Designing homes to conserve energy and use it efficiently, from sources that cause least environmental harm.

Renewable electricity generation

By far the most common renewable system for on-site electricity generation in New Zealand is a photovoltaic grid-connected system.

Properties can generate their own electricity from renewable sources such as photovoltaics, wind, and hydro.

On this page:

  • Buying electricity from renewable sources
  • Generating electricity from renewable sources
  • Key design decisions
  • Property type
  • Security of supply

Around 69% of New Zealand residential energy use is electricity and approximately 80% of electricity comes from renewable sources, including hydro, geothermal and wind. Property owners who want to use renewable energy sources have two options: buy from renewable energy sources, or generate their own energy using renewable sources.

Buying energy from renewable sources

Homeowners can buy electricity from a carboNZero retailer, which means that an equivalent amount of electricity to what they purchase is generated through renewable means. Where this is not possible, e.g. at times when demand exceeds supply of renewable energy, emissions are offset through investment in renewable energy projects.

Some companies generate more renewable electricity than others, and not all companies are both retailers and generators – some retailers buy electricity from the national grid.

Generating energy from renewable sources

Remote area power systems can be used to meet the electricity needs of an individual property or group of properties, by generating electricity close to where it will be used and using sustainable energy sources such as wind, sun and water. A renewable energy generation system involves a significant up-front capital outlay, which will then be offset by the benefits of self-sufficiency in electricity generation.

Interest in renewable energy generation is growing in urban areas too, especially as photovoltaic systems are rapidly falling in price, making them increasingly affordable.

Installed PV capacity as of December 2014 was 18.8 MW. The total generation from small solar PV panels in 2014 was estimated at 16 GWh, more than double the 2013 figure. This does not include off-grid generation.

Homeowners who want to future-proof their new house should install the necessary electrical cabling from their roof to their fuse box (or similar) at the time of construction, even if they don’t plan to install a PV system. This saves money later on, as internal wall access is simplified and no remedial work is required.

Key design decisions

For renewable electricity generation, decisions include:

  • which energy source or sources to use, e.g. photovoltaic, wind, micro-hydro or a combination of all of these
  • energy requirements, i.e. how much electricity is needed to meet peak and overall demand
  • type of electricity storage and/or backup options to use
  • stand-alone or distributed generation system.

Systems must be designed to take account of local conditions (rainfall, wind and town planning) and capacity to meet demand (on-going and peak).

Cost-effectiveness and security of supply should be enhanced by also utilising other energy efficiency measures such as:

Property type

Wind and hydro systems are generally suitable only for larger rural sites or remote locations. Photovoltaics and small-scale wind generation (if permitted) may be used in urban areas.

Security of supply

An electricity supply must be available at all times, able to meet peak demand and cope with the irregular supply of renewable of renewable energy sources. Batteries for storage of electricity are therefore an integral part of the system.

Alternatively, a diesel generator or connection to the grid is required to ensure a continuous supply of electricity.

More information


Updated: 8 October 2015