Hydrogen electrolysis

How much energy is produced?

Electrolysis of ammonia in waste water consumes just 1.55 kWh of electrical energy to produce 1 kg of hydrogen. When used as part of a fuel cell, 1 kg of hydrogen can produce up to 23 kWh of electrical energy, but this figure could be lower with an older battery.

If the electricity for electrolysis comes from renewables (wind and solar), there is no ‘direct’ release of CO₂ when generating, or burning, the hydrogen.

What are the benefits?

So what are the benefits of this abundant, clean (the waste product is water) and potentially valuable energy source?

Some pig farmers in the UK have used this method to produce hydrogen. Firstly, they found out how much ammonia and hydrogen is harvestable using a slurry flushing system, and at what value in carbon and monetary terms. Simply put, it’s worth circa £300,000 per year on a 500-sow unit (£20 per finished pig).

It can also be part of a strategy to achieve zero emissions, with the hydrogen used to power machinery, grow cereals and combined with the use of co-products, where carbon is counted in the primary product. Using heat recovery with segregated air inlets via underground cooling ducts for all-year-round temperature stability, with harvested heat used to evaporate water from slurry, producing saleable pelleted fertiliser, there is no need for a slurry store.

Hydrogen technology is not new, hydrogen has been extracted from ammonia sourced from fertiliser production for years, but it could be fossil-fuel free. 

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