Nowadays, the negative impact of fossil fuels on the environment is becoming more pronounced. In order to reduce it, the IMO has adopted regulations in the form of an addendum supplementing the International Convention for the Prevention of Pollution from Ships MARPOL 1973/78. The amendments concern Annex VI, which regulates the release of gases into the atmosphere from ships harmful to human health and the environment. Strict requirements in the new regulations have conditioned the development of new technologies in marine energy systems that help reduce harmful emissions. Certain technologies have already confirmed their economic efficiency and environmental friendliness as some continue to evolve. New technologies include the use of gas fuel, hybrid propulsion systems and renewable energy sources that seek to enable the use of hydrogen, ammonia, wind and solar energy. In order to encourage the development and evaluation of modern technological solutions that contribute to improving energy efficiency and environmental protection, new rules in Annex VI contain a chapter for determining the project energy efficiency index (EEDI). This index is defined as the ratio of carbon dioxide (CO2) emissions to economic performance. This paper presents the administrative framework applied in shipping, the already applied and confirmed technologies are described, and an example of calculating the project energy efficiency index is presented on the example of one ship.