Micro Hydro - Operation and Maintenance

Operation and maintenance (O+M) procedures must be planned and put into action in the initial stages of any scheme to prevent breakdowns and reduced power outputs. The failure to use O+M procedures will result in financial problems and loss of confidence in the value of micro-hydro. The design engineer, the equipment installers and the users of the scheme, all have important parts to play in the O+M of micro-hydro schemes.

Ongoing operation, maintenance, and surveillance (OMS) are required to keep a plant running smoothly. However, OMS should not be considered only after building a micro hydro facility. It should be considered in choosing a site, designing the facility and when looking for financing. Sites that are remote or have poor access will have greater servicing costs. Facility design can greatly influence ongoing OMS costs including surveillance requirements and replacement and repair costs. Consideration should also be given to the availability of spare parts and the possible purchase of spare parts in advance. In financing the project the annual OMS costs need to be factored into the overall project cash flow. Thus, OMS should be thought of continually throughout the development of the micro hydro project.

Design considerations

It is essential that the long-term OMS costs be considered during the design of a micro hydro facility. For instance, it may be initially cheaper to buy and use uncoated steel pipe rather than a pipe coated for corrosion protection. Once the maintenance costs (the cost of replacing or field coating steel pipes to deal with corrosion), operating costs (increased friction and reduced energy with uncoated pipe), and expected life span are considered it may be cheaper to purchase coated steel pipe. This type of lifetime and reliability analysis should be considered carefully in all aspects of the design – it could save a lot of time and money.
The ease with which maintenance can be performed should also be considered during the design phase of a micro hydro facility. For example, equipment that requires regular maintenance should be located in a place that is easily accessible, and not located in a confined space. Also, if any equipment may need to be removed for maintenance during its lifetime, the means of achieving such a task should be considered. For instance, if any part of the generator needs to be removed for replacement, repairs, or upgrades - is there an economical way of doing it? Is there a hoist or crane capable of moving all the pieces of the generator? Can the roof of the building be removed easily for external crane access? By meticulously thinking through all the possible OMS scenarios that may occur, a lot of time and money can be saved over the life of the project.

Managing OMS
Even for the smallest micro hydro installations, a plan that ensures the consistent operation, maintenance, and surveillance of the facility is useful, if not necessary. To accomplish consistency in OMS, plans and procedures should be developed. These plans are typically located in the following documents:

• OMS Manual - The OMS Manual contains the operating instructions for the plant. It is written in a language that the operators can easily understand. OMS Manuals ensure consistent error-free operation of the plant.
• Equipment Manuals - Manufacturers usually provide Equipment Manuals for most equipment (i.e. turbines, hoists, pumps, switches, etc.). The availability and organization of equipment manuals greatly help OMS efficiency. A great deal of time and money can be spent on trying to find out how to do the necessary OMS, when the actual OMS may take little time or money to complete.
• Facility Drawings and Design Information - Make sure to keep the proper design information and drawings for all aspects of the plant that are uniquely designed. This information can make future repairs and modifications much easier.
• Maintenance Schedule - A Maintenance Schedule outlines when and what maintenance should be done. A schedule should be made according to a specific plant’s equipment OMS needs. It could consist of a checklist that must be signed by a supervisor or a worker once the maintenance has been completed. It could be a schedule developed using specially designed scheduling software.
• Log Books and OMS Records - Log Books record what OMS has been completed, and what has happened in the day-today operations of the plant. This can help trouble shoot problems regarding the facility’s OMS down the road. If any major work is completed that greatly changes the facility’s design or operation, a record should be kept for future reference. Over time, new operators will be hired and they can benefit from the recorded experience of their predecessors in operating the plants.

Source: Handbook for developing micro-hydro in British Columbia (2004)

Further reading:

Micro-hydro design manual: A guide to small-scale water power schemes by Adam Harvey, Allen Inversin, Andy Brown, Priyantha Hettiarachi (1993)