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17/10/2021

O balão de hidrogénio do Dr. Galamba ou mais um elefante branco a caminho (5) - Antes de se começar a torrar o dinheiro conviria perceber o que se pode fazer com o H2

«Amid the excitement, it is worth being clear about what hydrogen can and cannot do. Japanese and South Korean firms are keen to sell cars using hydrogen fuel cells, but battery cars are roughly twice as energy efficient. Some European countries hope to pipe hydrogen into homes, but heat pumps are more effective and some pipes cannot handle the gas safely. Some big energy firms and petrostates want to use natural gas to make hydrogen without capturing the associated carbon effectively, but that does not eliminate emissions.

Instead, hydrogen can help in niche markets, involving complex chemical processes and high temperatures that are hard to achieve with electricity. Steel firms, spewing roughly 8% of global emissions, rely on coking coal and blast furnaces that wind power cannot replace but which hydrogen can, using a process known as direct reduction. Hybrit, a Swedish consortium, sold the world’s first green steel made this way in August.

Another niche is commercial transport, particularly for journeys beyond the scope of batteries. Hydrogen lorries can beat battery-powered rivals with faster refuelling, more room for cargo and a longer range. Cummins, an American company, is betting on them. Fuels derived from hydrogen may also be useful in aviation and shipping. Alstom, a French firm, is running hydrogen-powered locomotives on European tracks.

Last, hydrogen can be used as a material to store and transport energy in bulk. Renewable grids struggle when the wind dies or it is dark. Batteries can help, but if renewable power is converted to hydrogen, it can be stored cheaply for long periods and converted to electricity on demand. A power plant in Utah plans to store the gas in caverns to supply California. Sunny and windy places that lack transmission links can export clean energy as hydrogen. Australia, Chile and Morocco hope to “ship sunshine” to the world.»

Excerto de Hydrogen’s moment is here at last

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