renewable energy integrated microgrid for rural electrification and productive use

Renewable Energy Integrated Microgrid forRural Electrification and Productive use

Muhammad Taheruzzaman

BTU-Brandenburg Technical University [email protected]

adfa, p. 1, 2011.

© Springer-Verlag Berlin Heidelberg 2011

Renewable Energy Integrated Microgrid for Rural

Electrification and Productive use

Muhammad Taheruzzaman

BTU-Brandenburg Technical University Cottbus

[email protected]

Abstract. Electric power crisis is one of the major problems in developing

countries, and Bangladesh is one of them. The breach between demand and

supply is increasing disturbingly. Yet 52 % of the total population has no access

to electricity in Bangladesh, and 75 % of them are the rural and isolated

community. This paper addresses the renewable energy integrated small-scale

power system for rural electrification in the developing countries like

Bangladesh. This paper also concentrates on optimal design, sizing, and

planning of distributed generation sources. Investigating the optimum design

and sizing of generation unit for reliable and cost effective operation of

microgrid; four different configurations including only biomass generator,

biomass, PV/wind mix system, and further planning the main grid can also

connect take into account. Lastly, technical and economic feasibility and

optimization compared for both standalone and grid connected system for the

community based electrification.

Keywords: DC Microgrid (DC-MG), solar home system (SHS), renewable

energy, rural electrification.

1 Introduction

The global energy system trends have been struggling against global warming

petrifyingly since surface temperature is also rising, the transition of energy system

transform to a fully sustainable based local renewable sources would be a great

solution to protect the environment. To increase about 124 % of renewable energy and

209% of biofuel by 2020, cut off half of greenhouse gasses by 2050 [1]. At present,

1.2 billion of total global population, which means around 20 % of total population

have no access to electricity, South Asian countries accounts for 37% of the world's

population without access to electricity [2]. The gap between demand and supply is

increasing petrifyingly, due to high population growth in Bangladesh, the demand of

electrical power increases and number of people are living in energy poverty, despite

a continued positive efforts experienced for electrification across all over the

Bangladesh [3]. Approximately less than 60 % of the overall population in the

c○ M. Kratky, J. Dvorsky, P. Moravec (Eds.): WOFEX 2016, pp. 549–556.VSB – Technical University of Ostrava, FEECS, 2016, ISBN 978-80-248-3961-5.

550 Muhammad Taheruzzaman

developing countries have access to electricity, whereas urban electrification 80 %

and about 15-25 % of rural areas are electrified. support rural electrification efforts by

the respective country governments including use of renewable energy technologies

including PV, wind, and biomass. Despite the continuous efforts of the international

community and governments throughout the world, the pace of rural electrification in

many developing countries is still very slow [4]. Rural electrification typically poses

more challenges than urban electrification in terms of policy, finance, and institutional

setup because of its distinct features. While the initial solution for rural electrification

can be spreading the main grid by extending the transmission line, but some instance

not technically and economically possible [5]. It is commonly agreed that to meet the

present demand is the burden for natural gas and other conventional fossil fuels,

integration of local renewable sources such as solar PV, small wind turbine (SWT),

and biomass would be the alternate source of energy. Furthermore, the isolated and

remote areas, RES distributed sources are being significantly recognized as cost-

effective sources [6]. The remote areas, higher transmission line losses, and higher

cost of transmission lines are encouraging to use of distributed renewable energy.

With declining the cost of PV and increasing the performance of small wind turbine

(SWT), in addition to improvement of the technologies including control system, and

storage system, standalone renewable integrated system significantly enhances its

stride [7]. Due to geographical location country like Bangladesh is blessed to

generates PV and wind energy based electricity, unremitting deterioration of the

prices and soft loan arrangement by state owned organization Infrastructure and

Development Company Limited (IDCOL) of Bangladesh already installed 3.2 million

solar home system (SHS) by 2014 and extent the number of 6 million by 2017

through installing 50,000 SHS each month [8].

2 System Description

The community based µ-grid consisting of small scale biomass-fueled generator,

distributed micro generation unit including PV system, and small wind turbine

(SWT). The distributed micro generation sources are being well popular in the

developing eventually in the isolated community from the utility network. For

enhancing rural electrification and access to electricity µ-grid would be the best

possible solution. The concept of community based µ -grid which acknowledges

integrating distributed µ-generator sources to the low voltage (LV) distributed

network [9]. The proposed system where PV system is considered as several solar

home systems (SHSs) connected to the system as distributed µ-generation sources and

defined as prosumers1, SWT and biomass fueled generator shows in fig.1 . The choice

of generator is driven by the need and local conditions at the target to end user,

keeping in mind that the system integration should have a good balance of being most

efficient, reliable, cost-effective, socially beneficial, least polluting and sustainable in

1 Solar home system (SHS) integrated microgrid; where SHS act as feed electricity into the microgrid and consumer electricity as well

Renewable Energy Integrated Microgrid. . . 551

the long run. In developing countries hybrid renewable integrated system have a

particular strong relevance in improving the quality of life, especially among rural

communities. The electric load in the system considered in DC, including households’

appliances, irrigation pumps, rice husking machine, cold storage refrigeration system.

The biomass-fueled generator is the primary main source of energy and SHS and

wind turbine used for an additional source for electricity to meet the base load of the

system, and utilize the use of cost free fuels.

Fig. 1. Proposed Community based DC-MG

3 Model Assumption and Input

3.1 Electric Load

The fig.1, representation of a hypothetical load profile of a community in Bangladesh.

The proposed system, the community households consumed 70 kWh per day with

maximum peak 15 kW at the evening. The demand data is synthetic and 5% day to

day variation considered, and Homer tool randomly inducements the daily

perturbation factor in the very hour. Bangladesh is a tropical country as winter

demand is comparatively lower than the other seasons.

3.2 Productive Usable Load

The productive load considered as Irrigation pump operates between 7:00 to 11:00

each day from October to March. A small size community based cold storage working

for 24 hours a day with the capacity of .8 kW and a rice husking mills peak load 1.3

kW and operates 8 hours a day except the weekend. Total consumption including

households and productive loads 36,885 kWh per year.

3.3 Local Renewable Potential

The solar irritation profile of kaptai, Chittagong (26°26´ N, 96°16´ E) assume for

this work. Solar radiation data is taken from the NASA surface metrology and solar


energy2. The proposed location monthly average solar radiation 4.63 kWh/m2/day.

The monthly average wind energy 5.79 m/s respectively. Biomass combustion has

68-79 % efficiency depending on fuel moisture content, and combustor design, and

combustion operation [10]. The community food waste, crops, leafs, and animal

manure to generate biogas that landfill avoided which reduces methane potential

damage the atmosphere [11]. The local cows and buffalos roughly produced 10

kg/day, and approximately 60 % of Agricultural residues, 30 % of animal waste

and poultry and 10 % of others average biomass production. The average biomass

production = 2.04 tons/day.

3.4 Community Based Battery Storage System

The proposed system where comply the meet the load and supply, a community

based battery storage is recommended. As the distribution system defined as 12 V, the

battery nominal voltage 12 V has considered as the terminal voltage. The nominal

capacity of each battery assumes 1 kWh, and maximum capacity 80 Ah. Initial state

of charge 100% and minimum charge 40% considered for the system optimization.

4 Result and Comparison of various cases

In this section, four difference cases according to system configurations for analyze

all assumptions and constrains for the favorable optimal design option for MG

planning as shows in table 1. The first case assumes as an isolated network system fed

by a biomass generator. However, the system capital investment is very high

installation, operation and maintenance cost, though the fuel cost not so expensive as

compare to other traditional fossil fuel such as diesel or furnace oil system. In case-2

the system configures along with number of SHS, SWT, and biomass fueled

generator, while case-1 only biomass dependent system, and case-3 is also mixed fuel

based configuration but number of SHS increases from 20 to 25 (i.e. PV system

capacity increases to 2.5 kW). The case-3 configuration mainly instigates from

bottom up swarm electrification concept, where the surplus electricity can be supply

to the new users without interrupting present participants. Finally, case-4 assumes

similar to case-3 but operates grid connected mode, and the MG system operation

adopt to purchase electricity from the grid and sell back surplus unit to the grid.

Designing and planning of optimal MG system for rural electrification different

configuration taking into account. The main objectives of these interpretation finding

the least-cost, self-dependent system, effective use of biomass and other renewable

sources for renewable contribution.

2 HOMER Analysis https://analysis.nrel.gov/homer/.


Table 1: Summary of different configurations for optimal studies

Cases Description of various scheme

case-1 Biomass fueled generator

case-2 Renewable mixed: Biomass generator, SWT, SHSs

case-3 renewable mixed: increase capacity of PV

case-4 Grid Connected with DC-MG: allow purchase and sellback

The first configuration (case-1) consists of only a 15 kW biomass generator which

operates 6423 hours and produces 38,791 kWh per year. The produced electricity is

not only meeting the total demand of community loads including households but also

productive use, and 139 kWh of excess electricity produces. The precise design can

be optimized with 12 battery integrate within the system. While case-2, renewable

mixed system cogitates along with 10 kW biomass generator, 2.0 kW PV (i.e. 20

SHS), 2 SWT (turbine capacity 1 kW each). The mixed fuel system all together

produces 38,440 kWh per year, alone biomass generator produces 31,000 kWh by

operates 4852 hours every year, aside the 20 SHSs and 2 SWT produces 3,197 kWh,

and 4,274 kWh respectively. The total production of electricity for case-2 shows in

fig. 2(a), and the PV system and SWT operates roughly 4400 hours and 4700 hours

respectively per year for each case.

Fig. 2. Electricity Production in MG (a) case-2 and (b) case-3

The renewable mixed fuel MG in case-3 configures along 10 kW biomass generator,

2.5 kW PV system (25 SHS system), and 2 kW SWT, where the biomass generator

operates 4791 hours and generates 31,657 kWh, and SWT produces same as previous

configuration 4,274 kWh per year. As the number of SHS has considered in case-3,

production increases to 3,990 kWh. In case-3 total production 39,921, kWh per year

by the renewable mixed fuel system, the biomass, wind energy, and PV contributes

78%, 9%, and 13% individually shows in figure 2(b).

In case-4 consisting also of 2.5 kW PV (25 SHSs), 2 SWT, and capacity of biomass

generator similar as the previous cases 10kW. Among all together these sources

produce 51,148 kWh per year; while 6.5 % by PV, 8.5% by SWT, 72% by the

generator, and 13% from grid purchase shows in fig. 3(2), and the system surplus

electricity can be selling back to the grid shows in fig.3(b). The case wise comparison

among various cases precisely present in table 2, biomass generator fuel

consumptions and operational hours for different cases present in table 3.


Fig. 3. Case - 4 (a) electricity Production (b) Average monthly grid purchase and sell back

The case-3 and case-4 are the most economical possible solution for optimal

configuration. However, among all the configurations holds over 85% of renewable

penetration, case-4 (grid extension cost of capital not considered) is one of the

cheapest as the NPC, Levelized cost of economic (LCOE), and operating costs are

comparatively lower than any other cases of the configuration shown in table 4.

However, the LCOE is higher in case-1 and case-2 because of large capital cost. It has

shown case-1 is grip the largest cost components.

Table 2: Optimal configuration of various cases

Component Case-1 Case-2 Case-3 Case-4

Biomass generator [kWh/year] 38,791 31,000 31,657 36,879

PV system 0 3,197 3990 3,197

SWT 0 4274 4274 4,274

Grid 0 0 0 6,798

Total electricity 38,791 38,440 39,931 51,148

Renewable fraction [%] 100 100 100 86

Excess electricity (kWh/year) 139 0 1789 0

Number of battery 12 10 8 5

Table 3: Case-wise comparison of biomass generator

Biomass generator Case-1 Case-2 Case-3 Case-4

Number of operation hours [hour] 6423 4852 4791 3726

Fuel consumption [tons/year] 22.4 17.6 29.89 17.62

Table 4: Comparison of cost constrains for various cases

Economic Constrains Case-1 Case-2 Case-3 Case-4

Net Present value [$] 106,303 103,235 91,737 63,377

LCOE [$/kWh] 0.203 0.113 0.113 0.091

Operating cost [$/year] 7,364 8,394 4,551 2,731


5 Conclusion

An acceptable amount of power generation in a sustainable way is an important

issue for rapidly increasing population and economic development in the low-income

and developing countries. Renewable energy can play an effective role to meet energy

demand. Since it is an agrarian country, biomass is one of the potential renewable

energy sources in Bangladesh. Agricultural crop residues, residual waste, woods, and

animal manure are the major sources of biomass energy in the remote areas country.

In this paper has determined the potential of biomass that operates various ranges

of generator fueled by the available local biomass, focuses the optimal design and

compare different feasible configuration that complies the local biomass potential.

The studies also determine the opportunism of other sources including solar PV and

wind energy, and the renewable integrated system would be the ultimate solution for

the electricity access into the rural community. The investigation also focuses the

break-even point of grid connected system, technical and economic feasibility of the

proposed standalone DC-MG configuration care case -2 and case-3. If grid connected

is available, then (case-4) is the most economically promising solution. In addition,

SHS also illustrate in this paper which also one of the emerging technology in

Bangladesh. The social context in Bangladesh stimulate house-owns SHSs, the excess

electricity can be stored in the community based battery storage, and shares among

other end-users. The SSHs are the prosumers, end users and productive loads are

consumers in the DC-MG system.

It is to be noted renewable mix more need to study as a consequence of higher

investment costs and replacement costs. The government of Bangladesh may

introduce the feed-in tariffs to encourage more renewable penetration for present and

future electricity demand, and significant role in the renewable integration. Finally, 10

kW biomass-fueled generator, 20 SHS, and 2 SWT is the optimal solution for the 50

households and other community based productive usable load. .

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