Content uploaded by Gholamreza Zahedi
Author content
All content in this area was uploaded by Gholamreza Zahedi on Apr 07, 2015
Content may be subject to copyright.
1 23
Arabian Journal for Science and
Engineering
ISSN 1319-8025
Volume 38
Number 2
Arab J Sci Eng (2013) 38:317-328
DOI 10.1007/s13369-012-0436-6
A Review on the Drawbacks of Renewable
Energy as a Promising Energy Source of the
Future
Abbas Azarpour, Suardi Suhaimi,
Gholamreza Zahedi & Alireza Bahadori
1 23
Your article is protected by copyright and
all rights are held exclusively by King Fahd
University of Petroleum and Minerals. This
e-offprint is for personal use only and shall
not be self-archived in electronic repositories.
If you wish to self-archive your work, please
use the accepted author’s version for posting
to your own website or your institution’s
repository. You may further deposit the
accepted author’s version on a funder’s
repository at a funder’s request, provided it is
not made publicly available until 12 months
after publication.
Arab J Sci Eng (2013) 38:317–328
DOI 10.1007/s13369-012-0436-6
RESEARCH ARTICLE - SPECIAL ISSUE - MECHANICAL ENGINEERING
A Review on the Drawbacks of Renewable Energy as a Promising
Energy Source of the Future
Abbas Azarpour ·Suardi Suhaimi ·
Gholamreza Zahedi ·Alireza Bahadori
Received: 11 March 2012 / Accepted: 25 June 2012 / Published online: 5 December 2012
© King Fahd University of Petroleum and Minerals 2012
Abstract A common misconception of renewable energy
(RE) is that it could serve as a holistic solution to the prob-
lems associated with the disreputable but yet reliable fossil
fuel and nuclear energy. Energy supply and related environ-
mental problems, especially global warming could be suc-
cessfully addressed just by switching from the conventional
fossil fuel and nuclear energy to purportedly environmen-
tal friendly and sustainable renewable sources. But this cre-
dence is proved to be a fallacy as RE sources could not meet
the demand of energy that is growing globally without pos-
ing certain associated problems to human and the environ-
ment. RE supply from domestic wind, hydroelectric dam,
solar energy, ground-source heat, and biomass waste was
proven to be incapable of meeting energy demand. The scale
of demand for these resources combined would be highly
colossal and there are bound to be problems in integrat-
ing massive amounts of intermittent RE into existing sup-
ply systems. This paper will discuss problems-related RE
(biomass sources, wind, solar, hydropower and geothermal
energy combined) from engineering, environment, health and
economy perspective.
Keywords Renewable energy ·Wind ·Geothermal ·
Solar ·Biomass ·Source
A. Azarpour ·S. Suhaimi ·G. Zahedi (B
)
Process Systems Engineering Centre (PROSPECT), Faculty
of Chemical and Engineering, Universiti Teknologi Malaysia,
UTM Skudai, 81310 Johor Bahru, Johor, Malaysia
e-mail: grzahedi@cheme.utm.my; grzahedi@yahoo.com
A. Bahadori
School of Environment, Science and Engineering,
Southern Cross University, Lismore, NSW, Australia
1 Introduction
Energy is the exchangeable prevalence of technology. When
populations increase at a rate higher than the average 2 %,
the necessity for more energy should be considered. Change
in lifestyle along with wealthy industrialized economies has
contributed to an inevitable increase in global energy demand
[1]. With projected energy demand of 1,000 EJ by 2050,
world energy crisis is imminent if current trend of energy
usage persists [2]. Dependencies on non-renewable energy
(non-RE) sources which include nuclear, fossil fuels and
coal would further accelerate the rate at which these non-
RE sources deplete due to the inevitable increase in global
energy demand. Apart from depletion, other problems asso-
ciated with the aforementioned non-RE sources are related
123
Author's personal copy
318 Arab J Sci Eng (2013) 38:317–328
to environmental concerns like air pollution, acid precipita-
tion, global warming, ozone depletion, forest destruction, and
radioactive substances emission. The growth of world popu-
lation leads a corresponding increase in energy needs. World
population reaching 7 billion people is a major achievement.
Since 1968, the population of our world has doubled. How-
ever, despite major declines in the average number of chil-
dren per women, population growth is projected to continue
at least until the middle of the 21st century. Nearly all of this
population growth will occur in less-developed countries and
in countries that already face major difficulties in meeting the
basic needs of their citizens [3].
One remedy to the forthcoming energy scarcity and depen-
dency on the depleting non-renewable energy sources is to
increase the utilization of renewable energy (RE) sources.
The concept of renewable energy was introduced to address
this issue and it was unanimously accepted as suitable solu-
tion. Renewable energy could be defined as the energy that
could be derived from renewable sources; thus, the problem
of depletion as in the case of fossil fuel is all but artifact. Apart
from its renewability, another compelling aspect of renew-
able energy is its green nature as it would not produce green-
house gases which are the major setback of fossil fuel. This
article discusses all types RE sources beginning with their
respective advantages as well as disadvantages. The main
concentration of this study is to present the drawbacks of the
renewable energy sources which are regarded as a solution to
the increasing demand of the world energy. The view of not
relying on the RE sources has been scarcely focused in the
literature, especially in one collection of investigations. Here-
after, the renewable energy is described generally following
their advantages and, more importantly for this survey, their
drawbacks.
1.1 Renewable Energy
All energy stocks on Earth originate from the sun in the form
of solar energy which is completely sustainable, and it could
be transformed into other forms of useful energy. There are
many factors that should be considered to achieve sustain-
able development in energy supply, with the renewability
of the energy resources ranked first in priority. Other fac-
tors include impacts to environment, health and economics
viability [4–6].
During the past two decades, environmental deterioration
have become more apparent, where most of the impending
problems are related to the current sources of energy. The
major areas of environmental impacts may be categorized as
follows.
–Major environmental accidents
–Water pollution
–Land use and siting impact
–Radiation and radioactivity
–Solid waste disposal
–Hazardous air pollutants
–Ambient air quality
–Acid rain
–Stratospheric ozone depletion, and
–Global climate change (greenhouse effect).
Table 1gives information on the renewable energy tech-
nologies as a combination of several old views like hydro-
power, geothermal, and biomass and new technologies such
as solar and ocean thermal [7].
In the literatures, many advantages have been mentioned
regarding the renewable energies. Some of them have been
notified here to present an overview of the benefits of renew-
able energies.
1.1.1 Wind Energy
Wind is created when the earth’s equatorial regions get more
solar energy than the polar regions forming large-scale con-
vection streams in the atmosphere. Meteorologists predict
that about 1 % of the received solar radiation is turned to wind
energy due to considerable temperature gradient that could
result in substantial convection and thus wind. Considering
the energy content of solar energy radiation within just
10 days is equivalent to the world’s whole fossil fuel stocks,
Table 1 Maturity of renewable energy technologies
Proven capability (Hydropower) Transition phase (Wind) Future potential (Advanced Turbine)
Geothermal Hydrothermal Hydrothermal Hot dry rock Geo-pressure magma
Biomass Direct combustion gasification
Biofuels Ethanol from corn municipal wastes Methane
Passive solar Buildings
Active solar Buildings process heat
Solar thermal Thermal/gas hybrid Advanced electricity high-temperature process
Photovoltaics Small remote specialty products Remote power diesel hybrid Utility power
Ocean thermal
123
Author's personal copy
Arab J Sci Eng (2013) 38:317–328 319
Fig. 1 AwindfarminManjilofIran
the potential of tapping wind energy which accounts for one
percent of the total solar radiation is significant [8]. Wind
generation is growing significantly as a choice of technol-
ogy for new capacity supplements in power systems world-
wide [9–11]. Recently, a survey has been done to predict the
medium monthly wind speed at a couple of areas in Saudi
Arabia by employing Abductory Induction Mechanism to
establish a wind-speed map over the whole country [12].
Another study has been carried out in Algeria to evaluate
the reduction of CO2emission into the atmosphere by the
development of a wind farm [13]. The review of McVicar
et al. indicates that earthly observed near surface wind veloc-
ity is extensive across the globe and the rate of evaporative
demand is declining. In addition, they suggest that evalua-
tion of evaporative demand trends needs involvement of wind
speed, atmospheric humidity, radiation, and air temperature
[14]. There are some investigation which discuss on wind-
speed analysis and optimization of wind-energy yield [15–
17]. Figure 1depicts a wind farm located in Manjil of Iran,
a region that is famous for its windy microclimate.
Wind energy has many advantages like low cost, cleanli-
ness, and abundance. Unlike coal or petroleum that produces
harmful gases such as CO, CO2,NO
xand SOx, renewable
energies are clean, cost-free and abundant. There is no trans-
portation problem and no requirement for a high technology
to tap the wind energy. The technology of changing wind
energy to mechanical and electrical energy is more econom-
ical in comparison with other energy conversion systems.
Thus, at the areas having sufficient wind densities, huge eco-
nomic benefits can be gained by setting up wind energy con-
version systems (WECS) [18,19].
1.1.2 Hydropower Energy
Hydropower provides 20 % of the world’s power generation.
As a matter of fact, it allocates the most important supply
of 55 countries. For many countries, hydropower is the only
homely energy resource. The current role of hydropower in
electricity generation is considerably greater than any other
renewable energy technology, especially in the less-devel-
oped countries. It is limited to the places where water is avail-
able and there is proper geomorphology. The flexibility of
hydropower and its reliable technology distinguishes it from
other renewable energy sources [20,21]. Since hydropower
does not utilize or contaminate the water to produce power,
disruption in clean water supply is less. Simultaneously, the
revenues attained by electricity sales can be invested to pro-
vide other essential amenities for human well-being. This
might consist of potable water supply systems, irrigation
plans for food production, establishments boosting naviga-
tion, recreational facilities and ecotourism [22–24].
1.1.3 Solar Energy
Solar energy is another clean resource which does not bring
any direct negative effect to the environment. The abundant
solar energy is frequently called “alternative energy” to fos-
sil fuel energy sources such as oil and coal. The depletion of
fossil fuels has caused global concern in shifting toward the
utilization of solar energy [25–27]. Although it is currently
the most expensive type of renewable energies that embodies
only a minor portion of global energy demands (5 % of the
total chief energy supply), solar power is a type of energy
with great future potential. In some regions of the earth, it
might be regarded as today’s best solution for a decentral-
ized energy supply [28,29]. In assessing the global potential
of solar energy, a study to estimate of global solar radiation
based on measurement from 52 cities of 11 different countries
has been conducted and it was concluded with an improved
model that could sufficiently estimate solar radiation with
better accuracy [30]. In accordance with the 2010 BP Sta-
tistical Energy Survey, the world aggregate installed solar
energy capacity was 22,928.9 MW implying an improvement
of 46.9 % in comparison with 2008 [31]. In addition, various
studies indicate that solar energy may become a likely energy
of the future [30,32–42].
An improved model has been developed to predict the
contribution of solar energy to the future energy needs [30].
Using this model, it has been predicted that solar energy
could provide significant amount of energy especially in the
regions with high solar radiation throughout the year [40,41].
1.1.4 Biomass Energy
Biomass is getting more attention as a clean alternative
source of energy to fossil fuel due to an appreciable increase
in energy demand, increase in fossil fuels’ price and dimin-
ishing supply and associated environmental concerns,espe-
cially, the greenhouse effect [43–45]. Several bioenergy pol-
icies like the Brazilian Biofuel Law, the Indian Biofuel
Policy, the US Renewable Fuel Standard, and European
123
Author's personal copy
320 Arab J Sci Eng (2013) 38:317–328
policies such as the Renewable Energy Directive, Strategy
on Biofuels and the Biomass Action Plans motivate the
use of biomass to decrease fossil fuel reliance and to ful-
fill the greenhouse gas reduction strategies. These policies
were developed as guidelines to ensure the sustainability of
large-scale bioenergy crop production. Main negative effects
include the direct and indirect land-use change [46–49] and
biodiversity loss [50,51], water supply availability [52–54],
increasing agricultural products cost and risks of food secu-
rity [55–59]. These threats have to be evaluated against likely
advantages like boosted greenhouse gas balance, business
and earnings generation, agricultural evolution, conversion
of prevailing industries and enhanced security of energy
resources [60,61].
Biofuels encompass an extensive range of fuels which
originate from biomass. The term includes solid biomass, liq-
uid fuels and various biogases. The first-generation biofuels
are made from the sugars and vegetable oils found in arable
crops, which can be easily extracted using conventional tech-
nology. In comparison, the second-generation biofuels are
made from lignocellulosic biomass or woody crops, agricul-
tural residues or waste, which makes it harder to extract the
required fuel. Currently, there are at least five different forms
of biofuels: (1) bioethanol produced from starch-rich crops
like sugarcane, wheat, cassava, sorghum and maize; (2) bio-
diesel produced from oil-rich seeds such as soya, oil palm and
jatropha; (3) biogas generated from the biological disintegra-
tion of organic matter such as animal or human wastes and
other biomass; (4) biomethanol produced from cellulosic;
(5) biohydrogen produced from biomass or by synthesis of
methane by steam reforming [62]. By the improvement of
the technology, cellulosic biomass like trees and grasses are
also employed as feedstocks for ethanol production. Etha-
nol can be utilized as a fuel for vehicles in its pure form,
but it is commonly employed as a gasoline additive to boost
octane and improve vehicle emissions. Bioethanol is broadly
utilized in the USA and Brazil.
Pure biodiesel, also known as B100, can also be used as
a fuel for vehicles, but it is usually utilized as a diesel addi-
tive to decrease the levels of particulates, carbon monoxide,
and hydrocarbons from diesel-powered vehicles. The use of
biodiesel is the most common biofuel in Europe. Biofuels
supplied 2.7 % of the world’s transport fuel in 2010 [63].
Extensive studies in the literature show that ethanol could be
produced from different raw materials. Table 2provides an
overview of the global long-term bioenergy supply potential
by source [64].
1.1.5 Geothermal Energy
Geothermal energy is thermal energy produced and stored
below the surface of the Earth. The source of this type of
energy is related to the internal structure of the Earth and
the associated physical phenomena. The main problem with
geothermal energy is that it is erratically spread, scarcely
concentrated, and, generally, at depths very far to be indus-
trially exploited. Earth’s geothermal energy is derived from
the original formation of the planet (20 %) and from radio-
active decay of minerals (80 %) [65]. The geothermal gra-
dient, which is the difference in temperature between the
core of the Earth and its surface, creates a continuous con-
duction of thermal energy in the form of heat from the
core to the surface. It can be felt since the temperature of
rocks improves with depth, verifying that a geothermal gra-
dient exists and its average value is 30 ◦C/km of depth
[66]. Geothermal energy has been tapped since the era of
ancient Rome, especially in the public bath, but it is now
well known for electricity generation. Direct geothermal for
heating is also growing rapidly. Geothermal power is cost
effective, reliable, sustainable, and environmentally friendly
[67].
While it is true that geothermal wells emit greenhouse
gases that stuck deep within the earth, these emissions are
much less than those of fossil fuels. Consequently, geother-
mal power has the potential to help relieve global warming
providing broadly distributed in place of fossil fuels. The
United States is pioneer in the world in geothermal electric-
ity production with 3,086 MW of installed capacity from 77
power plants in 2010 [68]. The Table 3illustrates the renew-
able energies from 2004 to 2010 [69–71].
2 Disadvantages of RE
Unfortunately, the drawbacks of this supposedly promising
energy are often overlooked to the extent that renewable
energy is unanimously viewed as an ideal solution to replace
the depleting non-renewable energy sources of today. The
first major concern is the capability of RE to meet the grow-
ing demand of energy. Based on the current trend of energy
demand and supply, fossil fuel is still the major source of
energy with more than 80 % contribution to global demand
[1]. This indicates how dominant fossil fuel is due to its reli-
ability compared to RE. Moreover, there are uncertainties
with RE and extensive ongoing research and the improve-
ment of the feasibility of changing from fossil fuel to RE are
still at the preliminary stage. With only less than 20 % input,
the potential of RE to become a major source of energy for
tomorrow still remains in doubt.
RE sources are vulnerable to climate change due to its
inherent nature [2]. A shift in global climate would inevi-
tably affect RE to some extent. For instance, long drought
season would affect stream level, hence, flow and ultimately
the available energy for the generator in hydroelectric dam to
convert to electricity. The same circumstance could also be
expected in the case of wind energy as climate change would
123
Author's personal copy
Arab J Sci Eng (2013) 38:317–328 321
Table 2 Global long-term bioenergy supply potential by source, 2050 [64]
Biomass category Bioenergy potential, 2050 (EJ) Main assumptions and remarks
Agriculture residue 15–70 Relied on predictions from various studies. Potential counts on yield/product
ratios and the total agricultural land area as well as type of production
system: large production systems need reutilization of residues for keeping
soil fertility. Comprehensive systems enable higher utilization rates of
residues
Forest residues 30–150 (or possibly 0) Amounts incorporate processing residues. Part is natural forest (reserves).
The sustainable energy potential of the world’s forests is unclear. Low
estimates based on sustainable forest management; high value reflects
technical potential
Organic wastes 0–50 +aBased on estimates from various studies. Include the organic fraction of
MSW and waste wood. Strongly dependent on economic development,
consumption and the use of biomaterials. Higher values possible by more
intensive use of biomaterials
Animal dung 5–55 (or possibly 0) Use of dried dung. Low estimate relied on global current utilization; high
estimate demonstrates technical potential. Use (collection) in longer term is
uncertain
Energy farming (on
current agricultural
land)
0–700 (100–300 is more
average)
Likely land availability: 0–4 Gha, although 1–2 is more average. Relied on
productivity of 8–12 dry tonne/ha/yearb(higher yields are feasible with
better soil quality). If transformation of thorough agriculture production
systems is not likely, bioenergy stock could be decreased to zero
Energy farming
(on marginal lands)
60–150 (or possibly 0) Potential maximum land area of 1.7Gha. Low productivity of
2–5 dry tonne/ha/yearb. Bioenergy supply could be low or zero due to poor
economics or competition with food production
Biomaterials Minus 40–150 (or
possibly 0)
These provide an additional claim on biomass supplies. Land area required to
meet additional global demand is 0.2–0.8Gha. Average productivity: 5 dry
tonnes/ha/yearb. Supply would come from energy farming if forests are
unable to meet projected demand
Total 40–1100 (250-500 is
more average)
Pessimistic scenario assumes no land available for energy farming, only
utilization of residues; optimistic scenario assumes intensive agriculture on
better-quality soils. More average potential: more likely in a world aiming
for large-scale utilization of bioenergy
EJ exajoules (1018 J), Gha billion hectares
aThe energy supply of biomaterials ending up as waste varies between 20 and 55 EJ (1,100–2,900 Mtonne) dry matter per year (biomass lost during
conversion, such as charcoal, is logically excluded from this range). This range excludes cascading and does not take into account the time delay
between production of the material and release as (organic) waste
bHeating value: 19 GJ/tonne dry matter
Table 3 Selected renewable energy indicators
Selected global indicators 2004 2005 2006 2007 2008 2009 2010a
Investment in new renewable capacity (annual) 30 38 63 104 130 160 211 billion USD
Existing renewable power capacity, including large-scale hydro 895 930 1,020 1,070 1,140 1,230 1,320 GWe
Existing renewable power capacity, excluding large hydro 200 250 312 GWe
Hydropower capacity (existing) 950 980 1,010 GWe
Wind power capacity (existing) 48 59 74 94 121 159 198 GWe
Solar PV capacity (grid-connected) 7.616 2340GWe
Solar cell production (annual) 6.91124GWe
Solar hot-water capacity (existing) 77 88 105 120 130 160 185 GWth
Ethanol production (annual) 30.5 33 39 50 67 76 85 billion liters
Biodiesel production (annual) 12 17 19 billion liters
Countries with policy targets for renewable energy use 45 49 68 79 89 98
GWe Gigawatt of electric energy, GWth Gigawatt thermal
aInvestment in new renewable capacity for 2011 was 260 billion USD
123
Author's personal copy
322 Arab J Sci Eng (2013) 38:317–328
Table 4 Disadvantages of renewable energy from different sources
RE source Disadvantages References
Hydro Loss of home and source of income for local inhabitants; possible extinction of freshwater
aquatic biota; risk of dam structure failure; disruption in natural river flow; decrease in
land fertility due to reduction in sediment deposition; risk of flood; decomposition of
immersed biomass would result in emission of greenhouse gasses
[73–77]
Wind Threat to birds and bats; disturbance resulting from vibration of the moving mechanical
parts; potential change in global climate; potential habitat loss
[73,78–83]
Biomass Produce yield will be affected by biomass crop; loss of biodiversity; elimination of current
biomass waste uses
[76,84,85]
Solar Photovoltaic cell production requires the use of toxic heavy-metals and rare earth minerals;
imbalance in the ecosystem of the affected area; not evenly distributed as only certain area
will experience certain level of solar radiation throughout the year
[39,73,81,86,87]
Geothermal Could induce micro-seismicity and land subsidence; could cause water and air pollution [73,88,89]
also has a significant impact on wind pattern and, thus, the
availability and opportunity to utilize this resource.
Another setback of RE is its distribution. Distribution of
RE sources is not uniform across geographical borders across
the globe. For instance, approximately half of world winds
energy available in just five countries with total population
of less than 10 % of global population (Argentina, Canada,
USA, Russia and Australia) [72]. If the energy harnessed
from these countries is not redistributed to energy-deficient
region, imbalance of energy supply per capita would be inev-
itable. But, redistribution might also pose another potential
problem which is loss of energy output when energy is dis-
tributed either via gridlines or through conversion to another
form of energy (e.g., chemical). The drawbacks of RE is
summarized in Table 4.
2.1 Hydropower Energy
Hydropower energy seems a very promising renewable
power source. The idea of harnessing the energy of the flow-
ing streams might seem so simple that its implications to
the environment and inhabitants are often overlooked, i.e.,
the social and environmental impact assessment is not thor-
oughly implemented [90,91]. It is shocking to reveal that
over the past 50 years, approximately 8 millions of people
have been displaced to make way for the construction of 300
hydroelectric dams. This trend is unlikely to change, because
recent studies reported that each year, an average of 4 million
people would loose their home; hence, livelihood as invest-
ment in this type of RE continues to grow [92].
In terms of impacts to environment, hydropower dam is
also known to cause several problems which include defores-
tation, change in water quality and hydrology, greenhouse gas
emission and derived impacts from dam construction activ-
ities [93]. Deforestation is necessary to make way for dam
construction, at the expense of the flora and fauna as well as
the livelihood of local people. For example, the Bakun hydro-
electric dam has seen 1.57 million hectares of forest cleared
affecting 44 species of protected birds, mammals and fishes
along with over 1,600 species of protected plants [94].
Related construction activities, especially, aluminum
smelting and improper drainage system are other major con-
cerns as inadequate management of these activities would
result in problems that could otherwise be avoided. Gener-
ated waste from aluminum smelting would result in the con-
tamination of stream by the leachate, while nearby areas are
at a high risk of flooding due to poor drainage system [77].
The natural flow of the rivers will also be negatively
affected as the sediments that are naturally carried by the
flow would be impeded by the dam impoundment resulting
in the accumulation of sediments, and eventually, the area
just upstream of the impoundment would become shallow.
This would require heavy maintenance to remove the sed-
iment’s deposit. The water at the downstream of the dam
would also become pristine clear indicating the lack of sedi-
ments that might also be the source of nutrient for the biota
[92]. This would expose important plant species just down-
stream of the dam to the risk of elimination, thus, altering the
ecology of the river. Several species of valuable fish native
to the constructed dam are known to migrate upstream from
estuaries during the spawning season. The dam structure will
also impede the migration of certain valuable or endangered
species of fish, exposing them to the risk of extinction [92].
Disruption of river flow would also carry another potential
catastrophic environmental problem; disappearance of Aral
Sea which could be described as the planet’s worst disaster
in history is perhaps the best example [95]. Figure 2shows
the diminishing Aral Sea from 1977 to 2006.
Without a careful planning and impact assessment to
the environment in hydroelectric dam construction, it is not
impossible that the same tragedy would occur again.
The failure of dam structures is the worst-case scenario as
it would just affect not only the biota but also the local inhab-
itants living nearby. Banqiao and Shimantan dam failure in
1975 was perhaps the worst case of such incidence causing
123
Author's personal copy
Arab J Sci Eng (2013) 38:317–328 323
Fig. 2 The diminishing Aral
Sea due to the diversion of Amu
Darya and Syr Darya rivers by
Soviet Union in the 1960s
more than 2,600 deaths and the destruction of 5.24 million
houses together with 1.13 million hectares of farmland [96].
Greenhouse gas emission that is frequently associated
with the agents of air pollution is surprisingly another prob-
lem that could arise from hydroelectric dam. Although it
seems quite perplexing, the biomass carried by the river
flow would become impeded and accumulated overtime. The
decomposition of these biomasses via microbial activities
would result in the emission of methane, carbon dioxide
and nitrous oxide with total estimated carbon emission of
10.1 million tons [93].
2.2 Biomass Energy
Biomass energy has been touted as an environmental-friendly
energy source as it produces a much lower emission that
could be detrimental to the environment. Low input energy
required would also increase its feasibility in terms of eco-
nomic viability. However, it can only provide just a fraction
of global energy needs due to the availability of the feed,
i.e., biomass [84]; beyond this, there are concerns about the
impacts of using land to grow energy crops as there is a pos-
sibility of competition between energy crop and food crop
[84,85]. How serious these impacts are will depend on how
carefully the resource is managed. The circumstance is fur-
ther complicated as there is no single biomass technology, but
rather a wide variety of production and conversion methods,
each with different environmental impacts. Furthermore, the
combustion of biomass could possibly produce air pollutants,
especially, in the form of nitrogen oxides (NOx), and partic-
ulates such as soot and ash at a larger magnitude than fossil
fuel [97].
2.3 Wind Energy
Wind energy requires substantial amount of land to install
related facilities particularly the wind turbine, thus it suf-
fers from practicality issues. The source of the energy, i.e.,
the wind could be described as intermittent would further
add to the sensibility of resorting to this type of energy.
For example, during a windy day, wind turbines could gen-
erate substantial amount of energy supply to meet energy
demand. However, during a still day, perhaps not even a sin-
gle watt could be produced. Storage could be an option as a
contingency whenever the turbines are producing more than
enough energy but it suffers from reliability and efficiency
issues.
Global climate change may also become another concern
as it would affect wing pattern in the long run. It has been
projected that China would experience about 14 % reduc-
tion in wind power within the next century as a result of
decreasing temperature gradient between the polar and the
lower-altitude regions [98]. Similar trend could be expected
in countries encompassed in the aforementioned region.
Installation of wind turbines requires a considerable use of
land, thus its impact to the environment should be thoroughly
assessed. For instance, if the area where the turbines would
be installed is a habitat to certain flora and fauna, the potential
habitat loss is should not be overlooked [78]. In addition, if
it is built in the vicinity of human settlement, the residents
would have to tolerate the noise and vibration resulting from
the movement of turbines’ mechanical parts [79]. Offshore
wind turbine may also pose potential adverse effects on sea
aquatic biota. There have been also some claims that large-
scale use of wind power can affect the pattern of wind flow
123
Author's personal copy
324 Arab J Sci Eng (2013) 38:317–328
to the extent that the weather pattern would be significantly
affected [99,100].
2.4 Solar Energy
Utilization of solar photovoltaic (PV) cells might seem an
interesting idea to tap the free energy from solar radiation as
the radiation is abundantly available at zero cost. However,
PV cells suffer from low efficiency and much of the energy
from solar radiation would be wasted as heat. Until 2010,
solar energy contributes to about 40 GW of power in terms
of electricity supply, a volume that is still considered as neg-
ligible relative to other sources of energy [101,102]. There
is also associated cost in the manufacturing of PV cells that
contributes to its considerably prohibitive price tag [103].
This would render the utilization of solar energy as unjusti-
fiable, especially in developing countries with a much lower
GDP per capita, hence, lower purchasing power.
There are other potential problems associated with solar
energy which is health hazard. Solar-energy panels or photo-
voltaic-cell fabrication uses chemicals that are potentially
harmful to human health, thus raising concerns about its
application. Chemicals with known risk to human health such
as germanium and cadmium are frequently used in the fabri-
cation of solar panels. Safe manufacturing methods and dis-
posal should be addressed by introducing certain standards.
Current photocatalysts that are produced from conven-
tional semiconductors are subjected to poor efficiency and
stability rendering their applications limited. Si, Ga, As and
Cd are among the semiconductors that are in use and fre-
quently associated with limited electrochemical stability.
Photons with energy lower than the band gap of such mate-
rials would cause temperature increase instead of electrons
liberation [87]. Heating of solar cells by low-energy photons
would negatively affect its performance to produce electric-
ity.
Efficiency is another major disadvantage of solar energy.
Storage of energy tapped by the solar panels also requires the
conversion of solar energy into some other forms of energy,
e.g., electrical, thermal or chemical. This would lead to a
drop in the amount of usable energy as conversion of energy
from one form to another heavily depends on the conversion
efficiency.
It was also reported that, in some solar energy power dis-
tribution, the net energy produced is negative, indicating that
energy is required in a much larger magnitude in distribut-
ing the energy [104]. Recycling of solar panels after it has
completed its shelf life requires energy as well [105].
In terms of availability, solar radiation which is the source
of solar power relies heavily on geographical location, dura-
tion of daylight, season, as well as local landscape and
weather [39,106]. Solar radiation can be classified as either
the direct or diffuse radiation. Not all the energy from the
sun beam that passed through the atmosphere will reach the
earth surface as some of it will be reflected, absorbed and
scattered by clouds, water vapor, air molecules, dust, smoke
from forest fires and volcanoes as well as air pollutants. This
type of radiation is termed as the diffuse radiation where the
reduction in radiation could vary from as little as 10–100 %
depending on the presence and level of the aforementioned
agents [106]. Direct radiation, on the other hand, refers to the
radiation that strikes the surface of the earth at perpendicular
or almost perpendicular angle with respect to the surface of
the Earth without being diffused. These factors would inev-
itably lead to variability in solar-radiation availability.
Most of the studies conducted to assess the feasibility
of solar energy were performed in the area near the tropics
that experienced virtually constant and direct solar radiation
throughout the year. The region includes countries of the
earth which includes India, Saudi Arabia, Malaysia, Thailand
and so on [42]. The observations from these regions tend to
overestimate the actual potential of solar energy as in some
other regions where direct solar radiation is rare. In the area
that receives low amount of solar radiation, or the diffuse
solar radiation, the use of solar panel to harness this so-called
free energy would be highly impractical, for example, at the
north and south poles and the nearby regions during the win-
ter where little or no solar radiation is available. In addition,
solar radiation also depends on the cycle and duration of day
and night. During the short duration of daylight in winter,
solar panels will produce less electricity as it would dur-
ing the summer. Energy storage would be a sensible option
but energy loss is inevitable whenever one form of energy
is transformed to another form. Moreover, energy storage
would also require some extent of energy inputs during its
fabrication, e.g., rechargeable batteries. However, the hybrid
energy-generating systems such as wind–diesel, pv–diesel,
wind–pv–diesel reveal more trustworthiness and lower cost
of generation than those that use only one source of energy,
they are still costly and strongly dependent on the renew-
able energy potential [32,107–110]. The feasibility of using
solar PV–diesel–battery hybrid system has been tested and
observed that there was an increase in the cost of energy by
as much as 15.3 % compared to a system employing die-
sel fuel alone. In addition, to be able to effectively capture
the solar energy, a large amount of necessary materials, i.e.,
the solar panels, is required. This would translate into much
a corresponding increase in cost as well as requirement for
available space where the panel should be installed [32]. Fur-
thermore, the utilization of batteries as convenient electrical
power source has enhanced and technology has not been able
to satisfy the needs. If renewable energy is to become a major
source power, immense electricity storage is the vital tech-
nology which is to be paid much attention. Energy-storage
systems (EES) cost embodies about 30 % of the total renew-
able power-supply system cost. Furthermore, the batteries are
123
Author's personal copy
Arab J Sci Eng (2013) 38:317–328 325
very vulnerable to some parameters such as temperature, rel-
ative humidity, barometric pressure, and wind speed [111].
These factors need to be considered thoroughly to ensure
that the actual potential of solar energy would not be overes-
timated.
2.5 Geothermal Energy
While the idea of harnessing geothermal energy is interest-
ing, the impact of implementing this idea to the environment
should not be overlooked. Scenic places that would otherwise
be reserved as recreational parks would have to make way
for plant construction. This would inevitably invite unwel-
coming responses from they society.
The risk of land subsidence is another matter that demands
a scrutinized investigation prior to the construction of the
plant [73]. In the event of landslide or subsidence, the con-
structed plant, human operators and local inhabitants would
be in jeopardy.
Change in micro-seismicity should not also be overlooked.
Enhanced geothermal system (EGS) has been shown to
induce micro-seismicity to a certain magnitude [89]. Even
though its effects are not that significant as currently pro-
jected, there is a growing concern on how would this induced
micro-seismicity influences the environment in future. Any
substantial increase in the magnitude of micro-seismicity
may cause certain level of discomfort, particularly, to local
inhabitants or in the worst case scenario, an induced earth-
quake.
3 Conclusions
It is absolutely understood that we need to substitute our
current reliance of fossil fuels before we encounter some
interrelated incidents which results in global tragedy of a
measure that has never been experienced in human history.
However, the disadvantages of renewable energy sources
such as intermittent nature of wind energy, high cost and
intermittent nature of solar energy, low potential of tidal
energy and catastrophic risk of hydropower and nuclear ener-
gies imply this attitude that they might not be a sufficient
substitution to non-renewable energies.
Based on the current findings, RE sources are incapable to
provide adequate energy to sustain the gradually increasing
global energy needs while minimizing the effects to the health
and environment. The preproduction expenditure to estab-
lish a renewable energy project is greatly huge, much more
than the conventional power resource. The cost-competitive-
ness of renewable energy sources, in spite of the momen-
tous progress in renewable energy technologies in the last
couple of years, still continues to exist as one of the big-
gest drawbacks of renewable energy. The geography plays
a great role while locating renewable power facilities. For
example, many places do not have enough steady wind to
bear a wind-farm installation, and geothermal-energy plants
are only feasible in specific locations where the geography
is proper. Renewable energy is still not very efficient with
its conversion process. For instance, the efficiency of solar
converters which change sun photons into electrical current
is about 15 %. Recently, the use of nuclear power has been
considered as one of the proper substitutions of non-RE. But,
during the last 30 years, three nuclear accidents happened in
Russia, the USA and Japan. The panic of experiencing such
a terrible event is so huge that regardless of the all safety
preparations peddled by the nuclear-equipment operators and
suppliers, nuclear energy comes up against an unpredictable
future. How would RE affect the society and environment at
large should be thoroughly examined before it can be imple-
mented locally and globally. Previous surveys and studies
have revealed that not everything is green and sustainable
with RE as it would compromise both the society and envi-
ronment well-being to a certain extent. Although the pros-
pect of using RE is very appealing, these tradeoffs should
be resolved to realize its full potential as the most potent
alternative to current world dependence on the depleting and
problematic fossil fuel. As a final word, RE is a panacea for
the demand of the energy for the future but a more reliable
solution should be looked for the huge need of energy.
References
1. Fells, I.: The problem. In: Dunderdale, J. (ed.) Energy and the
environment. Royal Society of Chemistry, UK (1990)
2. Moriarty, P.; Honnery, D.: What is the global potential for renew-
able energy? Renew. Sust. Energy Rev. 16, 244–252 (2012)
3. About 7 Billion & Me. http://www.7billionandme.org/about.php
(2012). Accessed 16 June 2012
4. Norton, R.: An overview of a sustainable city strategy. Report
Prepared for the Global Energy Assessment Planning for Cities
and Municipalities, Montreal, Quebec (1991)
5. Rosen, M.A.: The role of energy efficiency in sustainable devel-
opment. Technol. Soc. 15(4), 21–26 (1996)
6. Dincer, I.; Rosen, M.A.: A worldwide perspective on energy,envi-
ronment and sustainable development. Int. J. Energy Res. 22(15)
1305–1321 (1998)
7. Hartley, D.L.: Perspectives on renewable energy and the environ-
ment. In: Tester, J.W.; Wood, D.O.; Ferrari, N.A. (eds.) Energy
and the Environment in the 21st Century. MIT, Massachusetts
(1990)
8. Gourieres, D.L.: Wind Power Plants Theory and Design.
Pergamon Press, Oxford (1982)
9. Billinton, R.; Gao, Y.: Multistate wind energy conversion system
models for adequacy assessment of generating systems incorpo-
rating wind energy. IEEE Trans. Energy Convers. 23(1), 163–170
(2008)
10. Karki, R.; Billinton, R.: Reliability/cost implication of PV and
wind energy utilization in small isolated power systems. IEEE
Trans. Energy Convers. 16(4), 368–373 (2001)
123
Author's personal copy
326 Arab J Sci Eng (2013) 38:317–328
11. Manco, T.; Testa, A.: A Markovian approach to model power
availability of a wind turbine. Power Tech. IEEE Lausanne, pp.
1256–1261. Switzerland, 1–5 July 2007
12. Mohandes, M.; Rehman, A.S.; Rahman S.M.: Spatial estimation
of wind speed. Int. J. Energy Res. 36(4), 545–552 (2012)
13. Himri, Y.; Rehman, S.; Setiawan, A.A.; Himri, S.: Windenergy for
rural areas of Algeria. Renew. Sust. Energy Rev. 16, 2381–2385
(2012)
14. McVicar, T.R.; Roderick, M.L.; Donohue, R.J.; Li, L.T.; Van
Niel, T.G.; Thomas, A.; Grieser, J.; Jhajharia, D.; Himri,
Y.; Mahowald, N.M.; Mescherskaya, A.V.; Kruger, A.C.; Reh-
man, S.; Dinpashoh, Y.: Global review and synthesis of trends
in observed terrestrial near-surface wind speeds: implication for
evaporation. J. Hydrol. 417, 182–205 (2012)
15. Bagiorgas, H.S.; Mihalakakou, G.; Rehman, S.; Al-Hadhrami,
L.M.: Weibull parameters estimation using four different meth-
ods and most energy carrying wind speed analysis. Int. J. Green
Energy 8(5), 529–554 (2011)
16. Mahbub, A.M.; Rehman, S.; Meyer J.; Al-Hadhrami, L.M.:
Review of 600kw to 2500kw sized wind turbines and optimi-
zation of hub height for maximum wind energy yield realization.
Renew. Sust. Energy Rev. 15(1), 3839–3849 (2011)
17. Rehman, S.; Aftab, A.; Al-Hadhrami, L.M.: Development and
economic assessment of a grid connected 20 MW installed capac-
ity wind farm. Renew. Sust. Energy Rev. 15(1), 833–838 (2011)
18. Ackermann, T.: Means to reduce CO2-emissions in the Chinese
electricity system, with special consideration to wind energy.
Renew. Energy 16, 899–903 (1999)
19. Wen, J.; Zheng, Y.; Donghan, F.: A review on reliability assess-
ment for wind power. Renew. Sust. Energy Rev. 13, 2485–2496
(2009)
20. Kaygusuz, K.: Hydropower and world’s energy future. Energy
Sour. 26, 215–224 (2004)
21. Yuksel, I.: Hydroelectric power in developing countries. Energy
Sour. Part B 4, 377–386 (2009)
22. Kaygusuz, K.: Sustainable development of hydropower. Energy
Sources 24, 803–815 (2002)
23. Yuksel, I.: Hydropower for sustainable water and energy devel-
opment. Energy Rev. 14, 462–469 (2010)
24. Hopkinson, P.; James, P.; Sammut, A.: Environmental perfor-
mance evaluation in the water industry of England and Wales.
J. Environ. Plan. Manage. 43(6), 873–895 (2000)
25. Hasnain, S.; Elani, U.: Solar energy education: a viable pathway
for sustainable development. Renew. Energy 14(1–4), 387–392
(1998)
26. Bourdiros, E.L.: Renewable energy sources education and
research as an education for survival. In: Progress in Solar Energy
Education, Borlange, Sweden, vol. 1, pp. 12–16 (1991)
27. Hasnain, S.; Elani, U.; Alawaji, S.; Abaoud, H.; Smiai, M.: Pros-
pects and proposals for solar energy education programs. Appl.
Energy 52, 307–314 (1995)
28. EREC. European Renewable Energy Council: Renewable energy
target for Europe: 20 % by 2020. Brief Paper, Brussel (2005)
29. ESTIF. European Solar Thermal Industry Federation (ESTIF).
Solar thermal markets in Europe, Brussel (2006)
30. Rehman, S.; Halawani, T.O.: Global solar radiation estimation.
Renew. Energy 12(4), 369–385 (1997)
31. Othman, A.; Jakhrani, A.; Abidin, W.; Zen, H.; Baharun, A.:
Malaysian government policy. In: C.o.N.R.a.G. Technology (ed.)
Renewable Energy: Solar PV System, in World Engineering Con-
gress 2010, 2–5 August 2010. (2010) The Federation of Engineer-
ing Institutions of Islamic Countries, Kuching (2010)
32. Rehman, S.; AL-Hadhrami, L.M.: Study of a solar PV–Diesel–
Battery hybrid power system for a remotely located population
near Rafha, Saudi Arabia. Energy 12, 4986–4995 (2010)
33. Mohandes, M.; Rehman, S.: Global solar radiation maps of Saudi
Arabia, J. Energy Power Eng. 4(12), 57–63 (2010)
34. Rehman, S.; Mohandes, M.: Estimation of diffuse fraction of solar
radiation using artificial neural networks. Energy Sour. Part A
31(11), 974–984 (2009)
35. Rehman, S.; Mohandes, M.: Artificial neural network based esti-
mation of global solar radiation using air temperature and relative
humidity. Energy Policy J. 36, 571–576 (2008)
36. Rehman, S.; Bader, M.A.; Moallem, S.A.: Cost of solar energy
generated using PV panels. Renew. Sust. Energy Rev. 11(8),
1843–1857 (2007)
37. Rehman, S.; Shash, A.A.; Al-Amoudi, O.S.B.: Photovoltaic tech-
nology of electricity generation for desert camping. Int. J. Glob.
Energy Issues 26 (2–3), 322 (2006)
38. Al-Ali, A.R.; Rehman, S.; Al-Agili, S.; Al-Omari, M.H.;
AlFayezi, M.: Usage of photovoltaics in automated irrigation sys-
tem. Renew. Energy 23(1), 17–26 (2001)
39. Rehman, S.; Ghori, S.G.: Spatial estimation of global solar
radiation using geostatistics. Renew. Energy 21(3–4), 583–605
(2000)
40. Rehman, S.: Empirical model development and comparison with
existing correlations. Appl. Energy 64(1–4), 369–378 (1999)
41. Rehman, S.: Solar radiation over Saudi Arabia and comparisons
with empirical models. Energy 23(12), 1077–1082 (1998)
42. Rehman, S.; Halawani, T.O.: Development and utilization of solar
energy in Saudi Arabia: review. Arab. J. Sci. Eng. 23(1B), 33–46
(1998)
43. Kersten, S.; Wang, X.; Prins, W.; van Swaaij, W.: Biomass pyro-
lysis in a fluidized reactor. Part 1. Literature review and model
simulations. Ind. Eng. Chem. Res. 44(23), 8773–8785 (2005)
44. Bridgwater, A.; Meier, D.; Radlein, D.: An overview of pyrolysis
of biomass. Org. Geochem. 30(12)1479–1493 (1999)
45. Singh, J.; Gu, S.: Biomass conversion to energy in India—a cri-
tique. Renew. Sust. Energy Rev. 14(5), 1367–1378 (2010)
46. Searchinger, T.; Heimlich, R.; Houghton, R.; Dong, F.;
Elobeid, A.; Fabiosa, J.: Use of U.S. croplands for biofuels
increases greenhouse gases through emissions from land-use
change. Science 319, 1238–1240 (2008)
47. Lapola, D.; Schaldach, R.; Alcamo, J.; Bondeau, A.; Koch, J.;
Koelking, C.: Indirect land-use changes can overcome carbon sav-
ings from biofuels in Brazil. PNAS 107, 3388–3393 (2010)
48. IEA (International Energy Agency): Bioenergy: the impact of
indirect land use change, summary and conclusions from the
workshop on May 12 2009 in Rotterdam, The Netherlands (2009)
49. Schubert, R.; Schellnhuber, H.; Buchmann, N.; Epiney, A.;
Grießhammer, R.; Kulessa, M.: Future bioenergy and sustain-
able land use, report of the Germand Advisory Council on global
change. London, Earthscan (2009)
50. Lee, E.; Elsam, R.: Fuelling the Ecological Crisis: Six Examples
of Habitat Destruction Driven by Biofuels. BirdLife International,
Brussels (2008)
51. Hennenberg, K.; Dragisic, C.; Haye, S.; Hewson, J.; Semroc, B.;
Savy, C.: The power of bioenergy-related standards to protect bio-
diversity. Conserv. Biol. 24, 412–423 (2010)
52. Berndes, G.: Bioenergy and water-the implications of large-scale
bioenergy production for water use and supply. Glob. Environ.
Change. 12, 253–271 (2002)
53. Gerbens-Leenes, P.; Hoekstra, A.; van der Meer, T.: The water
footprint of bioenergy. PNAS 106, 10219–10223 (2009)
54. de Fraiture, C.; Giordano, M.; Liao, Y.: Biofuels and implications
for agricultural water use: blue impacts of green energy. Water
Policy 10, 67–81 (2008)
55. Tilman, D.; Socolow, R.; Foley, J.; Hill, J.; Larson, E.; Lynd, L.:
Beneficial biofuels: the food, energy, and environment trilemma.
Science 325, 270–271 (2009)
123
Author's personal copy
Arab J Sci Eng (2013) 38:317–328 327
56. Pimentel, D.; Marklein, A.; Toth, M.; Karpoff, M.; Paul, G.;
McCormack, R.: Food versus biofuels: environment and eco-
nomic costs. Hum. Ecol. 37, 1–12 (2009)
57. ActionAid.: Meals per gallon: the impact of industrial biofuels on
people and global hunger. ActionAid, London (2010)
58. Wolf, J.; Bindraban, P.; Luijten, J.; Vleeshouwers, L.: Explor-
atory study on the land area required for global food supply and
the potential global production of bioenergy. Agric. Syst. 76, 841–
861 (2003)
59. Cotula, L.; Dyer, N.; Vermeulen, S.: Fuelling exclusion? The bio-
fuels boom and poor people’saccess t ol and. International Institute
for Environment and Development, London (2008)
60. Richert, W.; Sielhorst, S.: Uitgangspunten voor Duurzame Bio-
massa-Deel 1: Risico’ s en kansen van de import van biomassa in
Nederland. Report commissioned by Milieudefensie Nederland.
AIDEnvironment, Amsterdam (2006)
61. Energy Transition. Biomass, hot issue. Smart choices in difficult
times. Report by the Biobased Raw Materials Platform, Senter-
Novem, Sittard (2008)
62. Demirbas, A.: Political, economic and environmental impacts of
biofuels: a review. Appl. Energy 86, 108–117 (2009)
63. Renewable Energy Policy Network for 21st Century (REN21).:
Renewables 2011: Global Status Report, 13–14 (2011)
64. Smeets, E.; Junginger, M.W.; Faaij, A.; Lewandowski, I.;
Turkenburg, W.: A quick scan of global bio-energy potentials to
2050. Prog. Energy Combust. Sci. 33(1), 56–106 (2007)
65. Turcotte, D.L.; Schubert, G.: Geodynamics. Cambridge Univer-
sity Press, Cambridge (2002)
66. Enrico, B.: Geothermal energy technology and current status: an
overview. Renew. Sust. Energy Rev. 6, 3–65 (2002)
67. Glassley, W.E.: Geothermal energy: renewable energy and the
environment. CRC Press, Boca Raton (2010)
68. Geothermal Energy Association.: Geothermal energy: interna-
tional market update, May, p. 7 (2010)
69. Renewable Energy Policy Network for 21st Century (REN21).:
Renewables: Global Status Report, p. 15 (2011)
70. Renewable Energy Policy Network for 21st Century (REN21).:
Renewables: Global Status Report, Update (2009)
71. Martinot, E.; Sawin, J.: Renewables Global Status Report 2009
Update, Renewable Energy World, September 9 (2009)
72. Honnery, D.; Moriarty, P.: Estimating global hydrogen production
from wind. Int. J. Hydrogen Energy 34, 727–736 (2009)
73. Moriarty, P.; Honnery, D.: Rise and Fall of the Carbon Civiliza-
tion. Springer, London (2010)
74. Abbasi, S.A.; Abbasi, N.: The likely adverse environmental
impacts of renewable energy sources. Appl. Energy 65, 121–144
(2000)
75. McCartney, M.: Living with dams: managing the environmental
impacts. Water Policy 11(Suppl. 1), 121–139 (2009)
76. Pimentel, D.; Herz, M.; Glickstein, M.; Zimmerman, M.;
Allen, R.; Becker, K.; et al.: Renewable energy: current and poten-
tial issues. Bioscience 52, 1111–1120 (2002)
77. Abdillah, A.; Selaman, O.S.: Catchment size, soil type and land
use to determine the amount and likelihood of flood in the Sara-
wak Corridor of Renewable Energy (SCORE) Region. UNIMAS
E J. Civil Eng. 1(1), 1–11 (2009)
78. Cho, A.: Energy’s tricky tradeoffs. Science 329, 786–787 (2010)
79. Boyles, J.G.; Cryan, P.M.; McCracken, G.F.; Kunz, T.H.: Eco-
nomic importance of bats in agriculture. Science 332, 41–42
(2011)
80. Kuvlesky, Jr. W.P.; Brennan, L.A.; Morrison, M.L.; Boyd-
ston, K.K.; Ballard, B.M.; Bryant, F.C.: Wind energy devel-
opment and wildlife conservation: challenges and opportunities.
J. Wildlife Manage. 71(8), 2487–2498 (2007)
81. Simon, C.A.: Cultural constraints on wind and solar energy in the
U.S. context. Comp. Technol. Transf. Soc. 7, 251–269 (2009)
82. Dean, W.D.: Wind turbine mechanical vibrations: potential envi-
ronmental threat. Energy Environ. 19(2), 303–307 (2008)
83. Kunz, T.H.; Arnett, E.B.; Erickson, W.P.; Hoar, A.R.: Johnson,
G.D.; Larkin, R.P.; et al.: Ecological impacts of wind energy devel-
opment on bats: questions, research needs and hypotheses. Front.
Ecol. Environ. 5(6), 315–324 (2007)
84. Moriarty, P.; Honnery, D.: Liquid fuels from woody biomass. Int.
J. Glob. Energy Issues 27(2), 103–114 (2007)
85. Makarieva, A.M.; Gorshkov, V.G.; Li, B.L.: Energy budget of the
biosphere and civilization: rethinking environmental security of
global renewable and nonrenewable resources. Ecol. Complex 5,
281–288 (2008)
86. Tsoutsos, T.; Frantzeskaki, N.; Gekas, V.: Environmental impacts
from the solar energy technologies. Energy Policy 33, 289–96
(2005)
87. Luque, A.; Heguedos, S.: Handbook of Photovoltaic Science and
Engineering. Wiley, West Sussex (2003)
88. Kintisch, E.: Out of site. Science 327, 788–789 (2010)
89. Majer, E.L.; Baria, R.; Stark, M.; Oates, S.; Bommer,J.; Smith, B.;
Asanuma, H.: Induced seismicity associated with enhanced geo-
thermal systems. Geothermics 36, 185–222 (2007)
90. Swain, A.; Chee A.M.: Political structure and ‘Dam’ conflicts:
Comparing cases in Southeast Asia. In: Waterand Politics: Under-
standing the Role of Politics in Water Management. World Water
Council, Marseilles, pp. 95–114 (2004)
91. Lee, R.: Environmental impacts of energy use. In: Robert Bent,
Lloyd, Orr, Baker, Randall (eds.), Energy: Science, Policy, and
the Pursuit of Sustainability. Island Press, Washington, pp. 77–
108 (2002)
92. Mamit, J.D.: Social and environmental impacts of hydroelectric
dam development: the Bakun HEP example in Sarawak, Malaysia.
In: Keynote Address presented at Third International Conference
on Water and Renewable Energy Development in Asia, Kuching,
Sarawak, Malaysia, 29–30 March (2010)
93. Sovacool, B.K.; Bulan, L.C.: Behind an ambitious megaproject
in Asia: The history and implications of the Bakun hydroelectric
dam in Borneo. Energy Policy 39, 4842–4859 (2011)
94. Choy, K.Y.: Energy demand, economic growth, and energy effi-
ciency: the Bakun Dam-induced sustainable Energy Policy Revis-
ited. Energy Policy 33, 679–689 (2005)
95. Whish-Wilson, P.: The Aral Sea Environmental Health Crisis.
J. Rural Remote Environ. Health 1(2), 29–34 (2002)
96. Huang, C.Z.: Guideline for China Flood Control. China Libera-
tion Army Press, China (1998)
97. Stupak, I.; Asikainen, A.; Jonsell, M.; Karltun, E.; Lunnan, A.;
et al.: Sustainable utilization of forest biomass for energy—pos-
sibilities and problems: Policy, legislation, certification, and rec-
ommendations and guidelines in the Nordic, Baltic, and other
European countries. Biomass Bioenergy 31(10), 666–684 (2007)
98. Ren, D.: Effects of global warming on wind energy availability.
J. Renew. Sust. Energy 2(052301), 5 (2010)
99. Saidur, R.; Rahim, N.A.; Islam, M.R.; Solangi, K.H.: Environ-
mental impact of wind energy. Renew. Sust. Energy Rev. 15,
2423–2430 (2011)
100. Pryor, S.C.; Barthelmie, R.J.: Climate change impacts on wind
energy: a review. Renew. Sust. Energy Rev 14, 430–437 (2010)
101. REN21. Global status report. Paris: REN21 Secretariat; 2005 to
2011 Issues
102. IEA. International Energy Agency Database Vol. 2010, Release
01: (a) Energy Balances of Non-OECD Member Countries; (b)
Energy Balances of OECD Member Countries; 2009
103. IEA-PVPS.: Trends in photovoltaic applications: survey report of
selected IEA countries between 1992 and 2006. IEA Photovoltaic
Power Systems Program (2007)
104. McCluney, R.: Renewable Energy Limits. The Final Energy Cri-
sis. Pluto Press, London (2004)
123
Author's personal copy
328 Arab J Sci Eng (2013) 38:317–328
105. Odum, H.T.: Net Energy Analysis of Alternatives for United
States. Part 1, Middle and Long Term Energy Policies and Alter-
natives. US Government Printing Office, Serial No. 94–63 (1976)
106. U.S. Department of Energy. www.energysavers.gov/renewable_
energy/solar/index.cfm/mytopic=50012 (2012). Accessed 10
June 2012
107. Muselli, M.; Notton, G.; Louche, A.: Design of hybrid-photovol-
taic power generator, with optimization of energy management.
Solar Energy 65(3), 143–157 (1999)
108. Bagen, B.R.: Evaluation of different operating strategies in small
stand-alone power systems. IEEE Trans. Energy Convers. 20(3),
654–660 (2005)
109. Himri, Y.; Boudghene, S.A.; Draoui, B.; Himri, S.: Techno-eco-
nomical study of hybrid power system for a remote village in
Algeria. Energy 33, 1128–1136 (2008)
110. Rehman, S.; Mahbub, A.M.; Meyer,J.P.; Al-Hadhrami, L.M.: Fea-
sibility study of a wind–pv–diesel hybrid power system for a vil-
lage. Renew. Energy 38(1), 258–268 (2012)
111. Rahman, F.; Rehman, S.; Abdul Majeed, M.A.: Overview of
energy storage systems for storing electricity from renewable
energy sources in Saudi Arabia. Renew. Sust. Energy Rev. 16(1),
274–283 (2012)
123
Author's personal copy
