Especially in professional, mobile, and safety-critical application environments, diesel is an important energy storage medium. Whether on construction sites, 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 netZero by 2050. Increasing electrification of all applications will increase electricity consumption by 2030. Hybridization of these generators can meet the rising consumption in a cost- and energy-efficient manner.

Hybridization in the true sense describes a mixed form of previously separate systems. For most people, the best-known example is probably the hybrid vehicle. Here, the diesel or gasoline-powered engines of the vehicles are augmented by an electric motor and a battery. The goal is to boost performance, reduce the load on the internal combustion engine, and thus lower fuel consumption. By coupling the two systems, individual technological features of each solution are combined to create unique benefits for the user.

The same principle can be applied to diesel or gasoline generators. The genset can be coupled with a battery storage system with corresponding power electronics. Especially under consideration of further increasing fuel prices in the future (CO2 tax), a genset can be operated economically for a longer period by reducing consumption. Especially in connection between generator, storage and PV array advantages can be realized. The additional solar energy stored in the batteries reduces the demand from fossil fuels and additionally lowers CO2 emissions.

Advantages of hybridization of diesel and gasoline generators

The combination of battery storage systems and generators alone creates advantages in use and financially. Ideally, the following benefits can be realized:

  • Up to 100% fuel savings.
  • Up to 90% less maintenance required on the generating set.
  • Up to 10 times longer genset life.

Each generator has a specific optimum speed range where power generation is most efficient. This is usually between 75 and 100%. If the genset is oversized, the supply becomes more inefficient in proportion to the oversized design. In hybrid systems, the consumer is supplied by the generator power 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 supplied by the stored capacity through the power electronics. 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 required on the generator due to higher running times in the optimum power range and fewer operating hours. Generator maintenance cycles are based on operating hours (or miles driven), just like cars. If the operating hours are reduced in each period, the maintenance cycles are extended accordingly.

Overall, the life expectancy of generators is increased, thus maintaining, or even increasing their economic efficiency even as fuel prices rise. Decisive for the increase in generator service life are downtimes and the capping of peak loads (peak shaving) by the power electronics of the battery storage system. More frequent and consistent use of the genset’s specific optimal power range also reduces loads and extends service life and efficiency.

In addition to the increase in efficiency, further fuel can be saved through the input of renewable energy, which additionally charges the coupled battery storage system. This further reduces energy costs, maintenance, and emissions. Below, the red line describes the ideal expression of all characteristics of an energy supply in a military environment. Possible total score is 110 points. Evaluation and comparison in the table below.

 PointsPercent
Total score110100
Diesel supply5045
Renewable supply8981
Hybrid supply10495

In addition to the increased efficiency of the overall system and the resulting reduction in costs (OPEX) due to fuel savings, the safety and resilience of the supply increase. Fuel savings reduce the logistical effort of the supply. Downtime increases convenience. Overall, the reduction in fuel and emissions leads to a more sustainable supply for the application.

In the hybrid vehicle, the power output of the internal combustion engine and electric motor is coupled to achieve tremendous acceleration values. The possibility of boosting the power output of the genset by the battery storage system means that 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 minimized and its service life extended.

HYBRIDIZATION OF DIESEL GENERATORS THROUGH THE SOLUTIONS OF AXSOL GMBH

AXSOL GmbH solutions are designed to be as independent as possible from the power source. All battery storage systems are chargeable by the grid, but also renewable and conventional generators. AXSOL GmbH products are the perfect complement for new and existing generators and realize benefits from the first use. Through their hybridization, immediate cost and emission savings can be realized.

For the ARVEY B2, specially designed for use in demanding terrain, hybridization 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 generator sources, the supply becomes increasingly hybridized and fuel consumption and emissions are further reduced.

It is worth combining a generator with an ARVEY E3 or E5 and connecting the storage between the generator and the consumer. Diesel generators up to 5 kW can be easily hybridized via the charging cable. Through 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 means 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 power to the application continuously. Depending on the load, the ARVEY E5 can serve the application for hours or days. Commercially available UPSs usually only achieve minutes.

The CNHybrid comes with an AXSOL-developed power system consisting of battery storage, a mobile solar array and a small generator to back up the supply. The electronic components are integrated in the floor of a folding container. The container interior is available for any requirement without restrictions. As standard, the CHHybrid is delivered with the foldable E-Fill X 2000. 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. Excess power is used to charge the battery.  Due to the input of solar power, the operating times of the diesel generator are minimized. Overall, the energy system can provide 100 % self-sufficient operation of the container. The 300 % resilient design of the overall system provides enough power for applications in and around the container in any situation. Up to 100 % of the self-consumption can be covered by the regenerative input.

Medium configuration: 31,95 kWh battery, 10 kVa electric output,
4 kWp solar, 6 kW diesel backup

With AXSOL GmbH’s Energy Container Solutions, even large generators can be hybridized without any problems. For this purpose, the generator is connected to the storage container as a grid substitute. Connected generators can be automatically started externally when the system control of the ECS gives the command to do so. 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, optimized 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 realize the advantages for the user.

Hybridization in the defense & security sector

In the course of the decarbonization of civil society driven by the Paris Climate Agreement, state security agencies must also increasingly develop concepts to perform their tasks and processes in a greenhouse gas-neutral manner. The high demands on power supply in terms of security, durability, high performance, 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 mission (BOS) is largely based on diesel generators.

Reducing CO2 emissions from energy supply is becoming a top priority to meet politically agreed energy transition targets. Armed forces worldwide are also bound by the 2015 policy decisions. Hybridization of energy supply through battery storage in combination with renewable energy reduces logistics costs and transportation risks as well as operational costs in the field. 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 realized among themselves. Within the NATO forces, the Bundeswehr plays the technological pioneering role.

The conversion of energy supply in the military will take place in two stages:

1. hybridization of diesel generators with PV and battery.

2. renewable energy as primary energy source with fuel cell and diesel backup (1st and 2nd stage for 300% fail-safe).

In the first step, existing and new diesel generators can be hybridized for this purpose. By hybridizing power generation, the advantages of stand-alone power 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 procured battery storage.

Smart battery storage supports both stages of the military energy transition. With complete independence from generation sources, centralized stationary storage (ECS) can operate 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 hybridization 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 perform two tasks:

1. prioritized charging for the fastest possible operational capability.

2. short-term expansion of the storage capacity of the central charging station in the event of peak loads in consumption or generation.

The intelligent system control of the ECS decides along the historical load curves how the coupled ARVEY B2s are used. Through full integration, the ECS becomes the data node where the load curves of the mobile and stationary units are aggregated. This allows additional information to be obtained about power usage in the field. The granularity of the data allows optimization 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 generating sets 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 operation. This potential danger can be contained by reducing fuel consumption. Hybridization complements existing and new power generation gensets, thus reducing the peak load demand on the genset and increasing the resilience of the supply.

Electric power consumption will continue to increase in the future due to increasing electrification of individual applications, unmanned vehicles, increasing computing power and new communication standards, and convenience. By making energy supply more flexible through battery storage, supply and demand can be more easily matched. This reduces inefficiencies in the system. Battery storage systems increase the tactical resilience of the energy supply system. Hybrid systems have enormous advantages, especially in first response and, for example, in disaster control. Because they can be deployed directly without set-up and commissioning times, energy can be provided and retrieved on an ad-hoc basis. Diesel generators take longer to get up and running in the field. Once these have been set up, a hybrid power supply can realize the advantages.

Hybridized diesel generators can also be relied upon in the continuous supply of power to camps and individual smaller applications. By operating the systems on a continuous basis, the realized benefits 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 systems 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 to the site of operation in the vehicle 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.

Hybridization in the future – Diversification of power generation

For the complete decarbonization of energy supply, a substitute energy carrier must be found that provides energy on demand, safely, without great expense, 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 hybridization 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. Fuel cells are increasingly being integrated into the overall system to safeguard the supply. However, as different generation framework conditions prevail for each application, different combinations of generators increasingly need to 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 generation sources (AC and DC) can be connected to the power electronics simultaneously. The intelligent system control bundles the data of the integrated generators and consumers and decides situationally on the energy flow in the system. The goal here is to give priority to renewable energy generators and minimize supply costs. The system control optimizes the energy flow and ensures the ideal energy mix in the supply.

Battery storage and renewables will play an increasing and more significant role in energy supply. Battery storage will become the data hub for decision making regarding energy distribution and use. Smart energy systems enable operational synergies 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 optimized during operation.

The battery capacity of the ECS is modularly adaptable to the application. In the maximum expansion stage, the total capacity can be scaled in 3 MWh steps. In the future, other storage systems, e.g. chemical storage, can also be integrated into the hybrid system to further reduce the dependency of the energy supply in 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. Due 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.