When I talk to people about the Dragonpipe (Mariner East 2 pipeline), they sometimes say, “Oh, there are many pipelines just like that, running through areas just like this. Don’t worry about it.” Even pipeline safety “experts” make similar statements.
For example, in the hearing for State Senator Dinniman’s “Emergency Petition” to the Public Utility Commission last May, Ginny Kerslake asked Sunoco’s pipeline safety expert, John Zircher, “Are you aware of any case of natural gas liquid pipelines like Mariner East that are in comparable areas of such high population density as West Whiteland Township, or is this unique?”
Zircher answered, “There are…thousands of miles of pipelines just like this in high population areas.”
Kerslake asked, “What is the total pipeline distance of natural gas liquids?”
Zircher answered, “Natural gas liquids? I actually don’t have a number for that. For hazardous liquid pipelines, it’s 200,000 miles of pipe.”
It’s important to understand that “hazardous liquid pipelines” include pipelines for refinery products such as gasoline, diesel, heating oil, etc., and most of the miles of pipeline Zircher was talking about carried those products, not NGLs. NGLs are far more dangerous.
Similarly, Richard Kuprewicz, the pipeline safety expert hired by Middletown Township, when asked this question at a recent public meeting, gave a similar answer to Zircher’s, without directly answering the specific question of whether similar NGL pipelines exist in densely-populated areas.
(Want to see the details of how badly-chosen the Dragonpipe’s route is? Check out “Population density maps: lessons on where NOT to put a pipeline”. That’s where you will find the full population density map containing the snippet that appears at the top of this post.)
To properly answer the question about whether our situation is unique, you need have a list of similar NGL pipelines, and you need to know where they run.
So where can you find similar pipelines? In tracking down the relevant pipelines, it is useful to separate NGL pipelines into two categories. “Local distribution” pipelines carry a single product (usually propane) from a storage hub to its point of use—typically to a local propane distributor (where it is loaded on trucks) or to a factory. Those kinds of pipelines are far smaller and shorter than the Dragonpipe, so they are not comparable. The Dragonpipe belongs in the second category, called “transmission” pipelines, which move large quantities of NGLs over long distances. There aren’t many of those.
Russell (“Rusty”) Braziel is an authority on oil, gas, and NGL markets. In 2016, he wrote a book, “The Domino Effect”, about how these three markets interact. In his discussion of NGLs, he lists the major pipeline systems that move most NGLs in the United States. There just are 14 of them, listed in the table below. As the table shows, six of them carry exclusively “Y-grade”, which is a raw mixture of NGLs. The Y-grade is transported to separation facilities where the ethane, propane, and butane are separated out into “purity products”. The other eight pipelines carry the three “purity products” cross-country. Some carry only one product, and some switch from one to another as necessary (which is how the Mariner system is planned to be used, although ethane is the main product).
Here are the 14 main NGL distribution pipelines:
| Pipeline | Owner | From | To | Product |
| MAPL (former MAPCO system) | Enterprise | Rockies | Hobbs, NM | Y-grade |
| Seminole | Enterprise | W. Texas | Mont Belvieu, TX | Y-grade |
| Chaparal | Enterprise | W. Texas | Mont Belvieu, TX | Y-grade |
| Overland Pass | Williams/ ONEOK | Rockies | Bushton/Conway, KS | Y-grade |
| Arbuckle | ONEOK | Conway, KS | Mont Belvieu, TX | Y-grade |
| Sterling | ONEOK | Conway, KS | Mont Belvieu, TX | Y-grade |
| MAPL (former MAPCO system) | Enterprise | Hobbs, NM & Conway, KS | Midwest | Mostly propane |
| Dixie | Enterprise | Mont Belvieu | Southeast | Propane |
| North System | ONEOK | Conway, KS | Midwest | Propane |
| TE Products (TEPCO) | Enterprise | Mont Belvieu | Northeast | NGLs |
| Atex | Enterprise | Marcellus | Gulf Coast | Ethane |
| Mariner West | ETP | Marcellus | Sarnia, Ontario | NGLs |
| Mariner East | ETP/Sunoco | Marcellus | Marcus Hook, PA | NGLs |
| Vantage | Pembina | North Dakota | Alberta, Canada | Ethane |
The major NGL pipeline systems. Data source: The Domino Effect, E. Russel (“Rusty”) Braziel, NTA Press, 2016.
I have looked at maps of each of these pipelines, to see which ones go through dense suburban areas. I can find no other example of an NGL pipeline similar to the Dragonpipe that goes through a similar area of major suburbs. In spite of what the pipeline “safety experts” may say, we are unique. This is a pipeline routing experiment that has never been tried before.
I invite others to point out counter-examples—places where similar NGL pipelines travel through dense suburbs—and prove me wrong. But I doubt any can be found.
Dragonpipe Diary 