6.2.5 FUTURE TRENDS

Although small hydro technology is mature and well-established in the market, there is a case for further work to improve equipment designs, investigate different materials, improve control systems and optimise generation as part of integrated water management systems. Widening the range of head and flow, which can be accommodated at acceptable cost (particularly for small capacity and low head equipment), is a particular priority.

The main technical targets as regards SHP systems are for standardisation in the areas of civil works, electromechanical equipment, control systems, grid connection arrangements, and authorisations and licences. There is a market need for cheaper equipment to exploit the extensive hydro resource available below 3m head. The following areas of technical development are foreseen:

Civil works

· civil works to accommodate submersible technologies;
· use of inflatable weirs to optimise generation head, without compromising flood defences;
· use of stone and brick masonry (rather than concrete) to achieve environmentally attractive solutions and provide local employment;
· siphon structures to improve aeration of the water and simplify turbine de-watering;
· head enhancement techniques.

Electromechanical equipment

· new low head turbine designs e.g. helical turbines;
· new construction materials e.g. plastics;
· submersible generators, to reduce manufacturing costs;
· small turbine packages (<5kW) for use in developing countries and in stand-alone applications;
· compact multi-pole generators to avoid the need for speed increasers;
· standardised, modular turbine designs for mass production;
· simplification of low head designs, for manufacture in workshops in developing countries using simple machine tools and materials.

Electrical equipment

· application of remote control, condition monitoring and metering equipment to aid automation;
· development of load control equipment and frequency converters to allow the use of unregulated turbines, particularly at low and variable head (and hence variable speed);
· control systems to allow stand-alone operation of induction generators.

Environmental

· fish guidance systems to deflect fish from small hydro intakes and outfalls, without the energy losses associated with physical barriers;
· ecological impact of run-of-river schemes.