The size and complexity of a micro hydro system will have a significant impact on the cost and the installation time. The time taken from feasibility study to commissioning is likely to be at least six months. This includes time for the Environment Agency to process the abstraction licence (minimum 3 months) and ordering times required by turbine manufacturers (minimum 3 months).

As a rule, the capital cost per kW of installed capacity falls in proportion to the size of the scheme, varying from around £1,000 to£3,000. In addition to 'economies-of-scale', the costs will be a function of:

• Type of components used - e.g. new or second-hand;
• Existing infrastructure available;
• Degree to which external contractors are to be used; 
• Reliability of the resource - is the flow constant throughout the year?