• Design issues

The load factor is the amount of power used divided by the amount of power that is available if the turbine were to be used continuously. Unlike technologies relying on costly fuel sources, the ‘fuel’ for hydropower generation is free and therefore the plant becomes more cost effective if run for a high percentage of the time. It is very important to ensure a high plant factor if the scheme is to be cost effective and this should be taken into account during the planning stage. Many schemes use a ‘dump’ load, which is effectively a low priority energy demand that can accept surplus energy when an excess is produced e.g. water heating, storage heaters or storage cookers.

• Connection issues

Where the power from a micro-hydro scheme is used to provide domestic electricity, one method of making it an affordable option for low-income groups is to keep the connection costs and subsequent bills to a minimum. Often, rural domestic consumers will require only small quantity of power to light there houses and run a radio or television. There are a number of solutions that can specifically help low-income households to obtain an electricity connection and help utilities meet their required return on investment. These include:

• Load limited supply - Load limiters work by limiting the current supplied to the consumer to a prescribed value. If the current exceeds that value then the device automatically disconnects the power supply. The consumer is charged a fixed monthly fee irrespective of the total amount of energy consumed. The device is simple and cheap and does away with the need for an expensive metre and subsequent meter reading.
• Reduced service connection costs - Limiting load supply can also help reduce costs on cable, as the maximum power drawn is low and so smaller cable sizes can be used. Also, alternative cable poles can sometimes be found to help reduce costs.
• Pre-fabricated wiring systems - Wiring looms can be manufactured ‘ready to install’ which will not only reduce costs but also guarantee safety standards. 
• Credit - Credit schemes can allow householders to overcome the barrier imposed by the initial entry costs of grid connection. Once connected, energy savings on other fuels can enable repayments to be made. Using electricity for lighting, for example, is a fraction of the cost of using kerosene.
• Community involvement - Formation of community committees and co-operatives who are pro-active in all stages of the electrification process can help reduce costs as well as provide a better service. For example, community revenue collection can help reduce the cost of collection for the utility and hence the consumer

• Assessing the site

To assess the suitability of a potential site, the hydrology of the site needs to be known and a site survey carried out, to determine actual flow and head data. Hydrological information can be obtained from the meteorology or irrigation department usually run by the national government.

This data gives a good overall picture of annual rain patterns and likely fluctuations in precipitation and, therefore, flow patterns. The site survey gives more detailed information of the site conditions to allow power calculation to be done and design work to begin. Flow data should be gathered over a period of at least one full year where possible, so as to ascertain the fluctuation in river flow over the various seasons. There are many methods for carrying out flow and head measurements and these can be found in the relevant texts.

Accurate measurement of head and flow are necessary to estimate the power potential at a site.

• Head Measurement - There are various methods of measuring the available head. For low head sites the most accurate method is using a surveyor’s level. At sites where the head is more than 25m a digital altimeter allows more rapid estimates. 
• Flow Assessment - The flow rate at a particular site is determined by the interaction of a number of factors including the size of the catchment area, the local rainfall, the rate of evaporation and the geology of the area. The flow rates in all major rivers UK rivers are measured continuously at Environment Agency gauging stations. The flow can also be predicted using computer programs which model flow variations through the year based on rainfall records and catchment area details.