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Power Plants and sustainability

The world is currently seeking more sustainable solutions for energy infrastructure. This development is driven by climate policies, energy security and economics. Carbon intensive energy sources are being replaced by low carbon fuels, such as natural gas and renewable solutions. Energy savings and efficiency improvements are being encouraged, and even legally enforced, at every level.

Wärtsilä's energy solutions offer a unique combination of flexibility, high efficiency, and low emissions. Many different fuels, including bio-fuels, can be used efficiently, which helps in reducing greenhouse gas emissions. The flexibility of Wärtsilä's solutions enables the development of a reliable energy infrastructure, wherein most of the sustainable characteristics are already known.

Efficiency development

We continuously seek improvements in the present engine portfolio, and are developing new engine concepts for the future. As a power plant contractor, we develop our power plants in parallel with the engines. This enables us to optimise both the performance and the reliability of our power plant offering. We offer high efficiency, single cycle solutions and focus on improving efficiency even further through the use of e.g. combined cycle solutions. Power plant net efficiency can be further improved by plant design and by optimising internal power consumption. Such solutions minimise not only fuel and water consumption, but also the emissions per unit of energy, thereby providing major environmental benefits.

Flexibility

Flexibility is one of the main features of Wärtsilä's power plant solutions. The high modularity of our products makes it easy for our customers to construct an optimally sized plant, and to later expand its size to meet future needs. Fuel flexibility has many advantages for our customers, notably the lowering of energy production costs by using low cost fuels, minimising CO2 emissions, and the ability to convert from one fuel to another based on fuel availability.

The unique operational flexibility of our products comprises:

  • Very fast plant starts and stops
  • High ramp rates
  • High part-load efficiency
  • A broad load range

Frequent starting and stopping does not affect the operational costs of the plant. This is unique, no other competing technology offers the same.

Towards an optimally sustainable power system

The power generation system of the future will contain a significant percentage of wind power capacity. Such capacity is non-dispatchable and variable, which creates potential for other power units to balance the system. Wärtsilä is in a good position to meet this need, as the operational flexibility of our products makes them easily adaptable to the needs of the grid.

Reducing emissions

Wärtsilä places high priority on developing diverse and flexible emission reduction techniques. Since emission requirements and the fuels used differ widely, a comprehensive range of products is required in order to offer competitive solutions.

Mitigating the effects of climate change calls for substantial reductions in greenhouse gases (GHG). We believe that the importance of natural gas will increase in the future. Consequently, the multi-fuel capability of our power plant solutions becomes an increasingly significant competitive advantage, as it enables the utilisation of all liquid and gaseous bio-fuels that may become available on a wider scale. Wärtsilä focuses on developing decentralised energy solutions that emit fewer GHG emissions.

Emission reduction technologies

Emission componentTechnologyPrincipleBenefitTypical use
Reducing particle emission Choosing a better fuel type (ash/sulphur) Using a fuel with a smaller ash and sulphur content reduces the particle emission produced during combustion. Fuel-specific Diesel engine / heavy fuel oil
  Electrostatic filter In an electrostatic filter, the particles in the flue gas are charged with an electric current and the charged particles are collected on the surfaces of the filter's collector plates. A smallish amount of flue ash is generated as an end product. The particle content achieved also depends on the quality of fuel used.   The particle content of gas discharged through the filter normally varies between 20 and 50 mg/nm3 (15% O2). Diesel engine / heavy fuel oil
Reducing NOx emission WetPac - H (humidity control) The combustion air is humidified by injecting water into it, which lowers the combustion temperature and reduces emission of nitrogen oxides. The amount of injected water required is determined according to air humidity, thus minimising water consumption. Typical emissions are reduced by approx. 15-20% at the minimum air humidity level. Diesel engine
  SCR (Selective Catalytic Reduction) Nitrogen oxides (NOx) are reduced into nitrogen (N2) and water vapour (H2O) using ammonia or urea at a suitable temperature on the surface of the catalyst. Process control enables the amount of inactive ammonia in the flue gas to be kept low. Collection efficiency 80-90%. Large collection efficiencies are possible, but not cost-efficient. Diesel or gas engine
Reducing SO2 emission Lower sulphur content in fuel The sulphur content of fuel is directly proportional to the sulphur dioxide emission generated.  Fuel-specific Diesel engine / heavy fuel oil
  NaOH FGD (Flue Gas Desulphurisation) Sulphur dioxide is removed from the flue gas in a tower washer. Sodium hydroxide is used to neutralise the washing fluid. The plant produces wastewater as an end product, which should be treated. A typical collection efficiency for SO2 is approx. 90%. Diesel engine / heavy fuel oil with low sulphur
  Limestone FGD
(Flue Gas Desulphurisation)
The limestone cleaner is based on a wet tower washer in which sulphur dioxide is absorbed form the flue gas. Calcium, for which a disposal procedure should be determined, is produced as an end product. A typical collection efficiency for SO2 is 80-90%. Diesel engine / heavy fuel oil with high sulphur
Reducing CO emission Oxidation catalyst Carbon monoxide is oxidised into carbon dioxide on the surface of the catalyst using the oxygen in the flue gas. Depending on the amount of catalyst used, discharge efficiency is 30-90%. Gas engines
Reducing hydrocarbon emission Oxidation catalyst Hydrocarbons are oxidised into carbon dioxide and water vapour on the surface of the catalyst using the oxygen in the flue gas Discharge efficient depends on both the catalyst chosen and the hydrocarbons involved. Gas engines

 Monitoring of emissions

Emission componentTechnologyPrincipleBenefitTypical use
Monitoring of gaseous emission Secondary method - fuel and process parameters The secondary method is based on periodical flue gas measurements as well as on the systematic monitoring and reporting of certain process and fuel parameters. Reliable measuring, minimal need for expertise at the plant, suitable for different market areas. Diesel engine - typically e.g. SO2 emissions
  Continuos emissions monitoring (CEMS  / AMS) Emissions levels can be monitored constantly using automatic equipment. The operation and maintenance of the equipment requires personnel expertise to ensure reliable performance. The results reported may be uncertain if the necessary expertise is not available. Actual emission and exceedings are monitored and registered continuosly. Diesel or gas engine - typically e.g. NOx emission
Monitoring of particle emission  Secondary method - fuel and process parameters The secondary method is based on periodical flue gas measurements as well as systematic monitoring and reporting of certain process and fuel parameters. Reliable measuring, minimal need for expertise at the plant, suitable for different market areas. Diesel engine
  Continous emissions monitoring Constant particle measurement is usually based on secondary monitoring, e.g. analysers that monitor opacity or light diffusion. Calibration based on reference monitoring gives a correlation with the parameter monitored. If the fuel and load conditions vary, the monitoring may not yield reliable results. The apparent emissions level is monitored constantly and any limits exceeded are registered automatically. Diesel engine

 

Compliance with regulations

Wärtsilä's modern gas engine technology enables current environmental requirements to be met throughout the world. As an example, in 2010 Wärtsilä handed over a 165 MW dual-fuel power plant in California that meets all local environmental demands. Californian requirements are currently considered to be the most stringent requirements anywhere.

Through the use of primary combustions methods, Wärtsilä's oil-fired power plants are also designed to comply with the World Bank guidelines on emission levels, and as required by ambient air quality, national legislation, or project-specific issues. As more and more financing institutions and export credit organisations have committed themselves to these guidelines, compliance has become increasingly widespread in power plant projects around the world.

We actively seek, develop, and deliver better, more modern and more sustainable solutions. We support our customers by providing advice on how to develop their systems and plant portfolios in order to cope with future requirements and norms.