Getting to net zero with rooftop solar

Jan 24, 2024 | Clean energy

The Australian government has a target of 82% renewable energy by 2030. In 2022, 32% of energy was renewable. Clearly, a very significant increase in renewable energy is needed if the 2030 target is to be met.

Large scale projects, such as the 20 projects which are planned or under construction in Victoria, are facing major hurdles in coming online.

The campaign in western Victoria by farmers against power lines crossing their farming properties (The Guardian, November 2022), is one example of the problems faced by renewable projects. Large projects need not only the obvious solar or wind panels and turbines, they also need transmission lines to connect to the grid.

Other forms of renewable energy also face hurdles. In the case of a proposed offshore wind farm in Westernport Bay, the Federal government has blocked the construction of a wind turbine assembly plant because of what it says are unacceptable impacts on important wetlands.

With these and other hurdles facing large projects, rooftop solar is well-placed to provide much of the answer. Currently, one in three houses have solar panels, generating close to 10% of Australia’s power. With solar covering only about 10% of the available roof space, there is room for expansion.

Currently, AEMO (the Australian Energy Market Operator), manages the national power grid, controlling how much electricity from large scale generators is fed into the grid.

However, AEMO does not control rooftop solar, and this is problemic. If rooftop solar generates the bulk of the power in a region, there may not be enough power to maintain balance and security in the grid. Another problem occurs when the rooftop solar generates power during low demand, potentially causing voltage in the grid to exceed safe limits. Also problematic is when unexpected events cause rooftop solar to disconnect for safety reasons.

These issues mean that rooftop solar owners can be disconnected from exporting to the grid, have their solar exports limited, or have the size of their solar systems limited, all of which disadvantage householders who have invested in solar power.

Various more solar-friendly ways of managing these issues have been devised by the energy providers, but they are relatively blunt tools and still limit the contribution rooftop solar can make to meeting the renewable energy target.

For solar power to be most useful, it makes sense to have it available when there is a demand for power. Ideally, the production of power would match the need for that power.

One way to come closer to achieving this is for consumers to use solar power when they need it. Running appliances when the sun is shining makes sense. Of course, this will only sometimes be possible, which is where electricity storage comes in.

Householders can store their own solar energy in a home battery or electric vehicle, with some EVs able to operate like household batteries and send power back to the house. Some energy retailers also offer Virtual Power Plant (VPP) programs, effectively networking household batteries and controlling when the power is distributed. They then provide subscribers with cheaper power.

There is increasing interest in community batteries, which can store excess rooftop solar production locally. The Australian government has a program to install 400 community batteries across Australia and under the Neighbourhood Battery Initiative (NBI), the Victorian State Government is funding some community batteries. While all community batteries are ‘solar soakers,’ Village Power in Alphington, is installing the first subscriber community battery which will involve the local community in the generation, storage and distribution of energy for its own use.

It is crucial that Australia meets – or exceeds – its renewable energy target. When it comes to locating renewable power equipment, there are obvious advantages to using already built structures, rather than taking over farms or other land. Managed well, rooftop solar power can play a major role in helping Australia reach its renewable energy target.

Note: The Sustainable Macleod Community Garden operates an off-grid solar power system. This means there is no connection to mains power and the energy produced at the garden is stored in a battery for use when needed. We run appliances, and operate our all-electric tools and powerful new chipper/mulcher, throughout the year, all from the sun.

Written by Paul Gale-Baker


The Conversation, January 9, 2024:

Solar Victoria:

Solar Victoria – VPPs:

Village Power:

The Guardian: