The memorandum says that the US state and the Canadian province will further research on offshore wind and tidal energy issues include community acceptance, wildlife impacts and grid stability.
It says Maine and Nova Scotia will share research in a timely manner.
Maine governor John Baldacci and Nova Scotia premier Darrell Dexter signed the MOU at an energy conference between New England governors and eastern Canadian premiers.
At the conference, the premiers of Nova Scotia, New Brunswick, Prince Edward Island and Newfoundland and Labrador said they were committed to the creation of a regional energy strategy and transmission enhancements to link the four provinces.
Dexter said: "Our colleagues in New England have told us they see real advantages to working with us as a region, and we have assured them that is how we plan to operate going forward."
The MOU said Maine and Nova Scotia would discuss the possibility of expanding the agreement by including other provinces and states.
American Wind Energy Association CEO Denise Bode said: "This type of partnership will help the North American offshore wind energy industry reach its potential, and realize its many environmental, economic and job creation benefits."