A stable energy supply will require balancing the fluctuations of renewable energy generation due to the transition to renewable energy sources. Intraday and seasonal storage systems are often limited to local geographical or infrastructural circumstances.

This study experimentally verifies the application of inexpensive and abundant natural iron ores for energy storage with combined hydrogen and heat release. The incorporated iron oxides are reduced with hydrogen from electrolysis to store energy in chemically bonded form. The on–demand reoxidation releases either pure hydrogen or high-temperature heat as valuable products. Natural iron ores as storage material are beneficial as the specific costs are lower by an order of magnitude compared to synthetic iron oxide-based materials.

Suitable iron ores were tested in TG analysis and in a 1 kW fixed-bed reactor. Siderite, a carbonate iron ore, was verified as promising candidate, as it shows significantly lower reaction temperatures and twice the storage capacity over other commercial iron ores such as ilmenite. The specific storage costs are as low as 80–150 $ per MWh hydrogen stored, based on the experimental in-situ tests. The experimentally determined volumetric energy storage capacity for the bulk material was 1.7 and 1.8 MWh m⁻³ for hydrogen and heat release, respectively. The raw siderite ore was stable for over 50 consecutive cycles at operating temperatures of 500–600 °C in in-situ lifetime tests.

The combination of high abundance, low price and reasonable capacity can thus result in very low specific energy storage costs. The study proofs that suitable natural iron ores are an interesting economic solution for large-scale and seasonal energy storage systems.

稳定的能源供应将需要平衡由于向可再生能源过渡而导致的可再生能源发电波动。日内和季节性存储系统通常仅限于当地的地理或基础设施情况。

本研究通过实验验证了廉价且丰富的天然铁矿石在结合氢和热释放的能量存储中的应用。掺入的氧化铁被电解产生的氢气还原，以化学键合的形式储存能量。按需再氧化释放纯氢气或高温热作为有价值的产品。天然铁矿石作为储存材料是有益的，因为与合成氧化铁基材料相比，具体成本要低一个数量级。

合适的铁矿石在 TG 分析和 1 kW 固定床反应器中进行了测试。菱铁矿是一种碳酸盐铁矿石，被证实是有希望的候选者，因为它的反应温度显着降低，存储容量是钛铁矿等其他商业铁矿石的两倍。根据现场实验测试，特定的储存成本低至每 MWh 氢气储存 80-150 美元。实验确定的散装材料的体积能量存储容量分别为 1.7 和 1.8  MWh  m ^-3用于氢气和热量释放。在原位寿命测试中，在 500–600 °C 的操作温度下，菱铁矿原矿在 50 多个连续循环中保持稳定。

因此，高丰度、低价格和合理容量的结合可以导致非常低的比储能成本。该研究证明，合适的天然铁矿石是大规模和季节性储能系统的一种有趣的经济解决方案。