Abstract Achieving sustainable development is a target that is becoming more and more important to world-wide public opinion. Energy is one of the issues that is causing the most controversy, as fossil fuels are the greatest pollutants and the greatest contributors to the greenhouse effect. It therefore stands to reason that industrialised countries, which are the greatest consumers of fossil fuels, should be investigating new energy systems based on renewable energies that do not pollute and which are inexhaustible, such as the solar–hydrogen system. Central and southern Spain exhibit an excellent solar climate which makes them ideal places for producing hydrogen by photovoltaic–electrolysis systems. A model for a solar–hydrogen system for Spain has been developed and its advantages have been studied in terms of import dependency on fossil fuels, the gross national product per capita, the reduction of pollution and improved quality of life. If the solar–hydrogen system is not introduced, Spain will continue to import large amounts of fossil fuels during the next century and at the same time damaging the environment. On the other hand, producing solar–hydrogen via photovoltaic-electrolysis, using the unproductive land in central and southern Spain, will reduce its dependency on external energy, and Spain may even become an energy-exporting country, which would have a favourable effect on GNP growth and the quality of life. Also, as a result of the greater efficiency of hydrogen, major energy savings will be made, and, as it is practically a non-polluting fuel, pollution and environmental damage will be reduced and⧸or eliminated.