Many industrial processes generate a large amount of heat that is disposed of as waste using cooling towers or other cooling mechanisms. This waste heat, usually of low-to-mid grade (temperature), is an energy source that can be redirected to useful purposes in the Sahara Forest Project. Low-grade heat (35–50 °C) will be used in the SFP facility to heat the greenhouses during winter nights, and to drive the night-time freshwater distillation process in the greenhouse roofs. In the standard configuration, this heat is waste from the CSP, and its utilization not only yields better growing conditions and freshwater, but serves as the cooling mechanism for the CSP steam cycle. The waste heat from other nearby industrial facilities can be used in exactly the same way. Moreover, low-grade waste heat can be used to drive additional evaporation from the Sahara Forest Project’s evaporative ponds. This will allow the ponds to be made smaller, reducing capital costs and allowing allocation of additional land within the SFP facility to other uses, such as revegetation.
Higher-grade waste heat, at about 70 °C, may be used to drive an MED thermal desalination facility. If such high-grade heat is available from a nearby industrial source, that waste heat could power additional freshwater desalination.
