2.4 Prior work on social aspects of curtailment

Whilst this report improves the evidence base available for decision making, further work is required through a ‘deep dive’ project and potentially periodic curtailment reporting, either by DNSPs if regulated to do so, or by independent organisations such as research institutes.

There is a paucity of research on the social dimensions of curtailment at present. The emerging research on the issue of curtailment tends to centre on the extent of utility scale PV curtailment occurring across a range of countries with fast-growing adoption, and the implications of various technological approaches to it [22]. There is a broad view that curtailment is a necessary part of energy futures that feature increasing levels of PV adoption at various scales, with Koerner et al. [21] stating that there is a need to for the “stigma” which frames curtailment “as a loss” to be re-examined considering changing grid and technological contexts. However, this recasting of curtailment as an issue to be managed, and not avoided, is complicated by issues of equity that are recognised in recent literature on the curtailment of D-PVs [1,23,24].

Stringer et al. [1] focus on the Australian energy landscape to illustrate how there tend to be two “competing narratives” concerning responsibility when it comes to the high voltage conditions that necessitate curtailment. One perspective is that over-voltage in the network is caused by the surge in DPV adoption and should thus be the focus of efforts to address the problem e.g., through the curtailment of exports. The competing narrative is that voltage conditions in the network are set inappropriately high e.g., to accommodate air conditioning loads, and thus network service providers (DNSPs) should be responsible for addressing the issue of over-voltage. Thus, Stringer et al. [1] highlight how the acceptability of curtailment as a means to manage high voltage conditions is contested.

Concerns regarding the equity of curtailment extend to how it is distributed across populations. Stringer et al. [1] demonstrate this through data from South Australia, stating that while curtailment was not deemed significant in broad terms, a small number of sites experienced significant losses of 46% - 95% of generation, particularly during spring. In a similar vein, Liu et al. [23] argue that while active curtailment can be an effective way to address technical issues in “PV-rich residential distribution networks”, applying it in a fair manner can be “quite challenging”. This study drew upon a 22kV feeder in Australia with “realistically modelled LV networks (4500+ households)” and used household metrics such as D-PV generation (total output measured at the PV inverter), energy exported to the grid, and the impact on electricity bills to assess the fairness of four proposed curtailment schemes, including comparisons to fairness outcomes through a Volt-Watt scheme. The study concluded that the “quantification of the cost of fairness may help to justify alternative avenues of addressing fairness” while acknowledging that the multi-faceted nature of the problem means that the ultimate fair solution may not exist.

Focusing on South Australia, Kuiper and Blume [25] offers a critical assessment of the curtailment of DPV exports as a regulatory response from technical, economic, and social perspectives in their briefing note. While this assessment relates to a case for curtailment to mitigate system stability risks in SA at times of low minimum demand, which differs from this study’s focus on the issue of high voltage in distribution networks, it highlights several broader issues of fairness from the perspective of rooftop solar owners. The authors emphasise the critical role that consumers are playing in the NEM by providing costeffective supply through their private investments in over $4 billion in generation assets (including batteries and electric vehicles) at the end of 2020. Illustrative of the different perspectives on curtailment in [1], Kuiper and Blume [25] argue that the Australian Energy Market Operator (AEMO) “is prescribing the technical requirements and the solution to a problem of its definition”. They [25] express concerns about the precedent that mandatory measures such as curtailment might set with respect to the “control of private, consumer-owned resources”, particularly when factoring in the growing adoption of electric vehicles. The lack of independent economic modelling of the costs of curtailment to households, and