[ieee 2014 ieee innovative smart grid technologies - asia (isgt asia) - kuala lumpur, malaysia...

Energy Evaluation and Smart Microgrid for Rural

Sarawak Jason K. S. Yeo and S. Chen W. X. Shen H. S. Chua

Thermal, Research & Development,

Sarawak Energy Berhad

Sarawak, Malaysia

Faculty of Eng. & Ind. Sci.,

Swinburne University of Technology

Melbourne, Australia

Faculty of Eng., Comput., & Sci.,

Swinburne University of Technology

Sarawak Campus, Sarawak, Malaysia

[email protected]

Abstract – The rural communities in Sarawak which consist of

approximately 22% of the state’s population are still relying on

expensive and noisy diesel generator sets for a couple of hours

every night simply because they are located in remote areas

where people have limited access to electrical grid. If electricity

is generated by means of potential Renewable Energy (RE)

resources which are incorporated with smart microgrid for

rural Sarawakians, there are many advantages that could be

insightful for the society and the environment. In this paper, the

availability of RE resources in Sarawak and their potentials to

supply power to rural areas in Sarawak is first discussed. A

smart microgrid concept for rural electrification in the state is

also discussed to provide an overview on its characteristics and

challenges.

Index Terms – Energy Sources, Renewable Energy Sources,

Rural Electrification, Smart Microgrid.

I. OVERVIEW OF SARAWAK

Figure 1. Southeast Asia: Malaysia.

Sarawak, which is also known as Bumi Kenyalang (Land of

Hornbill), is the largest state in Malaysia which covers a

wide area land of 124,450km2 spreading between latitude 0°

50’ and 5°N and longitude 109° 36’ and 115° 40’E [1]. The

rural places in the unique geographical State of Sarawak

have a variety of RE resources such as solar and hydro. In

the 2000 census, the rural population in of Sarawak

represents 37.8% whilst the urban shares the remaining [2].

Based on the 2010 census provided by the Ministry of Public

Utilities, there are 217,583 households (estimated population

of 1.24 million in the year 2012) have been electrified (rural

coverage of 78%). This further reflects on the rural villages

where more than 80% of them have the potential of being

electrified through the main grid while 20% remains off-grid

which may possibly be supplied through various RE energy

generation. The people living in these rural places who are

experiencing limited access to modern energy are located

remotely to the electrical grid due to the difficulty in the

extension of the main grid in terrain and thick jungle.

Moreover, the cost of extending the transmission line does

not balance with the amount of electric power consumption

they need. Therefore, it is not economically justifiable to

extend the transmission line towards these rural areas.

Until now, this is the logical reason given by power

companies as well as the government for not taking any

measures in extending the grid to these rural communities for

electrification. However, if a lasting economic development

and advancement in technology is needed throughout the

state and country, there is no better alternative than

electrifying the rural areas of the country as it is done to the

urban areas. Therefore, we discuss the availability of

distributed generations (DGs) in Sarawak through RE

resources and their potentials to supply power to the rural

areas in Sarawak and an approach that uses a smart grid

technology as viable solution to the rural communities,

ensuring a better and secure energy future for Sarawak.

II. DISTRIBUTED GENERATIONS POTENTIALS IN SARAWAK

There is high potential for DGs to supply electricity to the

rural parts in Sarawak using RE resources. Table I shows a

summary of reserves available in Sarawak. These RE sources

are then further explored and discussed in this section.

Table I. Indigenous Energy Resources in Sarawak.

RE Sources Exploitable

Reserves Units

Hydro > 20,000 MW

Solar 4.0 – 5.0 kWhm-2

/day

Wind Speed 1.19 – 1.75 ms-1

Geothermal Unknown MW

A. Hydropower

Hydropower is one of the most cost-effective and clean

energy for DG use if the resource is available. Sarawak

which has the most river networks and streams in the country

has abundant hydropower potential. Among the major rivers

are the Sarawak River, Lupar River, Saribas River, Rejang

River. Rejang River is the longest river in Malaysia with a

few smaller branches of river such as Baleh River and Baram

River, and Limbang River that flows towards Brunei Bay

2014 IEEE Innovative Smart Grid Technologies - Asia (ISGT ASIA)

978-1-4799-1300-8/14/$31.00 ©2014 IEEE 459

[1]. Furthermore, there are also many smaller rivers that flow

and complete the river network in Sarawak which have the

potential to be harnessed to produce small-scale electricity

particularly for the rural populations in Sarawak.

Hydropower generations are classified as RE sources in

Sarawak. The use of water resources towards power

generation has the most mature technology characterized by

highest prime moving efficiency and excellent operational

flexibility [1]. Moreover, especially small-scale hydropower

generations, they are established to be environmental

friendly [3] that produce negligible amount of greenhouse

gases.

In Sarawak, under the Sarawak Master Plan Study (SAMA

Study) in 1979, 155 sites were identified to have the

potential of developing hydro station. Among the 155 sites,

51 sites were short listed and have a total of approximately

20,000MW (annual generation of approximately 87,000

GWh). The first hydroelectric station in Sarawak situated at

Batang Ai was completed in 1985, it has a total capacity of

94MW. Since 1980, the power generation development in

Sarawak was emphasized on thermal power generation and

micro and mini hydro for which many small-scale hydro

power generations were built. Some of the selected hydro

generations are shown in Table II.

Table II. Micro and Mini Hydro in Sarawak.

Micro/Mini/Small Hydro

Location

Capacity (kW)

Sebako MH 300

Peninden MH 300

Sg. Pasir MH 800

Lundu MH 300

Semadang MH 200

Batu Lintang MH 100

Saliban MH 150

Sg. Kejin MH 500

At present, Sarawak has the biggest hydropower station in

South East Asia which is nearly to its 100% operation, the

Bakun Hydro Station that provides a total capacity of

2,400MW in full operation. In addition, another hydropower

project, the Murum hydropower which has a total capacity of

944MW, is anticipated to be in operation by the end of 2014.

Rural area in Sarawak which has many small rivers and

streams, the potential of having micro and mini hydropower

generations as electrical sources is highly in favor in the

state. Thus, it is a considerable option in powering the rural

communities as small-scale hydro is foreseeable to be low

cost.

B. Solar Energy

Humans have been utilizing a wide scale of continuous-

evolving technologies to convert solar energy from the sun to

electricity even since the ancient age, for warming and/or

cooling habitations and for water heating. Light and heat

energy from the sun are capable to be directly converted to

electrical energy through photovoltaic cells. According to

[4], the Earth receives 174 petawatts of incoming solar

radiation at the upper atmosphere. However, only

approximately half of the solar radiation reaches the surface

of the earth and the rest are reflected and radiated to space

from the atmosphere and etc. With this, solar energy can be

exploited in various levels around the world depending on

their geographical location. The closer the country locates

towards the equator, the higher the “potential” of solar

energy is available to be harnessed.

Sarawak, which is situated near to the equator, has been

estimated to receive over 4,000 hours (or more than 46%) of

sunshine per year and is able to receive solar energy between

4.0 - 5.0 kWh/m2/day [5]. In [6], it is observed that on

average, Malaysia receives approximately 4.96 kWhm-2

of

daily solar radiation in a year. The minimum and maximum

daily solar radiations received are 4.21 kWhm-2

and 5.56

kWhm-2

, respectively. The maximum daily solar radiations

are found to be mostly in Northern region of Peninsular

Malaysia and also Southern region of Sarawak while most of

the parts in Sabah receive the lowest solar radiation. This

can be seen in Figure 2.

Figure 2. Annual Average Daily Solar Radiation in Malaysia [6].

While inner parts of Sarawak are observed to have relatively

high solar radiation, this approach is considerable to be

exploited to solve energy difficulties especially to the rural

vicinity that has no access to electrical energy at all.

C. Wind

Many studies by researchers have been carried out on wind

speed especially for the purpose of generating energy. As we

know, wind energy is one of the alternative RE resources

that is clean and cost effective for many applications because

wind energy does not impose transportation problem [7].


460

However, wind strength is not constant and varies from zero

until storm force. In Malaysia, there is no consistent wind

strength as the country is situated along the equator. The

wind speed is generally known to be influenced and dictated

by the monsoon seasons, namely northeast and southwest

monsoons. Besides influencing the wind speed, these

monsoons also contribute rainy seasons in the country. The

northeast monsoon takes place in May until September

whilst the Southeast monsoon from November to March.

As shown in Figure 3 adopted from [7], the theoretical mean

wind speed that can be exploited in East Malaysia would be

in the range of 4.3 – 6.3 km/hour or 1.19 – 1.75 m/s. It is

observed that northeast region of Miri and Limbang as well

as the west of the capital city, Kuching have the highest wind

speed as compared to the inner region of Sarawak. The

average wind speed of these regions is approximately 6

km/hour. This signifies that the highest potential in

harnessing wind energy for power generation for the state

would be from these regions whereas the prospective of

utilizing wind energy for the inner region of Sarawak for

rural is unpromising.

Variability of wind is one of the major issues associated with

wind power [8]. The wind speed must not have high

variation which may cause structural damages. Thus, wind

turbines generally do not participate in voltage and

frequency control if any disturbances occur. Wind turbines

are disconnected and reconnected to the grid after the

stability of the system is resumed [10]. Considering the

theoretical mean wind speed in East Malaysia which is in a

range of 1.19 – 1.75 m/s, micro wind turbines (of 1kW and

below) could be deployed to generate electricity. The micro

wind turbine generally is less than 1kW and would be able to

generate electricity at the wind speed as low as even 1m/s.

Further studies and investigation of wind on-site as well as

detailed data on wind speed consistency throughout the day,

months and years are required to estimate the performance of

a wind project in the development of wind power generation

in Sarawak.

D. Geothermal

One of the RE technologies that have been given notable

attention to is the geothermal energy. Geothermal energy has

the incredible potential in supplying continuous energy

security in many countries including Malaysia which are

located within the Pacific Ring of Fire as seen in Figure 4.

Figure 4. Malaysia within the Pacific “Ring of Fire”.

Figure 3. Map of Wind Speed in East Malaysia [7].

Malaysia

Kuching

Miri

Limbang

km/hr


461

Figure 5. Distribution of Thermal Spring in Sarawak [5].

Malaysia together with its neighboring countries within the

Ring of Fire such as Indonesia, Philippines and Papua New

Guinea has huge potential in geothermal energy. Assessing

Malaysia alone, there are 79 confirmed geothermal

manifestation areas, 61 of which are in Peninsular Malaysia,

8 are in Sarawak and 10 in Sabah [5-9]. These 8 areas with

thermal springs are located westernmost of Sarawak [5] and

can be accessible by road, footpath and boat, as shown in

Figure 5. The potential of geothermal energy for generating

electricity in Sarawak is still at its surface of exploring,

further assessment is required to utilize geothermal energy as

potential power generation.

III. SMART MICROGRID

Mircogrid or also known as Smart Microgrid is a modern,

small-scale version of the electricity system. Microgrid is a

cluster of interconnected various sources that are referred to

as distributed generators, loads and immediate energy

storage systems (ESS) that co-operate with each other to be

collectively treated by the grid as a controlled load or

generator [11]. A typical structure of a smart microgrid can

be shown in Figure 6. Smart microgrid achieves local goals

such as reliability, carbon emission reduction, diversification

of energy resources and cost reduction, established by the

community being served. It serves similar to the bulk power

system grid where smart microgrid generates, distributes and

regulates the flow of electricity to consumers or a local entity

[12].

Research on smart microgrid has been actively pursued and

widely attracted throughout the evolution of microgird which

provides significant advantages compared to the traditional

power system. However, the applicability of a smart

microgrid is still in the preliminary stage where advanced

research and study are essential. Smart microgrid can be

employed in an urban and rural area. The major dissimilarity

between the employment of microgrid in an urban and rural

area is that rural microgrids are connected to weak

distribution networks [14]. Depending on the load

requirements and its grid topologies, it is vital to understand

the operation mode of smart microgrid by investigating its

advantages and disadvantages and whether it is economical

to be implemented into the distribution network.

Figure 6. Typical Structure of Smart Microgrid System [13].

There are a number of main issues addressed for the

implementation of rural smart grids as follows [14]:

a. Development of appropriate design methodology

b. Development of new operation and

planning/security practices

c. Lack of knowledge in rural loads and rural

distribution networks to simulation models

d. Improvement on communication systems

e. Design of control strategies

f. Design of new protections

Key point to decide on the performance of a smart microgrid

lies on the design and control issues [13]. As in [15], there

are two visions in designing and building smart microgrid:

from scratch or to modify an existing system into a smart

grid. For rural area, smart grid is implemented by converting

and upgrading certain or existing facilities into a smart

microgrid. Preliminary stage of having a more efficient and

reliable power system should look into the potential

resources available in the region of the rural community in

conjunction with its population dispersion as this may

influence the optimal solution of the distribution system

design and also the potential key control strategies in

telecommunication system to manage data.

There are three basic types of distribution system designs

[16] as categorized; Radial System (or Radial Grid), Loop

System (or Ring Grid) and Network System (or Meshed

Grid).

Radial system which is also known as radial grid, is the

cheapest distribution system to construct. It is broadly

AC

Generator

Wind

Turbine

PV

DC

AC

AC

DC

AC Load Battery Units

DC Load

AC

AC

DC

AC

DC

DC


462

utilized in sparsely populated vicinity where one power

source is connected in parallel with a cluster of user. It is the

simplest system design for a smart grid at the rural areas

[14], but on the negative side, if this power source fails, the

entire grid would be affected and requires restoration.

Second, a loop system or ring grid has power sources which

are able to provide a bidirectional flow of power routes. This

provides better reliability and security for the users. In the

event that fault occurs on the line, this will affect a minimal

power interruption to a fraction of users, unlike the radial

system. Finally, the network system or meshed grid is the

most complex and interlocking loop system [16]. The

network would be powered by many power sources. With

this, the reliability of the power system is much

strengthened. The main advantage of having a network

system is for its operational flexibility.

On the other hand, control system plays a vital role in

making the grid smarter in a microgrid. Without an advanced

telecommunication system to replace the conventional way

of power system, for example, the usage of advanced sensors

or any other automated technologies, the grid is less

efficient, less reliable and is time consuming to overcome

power failure if unwanted disturbance occurs. Control

system of a smart microgrid takes charge by means of

controlling voltage and frequency by providing quick or

instantaneous response on the differences of active and

reactive power between power sources and loads. An

islanded operation such as those for rural areas, the

frequency control is the most crucial challenge. Second

would be the voltage regulation. In order to control

frequency and voltage, the daily load profile is vital. The

control system would typically require a hierarchical

structure (see Figure 7) to overcome these challenges.

Figure 7. Typical Hierarchical Control Structure of Smart Microgrid [6].

To date, there are mainly two control methods which are

master-slave control and peer-to-peer control [17]. The main

control unit in the master-slave control adopts the V/f control

to maintain a constant voltage and frequency, where the PQ

control of the power generation units to output active and

reactive power. Different from master-slave control, peer-to-

peer control is based on declining external characteristics

which links frequency versus active power and voltage

versus reactive power. Control algorithm is then applied to

achieve regulated voltage and frequency without any form of

communication. Each of these two control methods has their

own advantages and disadvantages in certain mode of

operation which should be further studied in detail to obtain

an optimum smart microgrid system.

IV. CONCLUSIONS

The energy potential for rural electrification in Sarawak has

been accessed. Hydropower and solar generations are found

to be the main potential contributors for renewable electrical

sources. Micro hydro can be employed due to the availability

of rivers and streams in these rural areas while solar potential

is bright in the state specially the inner part of Sarawak due

to the availability of high solar radiation. Further study

should be carried out to ascertain the potentiality of utilizing

these renewable energy resources for smart microgrid for the

rural communities in the state. Smart microgrid is the

solution in integrating distributed generations and regulating

electricity to provide a more reliable and secure power

generation for the rural communities. Smart microgrid would

also allow changes in the passive distribution networks to a

smarter grid system which would definitely benefit the rural

communities in social and economic development as well as

education as electricity is one of the basic amenities required

by the rural people. With the integration of renewable energy

sources available in rural areas, a properly planned, designed

and optimized smart microgrid can be economically

justified.

ACKNOWLEDGEMENT

This research work was supported by Sarawak Energy

Berhad and Swinburne University of Technology. The first

author is very much grateful to his supervisors for their

continuous support, initiative effort as well as making

available their experience. The author is also very much

thankful to the Research and Development colleagues who

willingly allocated time in establishing the information for

this research work.

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