Using the organic waste or residues from land use, communities and manufacturing is a key objective of sustainable living and a circular bioeconomy. It also makes sound sense and can lead to economic benefits of new products and employment. We are good at producing waste from primary activities and we do it 365/24 so it is a no brainer that we should look at the value that we can extract from it. Energy and the co-products of energy are some of those products.
Most biomass used to produce energy in New Zealand is from residues or material which would otherwise be wasted to landfill. Recycling this material to produce energy follows the principles of a circular bioeconomy and the New Zealand Waste Strategy. Biomass that is purpose grown to be a feedstock for production of energy is generally only grown as a supplementary feedstock to manage fluctuations in residue availability. Some biomass is derived from a purpose grown energy crop but this is rarely done because there is generally adequate residues that would otherwise be wasted.
In some countries there are extensive areas of energy crops but in New Zealand this does not occur as the primary products from a plant, be it food, timber or other bio-based products, is the reason for the plant being grown, Recycling the residues to produce a co-product results in additional value being derived from that plant. The use of biomass residues is therefore fully sustainable.
Sources of sustainable biomass
Forests provide us with clean water, fresh air, biodiversity, recreation and help combat global warming. They also provide food, medicine and important natural resources, such as timber and paper. If managed responsibly, forests and plantations benefit forest people and the global community. However, in some countries as much as 80% of the timber is harvested illegally. This often involves violation of human rights and felling of protected forests.
Trees on farms as shelterbelts, woodlots or erosion control can be planted with the objective of sustainable farm management and land use. If planted so that the trees can be harvested at end of life or for best practice land use reasons, then this can be a source of farm income, lifestock greenhouse gas emission mitigation, and a source of either on-site energy production, or sale for other energy production.
Agriculture crops often produce a residue after the fruit, seed or food component is harvested.and which does not have a high value use and thus can be available as a source of biomass to produce energy. Dry herbaceous residues can sometimes be densified into a pellet form and used directly as a combustion fuel. Other higher moisture content residues my be better used as a feedstock for anaerobic digestion to produce biogas and biofertiliser.
Horticulture shelterbelts or crop residues can be recycled, dried and used as a combustion fuel as part of sustainable management of a horticulture operation.
Biomass from municipal applications could be treated used timber or aborist prunings.
New Zealand Government Biofuel Sustainability policies
In November 2022 the NZ Cabinet agreed the criteria for regulations to support the then proposed Sustainable Biofuels Obligation. Specifically, the Minister approving the regulations must be satisfied that both biofuels and feedstocks:
- are not likely to have a significant adverse effect on biodiversity;
- are not likely to lead to the deforestation of native forests or canopy forests or the destruction of wetlands or peatland;
- are not likely to adversely impact food and feed security;
- are not likely to have a significant adverse impact on water quality or significantly restrict its availability in an area;
- are not likely to be associated with a high risk of indirect land use change.
In addition the Minister must have regard to:
- the impacts on soil carbon of any activities that are associated with the cultivation, production and processing of feedstocks;
- the principles of the waste hierarchy.
Until the regulations are gazetted it is recommended that the criteria set out in this Cabinet decision are adopted.
Because bioenergy is sourced from combustion of plants who absorb CO2 to grow bioenergy is considered to be near carbon neutral. It is not 100% carbon neutral as some CO2 is produced from equipment recovering the biomass, processing it into fuel and transporting it to a customer.
Land use regulation
The Resource Management Act 1991 (RMA) is the main piece of legislation that sets out how the land is to be managed. The National Environmental Standards for Plantation Forestry (NES-PF) are the regulations made under this legislation that apply to any forest of at least one hectare that has been planted specifically for commercial purposes and is to be harvested. The NES-PF supersedes almost all district council plan provisions, and many of those of regional council plans, except in specific situations where the NES-PF allows councils to apply more stringent rules.
The intent of the regulations is to better protect the land and environment and to apply consistent environmental standards across the country while improving the productivity of the forestry sector and reducing operational costs. Councils previously managed the environmental effects of forestry activities through regional and district plans.
MPI has developed guidance to support implementation of the NES-PF. The guidance is targeted at regional councils, territorial authorities, and the forestry industry as the primary users of the NES-PF. The Guide is a useful tool to help interpret the rules.
The New Zealand plantation forest estate is covered by two voluntary certification standards administered by the Forest Stewardship Council (FSC) and Programme for the Endorsement of Forest Certification (PEFC)..
Many New Zealand plantation forests were originally planted for soil and water conservation reasons on erosion-prone hill country which was formerly in sheep and cattle pasture.
Once young radiata become established, they rapidly stabilise steep hillsides, protecting the soil and regulating the rate at which water is able to run off the land. The vegetative litter on the forest floor acts as a sponge — holding and slowly releasing water for many days after the last rainfall. This helps prevent destructive flooding.
Third party certification of sustainable management practices plays an increasingly important role in NZ plantation forest management. Half of the country's plantations and one-third of the annual harvest are already third party certified by FSC or PEFC.
Forest harvest practices
The Forests (Legal Harvest Assurance) Amendment Act 2023 establishes a regulatory system for providing legal harvest assurance for the forestry and wood processing sector. It is expected to operate in a manner that will:
- assist in the prevention of international trade in illegally harvested timber; and
- strengthen the international reputation of the New Zealand forestry and wood processing sector; and
- safeguard and enhance market access for New Zealand forestry exports; and
- reduce the risk that timber imported into New Zealand is sourced from illegally harvested timber.
The NES-PF providesd a consistent regulatory approach for various forestry activities including earthworks, crossings and harvesting. A major platform of the regulation is that a forestry earthworks management plan and harvest plan (a Management Plan) is to be prepared. The specifications in the NES-PF set out the details of the matters to be included in such a plan. There is a requirement to describe the management practices that will be carried ou
The Forest Practice Guides published by the NZ Forest Owners Association are to assist forest owners/managers and contractors to meet legislative requirements of the Resource Management Act 1991 (RMA) and in particular the National Environmental Standards for Plantation Forestry (NES-PF). The guides provide options and information on a range of practices and methods to manage effects of the operations on the environment.