In July 2020, the Northern Territory Government released the Northern Territory Climate Change Response: Towards 2050 report, which laid out the impacts of climate change in the Territory and detailed the government’s plan to achieve net zero emissions by 2050. To establish the foundations required to deliver this goal of an enduring and effective climate change response, the Territory Government introduced the Darwin-Katherine Electricity System Plan.
Northern Territory households and businesses continue to invest in solar power, with rooftop solar PV installations growing by an average of 45 per cent each year since 2010. While this is great news from a renewable energy perspective, the increase in solar energy in the grid does present a challenge to maintaining security and reliability in the Territory’s power system.
To make up for energy shortfalls when the sun isn’t shining, the Territory currently relies on provision of a gas-fired spinning reserve – a solution that is both expensive and a big contributor to carbon emissions through the use of gas. The Territory Government has said that the connection of large-scale solar projects to the grid presents challenges for system security and reliability, and while the technologies do exist to effectively manage these challenges, investors are looking for cost efficient ways to do so in order to ensure the lowest possible energy prices for Territorians.
To help chart a course towards its goal of net zero emissions by 2050, the Territory Government released the Darwin-Katherine Electricity System Plan. The Darwin-Katherine area is a key focus for renewable energy uptake due to its population and climate. According to the plan, the DKIS (Darwin-Katherine Interconnected System) provides electricity to 150,000 Territorians, including residential homes and a diverse range of small, medium and industrial-scale businesses.
A unique energy system
In 2021, about 88 per cent of energy was met by thermal generation. The generators connect to the electricity network, which transports the electricity to households and businesses. In 2021, approximately nine per cent of underlying energy was supplied by small-scale solar generation, and three per cent by large-scale solar generation.
The DKIS is unique, and quite different from most other power systems in Australia. These unique challenges impact the suitability of some types of renewable energy generation. Some of the key factors that contribute to these challenges of renewable energy generation and storage in Darwin-Katherine include:
- It is a small standalone grid, delivering the equivalent of only one per cent of total energy generated in the National Electricity Market. Economies of scale are notoriously difficult to achieve.
- Due to geographic remoteness, the DKIS is not interconnected with other regional networks, such as Alice Springs or Tennant Creek, meaning that fit-for-purpose, bespoke solutions are necessary.
- The operating environment is harsh and subject to weather volatility, particularly cyclones and monsoonal periods when the sun does not shine. Demand needs to be met despite the extreme weather, which can potentially also affect system security.
- Significant natural resource opportunities exist, including low-cost solar. However, there are current limitations with viably accessing alternative renewables (such as the wind, tidal, hydro, hydrogen and biofuels).
- There has been significant reform to the electricity market over the last decade, including structural separation of generation, networks and retail, and regulatory reform.
The Darwin-Katherine Electricity System Plan acknowledged that continuing reform will impact the deliverability of renewable energy goals, and noted the need to ensure that strategic policies and actions are complementary.
Delivering solutions
To help address these challenges, one of the key deliverables detailed in the system plan was the 35MW DK BESS (Darwin-Katherine Big Battery Energy Storage System), to be delivered by Territory Generation at the Channel Island Power Station.
The $45 million DK BESS is designed to provide power system services, including spinning reserve, equivalent to a Frame 6B gas generator. 192 batteries, each weighing 3.5 tonnes, have been installed for the DK BESS. For pre-commissioning testing, a temporary power supply was installed on eight Hitachi Energy modules – each comprising a bank of batteries, a set of inverters and a step-up transformer. The temporary power supply, in combination with an AC/DC power converter, charged and discharged the battery modules to test all their functions before being connected to the 11kV switch room.
With the construction and pre-commissioning phases now complete, the DK BESS is closer than ever to achieving full operation. Territory Generation is continuing to work with key stakeholders to begin rigorous testing, with power system modeling and connection agreement negotiations well underway. Full operation of the DK BESS is due to commence in 2024.
Territory Generation CEO, Gerhard Laubscher, said, “The successful installation of all batteries and progression to pre-commissioning is a significant step forward for the DK BESS.
“We recognise commissioning is a complex and time intensive process, and we are working closely with all stakeholders to support the fastest possible progression of these activities.
“The DK BESS is key to unlocking flexibility in our generation fleet. Once commissioned, it will be online continuously, helping to stabilise the impacts of solar and support the integration of more into the Darwin-Katherine grid,” Mr Laubscher said.
The Territory Government has estimated that having the DK BESS online and available to reduce reliance on gas generation would result in cost savings of around $9.8 million annually, as well as eliminating approximately 58,000 tonnes of carbon emissions each year. The government also projected a payback period of five years from connection to the grid.
Two is better than one
With the DK BESS successfully achieving key project milestones, Territory Generation recently announced that it is progressing works on a second large-scale BESS project for Darwin-Katherine, the DK BESS 2. Together, the two BESS projects are set to fulfill the Darwin-Katherine Electricity System Plan requirements for the installation of up to 105MW of high-specification batteries, enabling further uptake of both small and large-scale solar PV installation.
The DK BESS 2 will involve the deployment of large-scale batteries distributed across multiple locations throughout the DKIS. Unlike the original DK BESS, which has been built at one site, the DK BESS 2 battery system will be spread around the grid in order to further strengthen network resilience. The distributed network of batteries is designed to assist in ensuring system security and enable more solar energy penetration by providing essential frequency and voltage control services.
The DK BESS 2 will add to capability demonstrated by the first DK BESS.
Commissioning of the DK BESS 2 is targeted from 2026 onwards.
Northern Territory Chief Minister, Eva Lawler, said, “The DK BESS and DK BESS 2 are an important part of our transition to a renewable energy future.
“We are able to invest in our power grid because we own our assets like Territory Generation, Jacana, and Power and Water. By owning our assets, we can keep power prices low. Battery technology will play a significant role in our target of reaching 50 per cent renewable energy consumption by 2030.”
Northern Territory Minister for Renewables and Energy, Kate Worden, said, “The DK BESS 2 project will secure our energy supply for Territorians and stabilise our grid as we move towards integrating more renewable energy into our power use.
“As we move towards a future where renewable energy will play a greater part in our power supply, the DK BESS and DK BESS 2 projects will facilitate a major port of this change.”
The Expression of Interest assessment for the DK BESS 2 has been performed and is now closed, with a shortlist of proponents selected for the next phase.
Territory Generation said it is currently investigating other renewable generation and long-term storage solutions that will work in collaboration with both DK BESS projects to further advance the government’s renewable energy targets.
Territory Generation Chief Executive Officer, Gerhard Laubscher, said, “Territory Generation’s battery energy storage system projects will play a critical role in advancing renewables in Darwin-Katherine and other power systems across the Northern Territory.
“Adding more battery energy storage systems to Territory Generation’s portfolio will not only enable more renewables and efficient generation dispatch throughout the energy transition, but also fosters the evolution of various technological innovations and further support grid resilience.”
Featured image: TGen CEO, Gerhard Laubscher, Northern Territory Minister for Renewables and Energy, Kate Worden, and Northern Territory Chief Minister, Eva Lawler. Courtesy of Territory Generation.
