An innovative approach for access to electricity

1. Renewable Energy Integrated Microgrid for
Rural Electrification and Productive use
Muhammad Taheruzzaman
BTU-Brandenburg Technical University Cottbus
taher.tum@gmail.com
adfa, p. 1, 2011.
Renewable Energy Integrated Microgrid for Rural
Electrification and Productive use
Muhammad Taheruzzaman
BTU-Brandenburg Technical University Cottbus
taher.tum@gmail.com
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. Kr´atk´y, J. Dvorsk´y, P. Moravec (Eds.): WOFEX 2016, pp. 549–556.
VˇSB – Technical University of Ostrava, FEECS, 2016, ISBN 978-80-248-3961-5.

2. 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

3. 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

4. 552 Muhammad Taheruzzaman
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/.

5. Renewable Energy Integrated Microgrid. . . 553
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.

6. 554 Muhammad Taheruzzaman
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

7. Renewable Energy Integrated Microgrid. . . 555
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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