Montana Oil Spill Illustrates Climate Related Risks to Pipelines, Experts Say
Details are still sketchy on exactly how an oil pipeline buried under the Yellowstone River in Montana ruptured and spilled at least 42,000 gallons of oil, but indications so far point to river flooding as a likely contributing factor, revealing a largely unaddressed climate-related risk to energy infrastructure.
A rupture in the planned Keystone XL pipeline could release up to 6.9m US gallons into the very same Yellowstone river, a nightmare scenario far outstripping the present spill, a new report warns.
The report, produced by an environmental engineer at the University of Nebraska, sets out four worst-case scenarios for a spill on the Keystone XL project, which is designed to carry oil from the tar sands of Alberta to the refineries of Texas.
The existing Yellowstone spill, on a river running well above flood stage, may have scoured the bed and exposed the Silvertip pipeline, operated by ExxonMobil Corp., that was supposed to be buried more than five feet out of harm’s way. Once it was exposed, any debris carried along by the river could have struck the pipeline and caused the leak.
ExxonMobil took almost an hour to fully seal the pipeline after the accident – nearly twice as long as it had publicly disclosed. The company said that did not change its estimate of how much crude entered the river.
Transportation officials said Wednesday that oil was observed as far downstream as 240 miles in Terry, Mont. The agency said that information was provided by ExxonMobil, but company spokesman Alan Jeffers said he was not aware of any such sighting.
Questions About the Tar Sands Keystone XL Pipeline
An accident on the Keystone XL would carry an vastly greater risk, environmental groups argue. The ExxonMobil pipeline carried about 40,000 barrels a day. They Keystone XL, planned by TransCanada Corporation, would carry more than 910,000 barrels of a thicker, more corrosive slurry bitumen crude 1,700 miles from Hardisty, Alberta, across Saskatchewan, Montana, South Dakota, Nebraska, and Oklahoma. After connecting with an existing pipeline in Nebraska, the new Keystone XL would begin again in Cushing, Oklahoma and continue on to Houston and Port Arthur, Texas. There, company officials say, they would have the special refining capacity they need. It would cross the Missouri, Yellowstone, and Platte rivers, as well as important groundwater reserves.
U.S. Department of State
The proposed Keystone XL pipeline would move 910,000 barrels of a mix of bitumen, natural gas and undisclosed chemicals each day along a 1,800-mile route running from Hardisty, Alberta to Port Arthur, Texas.
The $7 billion pipeline, which must be approved by the U.S. State Department and the Environmental Protection Agency (EPA), has drawn both opposition and support across its route. But it has run into the fiercest resistance in the conservative farming state of Nebraska, largely because the pipeline would cross the Sand Hills. Should the toxic brew leak, it could pollute not only the water there, but could seep into portions of the Ogallala Aquifer, the 174,000-square-mile underground reservoir, fed in part by water from the Sand Hills.
Spills are not a far-fetched scenario. In a year of operation, a similar pipeline in the U.S. — the existing Keystone, also owned by TransCanada Corporation — had 11 spills. Most of them were tiny, but the largest, in southeastern North Dakota, was 21,000 gallons, and federal officials temporarily suspended the company’s operating permit. And last year a 30-inch oil pipeline owned by Enbridge, another Canadian pipeline company, suffered a 4-foot-long rupture and spilled nearly 20,000 barrels — 840,000 gallons — of oil into the Kalamazoo River in Michigan, killing much of the aquatic life for miles. It was the worst spill ever in the Midwest.
Petroleum pipelines that carry diluted bitumen, or “dilbit,” pose special risks. Dilbit pipelines use higher pressure and higher temperatures and need chemicals to keep the thick, tarry substance flowing. Some data suggests they suffer more ruptures because of these temperature and pressure extremes.
But the real problem, says Carl Weimer, the director of the Pipeline Safety Trust — set up after three young boys were killed by a gasoline pipeline rupture, explosion, and fire in Bellingham, Washington in 1999 — is that so little is known about dilbit pipelines. “We’ve asked those types of questions to the Department of Transportation and haven’t gotten an answer,” says Weimer. “Unfortunately no one has looked into these things.” The director of the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration, Cynthia Quarterman, testified recently to Congress that existing safety and environmental regulations fail to take this new kind of pipeline into account. Environmentalists have criticized Quarterman for her ties to the oil and gas industry, including providing legal counsel to the Enbridge pipeline company before joining the Obama administration.
Company officials say they are aware of the fragile nature of the Sand Hills. “We take safety and environment very seriously,” said Terry Cunha, a spokesman for TransCanada Corp. “This pipeline would not be the first to cross the Sand Hills. There’s already 3,000 miles of pipe crossing the [Ogalalla] aquifer.” Other conventional pipelines, not dilbits, do cross the Sand Hills.
Extreme precipitation events becoming more frequent
The immediate question arises of how likely such an event may be at the thousands of other pipeline river crossings around the country. And with climate change likely playing a role in changes to extreme weather events like those that have caused flooding through the first half of 2011, some experts say a warming climate could be putting pipelines at higher risk for more accidents like this one.
“I think that the Montana Yellowstone River oil spill has been a warning about what floods can mean for pipelines, even when they are buried deep under a riverbed,” said Susan Casey-Lefkowitz, director of the Natural Resource Defense Council’s International Program. “We need to take a hard look at our pipeline safety regulations, we need to update them, we need to take new information into account… and [that includes] things like the effects of climate change on infrastructure, and that’s not something that we had been talking about yet.”
There have been suggestions in the past that flooding, and changes to flooding frequency and severity, could affect pipelines, but analyses of the risk are lacking. Hurricanes Ivan, Katrina, and Rita reportedly damaged hundreds of pipelines, but those are on the seabed in the Gulf of Mexico; one study using unique measurements during Hurricane Ivan showed that the wind and waves caused severe stress to the seabed, and the stress lasted for a week after the storm passed through.
And of course, if hurricanes grow more severe as the climate warms, as some studies indicate, then the risks to those pipelines could increase as well.
River flooding in particular is largely absent from energy infrastructure risk assessments. One report by the California Energy Commission stated simply that: “altering patterns of precipitation that increase [flash flooding] events could result in a greater number of pipeline service disruptions.” Another publication by the National Research Council noted that pipeline regulations required a minimum of three feet of cover over a buried line, and that “intense precipitation can erode soil cover…. Scour and shifting of pipelines are a major problem in shallow riverbeds, where pipelines are more exposed to the elements.”
It is notable that in the Yellowstone River where the most recent accident occurred, the flooding was not a particularly extreme or rare event. According to John Kilpatrick, director of the U.S. Geological Survey’s Montana Water Science Center, these flow rates in the river tend to occur once every 10 to 25 years. For comparison, the massive Mississippi River flooding earlier this year was closer to a 500-year event (its second since 1993, incidentally).
And there is now reasonable evidence that conditions conducive to the kind of floods that have ravaged rivers from the Mississippi to the Missouri and the Yellowstone this year may become more and more common as the climate warms. In fact, scientists have already linked greenhouse gas emissions to changes in extreme precipitation events.
Two papers published in the journal Nature in February tied higher levels of greenhouse gases in the atmosphere to the observed trend of more intense rainfall events in much of the Northern Hemisphere. One of the studies found that emissions of greenhouse gases significantly boosted the odds of a particularly destructive flooding event in the UK in 2000.
Francis Zwiers, a climate scientist and director of the Pacific Climate Impacts Consortium, has published several papers showing that extreme precipitation events will become more frequent over the course of the century.
“Physically that makes lots of sense, you’ve got the warmer atmosphere, the warmer atmosphere can hold more moisture,” Zwiers said. “It doesn’t necessarily mean that it is going to rain more in any given location… but if there is more moisture available, then extreme events should become more extreme, and that’s exactly what we see in the models.”
Zwiers told Climate Central that comparing data from a number of climate models has suggested that a 100-year event in North America — meaning, a rainstorm of a severity that has a one percent chance of occurring in any given year — will become closer to a 70-year event by the end of the 21st century. A 50-year event will turn into a 25-year event, and as he and his colleagues showed in a paper in the Journal of Climate in 2007 a 20-year event will become a seven to 10-year event. This suggests, Zwiers said, that river flooding could become more common as well.
“So it means if you have designed infrastructure that will protect up to what you perceive today to be a 100-year event, that protection might not be quite as strong in the future,” Zwiers said. “You’ll have to deal with damages from excess water flow and so on more frequently.”
An increased risk of flooding also means an increased risk of exposed pipelines. “With higher flows you are more likely to have enough velocity to pick up and move sediment around,” said the USGS’ Kilpatrick.
Focus on oil and gas pipelines
Pipeline safety has jumped into the fore of energy conversations in the last year or so, beginning with a large oil spill into the Kalamazoo River in Michigan. That spill apparently also occurred when the river was above flood stage levels, though there is no indication that the flood itself caused the spill. There is also an ongoing controversy surrounding the Keystone XL pipeline, a huge project designed to bring tar sands oil south from Alberta to Texas.
“Keystone XL will cross rivers throughout the United States,” Casey-Lefkowitz said; this includes the Yellowstone, where the spill cleanup is ongoing. Her organization, the NRDC, has joined many other groups in opposing the pipeline; a final environmental impact statement is expected from the State Department this summer. “Right now TransCanada, the company that has proposed it, is saying that under the Yellowstone river it will be buried twice as deep as the Exxon pipeline was, but that’s not necessarily the case under all the rivers [the pipeline will cross].”
The July 11th study by the environmental engineer, John Stansbury, argues the pipeline operators TransCanada Corp, have significantly underestimated the chances of a spill and painted an overly optimistic picture of how long it would take to shut down the pipeline.
Stansbury notes that TransCanada, in its estimates, sees the possibility of 11 serious spills on the pipeline during the course of 50 years. He argues existing data suggests a more realistic estimate would be 91 accidents during that half century.
He also took issue with TransCanada’s claims that it could shut down a pipeline within 19 minutes of a leak. A slow leak in a remote area of Montana or Nebraska could go undetected for days or even weeks between inspections, he warned. It took 56 minutes before ExxonMobil crews managed to stop the leak into the Yellowstone this month.
The report goes on to estimate the potential consequences of spills on four separate locations: the Platte river and Sandhills in Nebraska, and the Missouri and Yellowstone in Montana. “Contaminants from a spill at the Platte river crossing would travel downstream unabated into the Missouri river for several hundred miles and affect drinking water intake for hundreds of thousands of people,” the report warns.
And though high profile spills like that in the Kalamazoo make the news, pipeline incidents have long been common events. The Office of Pipeline Safety – part of the Department of Transportation – has recorded an average of 282 “significant” incidents each year since 1991, with little signs of safety improvement over time. Will energy and pipeline companies take a changing climate into account in the future? For its part, ExxonMobil — owners of the Yellowstone River pipeline that ruptured — isn’t ready to commit.
A spokesperson for ExxonMobil, Kevin Allexon, told Climate Central in an e-mail that the company is “determined to learn from this so we don’t repeat [it],” but refused to answer questions specifically related to climate change, calling them “speculative.”
The oil carried by the flood waters at least 100 miles downstream from the Yellowstone spill is real enough, and the increased likelihood of extreme precipitation events as the climate warms suggests it won’t be the last such incident. As Kilpatrick, of the USGS, pointed out, “rivers are powerful things. If you put your infrastructure in the way of it, at some point, at some time, the river is probably going to have an impact on it.”
Some elements here adapted From David Levitan’s article in Climate Central