CATEGORIES OF HYDROPOWER PLANT
Hydropower plants are traditionally broken down into categories depending on their size. The usual categorization is shown in Table 8.3. The smallest plants, with capacities between 1 kW and 100 kW, are called micro-hydropower plants. Between 100 kW and 1 MW a plant is described as a mini-hydropower plant. Small hydropower plants are generally those with capacities between 1 MW and 10 MW, but this upper limit can vary from country to country and in some cases may be as high as 30 MW. Plants with capacities larger than
10 MW (or up to 30 MW depending on jurisdiction) are classed as large hydro- power plants.
Sometimes an intermediate category for Medium hydropower plants is also introduced between small and large hydropower. If used, this is typically for plants between 5 MW and 50 MW; those above are large and those below are small. From a global perspective large hydropower is the most important category and accounts for most of the hydropower capacity in operation today.
Technically, large hydropower plants are the most sophisticated and are generally individually designed for each site using turbines that have also been made specifically for the power plant. Small hydropower plants are similar to large plants but some use off-the-shelf turbines and other components rather than bespoke components. Mini- and micro-hydropower installations usually employ standard turbines and many involve novel, often cost-effective, designs not used in larger plants.