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As the world shifts towards greener and more sustainable energy sources, the energy system in Western Australia is transforming, primarily driven by the high uptake of rooftop solar. The move to renewables is positive for our environment and our shared desire to find cleaner, more efficient ways of powering our lives.

The abundant sunshine and clear, blue skies of WA mean that households and businesses are embracing rooftop solar panels in large numbers. In fact, more of our State’s energy is now supplied by renewable sources than ever before, with over 30% of homes having solar panels installed.

However, this trend does create some challenges for our energy system. As solar panels produce the most energy during the day when the sun is shining, demand for electricity from the grid can drop dramatically, leading to what is known as a ‘low load’ situation. This makes it challenging to maintain a stable and reliable electricity supply and increases the risk of blackouts occurring. 

At Synergy, we’re working closely with the WA Government and other stakeholders to address low load with a range of innovative solutions. 

So, what is low load and exactly why and when does it occur?

What is low load and why is it an issue?

Western Australia has one of the highest uptakes in rooftop solar panel systems in Australia. It’s estimated that solar panels (sometimes called photovoltaic or PV panels) have been installed by one in three households and businesses in WA. The advantages for our planet are clear, but low load needs to be addressed to make the most of our energy transformation.

Load simply means the demand for electricity on the grid. When the system is being supplied by a high level of rooftop solar generation – over the sunniest hours in the middle of the day – this can lead to a low load situation as demand drops. When demand for electricity from the grid gets too low, it does not support larger generators that provide essential services for maintaining a stable electricity supply.

As the sun goes down, the amount of solar energy being generated drops and there is a sudden increase in demand on the grid as we begin cooking, doing laundry, and turn on heating and aircon. When this occurs, the load can increase rapidly placing the grid under severe strain.

These extreme fluctuations in load make our energy system vulnerable to instability. The effect on the grid is a phenomenon known in the electricity industry as the Duck Curve.

How does the grid respond to low load?

Western Australia’s power system is supported by large gas or coal-fired generators that ensure a steady and reliable flow of electricity, to allow us to continue with daily life, from bingeing our favourite shows to charging up our devices.

Rooftop solar systems produce additional energy while the sun is shining. This power is used by households as it is generated during the day, resulting in low demand from the grid (low load) with excess solar energy being fed back into the system.

As the sun sets, or when cloud cover occurs, and during the night, your solar system cannot generate energy, and unless you have a battery you need to draw on electricity from the grid – which is typically produced by coal or gas-fired generators.

How does low load affect Western Australians?

Low load has an impact on the entire energy system. The way that we use energy day-to-day (time of day and source), contributes negatively or positively to grid changes and low load situations, so there are several ways we can respond to address these challenges.

Behaviour changes

For those with solar, shifting your energy consumption to the middle of the day where possible, so the solar energy generated is being consumed as it’s produced. Changing your consumption behaviour in this way can also help you make the most of your solar investment.

System changes

Given the increasing uptake of distributed energy resources (DER) like rooftop solar, Synergy is trialling the use of virtual power plants (VPPs), which coordinate DER in response to the needs of the electricity system. Unlike the current energy system, VPPs can more quickly respond to demand changes through the coordinated dispatch of energy when it is needed – helping to create a more stable energy system.

Low load impacts everyone, so these considerations are applicable to us all. There are also actions being taken by the WA Government to address these challenges.

How is the government addressing the low load issue?

The WA Government has already taken several clear steps to develop the State's energy future and set a number of actions in place. Its 2019 Energy Transformation Strategy, is focused on improving the resilience of the energy system, particularly through practical initiatives that address low load challenges. Learn about the strategy and what it’s already delivering.

With exceptionally high uptake of solar in WA, the State Government has also set out a 5-year Distributed Energy Resources (DER) Roadmap.

Synergy’s projects, pilots and trials are providing insights on how to manage low load

The success of the DER Roadmap is underpinned by a number of projects as well as pilots and trials to explore ways to address the challenges of low load.

Working with the State Government, Synergy is constructing a 100MW/200MWh battery at the Kwinana Power Station. The scale of the battery will allow it to store enough energy to power approximately 160,000 homes for two hours. This is intended to reduce the impact of low load on the grid as it can be charged during the day when solar generation is high and discharged during the afternoon and evening peak when demand increases.

Synergy’s Schools VPP pilot aims to trial how a network of DER, such as solar panels and batteries, can generate, store and supply power based on demand. While this pilot helps schools manage their electricity consumption, at Synergy we’re able to learn how VPPs can help manage low load and assist to provide stability in the grid to support WA’s renewable energy future.

Synergy is also participating in community battery trials, in conjunction with the network operator, Western Power. The current PowerBank pilot enables participants to virtually* store excess solar power to use later when the sun goes down and generation drops, but electricity demand increases on the grid. Community battery trials are showing new ways to manage low load, prevent stress on the grid, and still integrate more solar energy into our system.

* By virtual, we mean there is no physical battery connected to the premises storing electricity generated. Participants are allocated virtual storage capacity in the community battery in accordance with the pilot terms and conditions.

Projects, like the big battery at Kwinana, and pilots and trials, like PowerBank and the Schools VPP pilot are just some of the ways Synergy is working to help address low load and the transition to a renewable energy future.