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BCD Energy Energy Saving Products & Renewables

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Energy Store, Mitchel St. Thurles


Hydro Power

Hydroelectricity is derived from the power harnessed from the flow of falling water, typically from fast-flowing streams and rivers. Presently about 6% of Ireland's electricity generating capacity is in the form of hydropower. The Ardnacrusha hydroelectric station built in the 1920's is still the country's largest renewable energy generating unit.

Small-scale hydro

Small-scale micro hydro power is both an efficient and reliable form of energy. With the right site it is a viable way of providing power to houses, workshops or businesses that need an independent supply. Considerable unexploited hydropower potential exists in Ireland at the small to micro-scale level. Surplus electricity can be sold to the national grid.

Is my site suitable?

You may have wondered whether the stream flowing through or near your property can be used to generate electrical power using a hydropower system to power your home. Is a micro-hydropower system feasible for you?

  • Have you steep rivers or streams flowing year-round with high year-round rainfall. The best sites have a reliable water supply year-round and a large vertical drop in a short distance.
  • Have you a high head and flow rate.

Power Available from Hydropower

Determine the amount of power that you can obtain from the flowing water on your site. The power available at any instant is the product of what is called flow volume and what is called head.

A rough estimate of the power available at a specific micro-scale site can be calculated from the equation:

Power (kW) = 6 X Head (m) X Flow (m3/sec)

Head = the vertical flow of the water, essential for hydropower generation
Flow = volume of water passing per second
Note: Ideally the head should be 2m or greater

A comprehensive site survey can be carried out by our engineers for promising sites in order to gather information that is detailed enough to make power calculations and start design work.

Advantages and Disadvantages


It is now possible to sell back excess electricity produced back to the national grid. Up to 40% grants available. More information HERE.

Efficient energy source
It only takes a small amount of flow (as little as two gallons per minute) or a drop as low as two feet to generate electricity with micro hydro. Electricity can be delivered as far as a mile away to the location where it is being used.

Reliable electricity source
Hydro produces a continuous supply of electrical energy in comparison to other small-scale renewable technologies. The peak energy season is during the winter months when large quantities of electricity are required.

No reservoir required
Microhydro is considered to function as a 'run-of-river' system, meaning that the water passing through the generator is directed back into the stream with relatively little impact on the surrounding ecology.


Suitable site characteristics required
In order to take full advantage of the electrical potential of small streams, a suitable site is needed. Factors to consider are: distance from the power source to the location where energy is required, stream size (including flow rate, output and drop), and a balance of system components — inverter, batteries, controller, transmission line and pipelines.

Low-power in the summer months
In many locations stream size will fluctuate seasonally. During the summer months there will likely be less flow and therefore less power output. Advanced planning and research will be needed to ensure adequate energy requirements are met.


Misconceptions - Myths about hydro power

Small streams do not provide enough force to generate power

The Truth: Energy output is dependant on two major factors: the stream flow (how much water runs through the system) and drop (or head), which is the vertical distance the water will fall through the water turbine.

A large water reservoir is required

The Truth: Most small-scale hydro systems require very little or no reservoir in order to power the turbines. These systems are commonly known as ‘run-of-river’, meaning the water will run straight through the generator and back into the stream. This has a minimal environmental impact on the local ecosystem.

Hydro generators will damage the local ecosystem

The Truth: Careful design is required to ensure the system has a minimal impact on the local ecology. This will ensure that the project does not have an effect on local fish stocks. The Environment Agency requires that stream levels must be maintained at a certain level in order to sustain the life within. Since there is no loss of water in the generation process, these requirements can easily be met.

Micro hydro electricity is unreliable

The Truth: Technology advances (such as maintenance-free water intake equipment and solid-state electrical equipment) ensure that these systems are often more reliable in remote areas. Often these systems are more dependable than the local power main.

The electricity generated is low quality

The Truth: If the latest electronic control equipment, inverters and alternators are used, the resultant power supply has the potential to be of higher quality the main electrical power grid.

Further Information?

If you want a site survey or have any queries please do not hesitate to contact us or call into our energy store on Mitchel St. Thurles.


BCD Energy Consultants, Rossestown, Thurles, Co. Tipperary, Ireland
Telephone: 1850 223 223   Email: info@bcdenergy.ie

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