The lower the feed-in compensation for electricity from biogas plants or photovoltaic systems, the more attractive self-consumption becomes. In the future, energy generated within agricultural operations should be used more for mobile agricultural machinery. Focus is increasingly shifting to electromobility concepts. Which technologies do farmers require to intelligently combine electricity, agricultural machinery and electric vehicles? The leading trade fair for decentralised energy supply, which takes place in parallel with EuroTier in Hanover, intends to provide answers to these questions.
Sustainable mobility that does not impact on the climate: this sounds like a vision of the future to many people, but has long been put into practice on Ludger Willeke's farm with networking of regeneratively produced energy and charging infrastructure for e-mobility. To accomplish this, the farmer from Bergkamen in North Rhine-Westphalia has coupled his combined heat and power plant (CHP) with an ORC system. ORC stands for Organic Rankine Cycle and means the use of waste heat for subsequent electricity generation. While the electricity from the farm's own biogas plant is fed into the grid, the energy generated from the waste heat flows directly into an e-charging station. Naturally, the farmer himself drives an electric car – but he also makes his charging station available for public charging.
The electricity charging station on the farm
The example of Ludger Willeke shows that there is still a great deal of hidden potential in biogas plants in Germany. Farmers who have recognised this trend are working towards making their combined heat and power plants more flexible – and can therefore contribute to increasing the density of electricity charging stations in rural regions. Electromobility in combination with cogeneration is rapidly gaining in popularity. This basically involves a function on the CHP control panel which indicates that priority is to be given to immediate electricity generation at the push of a button. The electric vehicle charging function then remains activated for two hours. The heat produced during this time does not go to waste but is instead fed into a buffer storage system up to its maximum capacity.
Electromobility on the fast lane
There are multiple advantages to electromobility in agriculture. It is quiet, clean and – if the electricity is generated using renewable energies – environmentally friendly. Purely electrically driven wheel loaders, telescopic loaders, farm trucks or self-propelled feed mixer wagons are now available on the market in fully-developed form and for all needs. The requirements on the vehicles are clearly defined: they have to offer the same performance as the versions with a combustion engine and may not be significantly more expensive. Electric motors with high-voltage technology are responsible for their working and traction hydraulics. 48 volt lead acid batteries or high-powered lithium-ion rechargeable batteries are installed where the diesel tank is normally located.
The exhibitors at EnergyDecentral will present appropriate systems for enabling the combination of decentralised energy generation and electromobility. Different charging scenarios offer a practical solution for virtually any usage behaviour. The fully electric vehicles with all-wheel steering can be 'refuelled' using either a standardised CEE farm socket or a super charging option with direct voltage. This type of quick charging during the lunch break provides the driver with sufficient power throughout the working day. Partial electrification is another concept for integrating renewable energies into machinery used for agricultural purposes. The crucial element here is battery exchange concepts in which a mobile energy storage system is transported as required and used in another location. The key feature of this is that the lithium iron phosphate batteries are not installed directly in the vehicles but are instead coupled – in the place of a ballast weight, for example.
Diesel-electric drive as an alternative
The future of electric agriculture has begun. It is being spurred on by the prospect of new, high-performance electric motors. Not only Tesla and co. are now working feverishly to develop batteries with increased capacity and quick charging stations. Electric drives for commercial vehicles are being zealously developed in the design engineering offices of many manufacturers and in research facilities. Hybrid electric vehicles with either an electric or a diesel-electric drive are currently becoming established as an additional variant. Here, the engine practically carries its own power plant around with it and is used only to provide the energy necessary for the vehicle. It is completely decoupled in mechanical terms and is not directly related to the vehicle speed or PTO shaft speed. The diesel engine, which operates at a constant rotational speed, supplies the energy for the drive and charges the battery at the same time in hybrid mode. If the battery then supplies the complete drive system, the diesel electric vehicle operates entirely without emissions.