Solar Water Treatment in Nusa Penida
A solution to utilizing renewable energy for people benefit
photo source: www.godwinplumbing.com
In 2007, PT. Energy Management Indonesia in cooperation with Directorate
Electricity and Energy Utilization, Ministry of Energy and Mineral Resources,
Republic of Indonesia has installed two units of Solar – Reverse Osmosis for
Water Treatment in Banjar Angkal and Banjar Semaya, Nusa Penida Island.
Until now, the units are still running and giving benefit to both villages.
PT Energy Management Indonesia (Persero)
Jl. Wolter Monginsidi no 6, Jakarta, Indonesia
+62 21 7268881
+62 21 7268880
Solar Water Treatment in Nusa Penida
A solution to utilizing renewable energy for people benefit
By Noezran Azwar
PT. Energy Management Indonesia (Persero)
In 2007, PT. Energy Management Indonesia in cooperation with Directorate Electricity and
Energy Utilization, Ministry of Energy and Mineral Resources, Republic of Indonesia has
installed two units of Solar – Reverse Osmosis for Water Treatment in Banjar Angkal and
Banjar Semaya, Nusa Penida Island. Until now, the units are still running and giving benefit
to both villages.
For archipelagos nation like Indonesia, electricity and water supply become a big challenge
nowadays, especially for farther and smaller islands. Unfairly distributed population and
extreme topographic contour in some areas often become causes of high investment for
electricity and water grids development. Decentralized grid is one of the solutions and the
government built small power generators for the islands, and most of them are diesel
generators. Although these facilities built with smaller investment, they run with higher
operation expenses and very dependent with diesel oil supply. The government, several
years ago, introduces the utilization of local renewable energy resources for electricity
generation. And, it is growing along these years. Besides giving more access to the
electricity, renewable energy utilization also unequivocally improves living standards. In
water supply sector, renewable energy technologies widely known has been utilized for
pumping and water treatment purposes in many areas, especially in remote grids.
Nusa Penida lies near Bali Island, but has less fortune compare to the neighbor. The island
has hardly extreme contour from flat
shorelines to rock-hills with cliffs. Most
people are living along shore area. The island
has also long dry season (6 – 9 months).
Electricity mostly comes from diesel
generators and available grid is mostly
located in shore area and isolated from Bali
Island. The communities usually use
rainwater that they had save along rain
season in reservoirs called “cubang” for
drinking and cooking. Other water supply
comes from home wells, but the water is
brackish. When they experience longer dry season, they use this brackish water. The
wealthier ones bought mineral water in gallons for Rp. 18,000 to Rp. 20,000 (nearly 2 USD)
per gallon (19 liter). In 2007, PT. Energy Management Indonesia installed two solar reversed
osmosis units for water treatment in Banjar Angkal and Banjar Semaya, two small villages in
Nusa Penida. Until now, the units are still running and giving benefit to both villages.
The origin of the idea is how to improve drinking water quality and how to make the
solution be sustainable.
As mentioned previously, the communities in Nusa Penida shore line experienced drinking
water supply problem. The problem was hard to solve especially when long dry season.
Available water supply comes from brackish water wells. The salts concentrate measured
about 1500 mg/L which above Ministry of Health Drinking Water Quality Standard, but
could be reduced with available reversed osmosis technology.
The systems installed were consisting of submersible water pump reversed osmosis unit
equipped by filtration and ultraviolet unit. Although there is available electricity grid nearby
the installation sites, the power source
of the water treatment systems comes
from electricity generated by solar
panels. Both systems were designed as
off-grid. The idea comes from the
community poor wealth condition that
they could not be burden by extra
Both systems were being managed by
local cooperatives. They were selling the water at minimum price and the income was being
used for O&M cost and dividend for the cooperatives.
The project planned through techno-economic and socio-culture approach. In earlier stage
of the project, the works were dominated by gathering much information through literature
study and site survey. The survey mapped what were the needs of communities, what
solutions should be offered, how to build communities awareness and get their
participation, what would be the obstacles, etc. The information collected was analyzed to
refine the work plan. The socialization of the project was the last stage before the
construction and installation begin. The socialization introduced the idea of the project,
offered solution, and yet to invite communities participation in the project works. In this
phase, the communities were persuaded to utilize cooperatives for managing the operation
and maintenance of installed systems. The concept of simple drinking water business was
introduced. The technical training for the operator was also conducted. The construction
and installation of both systems conducted in 2 months.
Environment and Social Consideration
The impact of a reversed osmosis unit to the environment usually is the brine water as the
byproduct of the process. The government has stated the threshold of salt minerals
concentration as total dissolved solid (TDS) in waste water disposed to the sea is 4000 mg/L
(The State Ministry of Environment, Ministerial Decree no 4/2007).
The water treatment systems were located in communities land nearby the coast (10 – 15m
from shorelines). Raw water came from 7 – 10m depth wells. The salts concentrate
measured in raw water as total dissolved solid (TDS) was about 1200 - 1500 mg/L.
The reversed osmosis technology used
in this project were using low pressure
process, therefore not all the feed water
being permeated through the
membrane (about 10% of feed flow
rate). The produced brine water then
mixed with this bypass water and has
TDS about 1600 to 2000 mg/L which still
below government requirement.
Since the systems were off-grid, there is avoided CO2 emission. Nusa Penida existing grid is
mostly supplied by diesel generators. With this baseline and other technical assumptions,
implementation of solar technology of 4.2 kilowatt peak can avoid minimum 15 – 20 tones
of CO2 annually for each water treatment system.
Almost all people in Nusa Penida devote
to Bali-Hindu religion and hold it as their
culture. They have two rural
administration in-effects. One is official
administration (government) called
Desa and the other is traditional-culture
system called Banjar. Although Banjar is
only based on Bali-Hindu culture, it has
stronger influence in people daily
activities. And almost all community
decisions mostly were being resolved in
Banjar. However, our project approaches are still considering those two administrations.
The common education level among the productive age is senior high school. Only fewer
people have higher education, the rest are the elders and children with basic education.
There are public medical centers and few doctors available in the area. Most medical cases
were being related to low income and poor living quality such as; poor children nutrition,
malaria, and diarrhea. The rate of these cases would increase when dry season occurred.
These identified conditions were being our consideration when we conduct the socialization
of the project.
By using Banjar leader (called Bendesa), Hindu priest, and leader of Desa (called Lurah), we
started to campaign and socialize the project. This was most the effective way, since people
were looking to their leaders. The
project was introduced as government
funded program and the people in
both Banjar’s would inherit the
installed systems. Some people in the
community were happy; some were
doubtful and worries that the units
would become their burden in the
future. With their urgent needs of
drinking water and sufficient education
level, the project succeeded to
introduce. People awareness was
developed and with their available knowledge, they organized themselves to participate in
process of the project. These were be advantageous for project completion, yet were giving
hopes that the installed systems had chances to sustain in the future.
Technical, Economic, and Market Consideration
The systems were designed compact, easy to operate, and minimum maintenance. Low
pressure - reversed osmosis technology were being used which had less energy
consumption. Since it used lower osmotic pressure, the yield between produced water and
feed water was also low. But, like previously mentioned, it was an advantage since the
mixture of “unprocessed” water and brine byproduct has lower TDS which fulfill
government requirement of disposed water quality.
Both systems were consisting same components;
1. Well pump; Lorentz PS150 which is a highly efficient submersible pump system.
2. Reversed osmosis feed pump; Pacific Scientific
3. Filters ; strainers, 20 and 5 filters, charcoal filter, PH neutralizer, and UV sterilizer
4. Automatic water flush pump
5. Reversed osmosis machine; 1800
liter/day production capacity, Sea
Recovery’s Ultra Whisper™
Desalinator with its unique
EfficientSea™ Energy Transfer
technology; brings efficient,
compact, extraordinarily quiet
water making to small and midsize
power or sail boats. The unit’s
Energy Transfer Device eliminates
the need for a high-pressure
pump, reducing the electricity
consumption of the R.O. system
by as much as 75%.The R.O.
process is achieved by recovering
energy from the pressurized brine
discharge and transferring that
energy to relatively low-
6. Solar panel of 4160 watt peak equipped with Lorentz ETATrack Active 1500 Solar
Tracker, VRLA batteries 2V – 800, and Plasmatronic PL 60 charge controller.
Most equipment was imported, but the spare parts are available in Indonesia. The
closest vendor office is in Bali Island and recently PT. Energy Management Indonesia has
awarded agency right from solar pump manufacturer.
Installation sites were easy to be accessed since nearby village main road which almost
10 minutes from the ferry harbor.
Economic, Market, and Financial
In Banjar Angkal and Banjar Semaya, most people live as traditional seaweed farmer and
fisherman. Since the limited electricity and insufficient facilities for product processing, the
seaweed and fish are brought to Bali Island to be processed for export purposes. To the
contrary, groceries are being brought from Bali Island by using ferry or boat. And as
guessed, all the prices are boosting up almost twice. Mineral water in gallon price is only Rp.
9,000 – Rp. 10,000 in Bali Island, and it’s
boosting up to Rp. 18,000 – Rp. 20,000
in Nusa Penida.
The communities were agreed among
themselves to sell the produced water in
gallons. The production rate is 90 water
gallons per day. They organized local
cooperatives to manage the business.
They were selling the produced water at
price Rp. 4500 per water gallon with
brands Suryaning and Segaria. Half of the revenue was used as operating expenses and
savings for maintenance cost. The other half was deposited to cooperative treasury for
dividend or financing Banjar activities.
Suryaning and Segaria have penetrated gallons water business in Nusa Penida. Product
distribution chains were through traditional market, small shops, and delivery order. Other
side products were growing. Instead of
only sell gallon water; some small shops
were selling lemonade, syrup, boiled
noodle, and other food and beverages.
Impact on economic growth in both
Banjars has not been quantitatively
measured yet. But some evidence in the
field shows that people has got
economic benefit from this business. An
interview conducted recently to a small
shop owner, Mrs. Ketut Lastriyani from Banjar Semaya; she said that her business was
growing because of selling the produced water and other side products. She even could
build a new shop across the old one. Pictures of Mrs. Lastriyani’s old and new small shop as
The fund of the project came from government spending. Each systems investment was Rp.
750,000,000. However, financial analysis was conducted with still considering government
spending as an investment. Analysis for each water treatment system is summarized below;
Project Lifetime 15 years
Payback Period 10 years
However, if the price per gallon is set at Rp. 7,000, which still competitive compared to
other commercial gallon water, the return will be much better. Calculated NPV and IRR are
almost doubled and estimated payback period is shortened.
Operating and Maintenance Scheme
The systems were being operated for 6 hours of daily operation. While the available
sunshine is 10 hours, the reliability of the system was secured by battery.
Both facilities open from 9 a.m. to 16 p.m. Daily production is 90 water gallons. The buyers
can come directly to the water treatment facility, or can order for deliveries, or can buy
from traditional market or small shops.
As mentioned previously, the systems were being managed by local cooperatives at each
Banjar. Simple organization structures were developed as below;
(Bendesa or Lurah)
The operators are responsible for operating and doing maintenance of the systems. They’ve
already equipped with O&M manual book written in Bahasa Indonesia.
Maintenance was being scheduled from daily maintenance (housekeeping, cleaning the
unused gallons), weekly maintenance (wiping out the solar panel, cleaning all the filters,
tubes, and hose), and other periodic maintenance (membrane cleaning, etc). If there is
system breakdown, the operators can call the closest vendor office in Denpasar, Bali.
The project is replicable for government spending project or private project. The technology
is available in the market from small scale capacity up to industrial capacity. The technology
is going to be cheaper, efficient, and more modular. And yet, the financial analysis shows
this type of can be a business model which has good financial valuation in certain
circumstances and assumptions. Those technical and financial views must be accompanied
by good socio – culture approach to make the project more sustainable.