BESS Operational Issues in Developing Markets (Part II) - Causes and Remedies

This is the second part of a three-part article on BESS operational issues in developing markets, by DNV's Energy Access Team. This article discusses the causes of Early BESS operational issues, which were identified in Part I of this series, and the remedies for each issue. Let's get straight into it!

Manufacturing defects

Manufacturing defects can be due to BESS integration being manual and labor intensive, leaving the door open for human error. Abnormally large temperature and voltage variations among cells within a battery module, charging or discharging failure due to wiring issues in a battery rack’s high voltage boxes, and thermal runaway initiated in one of the battery modules from internal short circuiting, are all symptoms of manufacturing defects.

Clean Energy Associates (CEA) has suggested mitigation measures for BESS failures related to manufacturing defects at cell, module and system levels [1]. The defects are attributable to low quality control in addition to the manual nature of module assembly and system integration processes. Manufacturing defects can be mitigated through implementing automated production lines and improving quality control practices. These practices will enable original equipment manufacturers to reduce imprecision and inconsistency in production lines.

Project developers in the energy access space should perform proper due diligence themselves or through third party consultants to ensure their equipment supplier and manufacturer processes meet industry leading expectations. Factory Acceptance tests and witness tests should be performed, and results requested. These actions mitigate several issues, including high O&M costs, replacement of equipment, and early degradation. Replacement of equipment are typically time intensive and costly, due to the remoteness of some of the project locations.

Poor commissioning

In most markets, there are no industry standard commissioning protocols for BESS equipment, with testing being left to the discretion of each manufacturer or the EPC contractor, which can lead to poor commissioning procedures.

Poor commissioning practices due to the lack of commissioning standards have led to failure mechanisms that would otherwise have been identified during the commissioning process. These issues can be mitigated through adopting comprehensive standard commissioning guidelines and establishing clear commissioning goals with suppliers during the contracting phase. In the absence of a commissioning standard, project developers can adopt commissioning guides produced by independent bodies such as ESIC. Ultimately, the goal of commissioning should be to confirm that all systems work as designed and expected, such as thermal management, safety, sensing, monitoring, communications, software, charging, discharging, and other auxiliary loads. Commissioning comes before performance testing which is the process used to determine the system’s performance meets expectations, such as confirming the MW and MWh capabilities align with contractual values or that response time and latency can meet the needs of the project.

The Energy Storage Integration Council (ESIC) is a council established by the Energy Power Research Institute (EPRI) and has published commissioning guides, such as the ESIC energy storage commissioning guide. The adoption of relevant test procedures in such commissioning guides as ESIC’s would help identify issues prior to operation and result in improved performance of operating BESS assets.

The North American Electric Reliability Corporation (NERC) is also working on a white paper on commissioning best practices for inverter-based resources (IBRs). It is important to note that commissioning and performance testing guides such as those developed by ESIC and NERC should not replace project and product-specific commissioning tests which typically go beyond these guidelines.

Additionally, performance tests should be performed in accordance with all operational requirements. For example, if there are specific offtake, grid or project requirements, then the BESS should be tested to confirm its performance can meet the operational requirements. In subsequent years, regular tests should be performed on capacity, availability and round-trip efficiency (RTE) to ensure the BESS is continually able to operate up to expectations and requirements. In emerging and even developed markets, these practices would cater overall to reduce early BESS failure rates.

Thermal management

Another common contributing factor to BESS failures is thermal management issues, which is related to poor design and inadequate field testing. Thermal management systems are critical to safety and performance by maintaining battery cell temperatures within their acceptable or optimal range during and after charging and discharging cycles. Design defects range from non-functioning sensors to thermal management not being applied to communication and control systems. As the energy management system is critical to proper system operation, it is imperative that the enclosure housing these computer components is adequately cooled. Heat waves due to climate change further exacerbate the issue. With developing markets being primarily located in warmer parts of the world, this issue is critical to address. It is recommended that thermal management systems are evaluated from a design and simulation perspective such as through the use of computational fluid dynamic models, and then performing tests in the factory or field to confirm the build meets design metrics. A good thermal system should be designed and specified to meet the environmental conditions expected on site and this should not be overlooked during the design and procurement stage.

Poor installation

Poor installation practices can contribute to early BESS failures. In developing markets like Africa, many countries are yet to set clear design and installation standards for BESS, which impact the quality of design, installation and subsequent commissioning. In a developed market like the US, the NFPA 855 is the installation standard for stationary energy storage systems in the US and is considered industry best practice, particularly regarding site layout and system integration. This standard has become widely adopted or referenced by other countries and a similar approach can be taken in developing markets. ?The guidance of NFPA 855 can be utilized with existing standards in developing markets, until regional standards are developed.

Interconnection and inverter stability

Another operational issue is related to interfacing with the utility or demand load, which can also be attributed to poor system design and commissioning. Due to poor commissioning practices, BESS ride-through performance is not adequately assessed during the interconnection process [2]. In developing markets, DNV’s energy access team has also noticed inverter performances through grid disturbances and transfers from one power source to another, are not adequately assessed during the interconnection and commissioning process. This leads to BESS projects tripping offline when they should be riding through short grid disturbances or switching power sources through outages, thereby impacting performance. Unreliable inverter ride-through performance, improper switching design / control, site metering issues, and meter misconfiguration should be identified as part of commissioning checks. Proper design and selection of compatible equipment and control components is also important. Suppliers should also be requested to test their products and be fully involved in the design and commissioning process, as well as selection of control system. ?

NERC has evaluated the issue of inadequate interconnection assessment and its impact on BESS reliability. Poor ride-through performance can be addressed via implementing robust interconnection agreements and performing comprehensive ride-through performance assessment prior to commissioning. NERC is in the process of modifying PRC-024 to accommodate ride-through assessment of IBRs such as BESS. DNV anticipates the requirement of thorough interconnection assessments to spread to emerging markets as the deployment of utility-scale BESSs increases in these markets.

Considering that grid codes in developing markets might not be as thorough and comprehensive as in mature markets, developing a custom testing framework by technical stakeholders is a necessary step to ensuring reliable operation of BESS in these markets. DNV has the

Gaps in division of responsibility

Some of the early operational issues can also arise from gaps in the division of project responsibilities between the different parties involved such as the developer, the EPC contractor, the equipment supplier, and the O&M provider, especially when these parties are involved in interfacing and limited capacities. It is common for both EPC contractor and equipment supplier to be involved in the commissioning process and to perform interfacing tasks, where one party supports, and the other party has a higher responsibility. In such cases, commissioning responsibilities should be made clear and operational handover from EPC contractor / BESS supplier to O&M contractor should be clearly detailed in the related agreements. Use of clear definitions and clauses should be employed where necessary. Division of responsibility matrix are usually employed in standard EPC contracts and show different levels of responsibilities and support, indicating the responsible party for each task. They help to avoid conflicting scope and thereby mitigate early failures that could arise from poor workmanship and scope management. If a performance test is initially passed but fails within a stipulated time after the initial test, the responsible party should be clear.

Other technical and commercial issues

From industry experience, DNV has observed some additional technical and commercial issues that generally affect BESS operations and are uniquely emphasized in emerging markets. Such issues include:

·?????? Poor internet connectivity impacting remote monitoring and control

·?????? Inadequate after-sales support from BESS OEMs and suppliers, who rather focus on developed markets with steady market growth, favorable policies and incentives

·?????? O&M contract (or long term service agreement) terms that are not adequate or aligned with the practical issues in these developing markets

·?????? Underperformance resulting from curtailment and unavailability of grid export in some emerging markets, mainly within Sub-Saharan Africa, including West Africa.

These issues can be mitigated through:

·?????? Investing in higher-quality local internet infrastructure or having cellular connectivity as a backup to relying on internet connectivity

·?????? Making service offerings a key component of supply agreements

·?????? Involving independent engineers early in the development cycle and performing due diligence at contract negotiation stages

·?????? Introducing policies allowing for residential and commercial and industrial (C&I) BESS installations to export energy to the grid

·?????? Government investments in favorable economic, supply and logistics landscape, to encourage local manufacturing or integration of BESS equipment

Conclusion

In this article, we have covered the main technical and non-technical issues driving the infant mortality of BESS. Most issues can be identified and mitigated by performing comprehensive due diligence on product suppliers and ensuring that installation and commissioning practices meet or exceed international best practices. The third and final part of this series will be released on October 5th, 2024 and will discuss the impacts of these operational issues on the various project stakeholders. The stakeholders include project owners, investors and contractors. The next article will also provide insight into the foreseeable future of BESS deployments in developing markets.

About us

挪威船级社 's Energy Access Team is part of the Energy Storage advisory team within DNV - Energy Systems , and leverages its knowledge of the US energy storage market to support energy access projects, including storage and solar projects, mainly in Africa, Latin America and SE Asia. With the support of DNV's local teams and subject matter experts in over 100 offices worldwide, the Energy Access team is able to leverage local and foreign experience to deliver quality work.

Speak with our Energy Access & Energy Storage experts at the Africa Investment Exchange (AIX) Power & Renewables 2024, 29 – 30 October 2024, in London, UK.

This article has been put together with contributions from Vera Gaddi Naphtal Haya Dev Desai Nate Kautzer, PE , and Valentine Aigbogun, P.Eng.

References

[1]Energy Storage News, "System-level issues account for nearly half of BESS production defects," 20 February 2024. [Online]. Available: https://www.energy-storage.news/system-level-issues-account-for-nearly-half-of-bess-production-defects-says-cea/. [Accessed 1 July 2024].

[2]Utility Dive, "Battery storage failures highlight reliability challenges of inverter-based resources," 4 October 2023. [Online]. Available: https://www.utilitydive.com/news/NERC-batteries-inverter-based-resource-faults/695611/. [Accessed 1 July 2024].

?