By Anthony Coker, Senior Vice President, MIDEL Americas
Our power networks are expected to be reliable, efficient and resilient. It’s an expectation so taken for granted that when a system failure does occur, the shock is palpable. The recent near-failure of the Texas grid is a vivid example of what can happen when power networks turn out to be more fragile than we thought. The Electric Reliability Council of Texas (ERCOT) reported that recent demand for Texas energy peaked at 69,000 megawatts at its greatest height, which was greater than its planned worst-case scenario. “None of their scenarios envisioned that we could possibly have over 30,000 megawatts of outages at the same time,” Dr. Daniel Cohan, an associate professor of civil and environmental engineering at Rice University in Houston, told the New York Times. “That’s more than double their worst-case.”
Ideally, resiliency in power networks should be “designed-in” to help counter unforeseeable events. Operators deploy many strategies to mitigate extreme weather events, even as they get more unpredictable and difficult to manage. But are there solutions available today that are being overlooked? Perhaps. In my dealings with network operators and transformer manufacturers, I’m sometimes surprised to learn that one proven element of a robust resiliency strategy can go unnoticed. Specifically, I’m referring to the use of natural and synthetic ester fluids to replace mineral oil in distribution and power transformers.
Ester transformer fluids can be split into two groups – synthetic and natural. They are all robust, fire safe and biodegradable. And crucially, synthetic ester fluids have a very low pour point and excellent oxidation stability, making them suitable for extreme cold conditions and in breathing systems where the fluid is exposed to oxygen from the air.
Synthetic ester fluids remain pourable (and thus, move freely to cool the internals) at extremely low temperatures, reducing the risk of freezing and ensuring cold start capability. Equally, in hot climates (or in areas like Texas that have recently seen the worst of both extremes), improved transformer fire risk mitigation can be delivered because natural and synthetic ester fluids have a much higher fire point than mineral oil; this also reduces the need for auxiliary cooling equipment.
Catastrophic loss of power can cause severe hardship for the people who rely on those power networks, especially as the failure of one source of energy is rarely an isolated event and typically leads to downstream effects and pressure on additional infrastructure, such as the water or gas supply systems. In the February 2021 Texas example, lack of power caused water in Texas pipes to freeze and then burst, affecting the total water supply. Similarly, when power was lost in one sector, the natural gas pumping stations went down, depriving gas fired generating facilities in other sectors of their fuel when needed most. When power networks are not capable of coping with stress, the knock-on effects can be devastating.
The failure of the Texas grid was multifaceted and wasn’t due to any one element – it was a systemic collapse. A collapse that was allowed to be designed into the systems from the start, based on economic risk analysis. It is akin to a homeowner taking the risk and building in a 100 year flood plain without spending the extra money on elevating the house, because “how often can you have a 100 year flood?” Or for Texans, how many arctic freezes can you have in a decade that knock-out your electric grid? (Answer: two – 2011 and 2021).
And weather conditions are not likely to grow less challenging. The Global Risk Report for 2021 suggests that extreme weather scenarios, from cold snaps, to floods, to heat waves and even wildfires, are likely to become more frequent and have serious negative effects on American infrastructure. But there are sustainable and effective actions that can be taken today to strengthen power network resiliency – and using ester transformer fluids is one example of such an action.
Resilient power networks require investment
First let’s consider resiliency from a financial perspective. Jesse Jenkins, assistant professor and energy systems engineer at Princeton University, made this recent comment “Preparing for extreme events is like buying home or health insurance: it costs you every year and you hope you’ll never use it. But when a crisis strikes, paying the premiums can look like the perfect decision in hindsight,” he told the New York Times.
This is an important point; the designing-in of network resiliency necessarily includes the calculation of the cost of those resiliency measures. In the 2020 MIDEL Transformer Risk Report, the findings revealed that while safety is perceived to be a top boardroom concern, many transformer industry professionals lack confidence in their senior management team’s ability to properly mitigate transformer-related risk. When asked about mitigating transformer-related risk, only 44 per cent of respondents received approval for all of their recent recommendations. Of those that found it difficult to have changes approved, the majority (56 per cent) cited cost as the main barrier. So, what price resiliency? (The answer is, of course, “What price non-resiliency?” In his recent podcast ‘Resilience Is A Choice’, FM Global’s Allan Johnson makes the extremely valid point that network power outages also have a real and negative impact on an operator’s profit, shareholder value and reputation.
Let’s look again at the Texas example – through the optic of resiliency cost. Although many fingers pointed to wind turbines (which did indeed freeze) to be blamed for the power failure, that blame lacks nuance. Wind turbines are successfully used to power extremely cold areas in Scandinavia, Alaska, Canada, and Inner Mongolia, Sirris/OWI-Lab reports. Wind turbines in those areas are appropriately prepared for extreme cold, and are functional in temperatures of below -45°C (-49°F).
Like many other elements of a fragile power network, Texas wind turbines weren’t equipped to deal with those particular conditions; why? Because wind turbine developers specify the climate package for the prevailing local conditions at the best value. This same oversight applies to the natural gas, coal, and nuclear facilities, as Bloomberg reports. Texas grid operators did not rely on wind turbines in cold conditions, so their loss wasn’t felt. They did rely on thermal plants to operate exactly as expected, but they failed for similar reasons; cold weather resiliency was value-engineered out from the start and it was not mandated by authorities.
In this unanticipated extreme event, the power grids were totally unprepared for spiking demand while generating units went offline. As these events are likely to happen with greater frequency in the future, it makes sense for Texas and other states to consider how they can reinforce the resiliency of their power networks.
Ryan Wiser, Senior Scientist and Head of the Electricity Markets and Policy Department at Lawrence Berkeley National Laboratory, made an interesting suggestion in his LinkedIn post. Renewable energy is often seen as “weather-dependent” or “intermittent”, he writes. Why not include natural gas, nuclear and gas power in the category of energy that deserves to have back-ups, fail safes and redundancies? “[W]e should … simply recognize that no generator is perfect, and better plan for common failure modes that can inflict all resources,” he concludes. Resiliency in power networks requires investment, but the investment will pay dividends.
Ester transformer fluids can strengthen power networks, especially when it comes to cold weather performance
In the long run, it’s far more cost-effective to understand that many “unforeseen” events can happen that would challenge a power network and build in resiliency to avoid them. This recent extreme weather event is a warning (although there were no reported substation fires or transformer incidents) – because we know there will be a higher rate and greater intensity of wildfires, floods, hurricanes, droughts and cold snaps in our future, putting an enormous amount of pressure on the electric grid. Resiliency in power networks can be gained through many methods, one of which is investing in transformers with less-flammable, biodegradable, non-toxic liquids. A synthetic ester liquid with a pour point of -56°C can be used to mitigate freezing and transformer fire risks; with higher flash and fire points, an external fault would be far less likely to lead to a failure or fire, therefore reducing the chances and potential severity of an incident, in a location where billions of dollars of investment have been made. Natural and synthetic ester fluids add resiliency in power networks both by decreasing the likelihood of a dangerous accident, but also by mitigating the potential results of one.
Let’s not kid ourselves – hurricanes are predicted to be more intense, temperatures more extreme and flooding more frequent. There will be more of these events as the extreme becomes the commonplace. Resiliency in power networks is a smart, and ever more necessary, investment against future climate traumas once deemed extremely rare, yet which now are clearly inevitable. There is an obvious imperative for utilities, developers and businesses to invest now in future-proofing power networks and for engineering firms to advocate for it. Technology such as ester transformer fluids is proven, is ready to deploy and can make a difference today.