سیستم های انرژی تجزیه و تحلیل چند منبع با استفاده از روش کمک تصمیم گیری چند شاخصه

In this article, an original multi-criteria approach is applied to multi-source systems used for the design and the choice of the optimal alternative. The high number of alternatives and potential solutions when dealing with multi-source systems require a decision support method to be implemented and easy to use. Information data on the economic variables, energy performance and impact on the environment of the systems are presently data which analysis and quantification is difficult. To deal with this high level of complexity and uncertainty, an evaluation approach is needed. The multi-criteria decision support methodology concept is described (ELECTRE III) and then applied for a case study. The decision support algorithm has its bases on the developed models and makes the outranking of possible solutions. It is also shown that multi-criteria analysis can provide a technical–scientific decision-making support that is capable to justify the clearly rank of the alternatives in the renewable energy sector. The use of multi-criteria decision aid for assessing the multi-source systems showed encouraging results and interesting insights.

The building sector - i.e. residential and commercial buildings - is the largest user of energy and CO2 emitter in the EU and is the major energy consumer of the EU’s total final energy consumption and CO2 emissions. Buildings account for 40–45% of energy consumption in Europe and China (and about 30–40% world-wide) [1]. Buildings are important consumers of energy and thus important contributors to the emission of pollutants into the atmosphere. The development and integration of appropriate renewable energy technologies in buildings has an important role to play. However, issues of cost, investment and ownership along with technical risk provide disincentives to the uptake of embedded energy technologies. The main issues of renewable energy sources large-scale use are related to the sizing of the systems, the choice among a large variety of alternatives face to a certain number of criteria, and finally the control of these sources. In the near future, more and more the renewable energy sources (RES) will cohabit with fossil energy source systems and research has to be pointed toward solutions that are energy efficiently, economical viable and environmental friendly. The goal of a multi-source system is to decrease at maximum the primary energy consumption by generating the needed demand by renewable sources like solar, wind or wood energy. The RES can be easily adapted and linked with conventional modern energy technologies to ensure security of supply at all times and at any location. A massive use of RES will not be a sustainable solution except if it is complemented with a valid evolution of the economic development pattern and through European directives. Moreover, it will be highly influenced by the fiscal measures like carbon tax and financial aids. The challenge of sustainability with regard to energy is shaped and the requirement for green sources has been established, but still a number of barriers need to be overcome before the contribution of RES becomes significant. In a management process of RES with classic fossil sources a number of processes should be considered by the decision makers, such as energy production, conversion and transmission. Furthermore, RES are subjected to uncertainties of economic and environmental implications. Therefore, effective planning for RES management systems under multiple uncertainties and dynamic complexities is desired. The RES will produce locally the energy needed for the building and the extra energy which is not necessary will be sent to the overall urban energy infrastructure (i.e. the case of photovoltaic power energy or wind energy). An example of multi-source system is between a solar thermal system used to produce domestic hot water, a photovoltaic system to generate electricity and a gas boiler heating system for the heating energy demand. Other examples can imply a wood boiler for the heating or an electric energy heating system.

The selection of an appropriate solution for the energy demands of a residential house is complex due to the large number of alternatives and criteria that need to be considered. The multi-criteria decision aid (MCDA) support can assist decision process in making appropriate decisions regarded to several criteria. The use of MCDA for assessing the multi-source systems showed encouraging results. There were obtained interesting insights and it is allowed a better view of the decisional process. The ELECTRE III algorithm turned out to be an appropriate approach for these kinds of situations, suggesting the alternative with better compromise, being well balanced. The proposed methodology should improve the integration and the choice of multi-source systems as it allows consideration for a large number of alternatives to be analyzed. The use of this method improves the quality of the decision by making it more explicit, rational and efficient. The main inconvenient of the ELECTRE III method which is an uncertainty in the criteria weighting and thresholds values can be easily solved by performing a sensitivity analysis and visualization of the outcome impacts. In conclusion, it is hoped that using multi-criteria decision aid could be a key component for improving the development of renewable energy systems and especially to facilitate the choice of the multi-source technology. A further research idea would be to apply this approach in with a larger number of criteria (i.e. degree of implementation, mean life time of the hybrid system, social impact).