Electricity network tariff targeting EV chargers : A socio-economic analysis

Abstract: The upcoming expansion of electric vehicles (EV) will bring an increase in charging infrastructure as well as other challenges for the local network operators (LNO). Higher power peaks could overburden the electricity grid resulting in large investments from the LNO to meet the increased demand on the grid. Meanwhile, the investment costs related to charging stations are high for a very uncertain business case, with roughly 60 % of the annual costs to be paid to the LNO. The hypothesis of this research is to create a tariff targeting EV charging stations making it cheaper to operate the stations, both for the LNO and station owner. This is achieved by surrendering 100 % electricity supply when the electricity grid is overworked to help the increasing power demand on the grid. In order to identify the strength and weaknesses of the suggested tariff from the station owners’ point of view, 20 interviews were conducted with LNO, charge point operators (CPO), and other charging station owners (CSO). Five key factors were identified: customer satisfaction, technological barriers, administrative issues, branding, and compensation. The CSO want a price reduction of 20-50 % to use this tariff. It was also investigated to see what would happen if already existing customers to Nacka Energi AB (NEAB) would decide to opt for this tariff if they install charging station, in order to make it cheaper for them as well. Data was collected from over 36 000 charging sessions. This was used to find the charging behaviour, power consumption peaks, and the cost items. The cost items were then manipulated in order to find a fair price reduction over all fuse sizes that would result in an annual price reduction of 20-50 %. The final recommendation for the tariff is to reduce the fixed fee by 40 % in relation to the potential future power tariff of NEAB, the rebate to 2 SEK/kW, power fee 25 SEK/kW and to set the volumetric price to 0.05 SEK/kWh. The discussion identifies the conditions which must be fulfilled by the CSO and the LNO to use this tariff. These include: Separate meter and fuse at the charging station, fuse must not be greater than 63 A, the connection may not be turned off for more than 100 hours each year, not be turned off for more than 3 consecutive hours and more than once a day, the customer may change tariff once a year and the rebate and power fee are based of the highest power consumption peak of the month. Conditions for existing customer was also evaluated. The conclusion to make charging cheaper for them is to remove the fixed fee since they already pay for it in their existing connection. Otherwise it will be more expensive than before.