Lubu HPP - Executive Summary

W eir Head Pond
Settling Basin
Penstock
Headrace Channel Powerhouse

Access Road

Lubu HPP

LUBU HPP

FEASIBILITY STUDY – EXECUTIVE SUMMARY

The planed Lubu HPP is located in Tanjungbetung Village, North Rao District, Pasaman
Regency, West Sumatera Province. At the feasibility study level, the Lubu HPP has a design
discharge of 12.0 m³/s, a net head of 249.03 m and an installed capacity of 20.076 MW.

Developer December

PT LUBU HIDRO ENERGI 2018
0 Prudential Tower, Penthouse 25th Floor Jalan Jendral Sudirman Kav.

29, Jakarta 12190

Consultant

INDONESIA HYDRO™ CONSULT Renewable energy
saves our Earth!
Bukit Golf Riverside II Block B01 No 46, Gunungputri, Bogor 16963
Phone: +62 21 84303098 Fax: +62 21 84302924
E-mail: [email protected] Website: www.indonesia-hydro.com

Lubu HPP River: Lubu

FEASIBILITY STUDY – EXECUTIVE SUMMARY The electric power will
be sold to PT PLN
General (Persero)

PT Lubu Hidro Energi is a company established to develop the Lubu HPP
hydroelectric potential in Pasaman Regency, West Sumatera
Province. One of the projects that will be developed is the Lubu
HPP project that utilizes the potential for flow and head on the
Lubu River. To meet this aim, PT Lubu Hidro Energi intends to
prepare the project feasibility study. While the discussion of
environmental aspects will be discussed separately in the
environmental management efforts (UKL) and environmental
monitoring efforts (UPL).

The electric power generated by the Lubu HPP is planned to be
sold to PT PLN (Persero).

The Lubu HPP project is located in Tanjungbetung Village, North
Rao District, Pasaman Regency, West Sumatera Province. This
project utilizes the Lubu River flow.

Lubu HPP

Project location:
Tanjungbetung Village,
North Rao District,
Pasaman Regency,
West Sumatera
Province

Figure 1- Project location

The planned electrical energy produced by the Lubu HPP will be
distributed to PT PLN (Persero) as a buyer, in this case PT PLN
(Persero) Region of West Sumatera.

1

Lubu HPP Figure 2- Map of the electricity system in the West Sumatera
Province
Some project areas are
in steep slopes and Topographic Conditions
some are in sloping
areas. The topographic survey of the project area has been carried out
which includes the installation of fixed control points
2 (benchmarks, BM), measurement of horizontal control
frameworks, measurement of vertical control frameworks and
detailed topographic mapping.

The results of topographic survey work are used to perform basic
designs, estimate project costs, estimate energy production, and
project financial feasibility.

Based on the topographic survey works that has been done, the
planned weir site is located between steep rock cliffs and dense
forests, the headrace channel is in a very steep cliff area, the
headpond plan is in the former mining area, the penstock is in a
steep slope and the powerhouse in a relatively flat bush area.

Geological Conditions

Geological investigation works of the project area has been
carried out including geological mapping, geological drilling on the
location of the main structures which also includes standard
penetration tests (SPT) and field permeability tests, and test pits
which also include disturbed and undisturbed soil samplings.

Figure 3- Geological map of the project area The geology of the Lubu HPP
weir is in a granite
The geological conditions of the project area can be described unit.
from the results of the field geological investigation works as The geology of the
follow. headrace channels and
the headrace tunnels
1- The planned weir is located in a granite unit. In this granite areas are in granite
there are two types of rocks, namely granite and diorite. and phyllite units.
The geology of the
2- The planned headrace channels and headrace tunnels are in headpond area is in a
granite and phyllite units. In addition, the headrace channel phyllite unit.
does not pass through the landslide area. The geology of the
penstock is in a phyllite
3- The planned headpond will rest on a phyllite unit. unit.
4- The planned penstock will be placed on the hillside which The geology of the
powerhouse is in a
occupies a phyllite unit to the powerhouse area. phyllite unit.
5- The planned powerhouse will be placed in a phyllite unit that There were no large or
small landslide or
has a relatively high bearing capacity. landslide potential
found, so that the sites
Based on the results of the field investigation it can be concluded could be said to be
that the entire structures will be on soil or rock which are stated safe.
to be very safe.
3
Flow Availability

The flow availability of the Lubu HPP is estimated based on the
following data.

1- Parameters of watershed area, slope of land surface, shape of
watershed, length of river network, slope of river network,
river network density, vegetation, land use and elevation.

2- The parameters of the extent of forest cover are obtained
from forest cover maps by the Ministry of Forestry, maps of
insular land cover by CRISP, maps of forest-non forest by JAXA
and interpretation of satellite imagery.

3- Potential evapotranspiration parameters are obtained from
the GDAS dataset.

4- Rainfall data in the watershed is obtained from the daily
rainfall data that has been obtained, namely the Tropical
Rainfall Measurement Mission (TRMM) Version 7, the Global
Precipitation Measurement (GPM) dataset Version 5, the
Surface Weathering Dataset for Southeast Asia (SA-OBS) and

sediaan

Lubu HPP records of daily rainfall gouging stations at Pasartangun, Siabu
and Rao.
The output of the flow availability analysis is a series of the Lubu
River flows at the planned intake of the Lubu HPP. From the flow
sequence, flow-duration curves can be formed as shown in the
following figures.

Figure 4- Flow-duration curve of Lubu HPP with TRMM and
GDAS datesets

Figure 5- Flow-duration curve of Lubu HPP with TRMM, GPM
IMERG and GDAS datasets

4

Figure 6- Flow-duration curve of Lubu HPP with SA-OBS and
GDAS datasets

Lubu HPP

Figure 7- Flow-duration curve of Lubu HPP with gauging
station records and GDAS datasets

The available average flows at the Lubu HPP are obtained from
the simulation results as follow.

Table 1- Summary of the results of estimated flow availability

asang Parameter TRMM TRMM SA- Gauging
ah 3209 and OBS Stations
ergi Average annual rainfall of GPM
n rata- watershed (mm) 3399 3286
Average annual actual IMERG
antara evapotranspiration of
dan watershed (mm) 3174
Faktor Average annual effective
al rata- rainfall of watershed (mm) 1410 1411 1410 1363
Average flow (m3/s)
antara Median flow (m3/s) 1799 1763 1989 1923 5
1%. 8.9 8.8 9.9 9.6
7.3 7.2 8.2 7.8

Development Scale Formulation Debit ra

The most economical development of the Lubu HPP is with design pekerjaa
discharges between 9.82 m3/s and 11.04 m3/s to produce a adalah s
minimum capacity factor of 65% with dependabilities between m3/s. De
29.27% to 30.15%. spesifika
peralata
Feasibility Study Level Basic Design
dan elek
The basic design work of civil and metal works has been carried sebesar
out based on the design discharge of 12.0 m3/s. This basic design
is then used to estimate the installed capacity, the energy
production and the project costs at the feasibility study level.

The main features of the Lubu HPP project are contained in
Appendix 1. The basic design drawings are attached in Appendix
2. The project layout is as follows.

Lubu HPP

The estimated project Figure 8- Lubu HPP Project Layout
cost of the Lubu HPP at
the feasibility study Poject Cost Estimates
level is
IDR 536,615,221,556. Estimated project costs calculated based on the basic design that
have been carried out with the current prices and the estimated
cost increases for the next 2 years show a total value of IDR
536,615,221,556 which is summarized in the following table.

6 Perkiraa

Lubu HP
sebesar
949,804

Table 2- Summary of estimated project cost

DESCRIPTION TOTAL COST WEIGHT

A. DIRECT COST (IDR) (% )

A.1 CIVIL WORKS 216,582,478,744 40.36%
A.1.1 Preparatory works 2,781,512,942 0.52%
A.1.2 Access road 4.99%
A.1.3 Weir and intake 26,756,496,985 5.71%
A.1.4 Settling basin 30,658,200,060 1.42%
A.1.5 Headrace channel 8.18%
A 1.6 Headrace tunnel 7,629,499,711 9.23%
A.1.7 Head pond 43,877,927,876 1.34%
A.1.8 Penstock foundations 49,547,813,374 7.28%
A.1.9 Powerhouse 1.69%
7,178,728,860
A.2 METAL WORKS 39,056,829,850 5.56%
A.2.1 Gates and trashracks 0.86%
A.2.2 Steel penstock 9,095,469,085 4.67%
A.2.3 Overhead traveling crane 0.04%
29,855,645,897
A.3 MECHANICAL AND ELECTRICAL EQUIPMENT 4,620,517,381 21.36%
A.3.1 Plant mechanical and electrical equipment 19.51%
A.3.2 Switchyard 25,035,128,517
A.3.3 Testing, commissioning and certification 200,000,000 1.68%
0.17%
SUB TOTAL A 114,633,500,000
104,687,500,000 67.29%
B. INDIRECT COST
9,010,000,000
B.1 Management and administration 936,000,000
B.2 Engineering
B.3 Land aquisition 361,071,624,641
B.4 Contingencies
B.5 Interest during construction 25,275,013,725 4.71%
B.6 Insurance premiums 7,221,432,493 1.35%
B.7 Value added tax 2.43%
B.8 Environmental mitigation 13,013,000,000 6.43%
B.9 Community development 34,520,780,169 9.21%
49,408,522,574 1.34%
SUB TOTAL B 6.71%
7,202,712,493 0.34%
36,013,562,464 0.20%

1,805,358,123 32.71%
1,083,214,874

175,543,596,914

TOTAL PROJECT COST (A + B) 536,615,221,556 100.00%

Estimated Installed Capacity and Energy Lubu HPP
Production
The estimated
Estimates of potential energy production are carried out by installed capacity of
simulating energy generation at each time stage along the the Lubu HPP is 20.077
availability of past data with inputs in the form of estimates of MW.
river flow availability, estimates of net head, estimates of
generation efficiency and estimates of installed capacity. The estimated average
salable energy is
The annual generated power and energy outputs are as follow. between 118,415 GWh
and 127,142 GWh per
Table 3- Average annual power and energy output year

Energy production TRMM TRMM SA- Gauging The average salable
and OBS Stations capacity factor is
Installed Capacity (MW) GPM 20.077 between 67.30% and
Average potential power (MW) 14.980 72.20%.
IMERG 131.311
7
20.077 20.077 20.077 6.676

14.425 14.244 15.285 124.634
70.80%
Average annual potential 126.437 124.845 133.917
energy (GWh) 6.491 6.431 6.775

Average annual unsalable 119.946 118.415 127.142
energy (GWh) 68.20% 67.30% 72.20%

Average annual salable energy
(GW h)

Average salable capacity factor

Project Implementation Schedule

The estimated schedule for implementing the Lubu HPP project is
shown in the following figure.

The project
implementation is
estimated to last for
21 months.

Lubu HPP Figure 9- Project implementation schedule

The Lubu HPP can be Financial Feasibility Analysis
stated financially
feasible using a The financial feasibility analysis of the Lubu HPP investment is
minimum selling tariff carried out in various scenarios as follows.
of IDR 971/kWh, a 12%
loan interest/year and 1- Base scenario
a 30% investor – 70% 2- Scenario with 20% increase of project cost
loan financing scheme. 3- Scenario with 20% decrease of project cost
4- Scenario with 5% increase of energy production
5- Scenario with 10% decrease of energy production
6- Scenario COD in wet year
7- Scenario COD in dry year

The financial analysis is carried out assuming an IDR 971/kWh
selling tariff, a 12% loan interest/year and a 30% investor – 70%
loan financing scheme. Based on the results of the financial
analysis of investment and with the scenarios reviewed, it can be
concluded that the Lubu HPP project is feasible both with the
base scenario and the scenarios with component sensitivity
analyses. By referring to the loan interest of 12% per year, the
project IRR and the investor are well above it.

The summary of the financial feasibility analysis of the Lubu HPP
investment is found in the following tables.

8

Table 4- Summary of the financial feasibility analysis with the Lubu HPP
TRMM dataset

Table 5- Summary of the financial feasibility analysis with the
TRMM and GPM IMERG datasets

9

Lubu HPP Table 6- Summary of the financial feasibility analysis with the SA-
OBS dataset

Table 7- Summary of the financial feasibility analysis with gauging
station data

10

Conclusion

Based on the results of the financial analysis and the investment
scenarios under review, it can be summarized as follow.

1. The analysis of the financial feasibility of the Lubu HPP by
referring to the base scenario and loan interest of 12% per
year shows the followings.

Parameters TRMM TRMM SA-OBS Gauging
and 16.70% Stations
Project IRR 15.70% GPM
19.10% 16.40%
Equity IRR IMERG

Project NPV 15.60%
(billion IDR)
Equity NPV 19.40% 21.00% 20.40%
(billion IDR)
Loan payment 132.322 130.202 169.572 157.204
period (year)
153.744 151.543 190.914 175.546

787 7

2. The financial sensitivity analyses show the lowest project IRR Lubu HPP

value in the scenario with 10% decrease of energy

production and the highest in the scenario with 20%

decrease of project cost.

3. With the conditions above, the Lubu HPP project can be
stated as financially feasible after technical and
environmental requirements are fulfilled so it shall proceed
to the next stage.

11

Appendix 1- Main Features

Locations Geographical UTM (WGS84) Zone -47

Bendung Longitude Latitude X (m) Y (m)
Kolam Penenang
Gedung Sentral 99° 51' 49.07" E 0° 48' 29.61" N 596094.75 89343.65

99° 52' 54.58" E 0° 48' 24.89" N 598119.74 89199.20

99° 53' 05.38" E 0° 48' 42.74" N 598453.45 89747.05

Hydrology 157
Area of watershed (km2)

- TRMM dataset

Average annual rainfall of watershed (mm) 3209
Average flow (m3/s) 8.9

- TRMM dan GPM IMERG datasets

Average annual rainfall of watershed (mm) 3174
Average flow (m3/s) 8.8

- SA-OBS dataset

Average annual rainfall of watershed (mm) 3399
Average flow (m3/s) 9.9

- Gauging Stations data

Lubu HPP Average annual rainfall of watershed (mm) 3286
Average flow (m3/s) 9.6

Weir

Type Overflow, gravity,

stone masonry and

concrete

River bed level (El m) (estimate) +745.53

Spillway

- Spillway length (m) 32.00

- Crest level (El m) +752.49

- 100-year return period flood level (El m) +756.37
- Design discharge (m3/s) Q100 = 532

Energy dissipator

- Type Stilling basin with

sub dam

- Length (m), width (m) 39.90, 32.00

- Floor level (El m) +744.00

- Top level of the side walls (El m) +751.80

Intake

Type Open with regulating

Design discharge (m3/s) gates
12.00

Number, width (m) 2 × 2.50

12 Sill level (El m) +749.54

Level of the wall top (El m) +757.37

Gate (type, opening nos × width (m) × height Steel sliding gates

(m)) 2 × 2.50 × 2.75

Trashrack (nos × width (m) × height (m)) 2 × 2.50 × 4.10

Flushing Non continuous Lubu HPP
- Type flushing
1.40 13
- Channel width (m)
- Gate (type, opening nos × width (m) × height Steel sliding gate
1 × 2.50 × 2.50
(m))
Settling basin Square cross section,
Type reinforced concrete
12.00
Design discharge (m3/s) 1
Number of chambers 82.00 × 7.30
Length (m) × width (m) 9.75, 11.39
Depth, upstream (m), downstream (m) +742.66, +741.02
Flor levels, upstream (m), downstream (m) +752.41
Level of the wall top (m)
Scouring Non continuous
- Type scouring
1.60
- Width (m)
- Gate (type, opening nos × width (m) × height Steel sliding gate
1 × 1.60 × 1.1
(m))
Downstream gates Steel sliding gate
- Gate (type, opening nos × width (m) × height 2 × 2.50 × 2.50

(m)) 12.00
Headrace channels and tunnels
Design discharge (m3/s) Closed channel,
Headrace channel type 1 reinforced concrete
- Type
Rectangular
- Cross section shape 3.00 × 4.40
- Width (m) × height (m) 189.24 + 115.98
- Length (m)
= 305.22
- Design velocity (m/s) 1.00
- Longitudinal slope
Headrace channel type 2 0.0174530%
- Type
Closed channel,
- Cross section shape reinforced concrete
- Width (m) × height (m)
- Length (m) Rectangular
2.10 × 2.86
- Design velocity (m/s) 27.76 + 433.51 +
- Longitudinal slope 135.59 + 530.66
= 1127.52

2.00
0.1115065%

Headrace tunnel

- Type Rotated D-shaped

- Top radius (R) × bottom width (m) × height 1.50 × 3.00 × 3.00

(m)

- Length (m) 70.85 + 506.59 +

293.35

= 870.79

- Design velocity (m/s) 2.00

Headpond

Type Trapezoidal cross

section with

reinforced concrete

Design discharge (m3/s) lining
12.00

Length (m) × top width (m) × base width (m) 24.80 × 13.90 × 6.20

Upstream, downstream depth (m) 12.22, 11.22

Level of the wall top (m) +747.98

Normal, low water levels (El m) +747.27, +745.18

Scouring

- Type Non continuous

Lubu HPP scouring

- Channel width (m) 1.60

- Gate opening (type, nos × width (m) × height Steel sliding gate

(m)) 1 × 1.60 × 1.50

Penstock inlet

- Type Bell-mouth

- Gate opening (type, nos × width (m) × height Steel sliding gate

(m)) with wheels,

mechanical lifting

1 × 2.60 × 2.60

- Fine trashrack (nos × width (m) × height (m)) 1 × 5.8 × 7.80

Penstock

Type Steel pipe with

anchor blocks and

saddle blocks

Main pipe

- Number × inner diameter (mm) 1 × 2500

- Length (m) 464.265

- Wall thickness (mm) 10 – 22
- Design discharge (m3/s) 12.00

- Design velocity (m/s) 2.44

Branch pipes

14 - Number × inner diameter (mm) 2 × 1800

- Length (m) 18.18, 14.40

- Wall thickness (mm) 16
- Design discharge (m3/s) 6.00

- Design velocity (m/s) 2.36

Powerhouse*) Above ground Lubu HPP
Type 17.00 × 24.50
Width (m) × length (m), column axes 15
Operation and maintenance floor level (El m) +502.41
Turbine floor level (El m) +498.36
Upper structure
- Type Reinforced concrete
frame
- Foundation
- Wall Reinforced concrete
- Roof Reinforced concrete
Foundations for mechanical and electrical
equipment Steel frame
- Type
- Deepest elevation (El m) Reinforced concrete
Draft tube gate +493.23
- Type
Steel sliding gate
- Opening (nos × width (m) × height (m) with

Access road gantry crane
Type 2 × 3.63 × 1.6

Pavement width (m) Flexible pavement
Shoulder and drainage channel width (m) with asphalt
Length, weir access road (km)
Length, headrace channel access road (km) concrete surface
Length, powerhouse access road (km) 3.50
Mechanical and electrical equipment*) 1.00
Number of units
Turbine 5.327
- Type 2.329
- Rated capacity (MW) 1.591
- Net head (m)
- Rated discharge (m3/s) 2
- Rated speed (rpm)
- Specific speed (rpm) Francis, vertical axis
- Runner diameter (m) 10.641
- Level of distributors (El m) 249.03
Generator 4.80
- Type 750
- Number of phases 114
- Rated capacity (kVA) 0.89
- Rated voltage (kV) +496.76
- Rated power factor
- Rated speed (rpm) Vertical axis
3

11,893
11 ± 10 %

0.85
750

Lubu HPP - Runaway speed (rpm) 1125
- Rated frequency (Hz) 50
- Number of poles 8
- Excitation system
- Insulation class Brushless with AVR
Class F with class B
Governor
- Type temperature rise

Inlet valve Hidraulic-electronic
- Type with PLC
Main transformers
- Type Butterfly

- Number of phases Oil immersed,
- Rated capacity (kVA) outdoor
- Rated primary voltage (kV) 3
- Rated secondary voltage (kV) 11,774
- Rated power factor
- Rated frequency (Hz) 11 kV -20 % + 5%
- Cooling 70 kV -20% + 5 %
- Insulator
- Vector group 0.85
- Impedance 50
Estimated power and energy *)
Design discharge (m3/s) ONAN
Normal water level (El m) Class A
Tailwater level (El m) YNd11
Net head (m)
Installed capacity (MW) 6%
Salable energy (MWh/year)
- TRMM dataset 9.60
- TRMM and GPM IMERG datasets +747.26
- SA-OBS dataset +497.00
- Gauging station data 249.03
Salable capacity factor (CF) 2 × 10.038
- TRMM dataset
- TRMM and GPM IMERG datasets 119,946
- SA-OBS dataset 118,415
- Gauging stations data 127,142
124,634

68.2%
67.3%
72.2%
70.8%

Note: *) May change to adjust to the mechanical and electrical

16 equipment used

Appendix 2- Basic Design Drawings

Layout

Lubu HPP

Weir 17

Plan

Lubu HPP Section A-A
Section B-B
Section C-C

18 Section D-D

Settling Basin Lubu HPP

Plan 19
Section A-A

Section B-B
Section D-D

Lubu HPP Headrace Channel

Plan
Typical cross section of headrace channel
Typikal cross section of headrace tunnel

Syphon

20

Plan and section

Headpond Lubu HPP

Plan
Section A-A
Section B-B

21

Lubu HPP Penstock

Plan

Longitudinal section
Typical cross section of anchor blocks
Typical cross section of saddle blocks

22

Powerhouse Lubu HPP

Plan 23
Section A-A

Lubu HPP Section B-B

Single line diagram of generating units

24

Single line diagram of switchyard Lubu HPP

25



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