In the town of Pieniężno at the Wałsza river, a water power plant was constructed in 1916. The water step situated there consists of the side earth dam supported by the tight Larsen wall.

Water is supplied to the power plant building with a canal, which is divided in its final part into two turbine supplies, and the main river current is directed to the relief canal, in which a damming weir is situated. It is a concrete barrier, with two spans, with a stabilizing dam from 67.18 m a.s.l. to 69.57 m a.s.l. and nominal head of 9 m. The fact that the water power plant is of flow character means that it is hardly possible for water to back.

Water Power Plant Pieniężno- view from outside

In the power plant there are 2 turbine sets with the power of: T-1 - 75 kW and T-2 - 145 kW
and discharge of water: T-1 - 1,25m3/s and T-2 - 3,3 m3/s. The voltage of the operating generators is 0,4 kV, and power is led out by means of a transformer 15/04 kV which is situated in a switching station of 15 kV in the power plant building.

The main building of engine room had at first four storeys. In machine hall there was a turbine set with a Francis turbine as well as a generator with Diesel engine.

Water Power Plant Pieniężno- view at generator

As a result of war operations, the power plant building was destroyed, and the power-generating unit with Diesel engine was blown up.

In December 1949, the power plant was taken over by the United Masurian Power Plants District in Olsztyn.

The reconstruction started in 1953 and was completed in 1958, on the basis of aquatic-legal permission of 17th August 1955. The current permission determines damming to the level of 69.57 m a.s.l. and collection of surface water from the Wałsza river amounting to 4,5 m3/s.

It results from the observations and analyses that the correct use of energy resources of the Wałsza river takes place in the summer. In winter, when the energy resources of water are considerably higher, the use of water is too weak.

The mountainous character of the river causes violent rise and quick fall of water after heavy rain and thaw, which is not favourable for full management of energy resources of the Wałsza river. The observation shows potential possibility to improve such state of things in the power plant in Pieniężno.

The study performed in 1989 by Hydroproject in Gdańsk suggests possibility of additional retention in the Wałsza valley, above the level of power plant in Pieniężno. A weak point of the power plant is also small efficiency of the turbine set no. 1. The improvement of the situation in scope of better use of the damming step should be perceived in both directions, i.e. small retention and assembly of new, highly efficient turbines.