Greenhouse gas and energy generation
A changing profile
Use of fossil fuel for stationary and transport energy purposes is the dominant source of greenhouse gas emissions in SA, Australia and globally. The electricity generation mix continues to evolve both in SA and across the national electricity market (NEM), as shown in Table 4.
The commercial decision to close the ageing Northern Power Station by the station’s owner, Alinta, in May 2016, removed 546 MW of capacity and marked the end of coal-fired generation in SA. This has led to a significantly increased reliance on gas-powered generation and Victorian imports of electricity through the Heywood and Murraylink interconnectors in 2016–17. Gas-fired generation increased by 23% from 2015–16 to provide just over 50% of SA’s electricity generation in 2016–17 (Table 4).
Rising gas fuel costs contributed to the mothballing of the Pelican Point Power Station by its owners in 2015, but one unit was returned to service in July 2016 following intervention by the SA Government. The Heywood Interconnector flow capability was increased in December 2015, with a 40% increase in total net imports over the last year (Table 4). Net imports of electricity to SA have been generally trending upwards since 2007–08.
Table 4: SA’s electricity supply by fuel type, comparing 2015–16 with 2016–17
|Local generation by fuel type||2015–16 (gigawatt hours or GWh)||Percentage share||2016–17 (GWh)||Percentage share||Change (GWh)|
|Diesel and small non-scheduled generation||113||0.9%||122||1.1%||9|
|Interconnector net imports||1,941||–||2,725||–||784|
South Australia continues to have the highest proportion of renewable energy of all regions in the NEM. Wind and rooftop photo voltaic (PV) capacity in SA has continued to grow to 2.5 gigawatts (GW), providing 48% of SA’s generation in 2016–17 (Table 5). South Australia’s 18 wind farms, most of which were built under the national Renewable Energy Target (RET), reflect the existence of high-quality wind resources in proximity to the transmission grid and a supportive government policy.
Table 5: South Australia’s registered capacity and local generation by energy source 2016–17
|Energy source||Registered capacity||Electricity generation|
|MW||% of total||GWh||% of total|
|Diesel and SNSG||289||5.3%||122||1.1%|
Table 6: Historical SA generation and net interconnector imports (GWh)
|Interconnector net imports||1,377||1,637||1,528||1,941||2,725|
|Small non-scheduled generation||79||82||99||105||95|
South Australia’s installed rooftop PV capacity has grown strongly since 2009, mainly due to the SA Government feed-in tariff, the small-scale technology certificate multiplier, falling system costs and increasing electricity prices. More than 30% of SA dwellings now have rooftop systems installed. Rooftop PV generation is estimated to have provided 9.2% of SA’s electricity generation in 2016–17 and this is projected to double over the next 10 years.
Residential and commercial rooftop PV systems are already having a material impact on the operation of the electricity supply system, reducing electricity demand from the grid and shifting the peak demand to later in the day, when solar generation is falling. With evolving technology and changes in relative costs, it is increasingly technically feasible and economic to meet these peaks with demand reduction management and battery supply.
Committed or under-construction large-scale solar and wind projects under the RET, in addition to the projected increase of rooftop solar, are forecast to take SA’s renewable generation to 70% by 2020. With the plunging cost of large-scale solar, a number of projects have recently emerged, including the 220-MW Bungala solar farm near Port Augusta, 2 solar farms totalling 240 MW near Whyalla and another 100-MW solar farm at Tailem Bend.
Much of the recent, rapid growth in renewable capacity has been driven by large energy consumers underwriting projects to secure a supply of cheaper and clean energy. The new owner of Whyalla’s Liberty One Steel has announced major investment plans to power the steelworks with 1 GW of new dispatchable renewables to improve electricity supply reliability and drastically reduce costs. This marks a new approach to powering heavy industry and is one that the owner intends to roll out at other industrial sites around Australia.
A new gas-fired power plant will provide SA with a source of emergency electricity generation and the inertia to stabilise local renewable generation. In addition, construction of the Stage 1 and Stage 2 Barker Inlet and Reeves Plant privately owned gas-fired stations is planned, or currently being carried out, at a cost of $745 million and a combined 720 MW of capacity. While the government-owned plant is only intended to be switched on in times of emergency to avoid load shedding events, such as the one in February 2017, Alinta has indicated it will run its peaking power station not only when demand for electricity is high, but also when market conditions are favourable.
A range of measures are being introduced to increase SA’s onshore and offshore gas exploration and production to diversify the economy and secure a local source of gas to meet the increasing proportion of gas-fired generation. South Australia has vast potential gas resources in the highly prospective regions of the Great Australian Bight and the Cooper Basin, with the latter alone having the potential to supply Australia’s energy needs for more than 200 years. There is renewed interest in the Bight, and a number of international companies are proposing significant exploration worth approximately $1.2 billion.
Gas has been characterised as a transition fuel on the pathway to a zero-emissions power system. However, rapid advances and cost reductions in renewable energy generation, storage technologies and demand responses, together with the rising cost of gas, mean renewable energy with storage can provide flexible, instantaneous and reliable generation that is already cheaper than new gas generation. While gas peaking plants may play a near-term role to continue to firm intermittent renewables until more storage comes online, renewables and storage have become competitive with gas as a source of new power supply.