Coal is recognized as a reliable source of energy, thanks to its quantitative diffusion and geopolitics, and is undoubtedly an inexpensive source when compared with oil and natural gas; instead, it is not considered a clean source, at least in the short term. The development of thermal power plants with a new design, higher yields, lower emission levels and "zero emission" plants with geological sequestration of CO2 and co-production of hydrogen represent the most advanced target for the clean use of coal.
In Italy, coal currently has a pretty marginal role in the generation of electricity with a contribution of 13% of the total, compared with a value of 27% of the EU average. The increased use of coal would reduce the price of electricity and reduce Italian energy dependence on foreign countries. In fact, given the absence of nuclear power and the supply criticality of oil and natural gas in the Italian electricity system, coal acquires a more important role and almost appears as obligatory. The technologies for a clean use of coal and the research and development to support the introduction of these technologies seem essential for coal to actually be considered competitive in the production of electricity.
Internationally, coal is the main source for the production of electricity with a percentage higher than 35% of the world's electricity. If for some countries, such as Poland, South Africa, India, Australia and China, coal is the main indigenous resource (in these countries it represents between 75% and 90% of the sources for electricity production), even in the most advanced economies, coal is the primary source for power generation (52% of the overall production in Germany, 50% in the U.S. and 33% in the UK). In this scenario, France is an exception, a country in which nuclear power plays a major role. The International Energy Agency (IEA), which has always recognized coal as one of the main sources of energy worldwide, stated that coal can be a safe and economical fuel for the production of electricity and for the industry if there is extensive use of innovative technologies to improve environmental performance in the early extraction stages and its use. The activities carried out by RSE as part of System Research, have provided the Italian electricity system with knowledge, research, technologies and methods that are useful for the efficient use of coal with particular reference to the problem of reducing emissions, considered the most critical for this source.
In particular, with reference to the advanced coal cycles, given the short to medium term solution for increased use of coal, aspects regarding the following have been addressed: the optimization of the life cycle of critical components, the reduction of gaseous pollutants, technologies for 'zero liquid discharge' in coal steam cycles, systems and methods for the control and optimization of the cooling systems in coal steam cycles. For coal integrated gasification combined cycles (IGCC) and externally fired combined cycles (EFCC), the most critical aspects which constitute a barrier to their technological affirmation have been investigated.