Assessment of Energy Efficiency and Flexibility Measures in Electrified Process Heat Generation Based on Simulations in the Animal Feed Industry

Abstract

A large part of the energy demand in industry can be attributed to the provision of heat. To reduce greenhouse gas emissions, the energy demand must be reduced and renewable energies must be integrated. Since the capacity of renewable heat sources is often limited, the electrification of processes is a promising solution. Due to the increasing share of fluctuating renewable energies in the electricity mix, it is advantageous if consumption can be flexibly controlled. Thus, in-house energy management in industry faces many challenges. On the one hand, general consumption must be reduced through the efficient use of energy; on the other hand, load shifting and flexible use of energy may reduce both, emissions and costs. Often, however, both alternatives interfere with each other, and an either-or decision is the result. A practical efficiency and electrification measure is the use of heat pumps. This can reduce the final energy demand for heat generation, but the constant mode of operation due to the coupling of heat sources and heat sinks leaves little room for grid-serving operation. Other electrification options, such as an electric boiler, offer greater flexibility in combination with thermal storage, but have lower efficiency. To quantify the energy requirements as a basis for comparison, the heat pump as an energy efficiency option and an electrode boiler in combination with a thermal storage tank as a flexibility option are simulated along a typical demand profile in the animal feed industry. To ensure maximum heat recovery, the heat pump is optimised using pinch analysis and designed for the respective process. For the flexibility option, an operational optimisation is carried out using Linear Programming. In addition, a hybrid variant is considered using Mixed Integer Linear Programming. While no electrification measure is currently more economical than the gas reference case, the electric boiler option is significantly more expensive than a Very-High-Temperature Heat Pump. The hybrid can reduce the size of the heat pump and get a further benefit from flexible prices, which gives it cost advantages.

Keywords

• electrification; process heat; energy efficiency; flexibilisation; heat pump