The industrial sector is a key global source of wealth, but it is also recognized as a major challenge toward worldwide decarbonization. Today the industrial sector requires more than 22 % of the global energy demand as thermal energy and produces for this about 40 % of the total CO2 emissions. Solutions to efficiently decarbonize the industrial sector are deemed. This work presents a comparative techno-economic performance assessment of a high temperature heat pump integration within a molten salts based power to heat system for industrial heat flexible generation. The main system performance is reported in terms of required working conditions and temperature for the heat pump and thermal demand size as well as reduction of the attainable levelized cost of heat (LCoH) against non-flexible electric boiler based systems. The impact of different industrial load profiles, electricity prices, heat pump capital cost and heat pump real to Carnot efficiency ratio are also presented. The results highlight that the proposed system can be cost-competitive, particularly for thermal demand around 10 MW and waste heat temperatures above 80 degrees C. Under these conditions LCoH reduction higher than 15 %, with respect to the considered non-flexible electric boiler alternative, are attainable. These LCoH reductions are primarily driven by savings in electrical consumption as high as 30 %. This study sets the ground for further power-to-heat techno-economic investigations addressing different industrial sectors and identifies main system and components design strategies, integrations, and targets.