both high renewables and load shifting, were applied demonstrated the least CO₂ emissions. The trend in increasing CO₂ emissions continues 2050. Among the BLUE smart grids, both cost and CO₂ emissions were decreased when load shifting was applied. Temporal change of CO₂ emissions clearly shows a decreasing trend. Then, the capacity of the electric storage required for the integration of renewables at 2050 was estimated to be 9.0GW. Batteries used in electric vehicles will be used for the electric storage at low cost. Finally the cost saving for the load shifting was estimated to be 1.64 × 10¹¹ USD by a break-even point analysis. The cost saving is equivalent to the yearly saving of 3.64USD/household/year for forty five years. If the saving of 3.64USD/household/year is not enough for utilities to cover the cost increased due to the load shifting equipments, the utilities and customers have to share the extra cost.