"US Threatens Sanctions For European Firms Participating In Russian Gas Pipeline Project"

It's not just U.S. self-interest (selling some LNG) in play here, although that is part of the U.S. rationale, rather, there are actual security concerns.
Especially as the northern hemisphere winter of 2017 - 2018 enters its 15th month.
From ZeroHedge, March 22:

As previewed overnight, the U.S. State Department is warning European corporations that they will likely face penalties if they participate in the construction of Russia's Nord Stream 2 gas pipeline, on the grounds that "the project undermines energy security in Europe", when in reality Russia has for decades been a quasi-monopolist on European energy supplies and thus has unprecedented leverage over European politics, at least behind the scenes.

“As many people know, we oppose the Nord Stream 2 project, the US government does,” said State Department spokeswoman, Heather Nauert at a Tuesday press briefing. “We believe that the Nord Stream 2 project would undermine Europe's overall energy security and stability. It would provide Russia [with] another tool to pressure European countries, especially countries such as Ukraine.”

And speaking of Ukraine, recall that in 2014, shortly after the US State Department facilitated the presidential coup in Ukraine, Joe Biden's son Hunter joined the board of directors of Burisma, Ukraine's largest oil and gas company. Surely that was merely a coincidence.

The project which began in 2015 is a joint venture between Russia's Gazprom and European partners, including German Uniper, Austria's OMV, France's Engie, Wintershall and the British-Dutch multinational Royal Dutch Shell. The pipeline is set to run from Russia to Germany under the Baltic Sea - doubling the existing pipeline's capacity of 55 cubic meters per year.

Nauert said that Washington may introduce punitive measures against participants in the pipeline project - which could be implemented using a provision in the Countering America's Adversaries Through Sanctions Act (CAATSA).

 

“At the State Department, we have spent a lot of time speaking with our partners and allies overseas to explain to them the ramifications of CAATSA and how an individual or a company or a country can run afoul against CAATSA and fall into sanctions," Nauert said. "We don't tend to comment on sanctions actions but we've been clear that firm steps against the Russian energy export pipeline sector could – if they engage in that kind of business – they could expose themselves to sanctions under CAATSA.”

Several EU nations, particularly Germany, have repeatedly expressed interest in participating in Nord Stream 2, however the pipeline has been opposed by several minor bloc nations, including Poland, Latvia, Lithuania, Romania and Hungary. Ukrainian authorities are also staunchly against the project, as it bypasses Ukraine and would impact them monetarily....MORE

Wednesday:
"Germany’s Pivot From Russian Gas Will Be Costly"