If you want to use environmentally friendly solar energy, you may either install sun collectors (for warm water heating) or a photovoltaics system. The latter generates electrical energy from solar cells and, therefore, offers crucial benefits, since electrical energy demand is constantly high throughout the year. Any excess electricity will be fed into the public grid. The utility is obligated to compensate this electricity to the rate determined by the government. Conclusion: It is much more profitable to generate electrical energy from solar cells, since energy prices keep growing.