The long read: Scaling up standalone power systems

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From pv magazine 08/2021

In Australia’s far west, home to one of the largest isolated energy networks in the world, standalone power systems (SPS) – self-sufficient power installations combining solar PV and battery technology, backed up by diesel generators – have emerged as a more efficient and more economical alternative to replacing traditional overhead network assets in many particularly remote areas.

Western Australia (WA) grid operator Western Power is among those pursuing the technology as it looks to counter the challenges associated with maintaining network infrastructure and reliable power in remote areas, while also dealing with the challenges presented by extreme weather events. including bushfires and cyclones.

Australia’s biggest state in terms of physical area, WA has one of the largest isolated power systems in the world, with many customers tenuously connected to the grid via long skinny lines.

State-owned vertically integrated utility Western Power is responsible for building, maintaining and operating the electricity network within the South West Interconnected System (SWIS). The state’s primary electricity system, the SWIS has a network of more than 7,800 kilometers of transmission lines and currently more than 52% of the network services less than 3% of the users.

Western Power Project Manager Margot Hammond said that in the next few decades, much of the network will need to be replaced, as it is reaching the end of its life. This has sparked a search for more cost-efficient, reliable and flexible solutions that provide an alternative to traditional network infrastructure.

“Like many electricity networks around the world, sizable sections of our regional network are due for renewal, and we have been researching alternatives to replace the traditional poles and wires in these areas,” she said.

Hammond said SPS trials, first launched by Western Power in 2016, showed the technology provided impressive cost savings when compared to traditional network refurbishment, while the systems were generally 15 times more reliable and safer than poles and wires in remote areas.

“Our modeling shows that the installation of thousands of SPS over the coming decades could avoid millions of dollars in traditional network build,” she said. “They also require less maintenance, save on electricity costs, and can reduce or avoid outages. Over the three-year trial duration, more than 200 hours of outages were avoided.”

The results point to a bright future for the application and plans are taking shape to scale up SPS production as manufacturers seek to reduce costs and meet forecast demand.

SPS expansion

In the years since Western Power trialed its first six SPS, the network operator has installed a further 52 units on regional properties. It plans to roll out a further 98 in 2021-22 to replace around 330 kilometers of overhead powerlines, delivering what Hammond said is “a significant cost saving.”

Those numbers are set to increase dramatically in the years ahead, with the WA government committed to deploying 1,000 SPS over the next four years, while Western Power has modeled approximately 6,000 units being deployed over the coming decades.

Hybrid Systems Australia is among a handful of companies tapped by Western Power. Fellow WA utility Horizon Power, which is also pursuing a SPS program, plans to install units across the state too.

A subsidiary of QIC-owned Pacific Energy, Hybrid Systems, has been delivering offgrid power solutions for almost two decades. But earlier this year, it said it would build a new 16,000-square-meter production facility in Perth dedicated to the design and construction of SPS.

“The growing demand for these systems as the industry evolves is pushing industry to increase the ability to manufacture at a larger scale,” said Hybrid Systems Executive Director Michael Hall.

“We expect other states such as Queensland in particular to follow Western Power’s lead and are already seeing opportunities being presented by other national network operators as Western Power’s rollout of SPS proves to be beneficial. The new facility will also allow us to improve efficiencies and decrease the cost of building these systems within Australia.”

Cost reductions

Standardization is seen as key to delivering cost declines, with Hall confirming that Hybrid Systems has developed and continues to refine a modular and flexible solution that can be scaled up or down in capacity. This is paired with a solar PV array and is backed by a diesel-fueled generator.

“We’ve got a standardized product, which we call our HIPS platform (hybrid integrated power system),” Hall said. “Physically, it’s about 2 meters by 1 meter wide and 2.4 meters tall. That houses the battery, inverters, AC switchboard, and control panel. We’ve got varying capacity, anywhere from 5 kWh up to 90 kWh.”

However, Hall stressed that there are limitations on the ability to standardize the offerings for remote applications. He said the need to satisfy the individual requirements of each specific situation – including being able to cater for single-phase, split-phase and three-phase requirements – is paramount.

Despite these considerations, the physical dimensions and internal framework of the enclosure designed by Hybrid Systems remain the same regardless of the capacity of the system.

“The package is exactly the same for our bigger system as it is for our smaller system,” Hall said. “It’s the exact same platform, so the enclosure has exactly the same infrastructure to cater for one inverter to four and from one battery rack up to however many is required at 90 kWh. And it goes out with all the same infrastructure, so the end client can upgrade at a later date.”

That standardization has delivered impressive time savings when it comes to deployment, with the company claiming the installation period has been reduced to two days, including civil work.

“Now that we’ve standardized what our offering is and our manufacturing and design process is much more efficient, we’re seeing significant reductions in timeframe to get these out onto site,” Hall said. “We generally get all of our civils done within one day, that means underground cable run, which can be anywhere up to 120 meters, and the structural for the solar paneling, as well as the enclosure and fencing. Then we have another team come in and install the solar panels and the enclosure in a day, and then generally there’s a few days before Western Power comes in and does a changeover. To deliver the 45 that we delivered last year for Western Power, it was a year of work. To deliver 60 this year, we’ve refined it down to eight months. And there’s room for improvement.”

Hall said the manufacturing and installation efficiencies have delivered cost declines, but any future savings are most likely to be reliant on technology, with the evolution of the product slowing down in recent years.

Among the areas of interest is the declining cost of lithium-ion battery technology, with BloombergNEF’s battery price index showing that the volume-weighted average price of a typical lithium-ion battery has dropped by nearly 90% in the past decade. In 2020 the weighted-average price for lithium-ion storage batteries was $137 per kWh, down from nearly $1,200 per kWh in 2010.

Hall said that cost curve held real promise for further reductions of costs associated with the production of SPS units.

“A reduction in lithium battery costs is a key driver in current SPS commercial viability,” he said. “If the lithium product continues to follow the curve that it has been, the return on investment will be delivered in a much shorter period.”

Hydrogen energy storage and production is another area full of promise, with Hybrid Systems investigating the potential application of the hydrogen battery technology developed by fellow Australian company Lavo.

Lavo has produced a residential/commercial hydrogen battery which stores 40 kWh of energy and appears ideally suited to offgrid applications.

Hall claimed that it has the potential to not only produce cost savings, but also to add value to the SPS units. He suggested that it could initially be used in place of the diesel generator as a backup energy source.

“We’ve done some early scoping studies on the Lavo and looked at integrating it into our standalone power systems,” he said. “We’ve also looked at the possibility of adding that value train to our SPS instead of, or as additional energy towards the battery. I believe hydrogen will in time deliver cost efficiencies, but at the moment it adds value in other areas.”

While WA has emerged as a hot spot for the rollout of SPS, trials of the offgrid systems are currently underway in several other Australian states. And the technology is also earning favor in several international markets.

The work being done by Hybrid Systems is attracting attention, with the company fielding inquiries from the Asia-Pacific region, as well as Africa. Hall said SPS technology lends itself to widespread use in offgrid and edge-of-grid areas.

“We’ve designed our package for ease of deployment,” he said. “Our involvement on site for the actual battery package or our main piece of hardware is a straightforward drop onto the ground, and then it’s simply a very small portion of work to bring it online.”

Western Power expects the rollout of SPS in WA will also deliver valuable lessons for other utilities, both within Australia and internationally.

“Similar programs could be viable in other parts of our country, especially in regional and remote communities, as well as in areas that are prone to natural events,” Hammond said.

“From an international perspective, similarly to WA, there are many electricity networks around the world that need ongoing maintenance and renewal, and similar SPS programs could be viable in countries where a power system is geographically spread out.”

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