in different standard settings for the inverter and impact the resultant curtailment. On the other hand, the average D-PV system size from the analysed Solar Analytics fleet is 4.6kW which is consistent with the nationwide statistics [16]. As shown in Table XIII, total curtailed generation is calculated as 6,301 kWh/year and 4,434 kWh/year for the studied D-PV and BESS fleets where on average curtailment is 13 kWh/year for a D-PV site and 5 kWh/year for a BESS site (less than 1% of the total generation). As previously discussed, it is more difficult to define a definite curtailed generation loss for BESS, furthermore, BESS penetration is still very small across Australia. Therefore, we calculate the upscaled curtailed generation and emissions impact based on real D-PV curtailment results. Based on the estimated percentage of free-standing homes with rooftop D-PV [49] and total number of free-standing households across Australia [50], the upscaled curtailed generation is in the order of 22 GWh/year. Based on the reported CO2 emissions of the Australian energy mix [51], the upscaled curtailed generation has emissions impact of 16,5 mega-tonnes of CO2-e. Figure 47 summarizes the findings of the upscaled curtailed generation and emissions impact. Bear in mind that, the generation and CO2 emissions losses due to curtailment are more relevant to today’s grid where energy from DER isn’t sufficient to provide the network demand (except for a few instances in South Australia during Spring and Summer seasons) and hence curtailed D-PV is a lost opportunity to displace more expensive non-renewable generation. However, as we move into higher DER penetrations and determine an appropriate DER capacity for balanced outcomes across different seasons, the losses associated with curtailment may need to be re-evaluated given that at times of curtailment there may still be sufficient renewable energy to meet demand.
Figure 46 Estimated upscaled curtailed generation (GWh/year) and CO2 equivalent emissions (Megatonnes/year)
7 Socio-technical insights Key insights from the social and technical workstreams are compared in Table XV, with observations grouped in terms of: 1. What is the state of curtailment? 2. What are the impacts of curtailment? 3. How could curtailment be managed? It is important to note that the findings presented here are initial reflections, and that further work is required to consider more deeply how the social and technical workstreams can inform policy development and energy user engagement on DER curtailment.
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