Battery electric drives configure very well to powering the agricultural equipment incorporating these trends. But how can battery electric drives be realized based on the energy flows required to maintain or better the in-field productivity of modern farming operations?
In Future Farming’s Expert Opinion ‘Robots lead the way to diesel-free agriculture’, chief editor Geert Hekkert pointed out the constraints faced to replace traditional fossil fueled powered equipment with battery electric powered equipment. The energy balance just doesn’t add up and the prospects for electric batteries to compete against the current large scale diesel fuel powered equipment appears to be low.
However, in the article, Geert Hekkert also pointed out the trend towards the development of smaller scale, autonomous, battery electric powered equipment. This type of equipment coupled with the right type of battery charging system addresses the energy balance and affords the in-field productivity modern farming requires.
Biomass of All the World’s Mammals
Not 100% fossil fuel nor 100% one large scale battery
Essentially, one large scale, diesel fuel powered machine is replaced with several smaller scale, autonomous, battery electric powered machines and mobile, in-field, ultra-fast battery charging. The smaller machines cycle at staggered intervals between the in-field work and a continuously operating charger. Think of this approach as a redistribution of the energy flows, not 100% fossil fuel nor 100% one large scale battery. Fundamentally, this approach is a distributed battery model with base load charging.
As an example, one tractor converting 980 kW of diesel fuel power to 230 kW of drawbar power is replaced with eight 24 kWh battery electric autonomous tractors (each delivering 38.3 kW of drawbar power) and two 150 kW chargers. Six of the smaller scale, autonomous tractors operate in the field while the remaining two tractors are charging. A charge time of 8 min restores 80% of an individual tractor’s battery charge. The next tractor in the cycle requiring a charge returns from the field while a charged tractor returns to the field.
Containerized battery charging system
SANDGEO Inc. is developing a containerized battery charging system for the outlined scenario. Known as Bio-Charging™, the development involves the integration of (1) biomass fuel supply, (2) novel biomass fuel conversion technology (3) ultra-fast battery charging and (4) the equipment interface. The biomass fuels consist of sustainably sourced forestry wastes and/or crop residues. These types of renewable fuels provide the firm capacity required for the large power, high duty cycle charging at the field site. The field equipment is scheduled with the mobile, in-field charging system to charge equipment batteries between the optimal range of 10% to 90% of rated energy storage capacity.
In addition to agriculture, the concept and technology has wide ranging applications in the utility, transport, mining, construction, and forestry sectors. Any locations with large loads, high duty cycles and restricted access to significant utility power supply are a fit for Bio-Charging™
