Design criteria for distributed cogeneration plants

In countries where space heating demand is limited to a few months in the year, potentials for increasing the penetration of cogeneration (CHP) are strictly linked to sites where concentrated heat utilizations already exist. Hence the energy systems will move towards a larger number of small-medium since CHP plants, which is herein named distributed cogeneration. Design criteria are analyzed for plants in this context, from a technical and economical standpoint. A case study is reported, focused on the most suitable heat to work ratio. It is found that the pricing and tax systems, as they are stated by domestic legislation, push the design point and the operating conditions yielding the best economy, into a range where CO2 emissions are remarkably higher that the least possible.