Göteborg, Sweden, adopted a system that cuts emissions by 94-97% for ships at berth. It has done this by using renewable energy from wind turbines to power ships at berth. Currently most ships get their electricity supply through onboard power generation by auxiliary diesel engines – a highly polluting and energy consuming method. In 2004, the scheme won the European Commission’s 'Clean Marine Award’ for outstanding environmental achievement. While Göteborg does this on a small scale it has great potential to be expanded.
What is it?
Ports are not normally equipped to supply vessels with electricity from the shore, nor are vessels usually equipped to receive power in this way. Typically, the energy required for berthed ships is generated by the vessels’ own auxiliary engines, which run an electricity generator. The auxiliary engine consumes diesel or heavy oil, and generates both exhaust gases and noise. If power is supplied from the shore these environmentally polluting emissions and noise can be avoided.
Onshore Power Supply can be used for lighting, heating, pumps, and unloading and stops the ship from using their diesel-fuelled auxiliary or main engines. During an average harbour stay, a passenger ferry consumes around 5,000 kWh of electricity, equivalent to approximately 2150 kg C02 emissions – or the normal quarterly domestic usage for a detached house. The Onshore Power Supply system is currently used for 10-12 ships annually.
Göteborg adopted this program when the pulp and paper company, Stora Enso, looked at its supply chain and tried to raise environmental performance from source to sale. In an effort to win the company’s business, the Port of Göteborg developed comprehensive environmental strategies – including the adoption of Onshore Power Supply. Planning for the system began in 1998 and in 2000 the first ship was connected to high-voltage power supply.
How does it work?
Onshore Power Supply replaces onboard-generated power from diesel auxiliary engines with electricity generated on-shore. Studies suggest the average CO2 emissions from electricity production in the EU are around 330g/kWh, less than half the level of emissions from diesel engines (690-720g/kWh). This system reduces CO2 emissions by more than 50%, and use of renewable power sources can almost eliminate CO2 emissions.
An 'Onshore Power Supply' arrangement is required to power ships. This involves:
- Connection to the national grid of 20-100 kV; local substation to transform power to 6-20 kV.
- Cables to deliver 6-20 kV power from substation to port.
- Frequency conversion for some ships, from 50Hz to 60Hz.
- Distribution through canalized cables. Metering.
- Mechanisms to avoid handling high voltage cables. Ships require sockets for connecting cable.
- Ship transformer required to transform high voltage electricity to 400V (high voltage cables enable higher volumes of power to transferred through one cable, but this must be transformed back to 400V for operation). Then power can be distributed throughout the ship and auxiliary engines switched off.
Göteborg currently has 5 quays supporting this technology and is building its new quays to anticipate an expansion of demand for shore-side power. This includes canalization of the new quays, which reduces costs when future systems are installed. Once established, the systems require no extra manpower and ships at berth operate silently, reducing noise pollution.
At present, the Onshore Power Supply system is not used by all ships visiting Göteborg, as not all vessels have the requisite equipment and there are no international agreements requiring ships to use this technology. Many older ships need to be retrofitted to use 'Onshore Power Supply' and even then, some vessels (e.g. tankers) are dependent upon onboard pumping equipment for unloading.
The principal consumers are ferries and roll-on roll-off vessels. Roll-on roll-off ("roro") ships are designed to carry wheeled cargo, such as vehicles. These ships are particularly well suited to Onshore Power Supply, as they make short journeys and stop frequently. Moreover, as regular users of the same ports, their emissions savings can be more easily quantified.
CO2 emissions reductions
- Emissions at berth reduced 94-97% by participating ships
- Around 10 ships using scheme, including those of Stena Line ferry company
- 235.07 tonnes per year for an average ship (statistic from recorded data, 2003-6)
- 2394 tonnes of CO2 saved in 2003 by six ships
- Dramatic falls in levels of Nitrogen Oxide, Sulphur Dioxide and other pollutants
- Expected rise in participating ships, especially after 2010, when ships will be required to burn either 0.1% sulphur distillate fuel or use Onshore Power Supply during port stays in the EU. Both will drastically cut CO2 emissions for shipping.
- Estimated 60% of EU-flagged vessels are regular services that warrant implementation of shore-side power.
Environmental benefits depend on various factors, such as engine performance, fuel used, the length of time a ship is at berth.
The normal figure for port-port comparison is the throughput. In 2006, Europe’s largest port - the Port of Rotterdam - had a throughput of 650 million tons. In contrast, Göteborg, Scandinavia’s largest port, had a throughput of 40 million tons.
Göteborg calculated that the dirtiest 1% of ships frequently calling at the port are responsible for around 15% of GHG emissions. Whilst conditions between ports vary, this is likely to be typical for most ports.
- Total costs for the installation and maintenance of Onshore Power Supply systems can vary from as little as 60,000€ to 500,000€ per quay.
- Göteborg spent around €250,000 on each quay. In total, Göteborg has 5 quays with the system and each quay has its own substation.
- Electricity generation adds an external cost. At present, Onshore Power Supply is often more expensive than onboard generation. Using renewable electricity sources, as in Göteborg, reduces external emission costs to almost zero. When external emission costs are factored in, onboard generation becomes more expensive for ship owners than Onshore Power Supply.
From 2010, the EU requires all ships to use either 0.1% sulphur distillate fuel or use 'Onshore Power Supply' at berth. This, together with IMO attempts to develop international standards for ships, will lead to an increase in the number of ships making use of Onshore Power Supply at berth. Within Europe, ports with facilities, such as Göteborg, Helsingborg, Piteå, Stockholm and Zeebrugge, will have a short-term comparative advantage.
There are different types of 'Onshore Power Supply' system for differing needs – e.g. roro vessels, cruise liners, container vessels. Requirements and costs will vary, depending on the port’s traffic. However, it is important to note that from 2010, in the EU at least, the ability to offer Onshore Power Supply will become a basic condition for operation and thus commercial success.
Basic criteria for success:
- Conduct proper analysis of the vessels using your port.
- When possible, prepare new quays with canalization.
- Purchase renewable electricity from your power supplier or establish your own sources of renewable power.
- Lobby for national tax exemptions for ships using Onshore Power Supply.
- Encourage shipping companies to take up your services.
- Keep an emissions inventory of traffic using the system.
- Complement Onshore Power Supply with other initiatives to tackle emissions - e.g. use railways or trams for freight in the port area, or launch an "eco-driving" scheme. These can also significantly reduce the levels of emissions.