A British Army Challenger 2 tank on exercise in Oman.
The British Army has been told it must be environmentally friendly to attract future recruits.
Speaking in London at the defence and equipment event, DSEI, Chief of the General Staff General Sir Mark Carleton-Smith said the Army's current fleet of vehicles and tanks could be the last to run on fossil fuels.
General Carleton-Smith said the Army "is leading defence in sustainable energy solutions" but admitted more must be done.
"I think we may be at that inflection point in how we power our next generation of vehicles," he said.
"Our current equipment programme is possibly the last to be dependent on fossil fuel engines."
WATCH: How the Army could become more eco-friendly.
He also said he has ambitions for the UK to lead the world in the development of military equipment which is "not only battle-winning but also environmentally sustainable".
"Not only does that give the British Army considerable operational benefits, such as reducing our logistics drag, it also puts the Army and indeed your own organisations on the right side of the environmental argument," Gen Carleton-Smith added.
"Especially in the eyes of that next generation of our future recruits who increasingly make career decisions based on a prospective employers' environmental credentials."
The design of environmentally sustainable vehicles is now a priority for the Army after the Government announced plans to cut carbon emissions to zero by 2050.
Industry experts QinetiQ, who have been given a £3.5m contract to design hybrid land warfare vehicles, say they could be in service within a decade.
Lighter loads could also help fuel efficiency with some developers managing to slash the weight of ammunition by more than a quarter.
Richard Brown, from BAE Systems, told Forces News at DSEI: "If you take a pair of machine gunners, carrying perhaps a thousand rounds between them, this could save about eight-and-a-half kilos which is like the equivalent of three, heavy house bricks.
"It could make a real difference."
The burning of fossil fuels over the centuries has contributed to the release of carbon dioxide and other greenhouse gases into the air, causing temperatures to rise and changes to weather.
Data recently published by the European Union's Copernicus Climate Change Service showed that July this year was the warmest month on record for the world.
During General Carleton-Smith's keynote speech, he said climate change will have a "profound impact" on how the Army is going to operate in the future.