All three scenarios involve significant decarbonisation of the energy sector. Specifically, they involve significant take-up of energy efficiency opportunities, along with almost complete decarbonisation of power, transport and low-grade heat. Many of these opportunities are available at low cost and/or have significant co-benefits. As such, in a world in which all countries are moving towards the Paris Agreement goals, they are consistent with the continued growth of the New Zealand economy and improvement in the quality of life of its citizens.

The amount of electricity generation increases from 42 TWh to 76 TWh in Off Track and Resourceful New Zealand, and reaches 90 TWh in Innovative New Zealand. This implies substantial investment in new renewable capacity leading to a system that is almost entirely based on renewables. It has not been possible to model the precise investment in capacity required to support this level of generation; however, new investment would be needed across wind, hydro and geothermal resources. The cost of providing this new generation is likely to be lower than that of fossil fuel generation. Additional sources of flexibility are required to support this system. Much of this can be provided by demand-side response, which is a low-cost option that is easily facilitated by New Zealand’s flexible power market. Further investment in storage and gas may also be required, as well as in new grids, which would increase costs. New Zealand’s coal-fired power generation is phased out. These options largely rely on mature, proven technologies.

In the transport sector, the passenger vehicle fleet is largely decarbonised by 2050 with 3.5 million electric cars and light commercial vehicles on the roads. Electrification reaches at least 85 per cent in 2050; this is realistic, even factoring in the unusually long lifetime of the New Zealand fleet and slow turnover of the stock. International projections suggest that cost parity with the ICE could be achieved by the late 2020s. Prior to this, a programme to develop charging infrastructure in urban areas where demand is likely to grow initially is likely to require a degree of government support. Electrification spreads to the heavy vehicle sector but at a slower pace, reflecting the greater technological challenges associated with electrifying this part of the fleet, with 25 per cent of heavy vehicles electrified by 2050.

Low-grade heat is substantially electrified by 2050; at least 75 per cent of these energy requirements are provided by electricity. This requires 22 TWh of electricity in 2050, more than doubling the amount of electricity used for low-grade heat in 2014. This growth is concentrated in the residential, retail and services sectors. This switch to electrification can be undertaken as existing building stock and appliances reach the end of their useful life, and it makes use of technologies that are already established.

Industrial process emissions remain flat or decline. Emissions from potent refrigerant gases fall significantly, dropping by 85 per cent from 2014 levels in line with New Zealand’s commitments under the Kigali amendment to the Montreal Protocol. At the same time, uncertainties regarding New Zealand’s heavy industry composition have a major influence, with petroleum, aluminium and iron and steel industries facing an uncertain future. Emissions from the production of building materials increase as construction grows to keep up with population growth.

Agriculture sees continued increases in productivity and reductions in emissions intensities. Farm- and animal-based efficiency improvements are accelerated, while process improvements like precision agriculture further reduce emissions intensity by reducing fertiliser use. Targeted breeding of livestock leads to lower-emissions breeds, cutting the production of methane per animal by 15 per cent. The expansion of new feeding regimes that are higher in fat and lower in fibre reduce methane emissions by up to a further 10 per cent on the farms on which they are introduced. Nitrification inhibitors are reintroduced to treat waste on some dairy farms, improving water quality, while the spread of methane inhibitors in the dairy sector cuts methane further still. Overall emissions per dairy cow decrease by about 23 per cent, and 10 per cent for beef cattle and sheep. Emissions decline by a greater amount per tonne of product, by 33 and 22 per cent respectively. This would require ongoing support for R&D into new technologies, particularly the development and commercialisation of methane inhibitors and vaccines, alongside the expansion of price incentives to the agricultural industry.

Plantation forestry continues to expand over the next 50 years, adding at least 0.5 million hectares to the forest estate. Deforestation halts, and the use of forest biomass is transitioned to longer-lived products and bioenergy. Production of paper remains stable, while the use of forest biomass for construction materials, furniture and other solid wood products increases by at least 75 per cent. Use of biofuels expands for process heat, providing all the intermediate process heat required by the pulp, paper, wood- and dairy-processing industries.

New Zealanders reduce the amount of waste they produce per person, and a greater proportion of methane emissions from waste are captured and combusted. Quantities of organic household waste are reduced through a combination of recycling and composting. A larger share of the waste from construction and demolition is sorted at source and thus diverted away from landfill sites. Unmanaged disposal sites, including farms, are regulated to enable better measurement and management of emissions. These changes largely make use of existing technologies such an anaerobic digestors and methane-capture technologies.