Bergen Engines is introducing flexible energy solutions that will transition in parallel with the energy transition, ensuring that investments made today are valid also in a world where zero carbon fuels produced with power-to-x have replaced the conventional fossil fuels.
More renewable power will require more balancing power. To combat the climate crisis and meet the goals set forth in the Paris Agreement, our energy consumption must become compatible with net zero carbon emissions. A transformation of our global economy towards electrification, energy optimisation and a phase-out of fossil fuels are among the required initiatives.
Governments are currently doing a lot to create regulations that support and promote the production of carbon neutral fuels with the goal to reduce GHG emissions. The introduction of carbon taxes and increased CO2 prices in EU’s Emission Trading System are some of the European initiatives. Carbon free and carbon neutral fuels are exempt from the CO2 tax. Such taxes will help closing the cost gap between fossil fuels and green fuels and make the business case to invest in green fuels economically viable. Moreover, huge cost reductions in wind and solar power are likely to decrease the prices for green fuels produced from renewables in the decades to come.
There will be a massive increase in renewable power worldwide, and this will require increasingly more dispatchable power to balance out the intermittency from these power sources and keep the grid stable. Bergen gas engines already have low emissions and can therefore be an enabler for a widespread use of renewable power. The engines can start up fast, and perform well on part-load efficiency, making them a good match to balance renewable power and keep the grid stable.
The figure below shows an example of how the engines can fill in the gaps when the sun is not generating power. The gensets can start and stop according to the PV generation. The curtailed (surplus) energy can be used for power-to-x purposes, and the produced low carbon fuel can be used on the engines to reduce emissions and energy consumption further.
Natural gas operated engines can function as a bridging solution towards a zero-emission future where hydrogen plays a key role. Providing both power and heat in an economical and environmental way, without the risk of stranded assets, and making use of the existing infrastructure.
The graph shows two weeks of simulated power generation with gas and PV in a hybrid power plant operation. PV capacity is 160 MWp. The generating sets are of type B36:45V20, each delivering 11.7 MW electrical power. 12 units are installed to allow spare capacity for scheduled maintenance. When the PV is not delivering sufficient power, the necessary amount of gensets are started up to fill the gaps.
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 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.
Our natural gas engines can already operate on biogas and e-methane, without any need for modifications to the engines or fuel supply systems. Using these fuels will give you a carbon neutral power plant today.
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.
Concept illustration of a hybrid power plant with 1000 kWp solar PV on the roof, exploiting space to its maximum, and 24 genset units of type B36:45V20 delivering 240 MWe.
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.
We believe that the shift from fossil to carbon neutral fuels will be best achieved with an engine set up based on natural gas today – and then gradually mix higher proportions of H2 with natural gas, as it becomes available and economically viable
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.
- A H2 -based power plant will give you a zero carbon solution
- Safety measures related to storage, flammability and detonation energy must be implemented
- Liquified H2 tanks will be approximately 50% bigger than LNG tanks due to the lower volumetric energy density. Compressed H2 tanks will be almost 3 times bigger than LNG tanks
Steps for H2 blending:
- possibility to blend up to ~10 % H2 by volume with base gas at MN 80 or higher with minimal changes to the engine with today’s engine setup
- possibility to further increase H2 percentage up to ~60 % by volume through de-rating, with minor modifications
- beyond ~60 % a need for a modification of the engine and fuel supply system will be required
Further R&D development will provide more accurate figures and potential impact to existing engine setup.
Exhaust gas aftertreatment may be required to handle NOx emissions with high H2 volume blends.
We are currently performing tests of various H2 blends on a B35:40 natural gas engine in our test lab in Norway with the scope to launch a pilot project at a customer site in early 2022. Retrofit solutions that make it possible to blend different percentages of H2 in the natural gas will soon be ready for our B36 and B35 engine series.
*Compared to a diesel engine
CO2 reduction potential with H2 blends: Hydrogen has a lower energy density than natural gas, and the CO2 emission reduction potential is therefore not proportional with the volume percentage of H2 added to the natural gas.
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.
The concept drawing shows how renewable power can be the main electricity source when dispatchable back-up power from generating sets is available. The generating sets will balance any intermittency from the renewables and ensure grid stability. They can run with high efficiency on variable load, and start and stop whenever required.
Curtailed electricity from periods with overproduction from the renewables will charge the batteries which in turn can kick-in immediately if there’s a sudden drop in the renewables generation. This will give the generating sets the two minutes they need to ramp up to full load. The batteries do not have the capacity to take all the curtailed electricity, and a large part of it is used to power an electrolyzer that produces H2. The H2 is made available for operation on the generating sets in a blend with natural gas. As a result, the generating sets deliver low carbon power, in addition to heating and/ or cooling to the nearby city.
Take the first step towards zero carbon operation
By choosing a Bergen gas engine for pure natural gas operation as the first step towards neutral or zero carbon operation, you will have a flexible and highly efficient machinery that can be adapted to green fuels as they become available, meeting both existing and upcoming emission requirements, without the risk of stranded assets
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