One of the most important challenge, which combined heat and power plants in Poland have to face recently, is need to increase thermal power in order to cover peak heat demand. Therefore new investments need to be done. Making the right choice depends on several factors. Proper energy source, which can cooperate with existing devices, must be profitable at the same time. Profitability can be affected not only by chosen technology and its features such as fuel, efficiency or cogeneration. Regulatory environment might be crucial as well. This article addresses the issue of possibility to increase the capacity of heat production in terms of different work configurations, technological solutions and fuels. In economic and technical analysis there have been considered key elements, which have an influence on profitability of each proposed solutions. Non-support scenario for some energy technologies has also been examined. In addition, susceptibility of each variant for fuel, heat, electricity, carbon dioxide emission prices change has been studied. Basing on the results obtained, the most profitable and likely to implement solution is presented.