Hornsdale Power Reserve earns record revenue in September 2019

October 21, 2019

Hornsdale Power Reserve

The world’s biggest lithium-ion battery, the 100 MW/129 MWh Hornsdale Power Reserve in South Australia, has just earned its biggest monthly revenue from wholesale markets.

The ‘Tesla big battery’ as it is commonly known, was famously brokered via a deal on Twitter and has been operating in Australia’s National Electricity Market (NEM) since late 2017. We recently published independent analysis, which provides a deep dive into the operation, merchant revenue, and bidding strategies of the Hornsdale Power Reserve from January 2018 to September 2019. In this article, we look at just one of the many insights from the report.

Our analysis shows that the Hornsdale battery earned approximately $3.4 million from wholesale markets in September 2019 (see chart below). This is the highest monthly revenue that the battery has achieved. Note that this is inclusive of the cost of charging the battery. However, it does not include non-market revenue streams (such as the contract it has with the South Australian government), FCAS payments under the causer pays methodology, or any other factors which are private to the operator.

Hornsdale Power Reserve revenue from energy arbitrage and FCAS

The overwhelming majority of revenue in September came from providing frequency control ancillary services (FCAS). Contingency services, which correct major frequency deviations in the grid, accounted for the highest share of revenue (55%). This was due to a strong rebound in contingency FCAS prices. In September 2019, the Australian Energy Market Operator (AEMO) made changes to how it calculates FCAS requirements. This has resulted in a higher volume of contingency FCAS being procured, which has contributed to the upward pressure on prices.

Operating batteries has a learning curve

At a high level, the revenue that a battery can earn each month and how this is split across various markets, depends on two factors:

1. Prevailing market conditions; and

2. The strength of the battery’s trading strategy.

The Hornsdale battery may have earned the single highest monthly revenue in September, but it also missed significant opportunities throughout the month. In our analysis, we compare the actual operation of the Hornsdale Power Reserve with our optimised operation model. This comparison shows that there was potentially more than $1.1 million of additional revenue available in the market in September. This highlights the complexities of operating batteries under real world conditions and uncertainties.

Batteries are unlike any other asset in the NEM. A generator, such as a coal or gas plant, can theoretically keep producing electricity as long as the fuel continues to be supplied. In contrast, a battery has a limited capacity to charge or discharge energy at any point in time. As a result, previous charge/discharge decisions can have a big impact on future revenue. There is still much to learn about how to operate batteries in the most profitable way.


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Author: Marija Petkovic, Founder & Managing Director of Energy Synapse
Follow Marija on LinkedIn | Twitter


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Wholesale electricity prices reach record highs

August 29, 2019

Wholesale electricity prices reach record highs

Financial year ending June 2019 saw wholesale electricity prices rise in every state in the National Electricity Market (NEM). Victoria had the highest increase on the previous financial year at 19%, followed by South Australia (12%), Queensland (10%), New South Wales (8%), and Tasmania (3%) (see Figure 1). This data has been compiled using NemSight, a software developed by Creative Analytics (part of the Energy One group).

wholesale electricity prices at record highs

Wholesale electricity prices have tripled over the past decade in Victoria and Tasmania and have doubled in Queensland, NSW, and South Australia. This energy crisis has been brought about by a combination of factors coming together. These include high gas prices, a decade of policy uncertainty, exit of ageing generation, lack of competition, outdated market rules, and more. And it is still very much on-going. Prices in South Australia, Victoria, and NSW all reached record highs in the 2019 financial year.

Pricing in Tasmania peaked earlier in FY 2016, due to a prolonged outage of the Basslink interconnector, which links to the mainland grid.

Queensland peaked in FY 2017. In mid 2017, the Queensland Government directed state owned generators to alter their bidding practices and put downward pressure on wholesale electricity prices. This direction has been one of the main reasons why Queensland has had the lowest wholesale electricity prices in the NEM for the last two years, despite growing max demand. However, this bidding direction ended on 30 June 2019. It will be interesting to see whether the bidding behaviour from state owned generators reverts back to old patterns over the coming summer.

Victoria and South Australia battled record heat and coal failures

High summer prices drove the annual price increase in Victoria and South Australia as seen in Figure 2. This was largely weather related as Australia sweltered through the hottest summer on record.

However, it was also due to multiple failures at Victorian coal-fired power stations, particularly on the 24th and 25th of January. An extreme heatwave gripped South Australia and Victoria, with some regions experiencing record high temperatures. Multiple brown coal outages led to 1.1 GW of thermal generation being unavailable on 24 January and 1.6 GW being unavailable on 25 January (see report by AEMO). This created a shortage of supply, with the unfortunate result of load shedding in Victoria and record high electricity prices.

Victoria and South Australia average monthly wholesale electricity prices

NSW coal and hydro generators raised bids

In contrast to Victoria and South Australia, pricing in NSW was not particularly volatile. The main contributing factor to higher prices was a change in bidding behaviour from coal and hydro generators during the first quarter (Jan to Mar) of 2019.

Figure 3 shows that black coal generators reduced the amount of electricity they offered in price bands ≤$100/MWh and instead bid this energy into higher price bands between $100/MWh and $300/MWh.

The change in bidding behaviour was even more drastic for hydro generators, who significantly cut bids in the ≤$100/MWh and $300-13,000/MWh price bands and instead bid this energy at prices greater than $13,000/MWh. Dry conditions and low storage levels were contributing factors.

NSW coal and hydro generators bidding

Spreads in wholesale electricity prices on the rise

Another interesting trend over the past decade has been the growing spread (or difference) between the 10th and 90th percentile of pricing. This has interesting implications for energy storage, which is most economic when spreads are high.

Figure 4 shows the spread for each region in the NEM in the last financial year versus 10 years prior. Ten years ago, spreads very were small, varying between $17-24/MWh across states. This offered limited arbitrage opportunities in the spot market. In contrast, in the last financial year, spreads ranged from $60/MWh to $125/MWh. As an example, the Tesla big battery in South Australia achieved an average price differential of $76/MWh (inclusive of round trip efficiency losses).

Spread in wholesale electricity prices NEM

As more zero marginal cost renewable energy enters the market, we can expect wholesale prices to keep decreasing at the times when renewables are generating power.

Queensland gave the perfect example earlier this week when daytime prices hit zero/negative for a record nine consecutive days. This was predominantly due to high solar uptake, low electricity demand, and inflexible coal. RenewEconomy covered some of our commentary here and here.

In contrast, when renewable energy is less available, prices tend to go up.  The opening up of spreads is a predictable outcome of the transition to renewable energy. It will be largely up to energy storage, as well as demand response, to regulate spreads going forward.


Author: Marija Petkovic, Founder & Managing Director of Energy Synapse
Follow Marija on LinkedIn | Twitter

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