The Queensland Labor government is looking to change the state’s statutory voltage limits – and bring them in line with the rest of the country – to help encourage more rooftop solar and other renewable energy.
Energy minister Mark Bailey announced the proposals at an energy storage conference in Brisbane on Wednesday, saying that the government was looking to align the state’s current requirement of 240 volts and changing this to 230 volts, as in the rest of the country.
“We are confident it will allow more efficient management of voltage issues caused by high penetration of solar PV, and support more renewable generation on Queensland’s electricity networks without adding to network costs,” he said.
The Queensland government is aiming for 50 per cent renewable energy by 2030, and solar is its main focus, seeking another 3GW by 2020 and more than 10GW by 2030.
Bailey says the government is also looking to streamline assessment processes for rooftop solar and battery storage.
This would include changes to requirements of rooftop arrays of up to 30kW, setting technical assessment thresholds by export limit rather than inverter capacity; moving from a zero export limit requirement to full, partial and minimal export limit requirements; and allowing reactive control and response mode inverters.
Bailey says the changes will provide greater flexibility for electricity distributors to operate the electricity network, increase embedded generation (solar and storage) hosting capacity and lower costs for grid upgrades.
The lower voltages is considered crucial also for new concepts such as peer-to-peer trading and blockchain technologies, and is part of a push for the whole of Australia to shift the settings on its low voltage network – which services 8 million customers – to around 220 volts, in line with new appliances and other technologies, and international practice.
Experts say that the ability to lower the normal operating voltage of those segments of the network with a high penetration of rooftop solar reduces the risk of exceeding maximum voltages when generation levels are high.
Until now, the distributors have needed to rely heavily on connection restrictions or expensive network augmentation in places where the appetite for customers to connect embedded generation is high.
Queensland and Western Australia are the only states that still require the supply of electricity at a nominal 240 volts per phase, with other states having adopted the 230 volt level prescribed by Australian Standard 60038 some years ago.
The significant adoption of embedded generation within the low voltage supply system has brought a new awareness of the design, operation and future of the thousands of kilometres of low voltage circuits that supply energy to the vast majority of electricity consumers.
Previously the ‘poor cousin’ of distribution networks, the LV is now demanding much more attention on voltage management, fault protection and connection contractual arrangements with customers.
Experts say that distributors traditionally operate the distribution system close to the very top of the permissible voltage range, as a protection against the risk of the voltage falling below statutory limits at times of high demand.
In recent times, however, the energy feed-in from a high penetration of embedded generation leads at times to voltage rise, challenging this operating paradigm, and leading to significant increases in customer complaints of appliance damage or inverter tripping due to high connection point voltages.
So much has changed in the voltage requirements of residential appliances. Switch mode power supplies, low voltage lighting and appliances built to international 220-240 volt standards have become commonplace in recent years.
The key is for distributors to be able to adopt lower operating voltages, permitting more voltage rise from embedded generation; whilst at the same time reducing the risk of any new problems stemming from voltages falling close to 200 volts in homes at times of high demand and no generation.
Demand management, replacing old appliances and clever transformer tap controls all form part of this new balancing act.
As one source said: “The proposed change in Queensland is to adopt the wider voltage range, setting the stage for new thinking in the operation of low voltage supply networks by all distributors to, deliver a platform for local energy trading, greater penetration of embedded generation and more efficient appliance operation.”