Giving you the flexibility you need

Natural gas operated engines have an important role to play in the energy transition. In Bergen Engines, we pioneered the gas engine market, delivering our first lean-burn gas engine for power generation already in 1991. This engine is still running, and has clocked nearly 130.000 running hours, a proof of the reliability of our engines. Natural gas has contributed significantly to cleaner air and less emissions, replacing conventional power plants with highly efficient systems, often with combined heat and power, achieving efficiency levels of beyond 95%.

The pure gas engine technology is well proven and mature. Customer feedback from owners who have already made the transition to natural gas, has been overwhelmingly positive, both on land and at sea. Pure gas engines offer economic benefits through low fuel costs and limited maintenance. Natural gas is the cleanest fossil fuel, and our gas engines ensure a 92 % reduction in NOx emissions, and close to 99 % reduction in particulates/smoke compared to a diesel engine. The Bergen gas engines also have 18 % lower GHG emissions than equivalent diesel engines.

Methane slip

Methane slip is methane that evades combustion and is emitted via the exhaust and crankcase ventilation. Natural gas consists of 85-95% methane, which is a greenhouse gas much more potent than CO2 .

Bergen Engines takes the methane slip issue very seriously and is continuously working on reducing it further. Since the first gas engine was released, methane slip has been reduced by approximately 80 %. Optimization of the combustion process and timing, improvements of the control system and the engines’ efficiency, together with continuous Cylinder Pressure Monitoring (CPM), are some of the initiatives that have contributed to methane slip reduction. Other measures considered, are to reduce the number of pockets where unburnt gas can be trapped in the combustion chamber and optimising the valve timing and gas admission strategy. Current methane emissions from Bergen lean-burn gas engines are as low as 1.5-2.0 g/kWh.

Bergen Engines has also implemented a closed-circuit crankcase ventilation, ensuring that all methane that escapes from the crankcase is recirculated back to the combustion chamber.

Specific methane slip varies as a function of engine load, with a higher specific slip at lower loads. If your engines are used for grid balancing or in island mode, the load will vary, and to maintain a higher mean effective pressure load, the Bergen engines can be programmed to operate on variable speed. This means that the engine speed can be reduced, so that the mean effective pressure load can be kept higher, adapting to changes in the power plant’s needs. This also has a very positive effect on the engine’s efficiency, keeping it at its peak at all times. A frequency converter is needed with this setup.

Ensuring a smooth changeover to hydrogen

The energy transition will take time and happen at different speeds depending on the regions, countries and cities. An engine-based power plant is a long-term investment, and our Bergen engines will deliver reliable power for 30 years or more. Machinery chosen today must therefore be able to operate on the least GHG intensive fuel that is available now and transition to H2 as it becomes available.

The hydrogen production is being scaled up worldwide H2 is a versatile energy carrier that will become an important driver for decarbonisation of many energy intensive industries. Global H2 production is expected to increase significantly towards 2050 making this green fuel a central pillar of the energy system, replacing coal, oil and eventually gas, and having a key role in achieving climate neutrality. The H2 must be produced with electrolysis by means of renewable energy sources to be truly green. When produced from fossil fuels, the H2 is defined with other colours such as grey, brown, blue etc. depending on the production process and whether carbon capture & storage is involved.

Many countries have their own H2 strategies, aiming to create an enabling environment for the development of a secure, safe, affordable and just H2 economy. Today almost 98 % of the H2 is produced from fossil fuels, but with increasingly more renewables, the share of green H2 will increase. The ability to store renewable energy as H2 (power-to-x) during periods of peak production brings flexibility to the power sector. Also, current electricity grids were not designed to manage distributed renewable energy sources that are spread all over the countries and in the oceans, and the transmission capacity is insufficient. Most countries do however have a well-developed gas grid that can be adapted to H2 , alleviating the grid constraints. So instead of transporting electricity throughout the continents, a more cost-efficient way would be to transport green H2 as an energy carrier.

Governments in Europe are now establishing regulations that will require operators to blend the natural gas with a percentage of H2 , and some power plants are considering having their own electrolyser near the plant, producing H2 from curtailed energy from renewables, and thus becoming self-sufficient.

A gradual, increased percentage of H2 in the natural gas will reduce the power plant’s carbon footprint. The same generating sets can be used throughout the transition phase, ensuring an affordable and environmentally friendly changeover. Converting a conventional power plant to this future-proof concept will extend the power plants lifetime and contribute to the global shift towards a zero carbon future.

A practical example

A power plant with three B36:45L6A engines running 8 000 hours per year would emit 1 824 tonnes less CO2 per year with a 15% H2 blend.

To adapt the engine to a higher amount of H2 (above 60%) the engine modification can be done as part of a main service revision, so that much of the expense can be offset into the normal service cost. Most of the components that need replacement are in any case replaced or overhauled during a main service revision.

Hydrogen based cogeneration

Improving energy efficiency is key to tackle climate change, and the primary energy should be exploited to its fullest no matter what fuel is used. This can be done with combined heat and power, or cogeneration, where the “waste” heat from the engines is used to generate steam or hot water for industrial processes, for district heating, or to drive a combined cycle. The heat can also be used for cooling by means of an absorption chiller.

Commercial opportunities with cogeneration and H2

To get started with H2 blends in cogeneration, there are many commercial opportunities for the food, paper, textile, refinery and chemical industries, as well as in commercial and residential applications. The possibility to sell excess electricity from cogeneration to the grid, and excess heat to nearby users, will help to make the necessary investment to convert to H2 profitable.

When surplus renewable energy is employed to produce H2 the cogeneration plant can be used as an energy storage system (power-to-power) adding flexibility to the grid and making the cogeneration plant self-sufficient when it comes to primary energy supply. The engines can operate on the green H2 that has been produced from surplus renewable energy.

Industries that currently use cogeneration and consume H2 (refineries, chemical industries, steelworks, food processing etc.) are likely to become key for further development of cogeneration with H2 , since they already have access to this energy source, although not necessarily renewable H2 at this stage.

Benefits of cogeneration:

Very high efficiency: ~95 %, providing huge savings of primary energy
Increased profits and independency from the grid
Low carbon footprint
Cogeneration based on green H2 can potentially cover a significant part of a nations need for thermal and electrical energy, with zero emissions, contributing to a decarbonization of the system.

A seamless and sustainable energy system

An intelligent energy system that can deliver electricity, heating and cooling with minimum GHG emissions and maximised efficiency is best suited to meet our energy needs sustainably.