An energy system completely reliant on renewables requires an energy carrier to mitigate the geographic and seasonal variability of such resources. The cost of renewable electricity is now below the cost of hydrocarbon-generated electricity, and low enough that it is economically sensible to produce fuels using renewable electricity (Power-to-X). Aluminum is well suited to play the role of “X” in a power-to-X system. Aluminum possesses the characteristics that are most important for a sustainable energy carrier: high energy density, abundance, recyclability, and it is anticipated that the alumina-reduction process will soon be free of carbon emissions. Oxidation of aluminum yields a cycle efficiency of approximately 25% if the product(s) of oxidation are used to power a heat engine with an efficiency of 40%. This compares favourably to other proposed energy carriers, such as hydrogen and ammonia. These fuels yield cycle efficiencies of no more than 23% and 18% respectively, if the carbon-free production route is used to produce the hydrogen and ammonia. Aluminum fuel can be competitive with a $50 barrel of oil if the reduction process is powered by electricity priced at $26/MWh or less.

完全依赖可再生能源的能源系统需要能源载体来减轻此类资源的地理和季节性变化。现在，可再生电力的成本低于碳氢化合物发电的成本，并且足够低，以至于从经济上讲，使用可再生电力（Power-to-X）生产燃料是明智的。铝非常适合在Power-to-X系统中扮演“ X”的角色。铝具有对于可持续能源载体最重要的特性：高能量密度，丰度，可回收性，并且可以预期，氧化铝的还原过程很快将无碳排放。如果使用氧化产物以40％的效率为热机提供动力，铝的氧化产生的循环效率约为25％。与其他提议的能量载体，例如氢和氨相比，这是有利的。如果使用无碳生产路线生产氢气和氨气，这些燃料的循环效率分别不超过23％和18％。如果还原过程由价格为26美元/兆瓦时或更低的电力驱动，则铝燃料可以与每桶50美元的油竞争。