Clean energy technologies and systems for a sustainable world

This Special Issue contains a selection of papers from the proceedings of the Third International Conference on Applied Energy 2011, ICAE2011, which was held in Perugia, Italy from 16 to 18 May 2011. After the previous successful two ICAE conferences, which were held in Hong Kong and Singapore, Asia, the third one was the first organized in Europe. The theme of the conference was kept the same as the previous edition, ‘‘Energy Solutions for a Sustainable World’’, to show the continuity with the past and to confirm the need to continue our efforts to improve the performance of energy technologies and systems and to make energy conversion in all its forms more and more compatible with environmental protection and sustainable development. The conference attracted 300 participants from almost 50 countries of the five continents. The largest participation was from Europe with all countries of the European Union and from Asia. Approximately 600 abstracts were submitted, 350 of which were submitted as full papers for review. All submitted drafts were peer reviewed and the final number of paper included in the proceedings and accepted for oral presentation at the conference was 285. A further evaluation process was conducted with recommendation of about 150 papers for the consideration of further review for being included into this special issue. Following the journal review process, 116 papers1 were finally accepted to be included in this issue. The paper can be divided into the following main topics: (i) Energy policy; (ii) Greenhouse gas mitigation policies and technologies; (iii) Energy efficient buildings; (iv) Biomass and biofuels; (v) Innovation in conventional energy systems; (vi) Hydrogen and fuel cells; (vii) Energy storage, thermodynamics and heat transfer; and (viii) Solar and wind energy, and hydropower.