- Site Analysis
- Site Use
- Passive Design
- Material Use
- Space heating
- Lighting design
- Water heating
- Active ventilation
- Electrical design
- Renewable electricity generation
- Bioenergy and Biofuels
- Space heating
- Wet Areas
- Health and Safety
- Other Resources
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:
- 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 85% of electricity comes from renewable sources, including hydro, geothermal and wind. In other words, if you buy electricity from the national grid, most of your electricity already comes from renewable sources. If you want your power to come 100% from renewable resources, you’ll need to generate your own.
Generating electricity from renewable resources
Renewable energy 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 on-site electricity generation..
Photovoltaic systems have fallen in price, making them increasingly affordable. The Electricity Authority reported that the installation cost of PV systems in New Zealand fell 75 percent in the decade 2008–2018.
By the end of January 2023 there were 43,261 residential PV systems installed in New Zealand. The total capacity of these installations, together with around 3,000 PV systems on other types of buildings, was 260 MW – up from 195 MW a year earlier and just 9 MW in January 2014. (To put this number in perspective, the total installed hydro capacity is over 5,000 MW.)
In its July 2019 forecasts of future electricity generation and demand, the Ministry of Business, Innovation and Employment estimated that by 2050, there will be over 500,000 installed residential PV systems.
Research conducted by Transpower in 2017 found that New Zealand’s electricity system is well-placed to handle a significant increase in solar PV installations.
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:
- 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:
- solar water heating
- using energy-efficient appliances
- passive solar space heating
- solid fuel space heating (such as a pellet burner)
- high levels of insulation
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.
Before committing to a renewable energy system, get expert advice. SEANZ (Sustainable Energy Association of New Zealand) is the industry body and its members must work to a code of conduct.
Micro-generation systems cannot be installed as a DIY project. This is ‘prescribed electrical work’ under the New Zealand Electricity (Safety) Regulations 2010. Only a licensed electrician can carry it out.
Updated: 22 September 2023