NREL director of National Wind Technology Center, Fort Felker, said: "This agreement will lead to increased cooperation between NREL and ECN in the further development of wind energy systems.
"By sharing knowledge and working together, we will increase the scope and pace of our contributions to this important technology."
In December ECN signed a memorandum of understanding with Korean engineering group Posco Power to develop renewables initiatives.
The agreement covers wind, solar and bio-energy. A joint-statement said the greatest focus would be on developing Posco's first offshore wind farm in South Korea.