The main materials used in Wärtsilä products are various metals: cast iron, alloy and structural steel, aluminium alloys, and bronze. Recycled material content of these metals vary depending on the material and supplier in question. Recycled material, such as end-of-life coins and bronze propellers, is used for example in the casting of new propellers.

In 2022, the total material usage was 36,062 tons (42,751). The major material groups were various metals 87%, sand 2%, and various chemicals 2%.


Wärtsilä engines have an extremely long service life, usually well over 25 years. Long-life products make more efficient use of materials than products with a shorter life. The power-to-weight ratio of the engines has also improved, which means that more energy is generated for the same amount of material in the engine.


Because of their long service life, older engines are often modernized and improved so that they conform to current requirements, and also to reduce their environmental impact. During a normal service life, an engine is used for 100,000 – 200,000 operating hours. Wear components such as valves, piston rings and bearings are normally replaced about every three years and a more thorough engine overhaul is carried out two or three times during the life of the engine. During these, the pistons, cylinder heads, piston liners, connecting rods and turbocharger rotors are replaced or overhauled. Engine components taken out of use are scrapped. Overhauled components are reused, which means their service life is extended. The material from end-of-life components is often used to produce recycled material.

An engine is made up mainly of various metal alloys, so the material used in the engine and its components can be recycled. The most important structural materials in 4-stroke engines are cast iron, alloy and structural steels, and aluminium alloys. The three main elements used in the metal alloys are iron, aluminium and carbon.

Wärtsilä’s R&D works systematically to improve the wear resistance and extend the service life of components and materials. 

Power plants

Several materials are used in the construction of power plants, steel being the most heavily used material. Concrete is used with steel in the foundations. The building itself usually lasts for the whole working life of the power plant. The goal is always to make optimal use of materials in a power plant, in part to keep costs down. This is achieved through thorough planning that takes into account the conditions at the site.

Most of the power plant components, in some cases even the building, are transported to the site as prefabricated modules. This helps to minimize transportation needs and at the same time makes more effective use of materials by reducing the amount of waste at the building site. Local suppliers are used where possible to minimize environmental impact.

Plant manufacture and material

The materials used in the plants consist of various steels and masonry materials. Tubular structures, rolled steel and cast steel that withstand high temperatures are used in the boiler and combustion equipment. In plants where the flue gases are condensed, corrosion-resistant steels are used. The main material used in the building is usually concrete. Steel is used for load-bearing structures and normal materials are used for thermal and noise insulation. Safe, standard materials are used in electrical equipment for electricity transmission and protection.

Secondary cleaning equipment for flue gases

When secondary cleaning equipment is used, the material balance sheet of a plant may contain various reagents. It is then necessary to replace not just the normal spare parts, but also gradually the catalyst materials, for example when using SCR or oxidation catalysts. The catalyst materials that have been replaced are usually returned to the supplier for reprocessing.

Propulsion equipment and seals

All of Wärtsilä’s propulsion products are designed to last the entire working life of a ship, which may be as long as 30 years. Most of the materials are metals, which can be recycled. The products contain non-ferrous metals such as bronze, which is an alloy of copper, nickel and aluminium. Recycled material, such as end-of-life coins and bronze propellers, is used in the casting of new propellers, which reduces the environmental impact of the products. Propulsion products contain few wear parts and these are easy to replace. Lubrication oils or environmentally sound additives are also used in the products.

The sealing systems are optimized to reduce the risk of emissions and the propulsion systems themselves are designed to have minimum emission levels.