Implementation of OPS provides an opportunity not only to improve air quality, but also to reduce emissions of carbon dioxide, one of the main contributors to global warming. By switching from fuel oil to gas as an energy source or, better still, to sustainably generated wind power, for example, CO2 emissions can be curbed. According to the IEA, the 2 emission associated with power generation in the EU is 350-380 g/kWh Taking a figure of 220 g/kWh for fuel consumption, the corresponding CO2 emissions of auxiliary engines are around 680 g/kWh, implying a reduction of around 50% if vessels switch to OPS.
Coal or natural gas
The emission reduction per kWh of generated electricity depends on the energy source used for power generation. If OPS is sourced from coal-fired 2 emissions will increase by around 30 % compared to fuel-oil burning. The climate impact of natural gas-fired power plant is less than half that of coal-fired plant, implying a reduction of around 40 % compared with auxiliary engine use. Emission figures for different parts of the world are shown in the table below.
OECD N. America
Source: CO2 emissions from fuel combustion 1971-2004, IEA Statistics
If renewable energy from water or wind is used, CO2 emissions will be zero or near–zero, thus clearly giving the greatest CO2 reductions. Most electricity suppliers are able to supply renewably-sourced power. To calculate the effects of OPS on CO2 emissions the website provides an OPS calculation tool.