Energy related problems are part of the major challenges for humanity in this century worldwide. In most countries energy is the first national priority. Energy Systems aims for mathematical programming, control, and economic approaches towards energy systems related topics. The topics covered include power systems optimization, unit commitment, power generation, power trading, electricity risk management, competition in electricity markets, bidding strategies as well as market power issues. Mathematical theory and algorithms for stochastic optimization methods applied to energy problems are also included as well as modeling issues such as process optimization, synthesis, design and operation. The papers published in the journal deal with theoretical, computational, and applied aspects of 'energy systems' as well as state of the art review papers.