Renewable Hydrogen

The Rise of Solar and Wind

Electricity production from solar and wind is booming. This has put a big dent in consumption of fossil fuels for electricity. However, we’re still highly dependent on natural gas to generate electricity when the sun isn’t shining and the wind isn’t blowing. Furthermore, we’re highly dependent on fossil fuels for transport, heating, and industrial processes. Hydrogen might help replace much of this fossil fuel energy with solar and wind energy.

Renewable Hydrogen to Replace Fossil Fuels

Hydrogen makes it possible to cover up to 100% of our electricity needs using renewable energy. Here’s how it works:

  1. Produce hydrogen using surplus solar and wind power
  2. Store the hydrogen
  3. Use the hydrogen for backup electricity generation when solar and wind production are low

Alternatively, you can use hydrogen to power a vehicle or heat your home. It’s also possible to convert hydrogen into liquid fuels (petrol, diesel, and jet fuel).

Hydrogen Production Methods

Today, most of the world’s hydrogen is made using fossil fuels. Unfortunately, this process releases large amounts of carbon dioxide. This means that most hydrogen today is not environmentally friendly.

On the other hand, it’s possible to make hydrogen using electricity instead of fossil fuels. Basically, you pass electricity through water to create hydrogen at one side and oxygen at the other. This method is very environmentally friendly as long as the electricity comes from renewable sources like solar and wind. Therefore, it has the potential to contribute to a future low-carbon energy system.

On the left, the diagram shows water molecules and the hydrogen and oxygen they contain.  In the center is an electrolyeser.  On the right are the products of electrolysis: hydrogen molecules and oxygen molecules.
Water is made from hydrogen and oxygen. Electricity can split it into these gases. Image License: CC-BY. Credit: energyd.ie

Sustainable Hydrogen Challenge #1: Production Cost

For renewable hydrogen to catch on in a big way, it has to compete with conventional hydrogen on price. The price of renewable hydrogen includes two main components: electricity costs and capital costs. Thanks to solar and wind, electricity prices can already be extremely low, especially during bright or windy periods. On the other hand, the equipment to produce hydrogen from electricity tends to be more costly.

This leads to a dilemma: After making a big investment in hydrogen production equipment, you can’t afford to wait around for low electricity prices. For this reason, lower-cost hydrogen production equipment is critical to expanding the use of renewable hydrogen.

Renewable Hydrogen Challenge #2: Storage

There are many ways to store hydrogen, but all of them come with significant challenges. Improving the cost-effectiveness of hydrogen storage will be key to making hydrogen a viable energy carrier. On the other hand, hydrogen-to-X and direct use can be more viable than storing hydrogen in some cases.

Hydrogen-to-X

With a supply of carbon dioxide, you can convert hydrogen to liquid fuels like methanol to petrol. These fuels are versatile, valuable, and easy to store. On the other hand, the conversion process is inefficient. For this reason, it only makes sense with a very cheap supply of hydrogen. Another option is to convert hydrogen to methane. The methane can then be injected into the natural gas network. Converting hydrogen to methane wastes some energy, but not as much as the hydrogen-to-liquid-fuel process.

Direct Use

The oil refining and fertilizer industries use huge amounts of hydrogen. It’s totally possible for these industries to change over to renewable hydrogen. Additionally, renewable hydrogen can be used in place of coal to smelt iron ore. Direct use, without storage, is likely to be the first area where renewable becomes widely popular. In fact, renewable hydrogen is already economically competitive and being used in niche applications. Viable applications are likely to increase over the coming years, as the technology improves.

Conclusion

Renewable hydrogen is a very versatile energy carrier with great potential to contribute to our future energy systems. The growth of renewable hydrogen now depends on technology cost reductions.

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