Comment: Over the past two decades, Australia has quietly become a world leader in household solar power. About 4.4 million Australian homes have solar installed, among the highest rates of residential solar adoption anywhere on the planet.
This is in sharp contrast to New Zealand, where only about 75,000 households have installed solar, roughly four percent of homes.
The contrast is striking because New Zealand and Australia share many of the same advantages: abundant sunshine, growing electricity demand and a need to cut emissions while improving energy security.
The adoption of solar energy in Australia emerged from niche expensive off-grid use in the 1990s to the current widespread grid integration driven by government rebates, lucrative feed-in tariffs, and soaring retail electricity prices.
Australia leads the world in rooftop solar adoption, with more than 4.3 million rooftop solar installations and 28.3GW of installed rooftop solar capacity. The Australian residential rooftop solar contributes 11.2–14.6 percent of the national total electricity supply. The continued evolution of Photo Voltaic Solar Farms in New Zealand with large grid batteries should also be inspired by Australia’s many existing and planned large PV projects.
Why did Australia get so far ahead in the adoption of rooftop solar while New Zealand continues to lag so far behind? The short answer: Australia has had government incentives while New Zealand hasn’t. Contrary to common perception, though Perth and Brisbane receive more intense sunlight than any New Zealand city, major centres such as Auckland and Melbourne have similarly strong potential for rooftop solar.
A critical economic driver for a switch to solar in New Zealand is the progressively increasingly high cost of retail electricity prices. This is clear in a review of political party policies leading into this year’s election.
Several parties have already proposed measures to encourage residential solar, although the scope and ambition differ considerably, and none of them offers the full suite of measures that would be needed to close the gap with Australia. The relative commitment of the various NZ political parties to residential solar at present is as follows: Greens, The Opportunity Party, Labour, National and Act. In contrast, NZ First is promoting expansion of fossil fuels via a major oil survey.
Below are 10 ways we could accelerate solar adoption in New Zealand, some of which are supported by some parties. The list of suggestions are essentially technology steps while the political policies are obviously broader and more vague (wiggle room for each party). I have considered only those policies that seemed to have some serious priority for the parties.
- Low interest or government-backed finance for solar systems (Greens, TOP)
- Fairer export tariffs that better reward households for supplying surplus electricity to the grid (Greens, TOP)
- Require all new residential builds to include a basic solar system following the current EU policy (Greens)
- Incentivise the development of community-owned solar microgrids serving farms and remote communities, following the working examples of most Pacific Islands (Greens)
- Encourage virtual power plants that aggregate thousands of homes’ solar and battery systems including EVs
- Accelerating distribution network upgrades and smart metering (Greens, TOP, Labour)
- Streamlining installation and connection processes (TOP, National, Act)
- Supporting battery storage alongside residential solar (Greens)
- Encouraging the installation of domestic EV chargers powered by residential rooftop solar which makes family transportation much less expensive
- Accelerating the regulatory adoption of small portable solar systems for apartment living that can be plugged into a household power point
The timing of an expansion of solar energy in New Zealand is likely to benefit from the ongoing exceptional rise of new technologies leading to more efficient, flexible and versatile solar panels, combined with cheaper and safer solar batteries.
Perovskite panels (next-generation solar technology that uses synthetic crystal structures to convert sunlight into electricity) promise to increase efficiency from about 22 percent for silicon panels to about 28 percent. Flexible solar panels permit deployment directly on different types of building surfaces, thus increasing the overall surface solar exposure.
Recent global energy shocks have highlighted the value of locally generated electricity. Rooftop solar and household batteries can reduce pressure on the grid, lower bills and provide backup power during outages caused by increasingly severe storms.
Australia’s experience shows us rooftop solar does not spread because households suddenly become greener or more technologically adventurous. It spreads when governments make the economics stack up. New Zealand has the sunshine, the technology and the expertise. Now we just need a clear national commitment to unlocking the potential sitting on our rooftops, millions of square metres of underused roof space could become part of the country’s energy solution.
