Following on from the community consultation, three scenarios were developed for 2025. They were based on the community’s general interest in renewable energy, as well as the interest in particular types of projects designed to drive uptake (as discussed in Section 5.2). Note that scenarios are not predictions: they are simply used to illustrate the impact of different levels of electricity demand and electricity generation options.
Scenario 1 represents a fairly modest uptake of additional renewable energy options. Both solar water heaters/heat pumps and solar PV increase only moderately compared to the current levels. Solar water heaters/heat pumps increase from being on 32.7% of houses to being on 35%. Household PV increases from 14.5 MW to 21.4 MW (which includes the 13% increase in the number of households), while commercial PV increases from 1.5 MW to 2.5 MW. It assumes no additional large-scale PV, bioenergy, wind or hydro. It also includes no reduction in electricity use because of energy efficiency.
Scenario 2 represents a realistic but ambitious level of uptake of renewable energy. Total residential and commercial PV increase to 36.7 MW and 6.4 MW respectively. There are also increases in large-scale PV (5 MW), bioenergy (1 MW) and wind (0.2 MW), and the combined effect of increased SWH/heat pumps and energy efficiency almost cancel out the increased electricity use driven by population growth.
Scenario 3 is essentially an unrealistic target for 2025, but is used to illustrate the impacts of much higher uptake of renewable energy that could occur at a later date.
6.1. Modelling 2025 Electricity Use
The modelling was performed for the year 2025 using NEMO (National Electricity Market Optimiser), an open source electricity sector model (https://nemo.ozlabs.org). It was used to model the hour-by-hour dispatch of a range of electricity generation technologies according to the scenarios described below. Only technologies that are commercially available in Australia are used.
This firstly involved projecting electricity use from 2016 allowing for population growth, uptake of SWHs, and the uptake of energy efficiency options in general. Different levels of uptake of distributed smaller-scale PV, large-scale PV, wind, bioenergy and GreenPower purchase were then programmed into the model according to the following scenarios. It was assumed that electricity could be drawn from the National Electricity Market (NEM) when required (most likely overnight), then exported to the NEM when in excess (most likely during the day).
6.1.1. Population Growth
The Victorian Department of Environment, Land, Water and Planning produces ‘Victoria in Future’ reports on population and household Projections to 2051. The 2016 version expects the East Gippsland Shire population to grow from the current level of around 45,000 to around 49,000 by 2025. The number of households is projected to increase from the current level of about
24,450 to about 27,650 by 2025 (i.e. by 13%), which increases electricity use. We assume that an equal proportion are suitable for PV and SWHs as are currently suitable, resulting in 24,050 suitable dwellings.
6.1.2. Smaller-scale Technology Uptake
The following discusses the various options that can affect electricity use. They can be divided into those that (i) decrease electricity use (energy efficiency, including solar water heaters and air-sourced heat pumps, behaviour change), (ii) generate renewable electricity (PV, wind turbines, bioenergy), and (iii) GreenPower.
Decreasing Electricity Use
Decreasing electricity use through energy efficiency measures (also known as negawatts) is generally by far the cheapest way to reduce the amount of electricity drawn from the grid, and therefore greenhouse gas emissions. Load management is similar, but includes simply shifting loads from one time to another, without necessarily decreasing electricity use (some load shifting measures may in fact increase energy consumption).
They can provide value by (i) reducing the annual need for electricity, which makes meeting renewable energy targets easier, (ii) reducing demand at peak times, which reduces the amount of local renewable energy and network capacity needed at any one time, and (iii) reducing demand at times of low local renewable energy generation, which would reduce the amount of electricity that needs to be imported into East Gippsland Shire (for example, where large amounts of solar PV is used to meet electricity demand, overnight loads, such as off peak water heaters, should be moved to day time boosting).
Solar water heaters and air-sourced heat pumps
There are currently over 1 million solar water heaters (SWHs) or air-sourced heat pumps in Australia, with over 250,000 of these in Victoria.49 Information is available on the number of SWHs and air-sourced heat pumps by postcode from the Clean Energy Regulator. East Gippsland Shire includes the postcodes shown in Table VI. Of these, postcodes 3701, 3862,
3864 and 3898 include a proportion outside East Gippsland. The Australian Bureau of Statistics provides Australian Statistical Geographic Standard Correspondences that are a mathematical
method used to assign data from one geographic region to another.50 We have used these to
49 http://www.cleanenergyregulator.gov.au/RET/Forms-and-resources/Postcode-data-for-small-scale- installations#Solar-Water-Heater-and-Air-Source-Heat-Pump-Deemed
50 These can be obtained from http://www.abs.gov.au/AUSSTATS/abs@.nsf/DetailsPage/1270.0.55.006July%202011?OpenDocument
assign the SWH uptake from these postcodes to East Gippsland Shire. Thus, about 20.8% of suitable dwellings have SWHs, and about 11.9% of dwellings use air-sourced heat pumps for heating water.
Table VI Estimated Uptake of SWHs and Air-sourced Heat Pumps in East Gippsland Shire (Oct 2017)
Postcode SWH Heat pumps
3701 0 0
3862 0 0
3864 11 12
3865 35 20
3875 1,417 387
3878 112 35
3880 372 118
3882 95 53
3885 148 84
3886 18 35
3887 15 23
3888 170 294
3889 11 19
3890 13 13
3891 9 0
3892 144 45
3893 0 1
3895 3 3
3896 15 10
3898 12 11
3900 7 2
3902 38 22
3903 68 42
3904 138 102
3909 613 662
TOTAL 3,464 1,993
The amount by which SWHs reduce electricity use can vary greatly (eg. from 20% to 90%)51 depending on the orientation of the system, the amount of shading, the efficiency of the system, the design of the system (eg. flat plate or evacuated tube), the climate, the hot water demand, the boosting type and the time of day that hot water is used. Some of these issues do not affect heat pumps, for example, they are unaffected by orientation or shading and their efficiency is generally unaffected by hot water demand. SWHs and air-sourced heat pumps are often assumed to, on average, reduce the electricity used for the average hot water system by 70%.52 For the modelling conducted here, we have assumed that the average SWH or heat pump reduce electricity use by
4.9 kWh/day on average through the year. We apply this reduction between 11pm and 7am.53
The SWHs and heat pumps currently installed in East Gippsland Shire avoid the use of about
9,750 MWh of electricity per year (meaning that, without them, electricity use would be about
SWHs and heat pumps offset the use of off-peak electricity, which costs less than standard electricity, which means they have a longer payback time than PV systems. We don’t distinguish between SWHs and heat pumps because we have no data on the likely future split in uptake and it is likely they will have similar impacts on electricity use. Table VII shows the estimated uptake of residential SWHs and heat pumps taking into consideration the projected population growth.
Table VII Uptake of SWHs and Air-sourced Heat Pumps in East Gippsland (2025)
Dwellings SWH & Heat pumps GWh decrease a % decrease cf baseline b
Scenario 1 35% 3,100 8,560 5.55 2.0%
Scenario 2 45% 5,550 11,000 9.90 3.6%
Scenario 3 55% 8,000 13,450 14.30 5.2%
a: Decrease due to additional units
b: Decrease as a percentage of East Gippsland Shire’s 2016 electricity use
Other energy efficiency options
There is a wide variety of energy efficiency options available for households as well as businesses. Behaviour change (such as turning off lights, wearing warmer (or cooler) clothing, turning down thermostats etc) is also a very significant contributor to energy efficiency
51 Gill, N., Osman, P., Head, L., Voyer, M., Harada, T., Waitt, G. and Gibson, C., 2015, ‘Looking beyond installation: Why households struggle to make the most of solar hot water systems, Energy Policy, 87, p83-94.
53 SWHs and heat pumps would be much more effective in reducing electricity use during summer than in winter, and not all electric water heaters operate only between 11pm and 7am, however given the other estimates used here (such as uptake of these technologies), these assumptions are reasonable.
outcomes.54 The uptake of these options has been modelled as a general reduction in load between 7am and 11pm.
In order to create each Scenario we assume that these other energy efficiency options reduce East Gippsland Shire’s electricity use in 2025 by the amounts shown in Table VIII. Then, when combined with the impact of population growth (13%) and residential SWHs/heat pumps, the final outcome are changes of +10.4% to -7.9% with respect to 2016 levels. Note that the Subtotal isn’t the simple addition of the values above it because SWHs/heat pumps are assumed to decrease electricity use only between 11pm and 7am, and general energy efficiency is assumed to decrease electricity use only between 7am and 11pm.
Table VIII Combined Impact of Population Growth, SWHs/heat pumps and General Energy Efficiency - Compared to 2016 Underlying Electricity Use (with existing PV added back in)
Scenario 1 Scenario 2 Scenario 3
Population growth 13% 13% 13%
SWHs/heat pumps -2.0% -3.6% -5.2%
General energy efficiency 0% -10% -20%
Subtotal 10.4% 1.4% -7.9%
Distributed Solar PV
As discussed above, there are currently about 16,041 kW PV installed in East Gippsland Shire: consisting of 4,573 systems (14,489 kW) that are less than 10 kW in size, and 79 (1,551 kW) in the 10 kW to 100 kW size range. About 27% of suitable dwellings have PV, and the average residential system size is about 3.2 kW. As of 2017 there were just over 4,280 businesses in East Gippsland Shire. Assuming the 79 systems in the 10 kW to 100 kW size range are on businesses and other larger organisations such as government buildings and schools, only about 1.8% of businesses currently have PV, and the average system size is about 20 kW.
The assumptions and outcomes for each Scenario are shown in Table IX. In reality there will of course be a range in system sizes, with some installations being much less or greater than the
54 Strictly speaking, behaviour change is an energy conservation measure, not an energy efficiency measure.
Table IX Uptake of Distributed Solar PV in the East Gippsland Shire (2025)
Uptake Solar PV GWh generation a % cf baseline b
Residential Commercial Total
25% - 3.5 kW
3% - 20 kW
Residential Commercial Total
30% - 5 kW
7.5% - 20 kW
Residential Commercial Total
40% - 5 kW
15% - 20 kW
a: Generation due to total PV systems
b: Generation as a percentage of East Gippsland Shire’s 2016 electricity use
The amounts of large-scale ground-mounted PV, and the amounts of electricity generated, are shown in Table X. Businesses interviewed for this project expressed an interest in up to 3 MW of large-scale PV, so it is likely the actual amount installed will be between scenarios 1 and 2.
Table X Amount of Large-scale PV and Electricity Generated, East Gippsland Shire (2025)
PV (MW) Electricity Generated (GWh)
Scenario 1 0 0
Scenario 2 5 MW 6.0
Scenario 3 10 MW 12
East Gippsland Water currently operates a small bioenergy facility that uses waste methane. Their electricity generation was estimated by dispatching the full capacity of the biomass plant in each hour of the year. The assumptions and outcomes for each Scenario are shown in Table XI.
Table XI Uptake of Bioenergy in the East Gippsland Shire (2025)
Capacity MWh generation % cf baseline a
Scenario 1 0.04 MW 350 MWh 0.1%
Scenario 2 1 MW 8,770 MWh 3.2%
Scenario 3 5 MW 43,850
a: Generation as a percentage of East Gippsland Shire’s 2016 electricity use
Small-scale Wind turbines
We assumed there would be no large-scale (MW size) wind turbines, only some small-scale wind turbines. Figure 10 shows the Wind Map from the Victorian Wind Atlas produced by the Sustainable Energy Authority Victoria. The brown areas are the best places for wind turbines: which explains the tendency for wind farms to be along the southern coast of Australia. The Hepburn Wind Farm is located in the brown area north east of Ballarat. Although there are some brown areas in East Gippsland, they are too far from transmission lines large enough to connect to. The yellow areas in East Gippsland could have average wind speeds around 7m/s, but these are concentrated near the coast, where large-scale wind turbines are unlikely to be visually acceptable.
The electricity generation of small-scale wind turbines was calculated by scaling wind power data from the ‘AEMO 100% Renewables Study’.55 The contribution from wind in these scenarios is very low and so the accuracy of the wind data is not critical. The assumptions and outcomes for each Scenario are shown in Table XII.
Table XII Uptake of Wind Turbines in the East Gippsland Shire (2025)
Capacity MWh generation % cf baseline a
Scenario 1 0 0 0 Scenario 2 0.2 MW 606 MWh 0.2% Scenario 3 0.5 MW 1,514 MWh 0.6%
a: Generation as a percentage of East Gippsland Shire’s 2016 electricity use
There is likely to be a small amount of run-of-river hydro operated privately in East Gippsland Shire – some of which may not be grid-connected. This is already reflected in the underlying electricity use through the ZSs discussed above. To the best of our knowledge there are no plans for significant uptake of run-of-river hydro in the Shire and so we have not included any in our modelling.
GreenPower is accredited and independently audited electricity that is certified to come from renewable energy generation. It is additional to any mandated renewable energy targets, and so is bought by electricity customers so they can make their own contribution to increasing the amount of renewable electricity and so reducing greenhouse gas emissions. It generally costs about an extra 5c/kWh, and so for a household using say 11kWh/day (~4 MWh/year), would add about $50 to their quarterly electricity bill. Currently only about 0.5% of Australia-wide electricity sales are through GreenPower. The assumed purchases of GreenPower for each Scenario are shown in Table IX.
55 More information available here - https://www.environment.gov.au/climate-change/publications/aemo-modelling- outcomes
Table XIII Assumed Purchase of GreenPower in the East Gippsland Shire (2025)
GreenPower as a % of
Total Use Scenario 1 0.5% Scenario 2 1% Scenario 3 2%
6.1.3. Final Renewable Energy Mix
Table XIV shows the final capacity of each type of generator in 2025.
Table XIV Capacity of each type of generator in 2025
Scenario 1 (MW) Scenario 2 (MW) Scenario 3 (MW)
Existing PV 16.04 16.04 16.04 New residential PV 6.9 22.2 34.4 New commercial PV 1.0 4.9 11.3 New ground-mount PV 0.0 5.0 10.0 Bioenergy 0.04 1.0 5.0 Small-scale Wind 0.0 0.2 0.5
The following charts (Figure 11 to Figure 16) show the electricity generation from the mix of renewable energy technologies in each Scenario in East Gippsland Shire in 2025. For each Scenario, a summer peak week and a winter peak week are shown. Each of the colours represents a different technology (or category of technology such as residential or commercial PV). The two 47 MW gas turbines at Bairnsdale Power station are also shown. The slightly thicker black line shows the level of demand, and where generated electricity is exported, a paler version of the technology’s colour is used. The brown areas represent electricity imported from the Victorian grid. These charts are discussed below.
Firstly looking at the underlying load profile (the thicker black line), the times of the off-peak water heating are very obvious – being the regular high load spikes. We have been told that Bairnsdale Power Station is often switched on only to cope with the increased demand driven by off-peak water heating56 – and this is supported by the correlation between these peaks and the operation of Bairnsdale Power Station’s Unit 1 (BDL1).57
We have incorporated the operation of Bairnsdale Power Station’s two Units (BDL1 & BDL2) using actual half hourly data from 2016. BDL is operated to both bid into the electricity market and to provide network support. It is likely that the latter operation would be affected by the higher levels of penetration of renewable energy, particularly in scenarios 2 and 3, and so the actual operation could be different to that shown here.
In Scenario 3, which has the highest uptake of renewable technologies and the lowest electricity demand, it can be seen that in summer there is a significant amount of excess solar PV electricity that flows back up through the ZSs. This is partly because the PV generation is higher in summer, but also because the load is lower. However, this scenario assumes a very large amount of PV (a total of 71 MW, compared to 16 MW currently), and it is likely that a more realistic level of PV uptake would be somewhere between scenarios 1 and 2.
We have modelled the impact of one third of the households with PV in scenario 2 also installing batteries with a 10kWh capacity (8kWh useable)58. These are used to capture PV electricity that is in excess of the household’s needs, which is then used to meet their evening load. This is shown in Figure 17 and Figure 18, which show a peak summer and winter week respectively, where the electricity generation by the PV+batteries is shown in pink. The strange
shape, with the spike in the middle, is caused by the batteries being full and so excess PV electricity is exported. This effect is much less pronounced in the winter chart, mainly because of lower PV output but also because of higher load. Although larger batteries would reduce this effect, we have used 10kWh batteries because this is a common size for a residential system. The use of batteries in this way reduces the reverse power flow of PV electricity. Of course, load shifting through demand management, such as moving off peak water heating to the middle of the
day, would also be very effective.
56 Interview with Paul Guest, who used to run Bairnsdale Power Station.
57 BDL = Bairnsdale Power Limited
58 Assumes 80% useable capacity.