Novel short-, mid-, and long-term strategies to maximize the introduction of renewable gases into the gas grid

The desire to reduce CO₂ emissions and enhance the sustainability of the energy supply is driving the increased use of renewable gases, such as hydrogen and biogas. Injecting these gases into the existing gas grid is an effective means to avoid large investments in new infrastructures and to ensure the wide-spread use of these fuels by industrial, commercial and residential end users. This paper discuses short-, mid-, and long-term strategies to maximize the introduction of renewable gases into the gas grid in a safe and economically viable way. In the long term, the optimum (downstream) strategy to accommodate a broad range of renewable gases into the gas grid is to develop and introduce fuel-adaptive end-use equipment that optimizes the combustion performance based on the measured gas composition. Several examples of feed-forward fuel adaptive engine and burner control systems and their potential are described. Large-scale replacement of end-use equipment takes time, and a strategy is needed to maximize the incorporation of renewable gases into the natural gas grid on the short- and midterm. In this short- and midterm strategy, the amount of renewable gas that can be added to natural gas depends upon the combustion properties of the natural gas at the point of blending and on the types of equipment installed in the area in which the gas is being supplied. A midstream strategy is discussed for maximizing the injection of renewable gases while safeguarding end-use performance by implementing a smart gas network. The intelligence of this gas network is based on measuring the gas quality at the injection point by making use of gas sensors. The real-time measured gas composition in combination with the gas flow rate serves as input for combustion algorithms that calculate the maximum amounts of renewable gases allowed into the gas network while safeguarding end-use performance.