S2b: Assessing DER Hosting Capacity Capability Review

protection, stakeholders see value in increasing the public release of network model and dataset benchmarks, such as those developed by the National LV Feeder Taxonomy Study. Open-source data and models can foster collaboration and higher quality solutions, reducing duplication of work, increasing trust and credibility, and enabling more transparent and informed policy development.

S2b: Assessing DER Hosting Capacity Capability Review

Network hosting capacity refers to the amount of DER that can be accommodated by a distribution network (or part of it) without adversely impacting power quality or reliability for normal operation at any point in time and at a given location under existing control configurations and infrastructure. Hosting capacity assessments can be conducted to measure either the amount of energy consumption (i.e. load) or export that a given network segment can accommodate. Hosting capacity assessments vary by technology – a different assessment is required to determine PV hosting capacity compared to battery hosting capacity. The accurate assessment of network hosting capacity is becoming a foundational enabler for system planning and operation as network processes change with the increase of DER.

Hosting capacity is dynamic in nature and can change depending on the weather and the behaviour of customers and their devices. Hosting capacity can also change due to various control approaches taken by network managers. Therefore, matching the physical hosting capacity with the flexible operation and/or interconnection of DERs is an alternative to traditional distribution upgrades. To meet the ongoing customer demand for DER connection, DNSPs need to know and effectively communicate the physical hosting capacity of their networks.

A hosting capacity assessment is at core a power system simulation study in which DER are increased on a network model until the network’s technical limits are reached. The quality of the network model and data used in such studies are central to the accuracy of the assessment, which is affected by modelling and data errors and uncertainty. The intended use case is a key driver of the assessment, as it guides the selection of relevant impact factors – model inputs and associated assumptions underlying the calculation, such as network configuration, voltage regulation assumptions, thermal limits and target DER portfolio.

Best practise involves the following steps for the assessment of hosting capacity:

1. Establish a relevant stakeholder process,

2. Select and define the target use cases for the hosting capacity assessment,

3. Identify criteria to guide the implementation of the hosting capacity assessment,

4. Identify the network representation approach,

5. Develop a hosting capacity assessment methodology (or methodologies) and

6. Validate the results of the hosting capacity assessment over time against real data.

Poor access to LV network data and the lack of accurate network models increase uncertainty in hosting capacity assessments, leading to conservative operation and planning decisions.

The method selected to assess hosting capacity depends on the use case, data availability and model accuracy. Therefore, different methods can be used by different DNSPs. However, the lack of common service standards, or a common way for DNSPs to express and report on hosting capacity, can impact on the development of business cases and stakeholder decisions on DER integration, and the opportunity to connect DERs.

As a result, the equitable access of customer DER to network resources remains an open challenge due to several factors, including the inherent locational diversity of DER connections. Indeed, dynamic operating envelopes, an approach increasingly gaining favour in Australia as a cost-effective approach to integrating DER, rely on a regularly calculated hosting capacity assessment to identify the network operating envelope, and yet there is no clarity on what data and assumptions should be used and which ones are most critical to define accurate and equitable limits on customer DER. Both the ESB Data Strategy Consultation Report and the AER’s Value of DER Methodology study underline the importance and value of consistency and guidance (potentially from the AER) on methodologies for calculating hosting capacity.

To address current gaps and challenges in the assessment of hosting capacity, further research is recommended in the following topics: • Impact factors: Impact factors are data and assumptions used as inputs into hosting capacity assessments, including assumptions about network configuration, voltage regulation, customer and load behaviour, DER installation and inverter setting assumptions. Decisions on which impact factors to use significantly influence the assessed hosting capacity of a distribution network but modelling all potential impact factors is extremely difficult and computationally intensive. Further research is needed to define the most significant impact factors for each hosting capacity application use case.

• Optimal mix of data and models: Data requirements vary for different hosting capacity use cases, and network-wide monitoring can be expensive. Further research is required to evaluate data and model requirements to represent LV networks with the highest accuracy commensurate with the target use case for the hosting capacity assessment.

• Analysis framework: State estimation methods can be very effective to model networks with incomplete datasets. Further research is required to assess optimal mixes of data and models, and the importance of phase imbalance, data granularity and uncertainty per hosting capacity use case.

• Hosting capacity calculation methods: Hosting capacity methods differ in input data, accuracy, computation time, consideration of uncertainties, time resolution, and