Questões de Concurso Para unicamp

  Mining trucks are monstrous machines that guzzle fuel at a scarcely believable rate. Weighing 220 tonnes, they can get through 134 litres of diesel every hour. Little wonder then that mining companies are focusing their attention on these vehicles as the first step to reducing their carbon footprint.

    Anglo American, in collaboration with several partners, is retrofitting a mining haul truck with hydrogen power technology. A first of its kind, the monster mining vehicle is being piloted in Limpopo, South Africa, at the firm’s Mogalakwena platinum mine. Due to be launched early 2022, the truck will be hybrid, with a hydrogen fuel cell providing roughly half of the power and a battery pack the other half.

    Instead of having a tank of diesel that powers the motor, hydrogen enters the fuel cell and mixes with oxygen to create water in a chemical reaction catalysed by platinum, which generates the electricity needed to power the motors that drive the wheels. By rolling out this technology across its global truck fleet, Anglo American says it will be “taking the equivalent of half a million diesel cars ‘off the road”.

    The construction sector, which includes mining, accounted for 39% of energy-related CO2 emissions in 2017, according to Davide Sabbadin, from the European Environmental Bureau. He says the sector will need to reduce its energy consumption by a third if it hopes to be compatible with the Paris Agreement. “While electric-powered vehicles, generally speaking, are less damaging to the environment than internal combustion engines on a life cycle analysis, this does not mean that they are green,” he says. It all hinges on how the hydrogen is produced. Some hydrogen is created using fossil fuels, which of course means there are substantial emissions as a result. “We should refrain from presenting hydrogen as a technological solution to all problems… all forms of hydrogen come at an environmental cost – water use, impacts on nature,” says Mr Sabbadin.

(Jesse Preyser. www.bbc.com, 21.12.2021. Adaptado)