Wednesday, 26 August 2020
Ben Williams, Knowledge Transfer Senior Manager, explains why pig farmers need to consider investing in energy solutions as we continue to face the increasingly rigorous demands of permitted agriculture.
"I am a critic, not convinced of the ability of technology to deliver what we require." This is not the fault of the technology but the inability of policy, society and markets to provide a suitable ‘ecosystem’ in which that technology can deliver returns.
Evaulating existing and emerging technologies
We've recently commissioned NFU Energy to produce an analysis of existing and emerging technologies in light of the buildings survey.
The pork GrowSave report is a starting point for suggesting energy solutions UK producers may wish to invest in as the UK agriculture continues to drive towards net zero and face the increasingly rigorous demands of permitted agriculture.
Stalwart solutions – air scrubbers, heat exchangers, insulation and renewables – topped the discussion, but something different, those exciting what ifs, has also emerged, often already being trialled in the far corners of UK pig production.
One for me that needs to be explored is that of generating hydrogen from slurries, not because I believe we should switch the world to a hydrogen economy, as I don’t, but because it captures the true value of the pig – a circular economy.
"Pigs, for me, are the great improver, they take ‘waste’ – by-products from other industries – and they make them useful, as feed, bedding and now their own ‘wastes’ may power their environment, the machinery that produces their and our feed and so on."
Hydrogen electrolysis is a commercially viable solution backed by research. 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 33 kWh of electrical energy. If the electricity for electrolysis comes from renewables (wind and solar), there is no ‘direct’ release of CO2 in generation of the hydrogen or burning of it for power. So what are the barriers to making the most of this seemingly abundant (we all have plenty of slurry), 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. There is still work to do, with changes needed to government policy on local energy generation, making sure the technology is accessible to producers and, importantly, that adds up to a clearly defined return on investment.
Explore slurry cooling
The future is now; we will continue, as part of its strategy, to support producers to drive towards net zero. Starting with slurry cooling and moving forwards, we’ll produce more resources for producers to see what technology can deliver and, more importantly, what it will return for their business.
For further information visit on slurry cooling visit, ahdb.org.uk/knowledge-library/slurry-cooling