KenanZeynalov/petrol_data · Datasets at Hugging Face

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channel and bed (Hydromatch 2014). This ﬂow is considerably high in comparison
to other similar small streams with ﬂow rates in the range of 0.1–1 m3/s for widths
in the range of 1–8 m (WHO 1996). The ﬂow rate was measured in November, a
month characterized by draught based on the climatic and rainfall patterns of
Nigeria. It is therefore sufﬁciently accurate at pre-feasibility phase to use this
measured ﬂow as the ﬁrm ﬂow available at 95–100% of the time in order to evaluate
the power potential of the river. The residual ﬂow has been assumed to be nil at this
phase.
The land formation of the site is generally of gentle slopes. The approximate
head available was determined via topographical applications of Google Earth to be
3 m over a distance of 321 m. Although this value will generally be considered low
head (Adhau et al. 2012), the relatively high ﬂow compensates it in order to
improve the general potential of the site.
The environmental impact of the project has been considered in terms of civil
works. As a run-off river of low-power capacity, there is a need for the construction
of a shallow reservoir, for water accumulation and channelling through a penstock.
This will have minimum ecological modiﬁcation impacts to the natural ambience.
Nevertheless, an in-depth and compressive environmental impact assessment is
mandatory as part of the feasibility study in the advanced stages of such a project.
3.2
Technical Assessment
With a 50 kW peak load from the Tuwan agribusiness off grid system, this
hydropower plant is designed to supply half of the load that is currently fully
supplied with two 25-kW diesel generators. It is assumed that the small hydropower
plant runs all year round alongside one of the diesel generators to accommodate the
entire electrical load at TAR, while the second diesel generator is dropped as
standby and only activated to take care of peak load conditions or emergencies.
Fig. 4 Cross-sectional area
calculation (Joy et al. 2005)
Technical-Economic Prefeasibility Assessment of an Off-Grid Mini-hydropower. . .
1197
This project is a run-off river type considering a year-round ﬂow and the low
initial cost since there is no need to construct a dam. With a low head, a Kaplan type
turbine is selected for this system with the assumption that the ﬂow will be at least
1.2 m3/s all year round. Power generated from this system is predicted based on
Eq. 2 (RETScreen 2004):
Power kW
ð
Þ 7 Head m
ð Þ Flow m3=s


ð2Þ
Power kW
ð
Þ 7 3m 1:2m3=s 25:2kW
ð3Þ
By conducting a detailed Retscreen simulation, considering the hydraulic losses
and generator efﬁciency, the power output from the generator is about 21 kW. An
AC direct electricity system is chosen for this project. An asynchronous generator is
used due to the consideration that this type of generator is suitable for isolated small
hydropower of less than 100 kW installed capacity. It has several advantages, such
as cheaper price compared to synchronous generators and ease of maintenance
(Azhumakan et al. 2013). The electrical diagram for the system layout is presented
in Fig. 5.
As shown in the system layout, the output generator is connected to a rectiﬁer
and diversion load. This diversion load is used to consume any excess energy
generated. It also protects the generator and inverter from over speed and overvolt-
age, respectively. The DC system is then connected to the Inverter to provide the
energy to the load with 220 VAC, 50 Hz.
3.3
Cost and Financial Analysis
The entire 20-year lifespan of the project is considered in the cost analysis. This
comprises the initial cost, annual cost and periodic cost. Table 2 provides the cost
breakdown of the project.
The total initial cost prior to the operation phase of the project amounts to
132,887 USD which is based on the plant capacity and pricing of materials and
labour in local and international standards. This breaks down to feasibility study
Fig. 5 Typical arrangement of electrical system in mini hydropower plant (Home power 2008)
1198
V.H. ADAMU et al.
(3.8%), development (5.6%), engineering (11.3%), power system (53%) and bal-
ance of system and miscellaneous costs (26.3%). The bulk of the initial cost is taken
by the civil works, turbine, generator and electrical system.
On the other hand, the annual cost in terms of operation, maintenance and
payment of debt terms (up to 5 years) sums up to 36,451 USD per year. Meanwhile,
a periodic cost of 2500 USD every 5 years is allotted for the replacement of
inverters and other parts.
Fortunately, a projected grant of 50,000 USD that can be accessed from devel-
opment funding partners of PAD Ltd. should reduce the share of loan required to
fund the project. Thus, the debt ratio is only 20%, which means only 26,577 USD is
to be borrowed from the bank to be paid in 5 years with 11% interest rate. Inﬂation
is assumed to be 8.5%, while the fuel escalation is 10% from its present value of
0.54 USD per litre at year 2014. This project has a positive cash ﬂow of 65,723 USD
per year and a steadily increasing positive cash ﬂows in the long run as seen in
Fig. 6.
The income elements are mainly the amount of fuel savings and 15,000 USD
salvage value of the system at the end of the project lifespan as shown in Table 3.
Aside from the grant, another positive factor is the tax holiday of 5 years
(i.e. exception from 15% tax on income during the ﬁrst 5 years of the project)
granted by the government to agricultural organizations and rural infrastructural
development (KPMG 2012).
In summary, as indicated in Table 4, the project is viable with net present value
(NPV) of 568,178 USD (11% discount rate), internal rate of return (IRR) of 68.1%
and beneﬁt-cost ratio of 6.34.
Table 2 Project cost breakdown
Project cost summary
Initial cost
100%
Feasibility study

channel and bed (Hydromatch 2014). This ﬂow is considerably high in comparison

to other similar small streams with ﬂow rates in the range of 0.1–1 m3/s for widths

in the range of 1–8 m (WHO 1996). The ﬂow rate was measured in November, a

month characterized by draught based on the climatic and rainfall patterns of

Nigeria. It is therefore sufﬁciently accurate at pre-feasibility phase to use this

measured ﬂow as the ﬁrm ﬂow available at 95–100% of the time in order to evaluate

the power potential of the river. The residual ﬂow has been assumed to be nil at this

phase.

The land formation of the site is generally of gentle slopes. The approximate

head available was determined via topographical applications of Google Earth to be

3 m over a distance of 321 m. Although this value will generally be considered low

head (Adhau et al. 2012), the relatively high ﬂow compensates it in order to

improve the general potential of the site.

The environmental impact of the project has been considered in terms of civil

works. As a run-off river of low-power capacity, there is a need for the construction

of a shallow reservoir, for water accumulation and channelling through a penstock.

This will have minimum ecological modiﬁcation impacts to the natural ambience.

Nevertheless, an in-depth and compressive environmental impact assessment is

mandatory as part of the feasibility study in the advanced stages of such a project.

3.2

Technical Assessment

With a 50 kW peak load from the Tuwan agribusiness off grid system, this

hydropower plant is designed to supply half of the load that is currently fully

supplied with two 25-kW diesel generators. It is assumed that the small hydropower

plant runs all year round alongside one of the diesel generators to accommodate the

entire electrical load at TAR, while the second diesel generator is dropped as

standby and only activated to take care of peak load conditions or emergencies.

Fig. 4 Cross-sectional area

calculation (Joy et al. 2005)

Technical-Economic Prefeasibility Assessment of an Off-Grid Mini-hydropower. . .

1197

This project is a run-off river type considering a year-round ﬂow and the low

initial cost since there is no need to construct a dam. With a low head, a Kaplan type

turbine is selected for this system with the assumption that the ﬂow will be at least

1.2 m3/s all year round. Power generated from this system is predicted based on

Eq. 2 (RETScreen 2004):

Power kW

ð

Þ 7 Head m

ð Þ Flow m3=s

ð2Þ

Power kW

ð

Þ 7 3m 1:2m3=s 25:2kW

ð3Þ

By conducting a detailed Retscreen simulation, considering the hydraulic losses

and generator efﬁciency, the power output from the generator is about 21 kW. An

AC direct electricity system is chosen for this project. An asynchronous generator is

used due to the consideration that this type of generator is suitable for isolated small

hydropower of less than 100 kW installed capacity. It has several advantages, such

as cheaper price compared to synchronous generators and ease of maintenance

(Azhumakan et al. 2013). The electrical diagram for the system layout is presented

in Fig. 5.

As shown in the system layout, the output generator is connected to a rectiﬁer

and diversion load. This diversion load is used to consume any excess energy

generated. It also protects the generator and inverter from over speed and overvolt-

age, respectively. The DC system is then connected to the Inverter to provide the

energy to the load with 220 VAC, 50 Hz.

3.3

Cost and Financial Analysis

The entire 20-year lifespan of the project is considered in the cost analysis. This

comprises the initial cost, annual cost and periodic cost. Table 2 provides the cost

breakdown of the project.

The total initial cost prior to the operation phase of the project amounts to

132,887 USD which is based on the plant capacity and pricing of materials and

labour in local and international standards. This breaks down to feasibility study

Fig. 5 Typical arrangement of electrical system in mini hydropower plant (Home power 2008)

1198

V.H. ADAMU et al.

(3.8%), development (5.6%), engineering (11.3%), power system (53%) and bal-

ance of system and miscellaneous costs (26.3%). The bulk of the initial cost is taken

by the civil works, turbine, generator and electrical system.

On the other hand, the annual cost in terms of operation, maintenance and

payment of debt terms (up to 5 years) sums up to 36,451 USD per year. Meanwhile,

a periodic cost of 2500 USD every 5 years is allotted for the replacement of

inverters and other parts.

Fortunately, a projected grant of 50,000 USD that can be accessed from devel-

opment funding partners of PAD Ltd. should reduce the share of loan required to

fund the project. Thus, the debt ratio is only 20%, which means only 26,577 USD is

to be borrowed from the bank to be paid in 5 years with 11% interest rate. Inﬂation

is assumed to be 8.5%, while the fuel escalation is 10% from its present value of

0.54 USD per litre at year 2014. This project has a positive cash ﬂow of 65,723 USD

per year and a steadily increasing positive cash ﬂows in the long run as seen in

Fig. 6.

The income elements are mainly the amount of fuel savings and 15,000 USD

salvage value of the system at the end of the project lifespan as shown in Table 3.

Aside from the grant, another positive factor is the tax holiday of 5 years

(i.e. exception from 15% tax on income during the ﬁrst 5 years of the project)

granted by the government to agricultural organizations and rural infrastructural

development (KPMG 2012).

In summary, as indicated in Table 4, the project is viable with net present value

(NPV) of 568,178 USD (11% discount rate), internal rate of return (IRR) of 68.1%

and beneﬁt-cost ratio of 6.34.

Table 2 Project cost breakdown

Project cost summary

Initial cost

100%

Feasibility study