Background The increase of greenhouse gases in the atmosphere, and consequent global warming, is mainly a consequence of the continuous burning of fossil fuels as the main energy source for industry and transport. Deforestation aggravates the problem. Reducing the levels of greenhouse gases in the atmosphere is necessary to ensure a good quality of life for future generations. Implementing energy efficiency measures, especially in industrial sectors, is essential in order to achieve this objective. One of the industrial sectors with the highest energy consumption is the ceramics industry. This sector consumes large amounts of energy during all its processes, but mainly during firing, which is responsible for 50-60% of the total energy consumed. During firing, furnaces can reach very high temperatures that range between 800 and 1200 degrees Celsius, which requires a significant consumption of fossil fuels, mainly natural gas. Objectives The project's main objective was to reduce natural gas consumption and carbon dioxide (CO2) emissions from the firing of ceramic materials in a factory producing bricks and roof tiles. This goal would be achieved through an innovative method that uses calcium carbonate (CaCO3) nanoparticles in raw materials, which enables the firing temperature to be reduced. The project would design and develop a prototype to produce calcium carbonate (CaCO3) nanoparticles and introduce them into the ceramic mass in order to obtain an homogeneous mixture. The project would test the firing of the mixture at semi-industrial and industrial scale. In particular, the project would: Analyse the chemical and mineralogical composition of the clays that will be used as raw material; Determine the optimum composition of the calcium carbonate mixture, in order to achieve the greatest energy saving and the maximum emissions reduction; Establish a process for adding nanoparticles to the raw material to produce a homogeneous mixture; Demonstrate the process at industrial scale; Analyse the resulting ceramic material, and demonstrate its viability in structural applications; and Conduct an environmental analysis of the industrial process.Expected results: It was estimated that a 14 degrees Celsius reduction in the firing temperature for bricks and tiles would result in an 8% reduction in energy consumption, and a reduction of 17.1 kg/CO2 per tonne of fired product. Because of the small quantity of CaCO3 nanoparticles used, the CO2 emissions produced by its decomposition are very low and are not relevant in comparison with the CO2 emissions generated during the firing process. Previous tests have achieved a temperature reduction greater than 14ºC, and the project estimates that an overall energy saving of 10% can be achieved in the firing process, leading to a CO2 emissions reduction of 1 800-4 500tonnes/year. Results In December 2014, the Coordinating beneficiary formally notified the EC that both beneficiaries decided to end the project.