Pelton and Turgo Impulse Turbines for Pico Hydro Systems

This paper discusses Pelton and Turgo Impulse Turbines for Pico Hydro Systems. It explains their application, implementation, and power generation from sewage waste water. It also provides examples of their use in rural or poor urban areas. The paper is a great resource for students studying hydraulics.

HYDRAULICS
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1. Introduction
Pico hydro systems are said to be the best choice since they can be relied on, their robustness and
their efficiency in operation over varying rates of flow. The Pelton and Turgo are the mostly
used turbines when setting up this kind of hydro system. This is because they are both impulse
turbines. however, the two vary slightly, that is, the Pelton handles less rates of water flow as
opposed to Turgo.
2. Pelton Wheel
It was invented by Lester Pelton in the early 19 centuries. However, he received a patent for his
first wheel in the year 1878. It consists twenty blades connected to a. the water source is an
enormous head that is transformed to very large velocities at each opening which hit the buckets.
A curvature on each lip in the lower side enables the adjacent bucket to proceed through a given
distance before a cut off of a jet occurs. This also allows a becket to meet the jet smoothly. Its
design was specially designed to ensure that each jet hits the blades at an angle of about 165
degrees, an angle that prevents an interference between the preceding and the next bucket and the
jet. A head height of between 60 to 100 meters should be used.
According to Tang, “An alteration of the velocity of water occurs as the jets impact the blades.
This is done to ensure that the velocity is in line with the blade’s curvature” (61). The impact of
the jets causes the wheel to spin, this is a result of transformation of the momentum from the
water to the wheel. This is further passed to the turbine and to the generator. The impact of the
water jets makes the wheel to rotate thus mechanical energy is produced. Once this
transformation occurs, the energy is received by a generator which converts it to electrical
energy.
Referencing to Flexas “Almost the entire water energy is used to propel the blades while the
water that is deflected is directed to a path below it for discharge” (3791).

Photo 1.0 Pelton turbine. Source (Taih and Azeez)
Application across the world
Pico hydropower generation using the Pelton wheel is common across various nations in the
world. This is an effort to curb the inefficiency of electricity in small urban areas and to also to
generate energy that can be renewed in areas that lack grid power. The Pelton wheel technology
has been proven to be efficient and is considered as one of the biggest costs cutting electric
energy source.
Examples of application in rural or poor urban areas
Area Power
kW
Head
Meters
Rate of flow
1/s
Kathamba,
Kenya
1.1 28 8.4 Used by
approximately
65

houses
Svinuray,
Cashel
Valley,
Zimbabwe
10 100 20 Used to run a
grinding mill.
Cambamontera,
Peru
15 89.5 35 Used by
approximately
60 houses
Cajamarca,
Peru
35 50 110 85 houses
Table 1.0 hydro power plants(Benzon et al.)
One of its kind implementations of this generator is the Bieudron Hydroelectric Power station
located in Switzerland. The power plant produces 4000mw and above. The power plant has 3
Pelton turbines and every turbine has a rating of about four hundred and twenty-three megawatts
Reason for implementing Pelton wheel in rural/poor urban areas
 They are the largely used to generate power in situation where the source of water is has
an equinely large hydraulic head but at a reduced rate of flow. According to Adhikary,
Priyabrata, Runis, Kien and Pie “The wheel has proven to work best in this situation
when compared to other Pico hydro systems” (507). This means that when using the
Pelton wheel, it is possible to generate an equivalent high power when the source of
water has a relatively reduced flow with an increased pressure as compared to a source
with a bigger flow with a reduced water pressure.
 Pelton wheels are of varying sizes depending on area of operation and availability of
water. The small wheel Pelton are used in rural areas to generate electricity for use by the

locals. Due to the fact that they work well in the above stated conditions, hilly and areas
covered by mountains are the best areas to apply it.
 It is advantageous as opposed to the rest power generators due its ability to produce
substantial amount of energy despite a low water flow given that the head is equal to the
task (large to capacity). This explains why it is largely used in poor urban areas. Its
compactness makes it easy to install thus mostly implemented.
3. Turgo Wheel
It was in 1919 by Crewdson Eric. The patent as awarded to him in 1920. It is almost similar to
the Pelton wheel, since they are both Impulse turbines. It’s not efficient than a Pelton wheel
however, it is capable of handling rates of flow that are higher than that of Pelton.
Photo 2.0 Turgo wheel.(Taih and Azeez)
As indicated in the diagram above it consists of buckets that are stricken by a water jet with a
certain velocity from the inlet. Referencing to Eller “The nozzle ensures that the jet produced has
or ejects with the required velocity and that the angle of the strike is around 20 degrees before
exiting to another bucket. At the bottom of the wheel is discharge point which ensures that
there’s no collision between the arriving jet of water and that from the wheel. This sis somewhat
not achieved in Pelton thus an added advantage to the Turgo wheel. This enables the wheel to
operate under rate of flow that is higher than that of Pelton.

It is a modification of the Pelton so it’s able to produce a similar power to that of Pelton but at a
greater speed because of its larger diameter (two times that of Pelton). However, coming up with
this wheel has proven to be tedious.
Application
It is mostly applied in areas where the source of water has rates of flow that are reduced but at a
higher hydraulic head. It is commonly connected to the generator which converts the energy to
electricity
Examples of Turgo Power plants
A good example is the power plant in the islands of South Georgia, USA is the Grytviken power
plant, which was invented in 2007. It has the following features
 A head of about 210ft
 Produces power of over 260kW
 The water flow is of above1050rpcm
Pic 2.1 turgo turbine at the Grytviken power plant(source (Turgo Impulse Impulse Hydro
Turbine)

This is a remote power plant. The design of Turgo wheel makes it possible for remote power
generation.
Reasons for implementation of Turgo wheel
 Setting up the wheel is very easy
 No jet interference as the water strikes a specific blade at an angle.
 Few connecting parts that are straight forward and also allows for direct connection to
the generator without necessarily having to connect to an amplifier.
 It as a moderate efficiency hence reliable.
4. Generating Power from Sewage waste water
Sewage water can be collected and treated and reused to produce power. After the treatment the
velocity of the flowing of the water is high. According to Ohtsuka “This pressure can be utilized
to run the turban and Pelton wheel which are can be connected to generators to convert the
mechanical energy to electrical energy. This can prove to be useful instead of just channeling the
water to the receiving end. A penstock can be used to improve the pressure of the treated water
to achieve the desired velocity. Below is an illustration of how the above technique can be
implemented” (353).
Pic 2.3 Power generation from sewage water.
Examples

This method has been implemented in major plants that treat water in the United Kingdom. They
implement this on a plain terrain to ease the flow of the treated water using the force of gravity.
This technique is still a developing technique. there’s less implementation of this technique
worldwide.
A good example is in Boston at the Deer Island Wastewater Treatment Plant. the plant produces
around twenty six percent of the power it consumes energy generation techniques that are
renewable. As per now, they have put in place channels in place for the waste water to flow
through at a reliable velocity. According to Creek “The channel directs the water to a turbine
(turgo wheel) which transforms the impact of the jets into mechanical energy which is fed to a
generator connected to the wheel. The generators are responsible for generating over
6,000,00kW per hour at an annual rate. The energy produce is fed into the plant for use thus
cutting cost down by about 0.6million dollars” (2881). Apart from using the power generated,
they also feed it into the grids which is sold to the Water Resource authority. The power plant
account for about seventy percent of the power consumed by the authority.
The project was feasible because
 Availability of the needed technology. The plant computer enabled systems that offer a
great aid in implementation and maintenance of the system.
 Availability of waste material from the houses and other buildings around the plant.
There’s plenty of waste water flowing from the homes and other industries to this plant.
 Adequate infrastructure and facilities in place. The plant has waste water managing
facilities that treat the water to provide suitable water to drive the turbines without
halting the process of power production
 Adequate pumping station which pumps the waste water to give the needed flow rate and
velocity to run the turbines
Conclusion
For Turc “Impulse turbines that is Pelton and Turgo are the best choice for implementing Pico
system” (3254). As stated by the above paper, Pelton wheel are largely used to generate power in
regions where the source of water has a large hydraulic head but at a reduced rate of flow. The
wheel has proven to work best in this situation when compared to other Pico hydro systems. On
the other hand, the Turgo is capable of handling rates of flow that are higher than that of Pelton.

The two are advantageous in terms of cost, low power generation in rural areas or poor urban
areas and are easy to implement and maintain. They can be further associated with the
production of power from waste or sewage water after it has been treated. Although challenges
may be faced in running the two, their efficiency in power generation is far of greater.

References
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Power Generation for Decentralized Rural Electrification.” International Journal of
Engineering Trends and Technology vol. 4, no. 4, 2013, pp. 507, doi:10.9790/2402-
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Arabidopsis." Nature communications 9.1 (2018): 61 doi: 3884.
Eller. "Modelling tropical forest responses to drought and El Nino with a stomatal optimization model
based on xylem hydraulics." Philosophical Transactions of the Royal Society B: Biological
Sciences 373.1760 (2018) pp.21 doi: 20170315.
Creek. "Coordination between leaf, stem, and root hydraulics and gas exchange in three arid‐zone
angiosperms during severe drought and recovery." Plant, cell & environment 41.12 (2018):2881.
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Turc. "Drought affects abortion of reproductive organs by exacerbating developmentally driven processes
via expansive growth and hydraulics." Journal of experimental botany 69.13 (2018): 3254.
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