Costs of Renewable Sources of Energy Dhreen K. Tulsiani

Electrical Engineering and Computer Science Department, Wichita State University

1845 Fairmount, Wichita, KS 67260, USA

dktulsiani@wichita.edu

Abstract— Over the decades, the desire for replacing non-renewable sources of energy with renewable sources has

increased drastically. In this paper, I introduce the need of renewable sources of energy for generating electricity by

highlighting the high costs and the potentially disastrous impact on health and environment associated with non-

renewable energy sources. I will then provide some insight on the renewable sources of energy, specifically on solar power

and wind power by comparing the historical, current and future costs of both the renewable sources. I will provide

reasons as to why the costs are falling and I will draw conclusions based on my findings.

Index Terms— Renewable energy sources, Energy, Solar energy, Photovoltaic cells, Wind energy

I. INTRODUCTION

As the name suggests, non-renewable source of energy is the source of energy that cannot be replenished in a

short amount of time. Fossil fuels such as coal, oil and petroleum products, and natural gas are considered as non-

renewable energy sources [1]. Coal and natural gas are used to generate 42 percent and 22 percent respectively, of

the total electric power and energy in the United States [2]. As far as the consumption of petroleum products is

concerned, the United States is at the top of the list which is highlighted by the fact that 19.2 million barrels of oil

and petroleum per day were consumed in 2010 [2]. However, the concern that non-renewable sources are being used

up at such a fast rate is not the only concern. Cost, health and environmental concerns are associated with non-

renewable sources of energy as well.

In 2006, the fossil fuel expenditures accounted for $921 billion, which is more than what the country allocates its

expenses for education or military and for the first time ever in 2008, the national spending presumably surpassed $1

trillion [3]. These are some very high numbers but that’s not all as there are health costs associated as well. Health

costs account to $120 billion a year [4]. Health costs arise from the pollution caused by burning fossil fuels and they

have a severe impact on the health. Burning fossil fuel causes lung damage and each year about 20,000 people die

primarily due to the pollutants released by power plants and vehicles [4]. These pollutants are not only harmful to

the individuals, but they also affect the environment. Burning coal, which is a fossil fuel, includes coal mining and

coal processing, each of which contributes to pollution. Coal mining releases nitrogen oxide which adds to smog,

and also sulfur dioxide which leads to acid rain; and coal processing pollutes the rivers with the chemicals released

to filter the coal [4]. Another example of fossil fuels causing harm to the environment would be burning of fossil

fuels in general. 79 percent of the greenhouse gases in the United States were emitted from burning fossil fuels in

2010 [2]. This contributes to global warming. All of these burning, mining and processing techniques are potentially

disastrous and catastrophic to the environment and to our planet.

The need for the replacement of non-renewable sources of energy with the available options of renewable sources

has grown over the years due to the concerns described above. However, renewable sources of energy have not been

adopted widely. There are a few countries that have been switching to the renewable energy sector at a very fast

rate. For example, a report from 2010 states that Portugal would generate nearly 45 percent of the electricity from

only renewable sources that year, which would be an increase of 28 percent in just five years [5]. On the other hand,

a majority of the countries are still relying on fossil fuels for generating electricity and other energy purposes. For

instance, the United States currently produces only 12 percent of the country’s electricity by utilizing renewable

energy sources [6]. This means that 88% of the country’s electricity is still being produced from fossil fuels. Such

high dependence on fossil fuels would soon lead to its extinction.

There are various factors due to which renewable sources of energy have not been adopted on a large scale. One

such factor is cost. Historically, renewable energy sources such as solar photovoltaics and wind generators have

proved to be very costly. However, with time, there have been numerous improvements that have contributed to the

falling costs of these energy sources. Currently, they are priced at a much lower rate than they were decades ago.

Following the current trend, the future looks bright for renewable energy sources as the prices in the future will be

much cheaper, making the renewable sources of energy much more affordable to the common man.

II. BASIC CONCEPTS OF COSTS AND POWER

This paper discusses about costs and it is important to understand the different concepts of costs, power and how

they are related. Costs can be specified in price per kilowatt and price per kilowatt-hour. Kilowatt is a measure of

power whereas kilowatt-hour is a measure of energy. Power can be generated or used. For example, we consider

using solar energy as a renewable source because we are able to generate power. A solar panel rated 100 watts

would generate 100 watts of power. This generated power can be used to supply power to devices that consume

power. On the other hand, a bulb rated 100 watts will consume 100 watts of power when switched on. Energy is the

amount of power used in a given period of time (and not necessarily in one hour).

Price (or cost) per kilowatt is the cost that an individual would have to pay to purchase one kilowatt of a

particular device. In other words, it represents the cost of a machine. Price (or cost) per kilowatt-hour is the cost that

an individual would have to pay for using one kilowatt-hour. In other words, it represents the cost an individual

would pay when multiple devices are connected in a given period of time. It makes more sense to use price per

kilowatt-hour to calculate energy costs. This is the reason why electric companies include the amount of kilowatt-

hour used over a period of one month. The price per kilowatt-hour can be easily found by dividing the total cost to

be paid by the amount of kilowatt-hour used in that particular month. Kilowatt and kilowatt-hour can also be

represented in watt and watt-hour by making some conversions.

III. SOLAR ENERGY

A. An Introduction to Solar Energy

Energy can be harnessed from the sun. If the sun shines at a place, energy can be produced at that particular place.

Solar energy is the energy from the sun and humans exist because the sun shines. Trees and plants use sunlight along

with carbon dioxide during photosynthesis to release oxygen in the air. Humans complete this cycle by taking in the

oxygen and releasing carbon dioxide. In short, solar energy is vital for the survival of humans. Apart from being an

important factor of survival for humans, solar energy can be utilized in different ways. An example of utilizing sun’s

energy would be focusing the rays of sun on a sunny day on a piece of paper using a magnifying glass. The paper

will set on fire quickly. This simple experiment teaches us two things. Firstly, through various channels, we can

capture the sun’s energy in order to utilize it for various purposes. Secondly, the energy from the sun is so much that

a paper can catch fire quickly as described above. This makes solar energy a renewable source of energy.

Solar energy can be collected and converted into electricity. This is known as producing power from the sun’s

energy or solar power. Solar energy can be stored using solar panels and solar panels consist of about 40 solar cells

or also known as photovoltaic cells [7]. This technology is known as solar photovoltaic technology. A well-known

example of using the solar cells would be in a calculator. Using similar technology, solar panels can be installed in

homes too. The amount of sunlight that falls on the United States in one day is greater than twice the amount of

energy people utilize in an entire year [8]. This means that the amount of sunlight is in abundance and can be

utilized wisely by harnessing energy. People can install solar electric systems in their homes as they are built to last

30 years, and these systems pay for themselves after 4-5 years meaning the next 25-26 years of power consumed

would be free of cost [9].

B. Historical Costs

The first solar cells were made available to the public in 1956 with the cost of $300/watt [10]. As a result, the

popularity of solar cells was almost negligible during the late 1950s due to high costs. The official emergence of

solar cells and solar panels in the commercial market could be linked to the energy crisis during the 1970s [11].

Around this time, progress was made in the solar cell technology field as well. The energy crisis resulted in a

shortage and elevated prices of oil and petroleum products which led to an increase in demand for solar panels.

At the same time, the first factory for producing solar cells for daily applications, the Institute for Local Self-

Reliance, was founded in 1974 [19]. However in terms of energy costs in 1974, the cost of solar power was over

$3/kilowatt-hour [19]. Also, the price of solar panels was still as high as 30 times the current price during the 1970s,

whereas the solar electricity costs were more than 100 times the current price during that time [11], [19]. The price

of solar cells was at the high end of $70/watt in 1977 [12]. With such high prices, only a few royal homes could

afford the new technology.

The breakthrough in solar energy usage was when the 39th

President of the United States Jimmy Carter called for

a huge investment in June 1979 in the solar power industry by installing 32 solar panels at a total cost of $30,000 or

at $40/watt [13], [14]. It was a major breakthrough because it brought the solar technology into the limelight for the

first time. President Carter himself admitted that this step was only an experiment and was confident that the

technology would progress further and prices would fall as time goes by [13].

In terms of the cost of energy usage, the utility companies were charging more than $1/kilowatt-hour in 1980 [8].

The efficiency during the 1980s of solar panels was also quite low. A solar panel could only produce 22 watts of

power during the 1980s [15]. With such low power, small devices such as calculators could be powered efficiently.

As a result, Texas Instruments eliminated the use of batteries by introducing its first solar powered hand-held

calculator at a fairly reasonable price of $19.95 in 1981 [16].

As technology progressed, the price of solar panels fell considerably. The cost of solar panels during 1980s was

between $10/watt to $20/watt and during the 1990s, it was between $5/watt to $10/watt [17]. In 1990, the total

capacity of installed solar panels in the United States was about 200 megawatts, enough to power 4000 homes which

increased to about 135,000 homes being powered by solar power in the year 2000 [19]. Fig. 1 shows the falling

trend of solar photovoltaic panels [18]. The graph shows a steady decline in the prices of solar panels from 1977 to

2013.

Fig. 1. A bar graph to show the falling trend of solar photovoltaic panels

C. Current Costs

Fig. 1 clearly shows the falling trend leading up to the current year. Over the years, solar panels have improved

drastically. More than 1.5 million American homes can be powered with the current solar electric capacity [20]. If

we just take into consideration the recent history, the average cost of a solar panel has declined by 60% since the

beginning of 2011 [20]. People who install solar panels on their houses will end up paying lesser than ever before.

For the first time in the history of the solar electric technology, the price of solar panels fell below $1/watt as the

price of $1.2/watt in 2011 fell to 90 cents per watt in 2012 [21]. Fig. 1 shows a further fall in the price of solar

panels in 2013 as they are currently priced at 74 cents per watt.

As far as the energy usage costs are concerned, solar energy costs currently lie within the range of 12 cents per

kilowatt-hour to 30 cents per kilowatt-hour [22]. Different states charge different amounts. The energy costs are

expected to fall with the falling prices of solar panels in the similar fashion as it did in the past [22]. Cities such as

Arizona where the sun shines the most charge the lowest prices for solar energy distribution [23]. The current

situation is that big companies have started utilizing renewable energy sources to power their factories, facilities and

workplaces. Apple, an American multinational corporation, recently announced the construction of a new

manufacturing facility in Arizona that will operate on 100% renewable energy such as solar power from the very

first day of its opening [24]. Such investments by large and reputed multinational companies would encourage many

different companies and small business owners to invest in renewable energy sources such as solar power.

D. Future Costs

It is clear from the discussion above that prices of solar panels have been falling tremendously. Technology is

getting better every day which cause the fall in the prices. Apparently, the falling costs of solar panels follow the

Swanson effect.

Essentially, the cost of photovoltaic cells need to generate solar power falls 20%

with each doubling of global capacity. This has been dubbed the "Swanson Effect"

after Richard Swanson the founder of SunPower, the large US-based manufacturers

of solar cells [25].

Fig. 1 shows the Swanson effect over a period of about four decades. It is a very good indication that the solar prices

will fall in the future.

Greentech Media, a research company, initially in some of the earlier researches in 2012 anticipated that the cost

of solar photovoltaic modules to be around 50 cents per watt by 2015 [26]. However, a research by Greentech Media

in early 2013 contradicted its own forecast and claimed that the traditional silicon based solar panels would now cost

only 42 cents per watt by 2015 [26]. Such a low price has the potential to quite possibly start a revolution in the

energy industry as it would lead the United States and even other nations to re-consider the way electricity is

produced.

Silicon, which is a semiconductor to absorb sun light, has always been the material installed in solar panels.

Researchers have been looking into Perovskites, a material known for over a century, which can bring down the

costs of solar panels to about 10 to 20 cents per watt if installed in solar panels [27]. However, change is often

opposed by human nature. Current solar panels using silicon material have a very high record of reliability and

stability. Analysts claim that silicon solar panels have a proven track record of falling costs, and at the current rate

the costs would fall further up to 25 cents per watt, which would eliminate risking the technology using the new

material perovskites as the costs would be around the same level [27]. As a result, researches are being done to

install a material that can bring down the costs and increase the efficiency at the same time.

E. Why the costs are falling?

The Swanson effect exists due to various reasons. A lot of factors contribute to the falling costs of solar panels

every year. Every year there are numerous technological and manufacturing advancements. However, probably the

most important factors that are driving down the costs are due to economic factors such as economies of scale and

market maturation [28].

According to [29], economies of scale is a situation in the economy of a market which occurs when more and

more units of goods and services are produced on a large scale with falling costs. In the situation of the solar panel

industry, as more solar panels were produced, the costs came down [28]. A simple explanation of this could be that

as the solar panel costs drop, it encourages more people to adopt this technology. Thus, the solar power industry

grows at a faster rate which further lowers the costs of solar [28].

On the other hand, market maturation is also a contributing factor. Market maturation is a situation when the

market size in an economy is the highest which leads to high profits [30]. Market maturation is also a situation when

the market growth is slow [30]. This can be explained by the amount of time it took for the cost of solar panels to

fall. The number of people adopting the solar technology for energy purposes has been growing but was growing

slowly during the early days. However, as the market started growing faster, the competition increased. When

competition increased, the price of solar panels declined as sellers wanted their products to sell first [28]. This cycle

happened over and over again which eventually led to the price that we have today.

Looking ahead in the future, the cycles economies of scale and market maturation would repeat bringing the costs

of solar panels. Also, there will be a number of technological and manufacturing advancements as the technology

gets better each day. All of these factors would bring down the costs.

IV. WIND ENERGY

A. An Introduction to Wind Energy

Just like solar energy, another renewable source of energy is wind energy which is the energy harnessed from

wind. Theoretically, wind exists in infinite amounts. Some cities are known for excess amount of winds. Cities such

as Boston, Massachusetts; Oklahoma City, Oklahoma; and Wichita, Kansas are some of the windiest cities in the

United States. Such cities have great potential to produce and utilize wind energy on a large scale. Wind is nothing

but moving air currents on the surface of the earth. A simple example of this could be an empty boat in a sea. When

wind blows, the boat moves because the air is pushing the boat in a certain direction. This is a simple example of

wind energy where the wind was transformed into the energy of motion. Another similar example would be of golf.

Is it a well-known fact that a person should hit the golf ball taking into the consideration the direction of wind since

the wind will move the golf ball. As a result, wind moves the golf ball while in air. This is another example of wind

turning itself into energy to move the ball.

Different machines are designed to convert wind energy. Windmills are machines that convert wind energy into

rotational energy using blades. Windmills are used for milling grain and extracting groundwater. Wind generators

are used to convert wind energy into electricity. A windmill has more blades than a wind generator because a

windmill has to do a lot more physical work but a wind generator is a lot taller than a windmill. A wind turbine

converts the kinetic energy in the wind into mechanical power and a generator connected to the wind turbine can

convert this mechanical power to generate electricity [31]. A wind generator is also known as a wind turbine or a

wind power plant. For the purpose of this paper, wind turbines will be discussed hereafter and not windmills.

B. Historical Costs

The history of wind turbines can be traced back to 1931 when Russia constructed the first ever 100kW

commercial power plant, known as Balaclava Wind Generator which used wind turbines to generate electricity [32],

[33]. People showed their interest in it by claiming that this technology would change how the world produces most

of its energy. It is a well-known fact that the price of new technology is always high. Thus, it was a wind turbine

capable of producing wind power but at high prices.

This initial attempt by Russia never stood a chance to impact much in the long run. As a result, when fuel was

much cheaper at the end of World War II, people started losing their interest in wind turbines [34]. However, wind

turbines became popular again but not before 1970s. When oil prices peaked in the 1970s, people started gaining

interest in wind turbines again [34]. The fluctuations of fuel and oil prices impacted the wind turbines and this price

variation always existed in the early decades of the wind generators.

The urge for the need for wind energy accelerated when NASA stepped in the wind energy production programs.

In 1974, NASA led the U. S. Wind Energy Program to construct 13 large turbines [35]. The cost of wind power was

quite high in 1970s. In 1978, the cost of energy from wind turbines was more than $1/kilowatt-hour [38]. The

program led by NASA continued until 1981 and they created some of the strongest systems that are dominant today

with the basic view in mind to convert wind energy into mechanical and electrical energy [35].

The initiative by NASA caused a positive impact in the wind energy industry and this impact could be clearly

seen in the 1980s. During the 1980s, the cost of electricity generated from wind dropped drastically down to 30

cents/kilowatt-hour [36]. By the end of 1986, there were about 6,700 wind turbines just in the California area which

had been installed at a cost of $1 billion and each turbine was capable of producing about 100 kilowatts [37]. We

can perform some simple calculations to obtain the cost of one turbine per kilowatt.

Cost of one wind turbine 254,149$700,6

000,000,000,1$ per wind turbine

Hence, the cost of one wind turbine in 1986 was around $149,254. However, it should be noted that this cost is for

every turbine and each turbine could produce about 100 kilowatts. We can obtain the price per kilowatt per turbine,

which is the common convention.

Cost of one wind turbine per kilowatt 493,1$100

254,149$

KW per kilowatt

Thus, the cost of a wind turbine was around $1,500 per kilowatt by 1986.

By 1990s, the cost of wind power was around 7 cents/kilowatt-hour [39]. This was a tremendous drop from the

price of 30 cents/kilowatt-hour just a decade earlier.

C. Current Costs

Wind power industry is an industry that has been constantly developing with turbines becoming more and more

efficient and energy costs falling rapidly. While comparing current costs, it is important to consider the recent

history. In 2009, the cost of producing electricity from new wind farms was ranged between 4 cents/kilowatt-hour to

9 cents/kilowatt-hour [40]. The range exists due to the changes in fuel prices. People often fail to realize that

although there might be a fall in the price of fuel energy at a point of time, the short term looks more attractive than

the long run. A recent study at Harvard found out that the hidden costs of coal can add up to be 9 cents/kilowatt-hour

to 27 cents/kilowatt-hour higher than the original price [40]. The original price of coal was about 6.7 cents/kilowatt-

hour as of 2011 [40]. This means that fuel prices could actually cost a total of about 15.7 cents/kilowatt-hour to 33.7

cents/kilowatt-hour. Looking at these figures, it is easier to select an option that overall costs low.

In terms of the costs of wind turbines, the turbines have remained more or less at the same price. It is vital to note

that even though wind turbines are not any cheaper now than they were back in 1980s, their efficiency has vastly

improved. In other words, wind turbines now provide more value for the money. The Department of Energy, as of

2012, reported that the average cost of wind turbines was down by $200/kilowatt from the cost in 2011 and down by

$300/kilowatt from the reported cost in 2009 and 2010 [41]. For example, the 2012 version of a wind turbine has a

list price of $1,500/kilowatt [42]. This is the same as the price in 1986. However, an individual could naturally

expect numerous improvements and advancements in the wind turbines in the 2012 version.

As of 2013, the wind prices have fallen further. Currently, the cost of producing electricity from wind is about 4

cents/kilowatt-hour [43].

D. Future Costs

The future of wind power looks bright. The wind industry has specified its goals and has set a target of installing

wind turbines so that 100 gigawatts of power can be produced by 2020 [44]. With this viewpoint, projects and

initiatives are currently being undertaken in order to secure a strong future for wind energy. For instance, a large

wind farm, known as The London Array, is being constructed in United Kingdom about 20 kilometers off the Kent

coast and this project will have 300 wind turbines capable of producing a total of 1 gigawatt upon its completion in

2015 [45].

Wind power in the future is anticipated to cost about the same with little fluctuations in the wind energy prices.

The US Department of Energy has anticipated that the wind energy costs would be around 5 cents/kilowatt-hour by

2020 and around 4.2 cents/kilowatt-hour by 2030 [46]. However, the department has also anticipated that 300

gigawatts of power would be produced by 2030 [46]. This means that the costs would follow a trend that they have

been following until now. The turbine costs and energy costs would more or less remain the same. Wind turbines

would still cost around $1500/kilowatt and wind energy would still cost about 4-5 cents/kilowatt-hour by 2030.

However, wind turbines in the future will be developed with new systems that would reduce the overall costs. Wind

turbines would be manufactured to improve efficiency of the turbine blades by as much as 35% [47]. This means

wind turbines would be more productive in the future and they would provide a better value for the money.

An interesting research is being done to substitute cars running on fuel with electric cars. Gasoline costs as much

as $4/gallon in some areas in the United States with the average being around $3.50/gallon. The American Wind

Energy Association recently suggested the idea of using wind energy to power upcoming electric cars across the

country [48]. In case this becomes a reality, the cars would operate at most at a price of 3 cents/mile [48]. On the

other hand, vehicles operating today on gasoline operate at a cost of about 14.4 cents/mile [48]. It is clear that about

11 cents/mile can be saved by switching to wind energy in the future.

E. Why are the costs falling?

Wind power has been developing at a rapid pace. Wind generators have gotten larger as the years have passed by.

Wind turbines went from 1.2 megawatts on an average to 1.6 megawatts in just three years [49]. This indicates a

33% increase in the average capacity of the wind turbines. In fact, currently wind turbines capable of generating 2.3

megawatts are available and it is anticipated that turbines capable of producing 7 megawatts will be available soon

[49]. The increase in the capacity, and thus the size of the turbines, causes a significant impact on the prices of wind

power. Newer and larger turbines can produce more electric power from the wind as compared to the older turbines

[49]. This means that more electricity can be produced at the same cost as before.

There is a further drop in the prices of wind power because newer wind turbines operate just as efficiently at

lower wind speeds as they would at higher wind speeds [49]. This is an advantage to the cities who do not receive

wind. In the past, windy cities were preferred for generating wind power. However, with time the wind turbines

have become much more efficient as they are able to produce more wind power at lower costs (in terms of the value

for money).

Apart from these factors, wind costs are also affected by fuel prices. There is always an uncertainty in the prices

of fuel. When the price of fuel decreases, the demand for alternative sources decreases. However, when the price of

fuel peaks, this drives investors, households and businesses to consider alternative options as the price for alternative

sources such as wind power falls. History has shown a falling trend in the costs of wind power. Historically, wind

energy would cost more than a dollar per kilowatt-hour but currently, wind energy costs only about 4 cents/kilowatt-

hour. Fuel prices have played a key part throughout the history of wind power.

V. CONCLUSION

Renewable energy sources such as solar power and wind power are also known as green energy sources. They are

known as green energy sources because of the fact that these sources produce energy from sunlight and wind.

Sunlight and wind do not have fuel costs, carbon costs and environmental costs. They simply have the cost of

converting sunlight and wind into energy. In other words, the costs incurred are the costs to install and use solar

photovoltaics and wind turbines. There are no other costs such as health costs or environmental costs associated with

these energy sources that could potentially hurt an individual. This is the reason why progress in renewable energy

industry should be made immediately in order to conserve and utilize non-renewable sources wisely before they run

out. Solar energy and wind energy should be brought into mainstream and people should be educated about the cost-

effectiveness of these energy sources.

Solar power historically cost more than $3/kilowatt-hour but due to tremendous improvements in science and

technology, it costs as low as 12 cents/kilowatt-hour today. Solar photovoltaics cost as high as $300/watt in the

1950s but they cost only about 74 cents/watt. This fall is price is drastic in terms of both energy costs and

photovoltaic costs. Theories such as the Swanson effect have been proposed which define a trend for the falling

prices of the solar costs. Historically, the solar energy has followed the Swanson effect quite closely. It is safe to

claim that the prices would fall further in the future. Solar photovoltaics are anticipated to cost as low as 25

cents/watt in the future. With such low prices, it is an investment worth making.

As far as wind energy is concerned, wind power has had its ups and downs throughout the history. Oil and fuel

prices have always affected wind energy and the reason of this is because wind power was never seen as a potential

source to produce energy. In 1970s, the wind power would cost more than $1/kilowatt-hour. However, wind

industry has developed at a very good pace. This could be clearly seen by the falling costs of wind power. Wind

power now costs as low as 4 cents/kilowatt-hour and is expected to stay around this price in the future. Wind

turbines have cost the same throughout the history but there have been numerous improvements in technology which

have contributed to the efficiency of the wind turbines resulting in better value for the money. Investments should be

made to produce electricity from wind generators as wind energy prices are at an all-time low and wind turbines are

improving each year with technology.

All in all, solar power and wind power have come a long way. Numerous researches have been carried out in both

the fields resulting in efficient solar photovoltaics and wind turbines. It’s time for solar power and wind power to

change the world by producing green energy.

ACKNOWLEDGMENT

I would like to acknowledge Professor Boyd Teemant for teaching me in the second half of the Fall 2013

semester. He introduced me to the class of research writing by providing some simple examples of how to paint the

picture for the audience. He then provided instructions on how to develop a thesis statement, thesis paragraph and an

outline. All of these elements have contributed greatly in my research paper. He also provided feedback often to

make sure I was on the right track and heading in the right direction. Professor Boyd Teemant has been very helpful

all along and I would like to thank him a lot for that.

REFERENCES

[1] Energy Sources-Nonrenewable. [Online]. Available: http://www.eia.gov/kids/energy.cfm?page=nonrenewable_home-basics

[2] Fossil Fuels. [Online]. Available: http://www.eesi.org/fossil_fuels

[3] S. Payne and T. Dutzik. (2009, June). The High Cost of Fossil Fuels Why America Can’t Afford to Depend on Dirty Energy. [Online]. Available: http://www.environmentamerica.org/sites/environment/files/reports/The-High-Cost-of-Fossil-Fuels.pdf

[4] M. L. Wald. (2009, October 19). Fossil Fuels’ Hidden Cost Is in Billions, Study Says. [Online]. Available:

http://www.nytimes.com/2009/10/20/science/earth/20fossil.html?_r=3& [5] E. Rosenthal. (2009, August 9). Portugal Gives Itself a Clean-Energy Makeover. [Online]. Available:

http://www.nytimes.com/2010/08/10/science/earth/10portugal.html?_r=1&

[6] E. D. Elliott. (2013). Why the United States Does Not Have a Renewable Energy Policy. [Online]. Available: http://www.cov.com/files/Publication/ce0ce0e2-1d8b-4ef4-8dd9-5bffa4af86f8/Presentation/PublicationAttachment/5b91deeb-1583-46b7-

a048-624472b2d90f/Why_the_United_States_Does_Not_Have_a_Renewable_Energy_Policy.pdf

[7] Solar Photovoltaic Technology Basics. [Online]. Available: http://www.nrel.gov/learning/re_photovoltaics.html

[8] Chapter 17: Renewable Energy vs. Fossil Fuels. [Online]. Available: http://www.energyquest.ca.gov/story/chapter17.html [9] (2009, January). Own Your Power. [Online]. Available: http://www.nrel.gov/docs/fy09osti/43844.pdf

[10] W. Reece. The History of Solar Power. [Online]. Available:

https://www.experience.com/alumnus/article?channel_id=energy_utilities&source_page=additional_articles&article_id=article_1130427780670

[11] Photovoltaic (Solar Electric). [Online]. Available: http://www.seia.org/policy/solar-technology/photovoltaic-solar-electric

[12] B. McConnell. (2013, April 24). Solar Energy: This is What a Disruptive Technology Looks Like. [Online]. Available: https://medium.com/armchair-economics/cbc9fdd91209

[13] M. S. Smith. (2011, June 21). Spring deadline lapses, still no solar panels on the White House. [Online]. Available:

http://www.nbcnews.com/id/43479824/#.Uolrp8Ssim5 [14] C. Cameron. (2013, October 8). Solar PV Cell Cost Has Decreased an Incredible 99% since 1977. [Online]. Available:

http://inhabitat.com/solar-pv-cell-cost-has-decreased-an-incredible-99-since-1977/

[15] Residential Solar and Wind Systems: What are the costs? [Online]. Available: http://www.bounceenergy.com/articles/green-energy/residential-solar-and-wind-systems

[16] (2002, April 3). 20 Years of Contemporary History. [Online]. Available: http://www.thocp.net/hardware/ti_calculators.htm

[17] Chapter Three Solar Energy. [Online]. Available: http://www.seco.cpa.state.tx.us/publications/renewenergy/solarenergy.php [18] J. Romm. (2013, October 6). Must-See Chart: Cost of PV Cells has Dropped an Amazing 99% Since 1977, Bringing Solar Power to Grid

Parity. [Online]. Available: http://thinkprogress.org/climate/2013/10/06/2717791/cost-pv-cells-solar-power-grid-parity/

[19] J. Farrell. (2013, June 10). The Coming Solar Electricity Transformation. [Online]. Available: http://cleantechnica.com/2013/06/10/the-coming-solar-electricity-transformation/

[20] Solar Industry Data. [Online]. Available: http://www.seia.org/research-resources/solar-industry-data

[21] M. Kasper and R. Koronowski. (2013, August 13). It Keeps Getting Cheaper to Install Solar Panels in the U.S. [Online]. Available: http://thinkprogress.org/climate/2013/08/13/2455121/solar-getting-cheaper/

[22] Renewable Energy for America. [Online]. Available: http://www.nrdc.org/energy/renewables/solar.asp

[23] H. K. Trabish. (2013, September 9). Solar or Offshore Wind: Which is Cheaper? [Online]. Available: http://www.greentechmedia.com/articles/read/Solar-or-Offshore-Wind-Which-is-Cheaper

[24] J. Baptiste. (2013, November 5). Apple to Create Thousands of Jobs in Solar-Powered Arizona Sapphire Plant. [Online]. Available: http://www.forbes.com/sites/jeanbaptiste/2013/11/05/apple-to-create-thousands-of-jobs-in-solar-powered-arizona-sapphire-plant/

[25] M. Chandler. (2012, December 30). Great Graphic: Solar Energy and Swanson’s Effect. [Online]. Available:

http://www.marctomarket.com/2012/12/great-graphic-solar-energy-and-swansons.html [26] G. Parkinson. (2012, February 19). 2015 Solar Module Price Forecast Down to 42 cents per watt. [Online]. Available:

http://cleantechnica.com/2013/02/19/2015-solar-module-price-forecast-down-to-42-cents-per-watt/

[27] K. Bullis. (2013, August 8). A Material That Could Make Solar Power “Dirt Cheap”. [Online]. Available: http://www.technologyreview.com/news/517811/a-material-that-could-make-solar-power-dirt-cheap/

[28] Z. Shahan. (2013, September 19). Cost of Solar Power 60% Lower than Early 2011 in US. [Online]. Available:

http://cleantechnica.com/2013/09/19/cost-solar-power-60-lower-early-2011-us/ [29] R. Heakal. (2009, September 6). What are Economies of Scale? [Online]. Available: http://www.investopedia.com/articles/03/012703.asp

[30] Produce Life Cycle. [Online]. Available: http://www.frost.com/prod/servlet/mcon-mktmeasures-life-cycle.pag

[31] How Do Wind Turbines Work? [Online]. Available: https://www1.eere.energy.gov/wind/wind_how.html [32] Wind Energy History [Online]. Available: http://learn.kidwind.org/learn/wind_basics_history

[33] Part 2-20th Century Developments. [Online]. Available: http://telosnet.com/wind/20th.html

[34] History of Wind Energy. [Online]. Available: http://www1.eere.energy.gov/wind/wind_history.html [35] Glenn Responds to 1970s Energy Crisis. [Online]. Available: http://www.nasa.gov/centers/glenn/about/history/70s_energy.html

[36] Is Wind Energy Expensive? [Online]. Available: http://www.windustry.org/resources/wind-energy-expensive

[37] D. R. Smith. (1987, November). The Wind Farms of the Altamont Pass Area. [Online]. Available: http://www.annualreviews.org/doi/abs/10.1146/annurev.eg.12.110187.001045

[38] Part 5-The Future of Wind Power. [Online]. Available: http://telosnet.com/wind/future.html

[39] R. L. Bradley Jr. (1997, August 27). Policy Analysis. [Online]. Available: http://www.cato.org/pubs/pas/pa-280.html [40] Z. Shahan. (2011, May 1). Cost of Wind Power. [Online]. Available: http://cleantechnica.com/2011/05/01/cost-of-wind-power-kicks-coals-

butt-better-than-natural-gas-could-power-your-ev-for-0-70gallon/

[41] The Cost of Wind Energy in the U.S. [Online]. Available: http://www.awea.org/Resources/Content.aspx?ItemNumber=5547 [42] GudCraft WG1000 1KW 1000W 12 Volt Wind Turbine Residential Commercial Wind Generator. [Online]. Available:

http://www.amazon.com/GudCraft-1000W-Residential-Commercial-Generator/dp/B006EFYB5U#productDetails

[43] Z. Shahan. (2013, August 11). US Wind Power Prices Down To $0.04 per kWh. [Online]. Available: http://cleantechnica.com/2013/08/11/us-wind-power-prices-down-to-0-04-per-kwh/

[44] Electricity from Wind Turbines. [Online]. Available: http://zfacts.com/node/244

[45] The Future for Current Energy Sources. [Online]. Available: http://www.planete-energies.com/en/the-energy-of-tomorrow/the-future-for-current-energy-sources/renewable-energy/the-future-of-wind-energy-276.html

[46] Wind Power Program FY14 Budget At-a-Glance. [Online]. Available:

http://www1.eere.energy.gov/office_eere/pdfs/budget/windwater_ataglance_2014.pdf [47] Wind Energy Costs Trending Down. [Online]. Available: http://www.windustry.org/news/wind-energy-costs-trending-down

[48] (2011, March 1). AWEA Believes Climb in Oil Prices May Create Opportunity to Wind Power Your Car. [Online]. Available:

http://electriccarstocks.com/2011/03/01/windstocks-net-awea-believes-climb-in-oil-prices-may-create-opportunity-to-wind-power-your-car/

[49] Cost of Wind vs. Fossil Fuels. [Online]. Available: http://meic.org/issues/montana-clean-energy/cost-of-wind-vs-fossil-fuels/