Possible BTU Restrctions On Northern Border Gas Pipeline -- December 24, 2019

Possible BTU restrictions on the all-important Northern Border gas pipeline was mentioned by RBN Energy  in its daily blog.

Other links:

• Background, general: EIA, October 14, 2014. 
• From Reuters, John Kemp, October 26, 2012.
• Overview, SourceWatch. 
• Wiki: link here.
• abarrelful: link here.

From the RBN Energy post:

What’s behind the possible shift at Northern Border? Rising production of associated gas in the Williston Basin, combined with more gas processing capacity there, has increased the volumes of basin-sourced gas flowing into Northern Border, and also squeezed out more gas from Western Canada, which generally has less rejected ethane in it and therefore has a lower Btu content. Thus, as the volumes of Williston Basin gas received by Northern Border have increased, so has the overall weighted-average Btu content of the gas flowing on the big gas pipe. Our understanding is that while Northern Border doesn’t necessarily mandate a maximum Btu content, if the Btu content were to get high enough to cause problems for the utilities and other end-use customers it serves, Btu restrictions on the pipeline may need to be put in place.

I'm not going to explain it because I'll probably screw it up again, but when you read the paragraphs from the EIA below, note:

• BTU or heat content of methane vs ethane and propane
• heat content desired by end user
• ethane rejection

From the EIA report linked above:

The primary constituent of natural gas is methane, which has a heat content of 1,010 British thermal units per cubic foot (Btu/cf) at standard temperature and pressure. 

In July 2014, the heat content of natural gas in the United States was around 1,030 Btu/cf, or almost 2% more heat content than pure methane, reflecting the composition of the gases in the natural gas stream.

Natural gas requires a certain fuel-to-oxygen mix to burn properly, so stoves and other gas-fueled appliances typically require natural gas to be within a certain range of Btu content.

Pipelines also have a range of acceptable Btu content for natural gas going through their systems, which can vary from one pipeline to another.

High-Btu natural gas contains higher concentrations of natural gas liquids (mostly ethane and some propane) that have higher heat content than methane.

Pure ethane has a heat content of 1,770 Btu/cf and pure propane 2,516 Btu/cf.

Natural gas liquids are often removed during natural gas processing. However, because of the low price of ethane, many natural gas processors are choosing to leave ethane in the natural gas stream, a practice known as ethane rejection, rather than remove it for sale as a distinct product. A relatively high Btu content in a given state may be indicative of ethane rejection.