Introduction

This article summarises the content of a video interview conducted on the 13^th of December between myself (Matthew Dredge) and Chris Wallin, Community Battery Project Manager at Yarra Energy Foundation.

I am a final year engineering student at the Australian National University completing work experience with Energy Forever, a not-for-profit based in Port Macquarie, NSW. Energy Forever are looking to commission a community battery.

As part of my work experience, I am conducting a preliminary feasibility study for this community battery. While researching potential battery manufacturers I came across Yarra Energy Foundation’s media release.

This media release detailed YEF’s selection of the Pixii PowerShaper BESS (110kW/284kWh) for their community battery project in Melbourne’s inner-north. I contacted Chris with an extensive list of questions and he was extremely generous in responding. We conducted a video interview to discuss the battery request for proposal (RFP) process that YEF completed for the specific benefit others that may be completing similar RFP works in the future.

This is a summary of the interview and report.

Topic 1 – Technical Requirements

Technical requirements form the base of the decision-making process as a means of ranking the various replies to the RFP. The media release mentions several technical requirements including energy density, physical footprint, and noise levels. I asked Chris how YEF determined the relative importance of each technical requirement.

Chris opened by noting that installing a battery in an urban Local Government Area (LGA) such as the City of Yarra will present a different set of challenges than in a rural setting. The initial challenges were the physical footprint as land prices in Melbourne are at a premium, along with the need to minimise noise of the system (considering the close proximity of residential properties).

Chris repeatedly mentioned that the community values and priorities were at the forefront of the engineering analysis. Amongst several community engagement sessions, it was determined that the key priorities were minimising noise levels and reducing visual impacts. The quantitative requirements such as battery power (kW), battery capacity (kWh) and round-trip efficiency (%) amongst many others were also important in characterising the capabilities of the battery.

In addition, there were also a few qualitative requirements that I had initially overlooked in my own analysis. These include the capability for entering the Frequency Control Ancillary Services (FCAS) market (requires accurate interval measurements), the ability for a software to “dry-run”, i.e. to test software before installation, and the ability for integration through an Application Programming Interface (API) of the cloud-based Energy Management System (EMS) and the local Battery Management System (BMS). Chris mentioned several business considerations such as delivery/lead time, maintenance policy and costs, and the overall cost of system.

In summary, YEF well and truly did their due diligence in assessing the technical requirements throughout their RFP process. The physical footprint proved to be a challenge that some manufacturers didn’t understand at first, as most current systems are shipping container-sized and come in ‘pre-packaged’ solutions. Those that aren’t pre-packaged are custom designs which attract extra costs in design pushing them out of the $1000/kWh target. It was this constraint that pushed the case for the Pixii PowerShaper with its modular, scalable design, boasting high energy density.

Topic 2 – Relationships with retailers/distributors

The nature of community energy storage being a developing technology means that, for the most part, conversations with distribution network service providers (DNSPs) are happening for the first time ever. Therefore, it was important that CitiPower (the DNSP in YEF’s region) clearly understood the benefits a community battery could provide and were therefore onboard and supportive.

Data aggregators are also required for YEF as the battery does not meet the 1MW entry threshold required to participate in the FCAS markets and as such an aggregator will combine YEF’s battery with other batteries to bid.

Amongst all these relationships, sharing accurate and real-time data from the BMS is required. In particular, the DNSP having access to real-time data can help with fault prevention and network stability.

Topic 3 – Important RFP Areas

Chris mentioned the importance of detailing the installation situation to the battery manufacturers. Whether the battery is front-of-meter or behind-the-meter it requires different switchgear than if it is on the distribution side of the network. Some manufacturers could not provide the complete solution and disregarded this switchgear simply due to being unfamiliar with standalone community energy storage as a concept.

Chris also highlighted the range of offers received throughout the RFP process. The RFP was sent to 13 manufacturers and received 8 responses. These responses ranged from offerings between below $700/kWh to over $1300/kWh. However not all these bids met all technical requirements and as such were not considered. It was reassuring to hear YEF were not cutting corners and realised there is no point getting a cheaper system that is not technically compliant.

Topic 4 – Tariffs

The Local Use of Service price is the varied/discounted price from the Transmission Use of System (TUOS ) and Distribution Use of System (DUOS) costs usually charged to use the network. At the time of writing, the discussion with the DNSP is an ongoing negotiation to determine a fair price and structure. Chris mentioned in an email after the interview that the summary of the agreement currently is that the battery will not pay transport fees when helping the network (i.e. charging from excess solar, discharging during high demand) but will pay fees when operating for it’s own profits/benefits. “There is no cookbook for LUOS and each case is based on a philosophy of “cost-reflective use of system” however that is interpreted“.

[Update: After a long period of consultation and analysis, CitiPower has published community battery tariff that will be available from 1^st July 2022.]

Topic 5 – Forecasting and Projections

Predicting the operating conditions of the battery under forecasted weather conditions, consumption profiles and arbitrage prices is the golden question of community batteries. Chris stated that YEF’s approach is that of active learning. The battery will initially function with the target of one full cycle per day, charging throughout the peak of solar demand, discharging during the peak load in the evening and then utilising the remaining capacity for FCAS functions overnight. This philosophy of “start small, think big” is crucial in getting the battery operational. Chris also added his wishes that other batteries coming into operation will share their optimisations, forecasts and targets as part of a cooperative learning process.

Topic 6 – Battery Chemistries

I probed Chris on the level of research conducted on varying battery compositions and once again he proved YEF well and truly did their due diligence in their decision-making process. Whilst other compositions have their own benefits, Lithium-ion technologies were the only cost competitive solutions that met all technical requirements, particularly in physical footprint.

Topic 7 – Summary of Decision to Select Pixii

After the above discussion Chris took the opportunity to summarise the selection process of the Pixii battery. He added that past the attractiveness of the modular design and high energy density to physical footprint ratio, the Pixii PowerShaper had a other key selling points. The new facility at NorthVolt featuring high recycled content within the Northvolt battery cells and the ability to supply cell manufacturing with 100% renewables aided in meeting environmental standards. The design of the PowerShaper also helped to reduce noise levels. Other bids featured noise levels of around 80dB ay 1m which Chris compared to standing on the side of a highway, whilst the PowerShaper operated at around 60dB which is comparable to conversation level. Combined with the planned acoustic-dampening cladding on the adjacent wall, the closest residents (~35m away from battery) should hear next to nothing according to calculations and tests conducted by Pixii.

Conclusion

I would once again like to express my thanks Chris Wallin for his time and generosity in sharing information, throughout this interview and after the fact in further emails. For any further detail please see the interview recording below or contact the Yarra Energy Foundation via the online contact form or email information@yef.org.au.

Zoom Recording Link

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Written by Matthew Dredge, January 2022