Article   |   Dale Ramsawak   |   16.12.2021

Maintaining pipeline integrity during changing weather patterns

Throughout 2021, pipeline networks have had to withstand unseasonal temperatures, heavy rainfall, and prolonged periods of increased demand. Dale Ramsawak, Senior Pipeline Integrity Engineer, outlines examples of the impacts caused by climate change on pipeline structures and addresses some of the new challenges ahead in maintaining integrity in a changing world.

When you think of snow, the US state of Texas is seldom the first place that comes to mind. Though it does fall during the winter, the amount of snow is usually far below the levels seen in other states. That changed dramatically over the course of four days in February 2021 when winter storm Uri rolled in.

Aside from weather making roads treacherous, the storm took out the Texan electric grid, leaving millions without power. Worryingly, as the cold weather looms on the horizon once again and the fallout from Uri continues, Texas is reported to be 37% short of the total energy that it needs should another storm land.

In a report issued in November 2021, the North American Electric Reliability Corporation (NERC) called on grid operators to “adjust operating plans and keep the lines of communication open” throughout this difficult winter period. But Texas’s struggles are not a new occurrence – NERC and the Federal Energy Regulatory Commission (FERC) jointly wrote a raft of recommendations after a storm of similar proportions to Uri caused outages across North Texas in 2011 and again in 2018. This time round, however, climate change is fully on the world agenda, and the need for complete preparation takes on a whole new meaning.

Further north, in Canada, one of the two sections in the Westcoast natural gas pipeline were closed in November as a precautionary measure as the province of British Columbia battles floods and torrential rain. The pipeline, consisting of two lines of 30-inch and 36-inch in diameter supplies the equivalent of between 1.5 and 1.8bn cubic feet of natural gas to both British Columbia’s lower mainland and the US Pacific Northwest. A severe loss of supply here would be devasting to both regions, yet even with the shutdown of a section of the 30-inch pipeline, supply is forecast to still be close to expected capacity, though the reduction is unlikely to be a long-term solution.

Preparing for unforeseen scenarios is, of course, a natural part of conducting Pipeline Risk Assessments (PRAs), and the weather has long been a consideration in a network’s construction. For instance, the original plans for the Trans-Alaska pipeline, which date back to the 1970s, factored in changes in permafrost conditions, yet this particular pipeline – one of the world’s largest – is in danger from thawing permafrost causing a slope supporting a 246m stretch to shift and damage the supporting structures.

Similarly, being able to record the salinity and temperature of seawater allows for sections of offshore pipeline to be protected from corrosion before it can present a significant (not to mention costly) issue. Enhanced images of specific sections are routinely obtained from undersea vehicles equipped with the latest generation of cameras and other video technologies, therefore highlighting the most critical areas of repair while they are relatively straightforward to address.

Such threats are factored into all Pipeline Integrity Management Systems (PIMS), however with unusual weather patterns starting to become more common across the globe, the various sub-categories pertaining to individual weather threats are becoming increasingly fluid. There is every likelihood that degradation factors observed in one region or on a particular stretch of pipeline will start to be visible elsewhere for the first time.

The effects of changes in operational conditions can be observed over a period of time, which in turn provides data for long-term maintenance and degradation planning. This also makes preparations for sudden changes in the weather more efficient, with these also being made a fundamental part of the operator’s KPIs.

Like with most aspects of grid reliability planning and assessment, understanding the effect of the weather draws on innovative technology, as we have seen ourselves with our own software, Promaps, to determine the impacts of adverse weather before larger, and more costly challenges occur. Technology such as this is further supplemented by observed inspection techniques including, but not limited to, in-line inspection (ILI) and considerations surrounding the stability of both the ground and the structure itself taken into account.

In the US, weather-related outages are thought to cost the economy between $20bn and $55bn annually. 59% of the total number of outages of the past 15 years are attributed to storms or severe weather, albeit it is worth noting that these take into account minor outages caused by fallen trees taking out power lines for example.

That said, with storms and freak weather conditions expected to become more common because of climate change, the threat to power grids is very much real, as is rising sea levels to onshore pipelines. On the flip side, unusually low wind speeds are reducing the amount of power from wind farms, which puts the pressure on pipelines to bridge the gap.

The threats posed to the UK by our changeable weather is compounded by limited flexibility in terms of where we receive sources such as natural gas. In 2018, during the infamous Beast from the East, the National Grid warned that it might not have enough natural gas to fulfil consumer demand. Though it later withdrew the warning, thanks largely to a strong industry response, the situation could have been similar to that seen in Texas this year. And the threat does still remain, with the UK continuing, for now at least, to be reliant on fossil fuels. As the Westcoast pipeline situation shows, in a trade-off between a comparatively slight reduction in output and a complete loss of power, the former will be the more favourable outcome.

The world is changing, there is little doubt of that. However, for all the warnings, we should remember that we have the means to be as prepared as possible for the unpredictability to come. Taking a longer-term view and being willing to share forecasts with neighbouring regions which may be just as vulnerable keeps the international energy community one step ahead.

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