2. CURRENT ELECTRICITY GRID, USE & SOLAR
Electricity is provided to the Noosa Local Government Area (LGA) via transmission lines through zone substations and then through the distribution network. It is also provided by solar PV systems located on the distribution network. Figure 1 shows the Energex map of the Noosa area with the Zone Substations (ZSs) and the 132kV down to 33kV lines. Figure 2 shows a Google Maps view of the Noosa area with the locations of the lines down to 415V.
2. ELECTRICITY USE
The current electricity use in Noosa LGA was determined using 2016/2017 half hourly demand data from the Black Mountain, Cooran, Cooroy, Noosaville, Peregian and Tewantin Zone Substations. The total annual load through these substations into Noosa LGA is estimated to be 312,640 MWh,(1) and the aggregated annual demand profile is shown in Figure 1. It can be seen that the highest peaks generally occur in summer, although there is a solid level of demand in winter. Households make up about 56% of electricity use in Noosa,(2) with the remainder used by business and industry. There were 26,776 households in Noosa LGA in 2016(3), and so each house, on average used about 6,430 kWh/year, which is higher than the Queensland average of 5,173 kWh of grid electricity per year. (4)
1.1 Existing Distributed Generation
Solar PV is by far the most prevalent form of distributed generation in Noosa LGA. It reduces the amount of grid electricity used (by reducing the amount of electricity that is transmitted through the ZSs above). Therefore, to obtain the actual underlying electricity demand for the modelling, each half hourly period of electricity use was increased by the estimated amount of PV generation.
According to the Australian PV Institute Solar Map(5) there is currently 28,909 kW PV installed in Noosa LGA.(6) This consists of 8,031 systems(7) (26,064 kW) that are less than 10 kW in size (generally assumed to be residential systems), and 145 (2,845 kW) in the 10 kW to 100 kW size range (generally assumed to be commercial systems). Although there are about 26,766 dwellings in Noosa LGA, only about 23,263 of these are considered to have suitable roof space for PV and SWHs(8). Thus, with 8,031 PV systems in the sub 10 kW size range, about 35% of suitable dwellings have PV, and the average residential system size is about 3.25 kW. With an estimated 3,057 businesses in Noosa LGA, about 4.7% of them have solar PV, with an average size of about 20 kW.
Electricity generation by distributed PV was calculated by taking the average hourly generation of typical rooftop PV systems within Noosa LGA(9). This was then scaled according to the number and size of PV systems to produce an estimate of the hourly generation over a year. The same approach was used for future installations of behind the meter PV (household and businesses) for each Scenario. The generation from in front of the meter (ground-mounted large-scale PV) was modeled using AEMO PV traces for the area, which generates PV output data for a modeled single axis tracking ground mount PV system.
Thus, these PV systems generated an estimated 41,300 MWh of electricity in 2016/17 (or 13.2% of total demand), and so the real underlying electricity used in Noosa LGA was about 353,964 MWh. To illustrate the impact of PV on the daily load as seen by the substations, Figure 2 and Figure 3 show an average week in summer and winter respectively showing the load as seen by the substations (Net load, orange) and what the load would have been if it hadn’t been for the existing PV systems (Load, blue). The highest peaks in summer are most likely due to a combination of higher visitor numbers and air conditioning load, and are slightly reduced by solar. The small spikes visible in the winter evenings are when the off-peak load is activated(10). Although there is also likely to be some small-scale wind turbines and micro-hydro, they were not included in the baseline adjustment because they would have a negligible effect.
The current Renewable Power Percentage under the Federal Large-scale Renewable Energy Target for Australia is 16.06%. Thus, when the electricity generated by local solar PV is included, it can be said that Noosa LGA has a higher percentage, with just over 26% of the electricity currently used being renewable. However, very little of that 16.06% is currently generated in Queensland, with only 1.42% of the electricity used in Queensland in 2015/16 being renewable. Thus, it can also be argued that only around 12-13% of the actual electricity used in Noosa is currently renewable.
(1) The following percentages of the electricity through each zone substation was assumed to be for Noosa LGA: Black Mountain (90%), Cooran (90%), Cooroy (90%), Noosaville 100%), Peregian (25%) and Tewantin Zone (95%). These assumptions were provided by Zero Emissions Noosa.
(2) From https://www.energex.com.au/about-us/our-commitment/to-our-customers/connecting-with-you/data-to-share
(3) 2016 Census, ABS.
(4) AEMC (2016) ‘2016 Residential Electricity Price Trends’, Australian Energy Market Commission, Dec 2016. 2016 Census, ABS.
(6) As at May 2018
(7) To calculate the number of systems we have used the postcode to LGA conversion method discussed in Section 3.1.2**.
(8) Derived from the 2011 Census, and the APVI Solar Map.
(9) PV data was sourced from publicly available PV performance database, PVOutput.org.(10) Off-peak load is generally for water heating and is activated remotely.