The developers behind the controversial Cape Wind project have shelled out nearly $700,000 for federal and state lobbyists since the Nantucket Sound wind farm received federal approval four years ago, according to Herald analysis and a government watchdog group.

Cape Wind developers paid $380,000 to DLA Piper and $130,000 to Capitol City Group since 2011, according to the Center for Responsive Politics, which tracks federal lobbyists. The center has dubbed DLA Piper a “heavy hitter” — or one of the 140 biggest overall donors to candidates since the 1990 federal elections.

Developers for the Cape Wind project, which received federal approval in 2010, have paid Marshfield lawyer and state lobbyist Neal Costello $180,000 since 2011, records show.

Meanwhile, Gary J. Klein, a national lobbyist with DLA Piper hired by Cape Wind, gave $8,334 to his firm’s political action committee, which hands out hundreds of thousands of dollars annually to politicians, including those who lobbied for Cape Wind, according to the Center for Responsive Politics.

Center data also shows Gerald Harrington, Capitol City Group’s Cape Wind lobbyist, donated $36,300 to politicians and committees since 2013, including $3,600 to U.S. Sen. Edward J. Markey (D-Mass.); $2,600 to both the Democratic State Committee of Massachusetts and U.S. Sen. Jack Reed (D-R.I.); and $1,500 to U.S. Rep. Joseph P. Kennedy III (D-Mass.).