Power Plants - Compliance

Meeting World Bank guidelines has been a core principle of Wärtsilä for years in its development of power plants. In recent years, compliance with these guidelines has become increasingly widespread in power plant projects around the world. This is because more and more financing institutions and export credit organizations have committed themselves, through their environmental policies and general agreements, to complying with these guidelines. An example of this trend is the Equator Principles document by leading financial institutions, in which the signatory parties confirm their commitment to compliance with the World Bank guidelines in their financing activities.

World Bank / International Finance Corporation – Guidelines for new power plants
Wärtsilä power plants are traditionally designed so that their emission levels are lower than the World Bank limits, when using a suitable choice of fuel. Secondary and wet primary emissions reduction methods can be used, either to permit the use of poorer-quality fuels, or to enable even lower emission levels, for instance due to local ambient air quality issues or to reach better fuel economy.

The World Bank (WB) and International Finance Corporation (IFC) have been revising their guidelines. New limits for small plants (3-50 MWTH) have been published in the General Environmental, Health and Safely (EHS) guidelines of the IFC. The guidelines contain stack limits for NO_x, SO₂ and PM emissions for different types of power plants. The limits, as applicable to reciprocating engine plants unless ambient air quality legislation requires more stringent control, are given in the table below. Wärtsilä gas and diesel engines can reach the specified NO_x   emission limits, although higher NO_x emissions are allowed in order to to minimize fuel consumption, and hence greenhouse gas emissions, if justified by an assessment. As can be seen, fuel availability is taken into consideration. The preferred fuel qualities (column A) are not available at reasonable price levels everywhere, and hence alternatives fuels (column B) are allowed, providing they can be demonstrated as offering an environmentally sound solution in all respects.

Case B emission levels are allowed if justified by project specific considerations, such as availabilities of fuels, feasibilities of emission control or engine efficiency.

World Bank Guidelines for Thermal Power (1998) are applied for power plant projects bigger than 50 MWth until the new IFC EHS Guidelines for Thermal Power are released and come into force.

European Union stipulations for engine-driven power plants

The common European guidelines governing the permitting of engine-driven power plants in the EU were introduced during 2005 in the BREF document (Reference Document on Best Available Techniques for Large Combustion Plants). This document sets recommended emission values for various types of power plant based on BAT (Best Available Technique) thinking in emissions control. BAT is based on the idea of using the best technique available while bearing in mind cost feasibility. Wärtsilä considers the values to be reasonable in principle, but agrees with separate industry opinions on the need to evaluate the use, for example, of SCR.

Country-specific requirements

More and more countries have started to implement dedicated emission limits for reciprocating engine plants. Historically, one such pioneer has been Germany. The German TA-Luft emission regulations have been applied in particular to gas engines owing to their general applicability throughout Europe. In the USA, the Environmental Protection Agency (EPA) has been drawing up country-wide emission norms for both diesel and gas engines. India, for instance, has a long tradition of having its own emission standards for diesel engines. The emission requirements differ from one country to another for various reasons, including the requirements and availability of the fuel.

Reference oxygen 15 % O2, nm3 25 °C / 101,3 kPa