The one day of Blackout in Singapore gives solar system owners 4x the usual revenue, and cost consumers 3x the usual cost
Disclaimer: All information / data presented here are publicity available data and of my opinion to the best of my understanding. This does not represent the comment of any companies I have worked for, or with.
On 18 September 2018, at 1.18am (for the auspicious Chinese, it is 18, 18, 18), Singapore suffered a massive blackout that leaves 146,797 residents without electricity supply. Electricity supply was restored in just 38 minutes (another auspicious number!). This is by all means, a very impressive feat to achieve.
I will focus on the impacts of the blackout on Unified Singapore Electricity Price. The first thing we will look at is the historical market data. The follow charts show the energy market data of the week before the blackout and the week of the blackout.
The columns of the graphs are separated by days, starting from Friday. The half-hourly demands are plotted on secondary axis. In parallel, you can see the USEP price, primary energy, regulation and contingency price on the left axis.
There are several observations you can draw from the market data.
(1) There is no statistical significant change in the energy consumption
(2) There are several spikes on 18 September 2018.
(3) The price of primary energy surges on 18 September 2018.
The small spikes on 15 September and 19 September are of not significant interest at the moment. It occurs from time to time due to various reasons. The pool volatility was high in the past but has remain stable recently.
We will focus our analysis on the 18 September. The graphs below shows the energy data over the 48 periods.
The blackout occurred at 1.18am, which effectively occurs during period 3 (1.00am to 1.30am) , and lasted until period 4 (1.30am-2.00am). Interestingly, USEP remains stable in these two periods. The impact of blackout onto USEP seems to occur at period 5 (2.30am-3.00am), where the price of primary energy surges well above S$ 2000 / MWh, and sent the price of USEP to S$ 924.33 / MWh.
The price of primary energy seems too high. I’ll be cross validating this value.
Note that the USEP price for period 1–4 is S$ 172.36 / MWh, S$ 151.48 / MWh, S$ 137 / MWh, S$ 152.90 / MWh respectively. It was already higher than the average USEP price of S$ 110 / MWh. Could this be foreshadowing upcoming incident?
Over the next few periods, the price of USEP gradually dropped from S$ 924.33 / MWh to S$ 129.90 / MWh in period 12 (05.30am-06.00am). It is an expected behavior as the electricity supply would have been stabilized in over 4 hours.
The weirdest thing that happened in the next few periods is the surge of electricity price from period 12 onward, up to S$ 1354.60 / MWh in period 22 (10.30am-11.00am). This is the highest USEP recorded in the year of 2018.
The cause of this is unknown, but this is not the subject of interest here.
This represent tremendous revenue for solar owners who sells electricity back to the grid! For every kWh of electricity injected to the grid, solar system owners are paid the USEP price (minus other charges, but let’s keep things simple). Let’s assume that the solar system generate electricity with the following generation curve. For convenience, the USEP for 17 Sep and 18 Sep is plotted on the same axis. Note that USEP was stable at approximately S$110/MWh on 17 Sep.
The calculation is a simple sum-product of 48 periods. For a 1 MWp solar power system, assuming performance ratio of 1. The system is expected to generate S$ 1180 daily (based on 17 Sept 2018 USEP).
On 18 September, the solar power system would have generated S$ 4706! That is 300% more than what the system makes normally. However, we should also take into account that the weather is rather cloudy and rainy this week. The actual revenue is expected to be lower.
On the flip side, it is also worth mentioning the amount that the consumers would have ended up paying. By calculating system demand x 0.5 hour x USEP, Singapore consumers in totality pays S$ 16.87 million dollars for wholesale electricity (excluding transmission charges, etc) on 17 Sep. On 18 Sep, the amount rose to S$ 50.65 million dollars. Refer to table below for periodical comparison.
The real question is — who would be paying for the extra S$ 33.78 million dollars? I guess we all know the answer.
