System efficiency – Methodology for rating of industrial utilities in electricity grids with a high share of variable renewable energies – A first approach

System Efficiency can help to reduce greenhouse gas emissions significantly, because this approach offers the opportunity to integrate a higher share of renewable energies. This paper focuses on industrial utilities and gives a proposal to how a System Efficiency rating of utilities can be done. The dilemma of System Efficiency is that interactions between efficiency and flexibility can be intersecting or contrasting. This affects the greenhouse gas emissions and the profitability of utilities. Those effects have to be considered in the ratings to find an optimum solution. The purpose of the paper is to have a sufficient collection of technical and economical properties to describe System Efficiency. Therefore, a model defining four abilities efficiency, performance ability, reaction ability and demand adaptability that a utility must have to be system efficient is described. From the model four superior indicators that support future ratings, to describe the abilities are derived. These superior indicators are reduction potential of greenhouse gas emission, Flexfactor, reaction time and provision time. For economical rating, useful properties are listed. At last a first approach for a rating methodology is developed. The rating is based on the analysis of electricity price time series. This solves the common challenge of collecting explicit values for technical requirements. The rating is carried out for five exemplary technologies and shows promising results. Possible enhancements and deficits of the rating are discussed thoroughly.