GrowSave – Pork

In the pork sector, we have been reviewing existing, new and emerging technology and identifying where there are gaps or room for improvements. The aim being to find ways to improve business performance, increase energy efficiencies and climate control and reduce carbon emissions. This has included investigating best practices in the UK as well as in other European countries, particularly Belgium and the Netherlands.

Technology review

Our technology review is a starting point for suggesting energy solutions producers may wish to invest in as UK agriculture continues to drive towards net zero and face the increasingly rigorous demands of permitted agriculture. The aim of the initial stage was to identify emerging technologies in the pork sector and to investigate their viability and cost effectiveness.

Solutions such as air scrubbers, heat exchangers, insulation and renewables topped the discussion, along with slurry cooling and lighting. But another option also emerged – generating hydrogen from slurry.

The technique of cooling slurry before it leaves the pig shed brings two major benefits: ammonia suppression and heat recovery. Which of these has the upper hand depends on the individual installation.

Slurry breakdown is slowed by cooling from electric heat pumps, delivered via a network of pipes buried beneath the slurry channel; this makes the technology more suited to new buildings. Heat recovery at 45°C is most efficient, but 60°C is possible, being well suited to wash water preheating, or other heat demands. The quantity of heat generated depends on the amount of slurry and cost savings depend on the displaced heat source (e.g. gas boiler, direct electric).

Now energy-efficient LED lighting is widespread, specialist products with tailored spectral output are emerging. Providing a dairy herd with 16 hours per day of blue-rich light can increase milk yield – but the technique has benefits for pigs too. One supplier of such lighting claims that Danish studies on pigs recorded a growth increase of 3-5%, or about a week, sow lactation improved, piglets grew more quickly, and weaning weights increased.

Of course, the cheapest daylight is natural daylight. Now under development, a multi-layered fibre roofing sheet admits 20% daylight. Weighing far less than conventional materials, it needs less support, bringing cost savings for new buildings.

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 when generating, or burning, the hydrogen.