Superstructure-based Approach to Assess the Heat Pumping and Renewable Energy Integration Potential in the Sugar Industry

The study examines the feasibility of integrating heat pumps (HPs) and renewable energy in the sugar industry to advance decarbonization. It explores different routes for energy supply, contrasting them with a natural gas (NG)-fired base-case route. The alternatives include bio-digestion of beet and pulp waste to produce biomethane (bio-CH4) used in the process, hydrogen boiler, and electric boiler (full electrification using renewable electricity). Each route also incorporates HPs, utilizing waste heat primarily from evaporation and drying processes. Additionally, CO2 capture (CC) units can be optionally installed. Evaluation of the superstructure employs a systemic methodology with total specific cost (€/tsugar) and total specific emissions (tCO2/tsugar) as objective functions for each route. Detailed blueprint (BP) models of sugar production for each route cover mass and energy balances, CAPEX and OPEX, and material and energy resource costs. Optimization is conducted using the OSMOSE Lua framework with a mixed integer linear programming (MILP) approach. Three energy scenarios (2023, 2030, and 2050) are established, influencing prices of NG, hydrogen, electricity, and CO2 emissions. In the 2023 scenario, integrating bio-CH4 with HP emerges as the most cost-effective option, reducing costs by 15% compared to the base-case. However, the optimal solution adds CC and HP to the bio-CH4 route, reducing costs by 9% while achieving a 133% emissions reduction, resulting in net negative emissions. By 2030, routes with HP become more favorable with slightly lower electricity and hydrogen prices. bio-CH4 with HP and CC remains the best choice, cutting costs by 60% and maintaining 133% emissions reduction. In the 2050 scenario, decreased electricity and hydrogen prices, coupled with a higher CO2 emission price, make the base-case the most expensive. Nonetheless, bio-CH4 routes remain viable, with hydrogen and electric boiler-based routes also feasible due to cheaper energy prices.