Proposals in the U.S. Congress to tie green tax credits with local content materials risk holding back the American offshore wind sector even before it has started to flourish, a top executive at a major project offshore Massachusetts told the Financial Times. Democrats in Congress have proposed a number of tax credits and incentives for clean energy and electric vehicles (EVs) in the $3.5 trillion spending bill, but the proposals include tying some of the tax credits with the condition that the steel and other materials are produced in the United…