This thesis describes an investigation into a technique for converting the energy available at low head (2m) hydro sites into an air flow that could be used to generate electricity. After giving a rationale for the uses of this design at the many available sites in the U.K., a brief history of the development of water power and of the more recent research into this process is outlined. The investigation focused on the equipment employed in using a water siphon to induce air flow. The testing of various aerator configurations in a full scale laboratory experiment is described, and the difficulties encountered in the two phase flow that occurs in the process are examined. The on- site experiment at the Yorkshire Treatment Plant that is discussed, proved that this siphon system was robust and reliable. The laboratory experiment (with restrictions of space availability) results show that more than 30% of the energy available at such sites can be converted into a form of air flow energy. While this is a slight improvement over the previous work done in the field it must be noted that the highest power output of 460 Watts occurred at 32.3% efficiency in the high siphon. Suggestions of improvement on aerator design that could increase more power output and efficiency are given, while recognizing that there will be some further losses of energy when the system is used to generate electricity. The results indicate the technique devised is environmentally advantageous and economically feasible.'.