# How do you create hydropower

Small hydropower plants use the natural water cycle and its constantly renewing energy. How much water and what gradient do you need to operate an effective small power plant - and what do you have to pay attention to when designing the most nature-friendly design? You can find out here.

Hydropower supplies clean energy, but building a small power plant is an encroachment on nature. Construction elements that are close to nature, the availability of a reasonable amount of residual water and the use of high-quality construction elements to avoid noise and pollutant emissions are therefore basic requirements.

The decision about the expansion of a hydropower plant depends, in addition to the individual motives of the operator (preservation of a traditional plant, obligation through inheritance, etc.), essentially on the expected energy generation and the evaluation of the energy generated. The planning is also determined by the following criteria:

• Official permit
• Hydrology and height of fall
• local conditions
• Machine technology
• Construction engineering
• ecological requirements

Compared to other forms of electricity generation, the systems for using hydropower have the advantage of a very long service life.

### Performance and energy generation

The term “small hydropower plant” is usually used for systems up to 10,000 kW. In some countries, other limit values ​​also apply.

The power to be achieved from hydropower can be calculated using the following formula:

P = Q * H * g * efficiency

in which:

Q = amount of water
H = slope in m
g = acceleration due to gravity (9.81 m / s²)
P = power in kW

The overall efficiency of the system, which includes the losses of the turbine, the gearbox and the generator, is used as the efficiency. For a rough estimate, it is usually assumed to be 0.75. This can then be used to simplify the rule of thumb above as follows:

P = Q * H * 7 (in kW)

The annual generation of energy results in a maximum of 8,760 hours multiplied by the expansion capacity in kW. Normally, the systems generate less energy due to fluctuating water, overhauls, etc. The "annual work" is calculated with the water data and the system parameters as well as the revision times. There is also a rule of thumb for annual work for our climate zone (with an average degree of expansion):

Annual work = output * 5,000 hours