Especially in professional, mobile and safety-critical application environments, diesel is an important energy storage device. Whether on construction sites, on mobile film sets or for supplying aid missions and military infrastructures – electrical power is mostly provided by diesel gensets.
According to the climate agreement adopted in Paris in 2015, greenhouse gas emissions are to be reduced to net zero by 2050. Due to the increasing electrification of all applications, electricity consumption will rise by 2030. By hybridising these generators, the increasing consumption can be met in a cost- and energy-efficient way.
Hybridisation in the true sense describes a mixed form of previously separate systems. The best-known example for most people is probably the hybrid vehicle. Here, the diesel- or petrol-powered engines of the vehicles are augmented by an electric motor and a battery. The aim is to boost performance, reduce the load on the combustion engine and thus lower fuel consumption. By coupling the two systems, individual technological features of each solution are combined and unique advantages are created for the user.
The same principle can be applied to diesel or petrol generators. The genset can be coupled with a battery storage unit with corresponding power electronics. Particularly in view of the further increase in fuel prices in the future (CO2 tax), a genset can be operated economically for longer by reducing consumption. Advantages can be realised especially in connection between generator, storage and PV array. The additional solar energy stored in the batteries reduces the need for fossil fuels and further lowers CO2 emissions.
ADVANTAGES OF HYBRIDISATION OF DIESEL AND PETROL GENERATORS
The combination of battery storage systems and generators alone creates advantages in use and financially. Ideally, the following advantages can be realized:
Up to 100% fuel savings.
Up to 90% less maintenance on the power generator.
Up to 10 times longer aggregate life.
Each generator has a specific optimum speed range in which power generation is most efficient. This is usually between 75 and 100%. If the unit is oversized, the supply becomes less efficient in proportion to the oversized design. In hybrid systems, the consumer is supplied with electricity from the generator and the battery storage is charged with the excess power. When the battery storage is full, the generator can be switched off and the load can be supplied by the power electronics via the stored capacity. Only when the battery storage falls below a certain state of charge (SOC) does the generator start up again and supply the application and charge the battery.
Up to 90% less maintenance work on the generator due to longer runtimes in the optimum power range and fewer operating hours. As with cars, the maintenance cycles for generators are based on the operating hours (or kilometers driven). If the operating hours are reduced in a certain period of time, the maintenance cycles will be extended accordingly.
Overall, the life expectancy of the generators is increased and thus their economic efficiency is maintained or even increased even with rising fuel prices. Downtimes and the capping of peak loads (peak shaving) by the power electronics of the battery storage system are decisive for increasing the service life of the generator. More frequent and more consistent use of the unit’s specific optimum power range also reduces stress and extends service life and efficiency.
In addition to the increase in efficiency, further fuel can be saved through the input of renewable energies, which also charge the coupled battery storage. This further reduces energy costs, maintenance costs and emissions. The red line below describes the ideal expression of all properties of an energy supply in the military environment. Possible total score is 110 points. Evaluation and comparison in the table below.
| Punkte | Prozent | |
| Gesamtpunktzahl | 110 | 100 |
| Dieselversorgung | 50 | 45 |
| Erneuerbare Versorgung | 89 | 81 |
| Hybride Versorgung | 104 | 95 |
In addition to the increased efficiency of the overall system and the resulting cost reduction (OPEX) through fuel savings, the safety and resilience of the supply increase. The fuel savings reduce the logistical effort of the supply. The downtimes increase comfort. Overall, the reduction of fuel and emissions leads to a more sustainable supply of the application.
In the hybrid vehicle, the power output of the internal combustion engine and the electric motor is coupled to achieve enormous acceleration values. Due to the possibility of boosting the power output of the genset by the battery storage system, generators of a smaller power class can also be considered for demanding applications. By capping the load peaks and switching the power electronics to the sinusoidal wave of the genset, the load in the generator is minimised and its service life extended.
HYBRIDISATION OF DIESEL GENERATORS THROUGH THE SOLUTIONS OF AXSOL GMBH
AXSOL GmbH’s solutions are designed to be as independent as possible from the power source. All battery storage systems can be charged by the grid, but also by renewable and conventional generators. AXSOL GmbH’s products are the perfect complement for new and existing generators and realise benefits from the first use. Through their hybridisation, immediate cost and emission savings can be realised.
For the ARVEY B2, specially developed for use in demanding terrain, hybridisation is one of the basic functions. The portable 2.25 kWh / 2.3 kW battery storage follows the highest safety standards and can be connected to small diesel generators via a charging cable. An ARVEY B2 can be charged simultaneously by PV, a fuel cell and a diesel generator. By combining different generation sources, the supply becomes increasingly hybridised and fuel consumption and emissions are further reduced.
It is worth combining a generator with an ARVEY E3 or E5 and connecting the storage unit between the generator and the consumer. Diesel generators up to 5 kW can be easily hybridised via the charging cable. Thanks to the intelligent by-pass function, priority can be given to using the generator’s power at ideal speed for consumers and storing excess energy in the battery. This way, no energy is lost and costs and emissions are saved. For example, with a consumer of 1000 watts, the running time of the generator is reduced by more than 60 % and several hundred euros are saved per year. The built-in UPS (uninterruptible power supply) function kicks in if the generator fails and continues to supply the application with power continuously. Depending on the consumer, the ARVEY E5 can serve the application for hours or days. Commercially available UPSs usually only achieve minutes.
The CNHybrid is delivered with an energy system developed by AXSOL, consisting of battery storage, a mobile solar system and a small generator to secure the supply. The electronic components are integrated in the floor of a folding container. The interior of the container is available for any requirement without restrictions. The CHHybrid is delivered with the foldable E-Fill X 2000 as standard. The mobile PV array can be set up in less than 3 minutes and delivers up to 2 kWp. The diesel generator is controlled by an intelligent automatic start-stop system. When the battery is empty, the application is powered directly. Surplus electricity is used to charge the battery. Due to the input of solar power, the operating times of the diesel generator are minimised. Overall, the energy system can ensure 100 % self-sufficient operation of the container. Due to the 300 % resilient design of the entire system, enough electricity is provided for applications in and around the container in any situation. Up to 100 % of the self-consumption can be covered by the regenerative input.
With AXSOL GmbH’s Energy Container Solutions, even large generators can be hybridised without any problems. For this purpose, the generator is connected to the storage container as a mains substitute. Connected generators can be automatically started externally if the system control of the ECS gives the command to do so. In order to combine the advantages of conventional energy generation and provision with those of battery storage systems, AXSOL GmbH integrates higher-level intelligent control elements into the electronics. In this way, the individual components for energy supply can be networked, optimised according to demand and the supply can be made more sustainable by connecting regenerative energy sources. Generators can be coupled with the ECS to form a hybrid system, regardless of power and age, and realise the aforementioned advantages for the user.
HYBRIDISATION IN THE DEFENCE & SECURITY SECTOR
In the course of the decarbonisation of civil society driven by the Paris Climate Agreement, state security agencies must also increasingly develop concepts to carry out their tasks and processes in a greenhouse gas-neutral manner. The high demands on power supply in terms of security, durability, high performance and independence from climatic conditions are increasingly leading to a diversification of energy provision. The current energy supply of the military and authorities with a security mandate (BOS) is largely based on diesel generators.
Reducing CO2 emissions from energy supply is becoming a top priority in order to achieve the politically agreed energy transition goals. Armed forces worldwide are also bound by the political decisions of 2015. Hybridisation of the energy supply through battery storage in combination with renewable energies reduces logistics costs and transport risks as well as operational costs during deployment. As part of the renewal of the energy infrastructure of NATO forces, it is to be aligned in such a way that strategic and tactical advantages can be realised among themselves. Within the NATO forces, the Bundeswehr plays the technological pioneering role.
The conversion of the energy supply in the military will take place in two stages:
Hybridisation of diesel generators with PV and battery
Renewable energies as primary energy source with fuel cell and diesel backup (1st and 2nd stage for 300% fail-safety)
In the first step, existing and new diesel generators can be hybridised for this purpose. By hybridising power generation, the advantages of self-sufficient energy systems and those of power generation by diesel generators can be combined and enormous advantages in terms of efficiency, comfort, sustainability, cost reduction and safety can be achieved. In addition, the integration of renewable energy sources into an existing system is simplified. They can be simply scaled according to increasing requirements and restrictions and gradually integrated into the energy system via the procured battery storage systems.
Intelligent battery storage supports both stages of the military energy transition. With complete independence from generation sources, centralised stationary storage (ECS) can be operated effectively during the technological transition of generation sources. This not only increases security of supply, but also future-proofs current procurement procedures.
The combination of ECS and our new development for demanding applications – the ARVEY B2 – enables the exploitation of synergy effects between mobile and stationary storage units. Together, they can be used as an integrated system solution for hybridisation in the military sector according to demand. This makes energy usable in all applications.
The mobile units of the ARVEY B2 can be pushed into a rack and coupled with the central charging station (ECS). In doing so, the mobile units can basically fulfil two tasks:
- Prioritised charging for the fastest possible operational capability.
- Short-term expansion of the storage capacity of the central charging station in case of load peaks in consumption or generation.
- The intelligent system control of the ECS decides along the historical load curves how the coupled ARVEY B2s are used. Due to the complete integration, the ECS becomes the data node where the load curves of the mobile and stationary units are aggregated. In this way, additional information can be obtained about power utilisation in the field. The granularity of the data allows optimisation of the energy infrastructure of a camp or deployment scenario during operation.
HYBRID MISSION SUPPLY – INCREASING CONSUMPTION DUE TO ELECTRIFICATION
In military use, almost all applications are supplied by diesel generators. Whether in mobile or stationary use, the core of the power supply is one or more central units. From these, the electricity is brought to the respective consumers through distributors and cables. Due to the fixed power classes, oversized power generation units are often used to cover the supply. This leads to inefficiencies and increased emissions of heat and waste gases. In addition, there is a high potential for danger in the logistical handling of fuels in the area of use. This potential danger can be contained by reducing fuel consumption. Hybridisation complements existing and new power generation units, thus reducing the peak load demand on the unit and increasing the resilience of the supply.
Electricity consumption will continue to increase in the future due to the increasing electrification of individual applications, unmanned vehicles, increasing computing power and new communication standards as well as comfort. By making energy supply more flexible through battery storage, supply and demand can be matched more easily. This reduces inefficiencies in the system. Battery storage systems increase the tactical flexibility of the energy supply. Hybrid systems have enormous advantages, especially in the field of first response and e.g. in disaster control. Due to the direct operational capability without set-up and commissioning times, energy can be provided and called up ad-hoc. Diesel generators take longer to get up and running in the field. Once these have been set up, a hybrid power supply can realise the advantages mentioned.
Hybridised diesel generators can also be used in the continuous supply of power to camps and individual smaller applications. Due to the permanent operation of the systems, the realised advantages are even stronger. The power of large central diesel generators can be buffered in battery storage and distributed more efficiently throughout the camp. Especially due to the increasing electrification of vehicles, an adapted charging infrastructure is needed. Central battery storage can also be used to charge several vehicles simultaneously overnight without other applications experiencing a supply deficit.
Especially in mobile applications, battery storage units increase the flexibility in supplying the applications. Charged in central buffer storage units, mobile units such as the ARVEY B2 can be transported in the vehicle to the place of use and the stored electricity can be used immediately on site. In hybrid operation with a diesel generator, temporary applications such as radio or the complete supply of mobile warehouses can be operated.
HYBRIDISATION IN THE FUTURE – DIVERSIFICATION OF ELECTRICITY GENERATION
For the complete decarbonisation of energy supply, a substitute energy carrier must be found that provides energy on demand, safely, without great effort and regeneratively. In addition, the energy carrier must be easily adaptable in volume and scale to the requirements of the respective application. The first step on the way to an environmentally friendly energy supply is to exploit the potential for increasing efficiency and the hybridisation of existing diesel generators. Further down the road, energy systems will also become increasingly hybrid, i.e. more diverse. In the future, a mix of stationary, mobile and ultra-mobile battery storage systems will ensure that energy is distributed safely and reliably and made available as needed for each application. These will be charged by renewable energies from the sun, wind and water. To secure the supply, fuel cells are increasingly being integrated into the overall system. However, since different framework conditions for generation prevail for each application, different combinations of generators must increasingly be aggregated together via battery storage.
AXSOL Energy Container Solutions are perfectly suited to build hybrid energy systems and microgrids due to their independence from the generation source. Different generator sources (AC and DC) can be connected to the power electronics at the same time. The intelligent system control bundles the data of the integrated generators and consumers and decides on the energy flow in the system according to the situation. The aim is to give priority to the use of renewable energy generators and to minimise supply costs. The system control optimises the energy flow and ensures the ideal energy mix in the supply.
Battery storage and renewable energies will play an increasing and more important role in the energy supply. Battery storage will become the data hub for decision-making regarding energy distribution and use. Smart energy systems enable operational synergy effects between mobile and stationary energy supply. Such as between electric real estate and stationary storage for grid backup and support. In this respect, the public energy infrastructure can also be optimised during operation.
The battery capacity of the ECS is modularly adaptable to the application. The total capacity can be scaled in 3 MWh steps in the maximum expansion stage. In the future, other storage systems, e.g. chemical storage, can also be integrated into the hybrid system in order to further reduce the dependency of the energy supply during operation. For this purpose, hydrogen can be produced from the surplus production of renewable energy sources by electrolysis. This can be used in the power-to-X principle for heat or mobility, or converted back into electricity by fuel cells. Thanks to the freely adaptable platform of the Energy Container Solutions, future developments can also be integrated. Investments in the field of energy infrastructure thus remain future-proof even in the face of constantly changing circumstances.
