New Zealand pork industry revives interest in power from pig manure
New Zealand's agriculture authorities are probing the potential of pig manure to provide biogas for energy use on farms.
The Pork Industry Board, Ministry of Agriculture and Forestry (MAF) and the Energy Efficiency and Conservation Authority (EECA) will take into account the potential to not only produce heat or electricity, but to reduce greenhouse gas emissions.
Farm biogas digesters convert methane emitted from farm manure into renewable energy, and at the same time can limit nutrient run-off.
During the oil shock 35 years ago, some New Zealand farmers used a simple system to capture the methane gas from pig manure and used it to run vehicles or machinery.
Methods of using the manure can vary from anaerobic digestion, where pig manure is mixed with crop wastes and decomposes to produce methane feeding an electricity generator. The by-products from the process are a natural fertiliser, plus carbon dioxide when the methane is burned.
Other technologies include manure gasification, where the manure is heated to produce methane, and fast pyrolysis, where it is heated to produce a liquid fuel.
New Zealand's pork industry has potential to produce over 8500 tonnes of methane annually, generating over 100 Giga watt hours (GWh) of renewable energy each year.
Pork industry chief executive Sam McIvor said the sector had identified an opportunity to better manage emissions. McIvor added that they are committed to taking a lead role in the reduction of industry emissions and already have several projects underway.
The 8-month energy trial in partnership with EECA and MAF meant researchers could identify the most effective projects and share that knowledge with farmers.
The project will assess up to 10 individual farm biogas systems across various regions and farm sizes and the results will be used to inform the industry of the most effective opportunities for their farms.
McIvor said the feasibility studies will create a basis of knowledge for pork producers, whether small or large, to learn about new options to create additional energy, and therefore value, from manure.
The pork industry hoped that it might develop a regional biogas network to help the primary production sector as a whole reduce greenhouse gases, McIvor added.