The issue of energy cost is important for ship-owners. There is evidence that the overall cost of OPS electricity may be higher than the on-board generation for the following reasons:
- A tax on electricity will normally be applied if it comes from OPS. The tax level may change from case to case and country to country.
- The base cost of electricity as supplied to ports may be high.
- The port charges which are intended to cover the investment and running costs will be added to electricity price.
All the above require detailed studies for each port. To reduce the cost of pollutants on society and port areas, there may be a need to transfer the burden of cost to ships as they represent the main source of pollutant. However, since this may vary from port to port, it will have an impact on port business as well (MariEMS 2017).