HPP efficiency up to 95% – Pelton turbine
Today, the image of a Hydro Power Plant is cemented in our heads as a giant dam with giant jet-type turbines. A stream of water of incredible volume passes through the spiral blades, rotating them and generating energy. We also imagine hydroelectric dams in a certain sense as regulators of the flow of rivers, which prevent them from overflowing or drying out depending on the weather. That is, no one squeezes out all the crumbs of potential and kinetic energy from every drop of water and does not endanger entire ecosystems and settlements. Although the latter does not apply to the communists.
When can I pick up everything?
In cases where the construction of a dam and the operation of a hydroelectric power station has a minimal impact on the environment. A striking example of efficiency and environmental friendliness is the Swiss Biedron hydroelectric power station, built in 1993 and put into operation in 1998. The efficiency of this hydroelectric power plant is 92.37%, and its capacity reaches 1269 MW. For comparison, Dneproges has a capacity of 1569 MW, as well as a huge reservoir. Usually structures Bieudron Hydroelectric Power Station also owns a dam 700 m long, but the key difference in height, because the height of the Swiss dam is 285 m dam Dnieper -… 60 m
This dam height leads to the fact that the calculated pressure is 1883 m That is, to get. a similar pressure will have to be installed on a water tower at the top of Hoverla and drilled at the foot of a mine 500 m deep. And the pressure at which the turbines operate is 200.5 atmospheres. The speed at which water enters the turbine is 192 m/s or Mach 0.56. Boeing is just 150 km/h faster. And with all this, the hydroelectric station spends only 25 cubic meters of water per second, 200 times less than the previously mentioned Dnieper hydroelectric station. And this is despite the fact that the Biedron Swiss HPP is only 20% less powerful than the Dnieper power plant.
The secret to efficiency
Unlike most low-pressure hydropower plants, Switzerland’s largest hydropower plant uses Pelton turbines. This is not a very new invention. It was designed by Lester Alan Pelton back in the 1870s as a more efficient version of a water wheel that allows you to squeeze everything out of a water stream in a closed environment. Only the Pelton water wheel can do up to 3000 rpm, which is 6 times faster than the rotor of a helicopter.
Its principle of operation is that water is supplied from nozzles under high pressure. Its jet hits the spoon-shaped blades. This shape allows the maximum use of all the kinetic energy of the water jet instead of spraying it to the sides. From below, each blade has a drain for water that has already transferred kinetic energy. Thus, the Pelton turbine works best with small volumes of high pressure water, although its capabilities include operation even at pressures of 15 m.
The Pelton turbine has received relatively little changes over its 150 year history. For example, the material of the blades changed to tungsten carbide due to the fact that steel parts wear out quickly at such high pressure. Then they began to be replaced with composite or plastic ones with a shorter service life, but much less cost. The key change was the increase in the number of water nozzles. With only one nozzle, water can flow unevenly, which leads to uneven bearing wear and catastrophic consequences if the wheel is suddenly skewed and jammed. In addition, the use of 2-6 nozzles significantly increases the efficiency of the turbine.
Prospects for the Pelton turbine in Ukraine
The western regions of Ukraine are the most promising. The mountainous terrain and the presence of a large number of mountain rivers and springs will make it possible to combine an efficient hydroelectric power plant with Pelton turbines. But the Carpathians are much lower than the Alps, limiting the use of such hydroelectric power plants. It is also important to remember about the need to build a dam that will harm the environment. Therefore, now in the near future there are prospects for the construction of only small and ultra-small hydroelectric power plants based on the Pelton turbine.