Climate change has brought to the attention of politicians, researchers, and other stakeholders the need to protect the environment. The concerns at the international level are more and more intense, and the solutions found are multiple. One of the directions to follow is a new energy transition, which involves the use of renewable energy, but also techniques of cogeneration and trigeneration. This study presents the main research on increasing energy efficiency in the use of a primary energy source and the impact on the environment. Compared to the classical methods of obtaining heat and electricity from burning fossil fuels through separate technologies, the study brings to the fore two methods (cogeneration and trigeneration) that have much higher yields by obtaining two or even three forms of energy from the use of a single source of combustion. The impact on the environment is also significantly reduced by eliminating additional sources of pollution (reducing greenhouse gas emissions). Taking into account the evolutions of the energy market during this period, this article aims to analyze, from the point of view of the two most important influencing factors, the economic efficiency of processes and the reduction of greenhouse gas emissions by overlapping their effect, in case of the use of modern technologies (cogeneration and trigeneration), for the combined production of various forms of energy.