U.S. Senator Joe Manchin (D-WV) speaking at a press conference sponsored by the Problem Solvers Caucus and the Common Sense Coalition to announce "principles for legislation to lower prescription drug prices" at the US Capitol in Washington, DC.

Sen. Joe Manchin, D-W.Va., is raising alarm bells about an $83.7 billion investment in his home state pledged by China's state-owned energy giant.

"In West Virginia, they came and signed a [Memorandum of Understanding] for $83 billion, and I repeat, $83 billion over 20 years," Manchin said Thursday during a Senate hearing on innovation in the energy sector.

"When you put that in comparison to the state budget of West Virginia, our state budget only goes over $4 billion a year, so something doesn't make sense here, and we cannot find out what their intent is," he said.

Read more: West Virginia is still waiting on an $84 billion investment from China that was promised in 2017

The concerns echo those raised by lawmakers — including Manchin — in interviews with CNBC about the proposed size of the investment relative to the state's small output, as well as the opaque nature of the deal.