Optimal configuration, design and control of a binary geothermal combined heat-and-power plant

•Two-step thermoeconomic design optimization procedure including off-design.•Four low-temperature geothermal combined heat-and-power plant configurations.•Use of multiple configurations in off-design might improve the economics.•Better economics and energy source utilization than pure electrical power plant.•High-level optimization model for operational control driven by real price signals.