A Systems Approach to Energy Efficiency Assessment

In the absence of international unanimity on the effective solutions to global energy insecurity and global warming, renewable energies are becoming more popular in national energy policies worldwide. Proponents of renewable energies hope to decrease emissions and establish a more diversified and sustainable energy mix through replacing fossil fuels with the so-called "green energy sources." Although these energies are known to be more environmentally friendly, there is still a need to recognize the adverse environmental and economic impacts of such policies. In this paper, a general energy efficiency assessment framework is developed to determine the overall efficiency of different energy sources through a systems approach that takes into account the carbon footprint, water footprint, land footprint, and cost of different energy sources, which respectively represent their environmental efficiency, water use efficiency, land use efficiency, and economic efficiency. A number of stochastic multi-criteria decision making methods are used to determine the overall efficiency scores and final ranking of the energy sources, considering the uncertainties in performances of energies under each criterion. Results indicate that some renewable energy sources are not promising when the overall efficiency of the energy sources are evaluated based on multi-criteria decision making methods.