ME501: Renewable Energy Viability and Sustainability Report

This report investigates the viability and sustainability of renewable energy sources, focusing on wind, bioenergy, and solar energy, with a primary emphasis on wind and solar due to their scalability and potential for zero carbon emissions. The study evaluates the ability of renewable energy to replace conventional sources such as natural gas, nuclear energy, and coal, considering factors like intermittency and the need for backup systems. The analysis explores the impact of renewable energy on carbon emissions, the role of energy storage, and the lifecycle assessment of various energy sources, including biofuels and hydropower. It also assesses the viability of renewable fuels in transport, such as hydrogen and biodiesel, comparing their energy density, scalability, and cost to conventional fuels. The report concludes by examining the cost savings, job creation, and potential for lower greenhouse emissions associated with renewable energy sources.

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Viability and Sustainability of Renewable Energy
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Introduction
The recent developments in climatic change awareness and controversies over
conventional energy sources such as nuclear energy and fossil fuels have solicited the need to
eliminate conventional sources of energy in favor of renewable energy sources. This process is
procedural and cannot be accomplished overnight. Evaluation of renewable energy viability in
terms of cost and the impact of its utilization as a complete or partial replacement of the
conventional energy sources aids in determining the necessary conditions for such development
in power systems and confirming if indeed the cost will be worth it. Renewable, in this case,
refers to the inability to get depleted. The various renewable sources whose viability is
investigated in this paper encompasses wind, bioenergy and solar energy. The paper will put
more emphasis on wind and solar energy because of their relative advantage on scalability and
their perceived advantage of zero-emission of carbon (iv) oxide.
Viability is generally defined as being capable of functioning. In this study, if renewable
energy is confirmed to be viable, then it simply implies that renewable energy is capable of
replacing conventional energy sources. If renewable energy is not capable of replacing the
conventional power system sources in Australia, then this study will conclude that it is not truly
viable despite the numerous merits it is associated with. The conventional energy in this study
encompasses the energy sources currently used on large scales such as natural gas, nuclear
energy, and coal.
Problem statement
Despite its various known merits, renewable energy is intermittent in nature. In order to
provide reliable power to the grid, wind and solar sources must have a strong backup system that
matches the conventional system. Because of this, it is apparent that either wind or solar power
cannot considerable minimize the installed conventional power sources investment. Solar and
wind energy sources do not minimize capital investment in sources of energy. They generate
power while increasing the cost of the power system.
[body]
Climate change is currently one of mankind's greatest concerns, dominating scientific,
political and many other spheres of human life. According to [11] climate change is not a new
phenomenon, it has been occurring for centuries. However, the speed of change in the present
and especially in the 21st century is alarming. A transition in the global demand and supply of
energy is necessary to combat climate change and its associated impacts on the environment.
This transition can be achieved through the use of renewable sources of energy which have the
promise of saving the planet from huge quantities of greenhouse gas emissions, especially carbon
(iv) oxide. Over the past approximately 36 years, the rate of increase of carbon dioxide in the
atmosphere has increased averaging at about 2.0 ppm per year from 1995 [4].
According to [6] sustainable energy can be defined as the balance between the equitable
distribution of energy-intensive goods and services and the conservation of the planet for the
benefit of future generations. The growth of the world’s population over the years has greatly

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increased the demand for energy resources and making fossil fuels such as coal, oil, and natural
gas the major sources of energy. The use of fossil fuels revolutionized the transport and
industrial sector improving the lifestyles of millions of people since it represented a major shift
from traditional energy sources such as wood enabling the large scale production and provision
of goods and services. However, the challenges and effects associated with the use of fossil fuels
cannot be underestimated. Fossil fuels are unsustainable sources of energy since they get
depleted with time. They are also a source of military and geopolitical tensions as nations and
radical groups fight to control the valuable resource. However, the major challenge is their
impacts on the global climate considering the large quantities of carbon dioxide resulting from
their combustion. This has led to the development of alternative energy sources in an effort to
reduce pollution and environmental degradation. These energy sources are said to be renewable
since they can be deployed over and over without depletion. These energy sources include wind
energy, tide and wave energy, hydropower, solar, geothermal and bioenergy.
The use of renewable energy has been rapidly increasing. It is estimated that the installed
capacity for renewable energy increased by about 50 % from about 800 GW in 2004 to
approximately 1712 GW in 2014 [1]. Renewable energy sources account for about 19 % of the
global energy consumption which is still too low to make a significant impact on climate change.
The below 2 ℃ objective for global warming can only be achieved through national and
worldwide cooperation to enforce existing climate policies and to develop new ones to
effectively deal with the menace of climate change.
Despite the attractiveness and the advantages associated with renewable energy sources,
there is still controversy on whether it is feasible and viable to eliminate conventional fossil-
based sources of energy in favor of these renewable energy sources. According to [11], a viable
energy source must capable of functioning or practical. Most renewable sources of energy such
as sunlight and wind are highly dependent on climate. This means that power generation would
be discontinuous due to these seasonal variations. Consequently, the deployment of most
renewable energy generation sources requires complex design, control optimization, and
planning [11]. However, the advancement of technology and the use of computer modeling has
made these optimization problems less insignificant.
Renewable energy sources as standalone units
Due to the changes in the intensity of solar radiation and wind strength as well as its
direction, it is not possible to rely on these renewable sources as uninterrupted electricity
suppliers. Currently, they have to be backed from conventional power plants for continuous
reliable energy supply to meet grid requirements. Therefore, renewable sources cannot be
considered as standalone energy plants, at least not yet since they are still heavily dependent on
fossil energy sources for reliable operation [8]. For complete independence, renewable sources
must incorporate power storage devices to capture extra energy for supply when the sun or the
wind is unavailable. Several conceptual alternatives have been suggested for the storage of
electrical energy. These include flow batteries, compressed air, and flywheels [14]. The use of

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energy storage systems requires additional expenditure in considerable amounts for construction
and maintenance in addition to the cost of generation. Besides, to supply power to the grid while
simultaneously charging the storage systems would require the installed capacity to be several
times larger than the demand necessary to simply feed the grid [8]. Therefore renewable energy
is not a viable standalone system.
Renewable energy and carbon (iv) oxide emissions
The main objective of integrating renewable energy sources into the production and
supply of electricity and transport is to abate carbon (iv) oxide emissions. The electricity-
generating industry is regarded as the largest source of carbon emissions hence a priority for
climate policies. According to [6], even though renewable energy is not considered a viable
standalone power source, it can be incorporated with conventional energy plants to lower
greenhouse emissions. Despite the fact that both wind and solar are sources of renewable energy,
most of the installed capacity for renewable energy is provided by wind due to the higher cost
associated with solar energy. Directly, renewable energy sources such as solar and wind do not
contribute to carbon dioxide or other greenhouse gas emissions because they do not require any
biomass input. However, scrutiny shows that these energy sources have indirect greenhouse
emissions. Industries manufacturing solar panels, wind turbines and other plant necessities
consume huge quantities of electricity which is often produced from fossil-based fuels, mainly
coal [1]. This carbon debt must be paid off if these renewables are to be considered over their
lifetime.
Hydropower is also a green source of energy. The construction of hydroelectric power
plants displaces a lot of people in the creation of the reservoir behind the dam. The dam and
other structures interfere with the river’s ecology by hindering sediment transport and fish
migration downstream [4]. In cases where the reservoir covers substantial vegetation, there may
be methane gas formation from the rotting plants in the water [4]. The resource potential of
hydropower is subject to alteration due to climate change which can lead to reduced rainfall in
some areas. Consequently, the sustainability of hydropower is still uncertain if other causes of
climate change are not addressed.
The sustainability of biofuels is a matter of major concern considering that some forms
require food crops as inputs. The use of crops to produce biofuels in large quantities is predicted
to increase food prices and famine due to the limited available land. Although considered
insignificant in the context of global energy production, its impact on agriculture cannot be
underestimated. The extent to which biofuels affect the environment is largely dependent on how
feedstocks are produced [2]. Previously, it was assumed that replacing fossil fuels with biomass-
generated fuels would have considerable positive effects on climate change through the reduction
of greenhouse emissions. However, recent scientific studies indicate that biofuels vary in their
greenhouse balance compared to fossil fuels such as petroleum. According to [4] some crops
used in feedstock production can even produce larger quantities of greenhouse gases than fossil
fuels. For instance, the use of nitrogen fertilizers on crops releases nitrous oxide whose global

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warming potential is about 300 times that of carbon (iv) oxide [3]. Direct and indirect emissions
are also triggered by processes such as land conversion for crop production. For instance, while
corn produced for the production of ethanol can achieve emission savings of about 1.8 tonnes of
carbon (iv) oxide per annum per hectare, the land conversion of land to grow those crops can
produce approximately 300 tonnes of carbon dioxide per hectare [13].
Despite all the challenges discussed, there are still cost savings for renewables in
comparison with non-renewables under favorable conditions. Particularly, energy imports can be
lowered through the use of domestic renewable energy technologies that are already competitive
in remote areas devoid of centralized power access. Jobs can be created in the process although
the impact on net employment is still insignificant. Lifecycle assessment for the generation of
electricity indicates that, generally, greenhouse emissions from renewable energy sources are
considerably lower compared to those released by fossil fuels [8]. Besides, assessments show
that renewable sources can achieve lower emissions than fossil fuels employing carbon capture
under certain conditions. Disregarding emissions related to land use, the values for renewables
are in the range of 4 – 46 g of carbon dioxide per kWh while those for non-renewables range
from 469 to 1001 g per kWh [5]. The most current systems for the production of biofuels (next-
generation biofuels) such as liquid biofuels can provide higher emission reduction [9].
Incorporating carbon capture with bioenergy can lead to further reductions.
The viability and sustainability of renewables in transport
For renewable fuels to be considered viable, they must be capable of replacing
conventional fossil fuels such as gasoline, diesel and jet fuel. Viability means that these
renewable energy sources must be comparable with conventional fuels in terms of energy
density, scalability and cost [8]. Hydrogen gas is a potential source of renewable energy for
powering vehicles. Currently, the major source of hydrogen gas is from the synthesis of natural
gas through the steam reforming process [7]. However, the production of hydrogen by this
method would eliminate it as a renewable energy source since natural gas is a fossil fuel. It is
possible to generate hydrogen through emission-free processes such as electrolysis from solar
energy. However, the process is highly energy-intensive. Besides, the energy density for
hydrogen is very low which eliminates the possibility of hydrogen replacing fossil fuels as viable
fuel in the near future.
Biodiesel produced from the processing of waste vegetable oil is another possible
alternative to fossil fuels. It has also been produced from algae on a small scale. Its cost
competitiveness is however questionable. In addition, its scalability (ability to be expanded to a
reasonable percentage of the total supply) is quite limited [12]. The quantity of the available
waste feedstock such as vegetable oils and waste petroleum necessary to produce the millions of
barrels per day needed to replace even a segment of the total supplied by fossil fuels is simply
insignificant. The production of biodiesel from algae has not been proven to be cost-effective yet
or even scalable.

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Ethanol is the only renewable energy source with significant capabilities as a
transportation fuel. It is widely used as a gasoline additive to create blended fuel for vehicles. A
major advantage associated with ethanol is its low energy density. Its energy density is about two
thirds that of gasoline. This means that the range of an ethanol-powered vehicle is shorter for the
same size of the fuel tank [10]. The feedstocks from the production ethanol include corn,
switchgrass, and agricultural waste products. These feedstock sources are very limited for the
production of enough fuel to cover a considerable segment of the transportation needs. Corn-
ethanol can produce significant fuel per acre of land. However, the sustainability of the use of
land to grow crops for fuel production is questionable considering the rising global population
and limited land. The competition between food and fuel extends beyond corn production. The
production of more fuel from biomass would have adverse effects on other food commodities.
For developed countries, it is impossible for biofuel production to improve energy security to
any significant degree since it would require vast land tracts crowding various other land uses.
Usually, energy is required to produce energy. The production of energy from fossil fuels
is very efficient. It takes approximately 1 barrel of oil to produce about 10 barrels of refined
products [10]. Fossil fuels yield more energy than they consume. Renewable energy sources such
as biofuels are not yet as efficient as conventional fuels. It is still uncertain about the ability of
biofuels to produce considerably higher energy quantities than they consume or if they consume
net energy. According to [6] ethanol from corn may consume about 70 % greater nonrenewable
energy than the energy content produced. Just like solar and wind energy, ethanol has been
promoted as being able to cut emissions. However, according to [10] ethanol may actually
increase emissions if other factors are considered.
Conclusion
The viability and sustainability of renewable energy have been analyzed in depth through
the presentation of case studies and data for the comparison of the renewable sources of energy
and conventional energy sources. Evidently, standard energy sources still dominate over the
renewables in terms of energy density, scalability and cost competitiveness. Currently, most
renewable energy sources are such as bioenergy are not viable replacements for fossil fuels and
further research and development are necessary to achieve any significant impact. Besides, the
sustainability of most of these renewables as standalone energy sources is still questionable due
to the conflict between their production methods, food security, and carbon dioxide emissions.
Future recommendations
All renewable energy sources have great potential for sustainability. Therefore, further
research and development are necessary to improve the efficiency of the production methods as
well as developing new feedstocks independent of fossil fuels and free from competition
with food crops.
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