Leopard 2 with electric drive A big cat on quiet paws

Electromobility is becoming more and more widespread: after e-scooters, e-bikes and electric cars, trucks and buses, tanks are now also set to get an electric drive. At least that's what the German defense supplier Renk is planning: in collaboration with the British defense company QinetiQ, Renk wants to equip the Leopard 2 tank with a hybrid drive. But how suitable is an electric tank for everyday use on the battlefield?

Electric drives in a military context are not a new invention. Engineers were already experimenting with hybrid-electric locomotives during the First World War to bring ammunition trains closer to the front where steam boilers were too conspicuous. The problem: weight and sensitivity.

There were also similar experiments during the Second World War. German tank developers experimented with electric drive - for example in Ferdinand Porsche's Maus project. The 188-tonne colossus used an internal combustion engine to drive generators that fed the electric motors. However, the result was too heavy, too complex and too maintenance-intensive.

Even more recently, around the 1980s, the US Army tested all-electric vehicles for reconnaissance purposes. However, the batteries were still too heavy and therefore the range was too short.

Electric drives allow military vehicles to stalk silently

Thanks to the enormous progress made in battery technology, electric drives are no longer utopian, even in military technology. The Australian government, for example, is planning to gradually replace its army vehicles with electric equivalents. The advantage: electric military vehicles are almost silent on the road.

According to Renk, it is precisely this advantage that speaks in favor of the planned Leopard 2 with hybrid drive. The so-called "silent-watch operation" causes very little noise. In addition, the tank could quickly leave its position ("escape boost") in an emergency thanks to the additional electric drive, as starting a tank's diesel engine takes a lot of time.

In practice, the hybrid tank would drive purely electrically until the combustion engine switches on at a certain speed. Charging at a charging station is not necessary, as the batteries are charged by the diesel drive via a generator. Consequently, no charging stations need to be available on the battlefield.

Hybrid drives for military tracked vehicles

But would all-electric military vehicles also be conceivable? In the case of the Leopard 2, the answer to this question is currently still a clear "no". All you have to do is estimate the energy consumption of the 60-ton monster, as the e-engine electric mobility portal has shown. According to this, the fuel consumption of the Leopard 2 is up to 530 liters of diesel per 100 kilometers when used off-road; on normal roads, it is still around 410 liters.

The best cells currently available have an energy density of 450 Wh/liter. Since a purely electrically powered tank does not require fuel tanks, the Leo's tanks with their volume of 1,200 liters could be filled with batteries. This would result in a battery capacity of 540 kWh. As the MTU MB 873 Ka-501 turbine would also be eliminated, this would result in a gross battery capacity of around 1 MWh, of which 960 kWh would be usable based on experience.

1,200 liters of diesel weigh about 1 ton, the diesel engine about 2.2 tons. The imaginary battery would weigh around 6.25 tons. This would make the electric Leopard around three tons heavier than the diesel model. The electric Leopard would consume around 1,412.25 kWh per 100 kilometers, giving it a range of just 67 kilometers. If the energy requirements of the entire on-board electrics and electronics are also taken into account, the possible range drops even further - and it would be even shorter in winter.

As we know, there are no fast-charging stations on a battlefield, so the all-electric Leo would have to be constantly accompanied by a tanker with a diesel generator to recharge the batteries if necessary - a fantastic target for enemy attacks! With today's battery technology, an electric tank comparable to the Leopard 2 is therefore conceivable, but a very bad idea.

Fully electric wheeled armored vehicle with diesel engine as a range extender

But it doesn't have to be a 60-ton tracked vehicle if you're thinking of all-electric military vehicles. A few years ago, Flensburger Fahrzeugbau GmbH (FFG) proved what is possible with its all-electric Genesis wheeled armored vehicle, which can even dive. The prototype is an 8x8 wheeled armored vehicle in which each of its eight wheels is driven by a 171 kW electric motor. A diesel engine, which is also installed, works as a range extender that charges the batteries while the vehicle is in motion.

The Genesis prototype weighs 25 tons and can transport deployment modules weighing up to 15 tons. The vehicle reaches a top speed of up to 100 km/h and has a range of up to 150 kilometers in purely electric mode, and even up to 600 kilometers with the range extender running.

In addition to manned military vehicles, unmanned vehicles of up to 20 tons could initially also be equipped with hybrid engines. According to Renk, electrification and hybridization open up great opportunities for growth. The company is certain that military forces around the world will rely on hybrid drives and the digitalization of their vehicles in the future. However, this would entail higher costs. Renk CEO Susanne Wiegand therefore anticipates a massive increase in global defense spending.

This is also confirmed by an analysis by the global market research and management consulting company Global Market Insights Inc. according to which the size of the military vehicle electrification market amounted to around USD 4.7 billion in 2023 and is expected to grow to more than USD 38.5 billion by 2032.

Fuel must also be transported in the future

Electrification of military vehicles is certainly the right way forward for environmental reasons. However, it will ultimately not be possible to do without diesel, as the fuel will still be needed for generators to charge the quiet vehicles. One way out of this dilemma would be the fuel cell, which could charge the smaller and lighter batteries of fully electric vehicles. Numerous trucks and buses already on our roads today prove that it works. The tanker vehicles would then have to drive hydrogen instead of diesel to the battlefield. (tk)

Thomas Kuther is a freelance specialist journalist and owner of Kuther Media Service.