This study concerns the exploitation of the earth's heat (geothermal energy) for heating agricultural greenhouses, with the aim of increasing their yield. A simple energy balance model was developed, capable of representing the thermal behavior of the greenhouse. This study has shown that the choice and sizing of the components of a photovoltaic system to power a heat pump is based on an estimate of electricity requirements. The factors determining the choice of pump depend on two important factors: The energy requirement of the agricultural greenhouse, and the power needed for pumping. For this, we used the RETScreen software for the most optimized dimensioning, based on a database of pumps and solar panels, as well as reliable meteorological data or site surveys. Last but not least, financial optimization ensured an acceptable return on investment for the project. Finally, this type of project has many advantages: energy is renewable, inexhaustible and available just about everywhere. Economically profitable, it also creates jobs.