Water utility saves millions on energy with analytics

Analysing prices and costsSA Water has saved $3 million in annual energy costs by using analytical tools to aid energy purchases, buying power when cheap and avoiding non-essential operations when prices surge.

The utility reduced curtailable electricity bills 10-15% in 2013-14 using a range of data manipulation tools, said Network and Production Planning Manager Steve McMichael.

“Were we to just buy power blindly on the spot market, when the price shoots up the cost is astronomical, so we need to manage the risk of that price volatility,” he said.

With the utility responsible for up to 4.5% of South Australia's total power consumption, SA Water began to smarten up its power purchasing decisions around four years ago.

“We used our data warehouse, Bentley Systems Amulet, and other data manipulation tools to build systems to collect, manipulate and display information that helps us understand what is going on in the power marketplace,” McMichael said.

The system, with set parameters around operational requirements and risk tolerance, is fed with data from the Bureau of Meteorology, live data from the Australian Energy Market Operator (AEMO).

“We present the information to our control room operators so they can make smart decisions about when to operate our large pumps depending on how prices fluctuate, or how we anticipate they will fluctuate,” McMichael said.

“We have requirements for shifting certain volumes of water over fixed time periods but there is some flexibility in the time of day and the day of week we do it.”

With operators able to make decisions in real-time, the utility is able to maximise its use of low-cost power and minimise exposure to high-cost power.

“Crazy things happen. Negative prices occur on the spot market – especially in SA, which often has volatile prices,” McMichael said.

“Recently the price was around -$60/MW-hr for several hours. We turned on as many pumps as we could to constructively shift water by bringing forward pumping we anticipated doing in coming days.

“It's more common that the opposite happens though: we see a forecast that predicts a large power price spike – perhaps there's an infrastructure outage planned while high demand is forecast – so then we'll back off and shut down as much as we can and wait for a better opportunity.”

McMichael said the utility began developing the systems, consulting with outside experts and training control room operators around four years ago.

“It was a long process – we undertook lengthy trials where we had tech and engineering staff making operational decisions based on electricity market data to confirm the how it all worked,” McMichael said.

“Then we made electricity market information available to our control room operators, asking them to become familiar with the information and, initially, not worry about using the data to make decisions.

“We went about it cautiously at first – nobody wants a big mistake – and gradually we gained confidence.”

SA Water anticipates power savings this year will surpass $3 million given the dry conditions and large amount of pumping required as a result.