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THE FEASIBILTY OF SOLAR POWER

Thermal Design - MECE 4343

Prepared by:

SHAHMEER BAWEJA

ABSTRACT:

This document describes the way the solar power is being harnessed by various technologies for

several uses. The report also discusses on the political, economic, environmental and social

issues regarding the generation of solar power in the U.S. and their current/possible solutions.

Completed: December 28, 2014

UNIVERSITY Of HOUSTON

HOUSTON, TEXAS

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Problem Statement:

The U.S. is one of the largest consumers of energy as shown in Fig. 1

Figure 1: Energy per capita by country (World Bank)

The advent of solar power may decrease electricity prices, leading to decreases in tax revenues

for the government. Moreover, solar panels are relatively higher. There are other environmental,

political, and social issues as well.

Introduction:

All renewable energies, with the exception of tidal and geothermal, receive their energy from the

sun. Solar energy is one such example. It is radiant energy in the form of both light and heat

from the sun that is harnessed by various technologies such as solar photovoltaic (PV)

panels/cells and solar thermal collectors. The harnessed solar energy is usually converted to other

forms of energy such as chemical energy in solar fuels, electrical energy in lamps and generators,

and heat energy in HVAC systems and pumps.

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The most common use of solar energy is in the generation of solar power i.e. the production of

electricity from the sun’s rays. The most common technology deployed for this use is the

photovoltaic (PV) cells (a type of solar panels) which contain a semiconducting material that

emits electrons upon absorbing solar radiation (the photovoltaic effect). The solar panels fitted

onto the roof of a house and their relevant labeled parts are shown in Fig. 2 below:

Figure 2: Solar panels on a house rooftop [1]

The semiconducting material on the PV is usually silicone-based and placed between two

electrical contacts. The panels need to capture the maximum amount of sunlight with the

maximum possible time of exposure to produce as much electricity as possible (Fig 2.1a). A

sheet of glass (Fig 2.1b) protects the semiconducting material from hail, the dirt being carried

over by wind, and from wildlife’s reach. The semiconductor is also coated with an anti-reflective

substance (Fig 2.1c) to prevent scattering of the sun’s ray instead of absorbing it. When sunlight

strikes a panel and is absorbed, it knocks off electrons from the top surface of the atoms that

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make up the semiconductor (Fig 2.1d). The semiconductor has opposite electric charges on its

opposite sides, permitting the electrons to flow in one direction. The electrical contacts (Fig2.1e

and Fig 2.1f) take in this flow of current (Fig 2.1g) into the circuits. Electricity produced via the

PV panels (2) is Direct Current (DC). Before the current can be used for powering homes and

businesses, it has to be changed to Alternating Current (AC) using an inverter (Fig2.3). The

inverted current is then made to pass though the building’s fuse box (Fig2.4) and then from there

to the appropriate electrical appliances. [1]

Another type of solar panels used is the solar thermal which harness the sun’s energy through

solar thermal collectors to heat water than can be used in washing and heating as well as

indirectly produce electricity. The collectors absorb heat energy from the sun which may be used

to heat the fluid that is pumped through them. The fluid is then made to pass through the heat

exchanger where the heat is transmitted to the water in the storage tank. [2]

Solar Power in the U.S.:

Solar power provides unlimited source of renewable and free energy for electricity for various

appliances within various localities such as homes and offices. Unlike fossil fuels, the widely

currently used source of energy for power in the U.S., solar energy is a clean source of energy

that will never deplete in future. However, since the U.S. has abundant reserves of coal and gas

yet to be burned, fossil fuels will remain widely used source of energy until they deplete as they

are more energy effective than solar and relatively cheaper per kilowatt of hour (kWh) energy

produced. Yet, solar power are increasing in demand as fossils fuel resources are diminishing,

and oil and gas prices are steadily going higher. As of 2014, the U.S. is the third largest solar

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market after China and Japan according to Craig Lawrence on Quora. [3] The Solar power is on

the steady rise, and there is an estimation that solar will account for 13% of the national

electricity generation in 2050 up from a predicted 4% in 2030; the amount of PV installed in the

U.S. grew by 485 percent from 2010 to 2013. [4] Fig. 3 below shows the increased usage of PV

panels from 2008 to 2013.

Figure 3: The Growing Scale of PV by U.S. Sector [4]

By early 2014, the U.S. had more than 480,000 solar systems installed, adding up to 13,400 MW

of electricity which is enough to power 2.4 million homes. Since, there is plenty of sunshine

across the nation in the summer such as in Texas and California, solar energy has the potential to

supply a rapidly growing amount of electricity that is both environmentally and economically

attractive nationwide. When asked, greater than three-quarters of American politicians chose

solar energy as the source of energy that the country need to emphasize on most. [4]

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Technological innovations and investments will continue to boost further developments of solar

technologies, improving component, generation, efficiency and installation costs. The

minimizing of undesirable environmental effects through solar power will be playing a part in

enhancing solar energy’s significance. The policies that recognize the importance of reducing

reliance on fossil fuels will boost solar generation in the upcoming years. [4]. However, as with

all technologies, there are several issues that need to be dealt with.

Economics:

Due to the reduction in technology prices, innovative financing and developing system of solar

installers and financial partners, the PV panels are becoming increasingly cost effective for home

owners as shown in Fig 4.

Figure 4: The Falling Price of Solar PV by U.S. Sector [4]

“Prices for the household systems fell by 29% from 2010 to 2013, from an average of $32,000

for a 5-kilowatt system to under $23,000, before tax credits or other incentives” [4]. The steep

decline in installation costs of PV cells and policies favoring renewable energy led to an increase

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in Global Solar panel production from 24,000 MW in 2010 to 40,000 MW in 2013. [4] The

falling prices meant that the PV panel are getting more widely available. This led to increase in

the number of consumers which led to an increased demand for PV panels. The demand created

more jobs for solar manufacturing and development as shown in Fig. 5 below:

Figure 5: U.S. Solar Job Growth 2010-2014 [4]

Despite these favorable conditions for the potential widespread use of solar power, solar energy

still contribute a very small share of total electricity generation. The relatively high cost of solar

panels is the major reason. Solar collectors, panels and cells are very expensive to manufacture.

They can be as high as $1000 [5]. Whilst solar panels are expensive per megawatt, they provide

free source of energy/fuel i.e. the sunlight is free. In contrast, fuel from fossil fuels have to be

generated through the use of turbines, generator etc.

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Political:

Before the first oil embargo in 1973, the U.S. Federal policy was designed to foster growth of oil

and gas exploration and production for power. However, due to arising needs for renewable

energy for power, several policies promoting solar energy has been developed over the decades.

The Energy crisis in the U.S. in 1973 and 1978 led the U.S. Congress to realize the importance of

promoting renewable energy production and funded research and development (R&D) for solar

power and others form of renewable energy. In 1974, The Solar Energy Act was passed which

recognized the importance of solar energy as an energy source with a potential to fulfill the

demand of the nation going forward to non-polluting forms of energy. The Congress continued

promotion of solar energy with the 1978 Energy Tax Act (ETA) which The Energy Policy Act of

2005 provided $250 to federal officials to purchase solar systems in buildings [6]. The 1970s

energy crisis led to the call for promotion and development in solar energy and renewable source

of energy. However, despite these investments, solar energy still rely on financial incentives

from state and federal government in order to be cost competitive with conventional sources of

energy. The USA need a serious federal energy reform that will put a price on carbon that should

reflect the negative consequences of these conventional sources of energy which are mostly non-

renewable and pollutes the air like fossil fuels. In order for solar energy to be cost competitive

with conventional fuels, continuous funding must be provided for R&D alongside the federal

policy that will put that price on the carbon. As of now, the federal tax code provide investment

tax credits for solar power. There are mainly two issues with current policies regarding solar

power. Firstly, the subsidies for solar power are not large enough for solar to be competitive with

fossil fuels. Secondly, these tax credits must be financed in some way, either through higher

taxes or decreased spending. The most favorable solution would be to impose tax on carbon

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dubbed the “carbon tax”. The amount of tax and the rate at which it would increase would

determine the competitiveness of solar power with fossil fuels. The price on carbon would make

renewable sources of energy competitive but in the case of solar power, unless significant costs

have been reduces, solar is unlikely to be “least-cost generation option”. [6]

Availability:

Solar power provide unlimited and free source of energy and that comes from the sunlight from

the sun which is estimated to continue to exist for billions of years. On the other hand, huge

amount of fossil fuels are burnt at a plant and the energy release drive large turbines to generate

electricity. This suggests a finite and non-free source of fuel for such a non-renewable source of

energy. Solar energy can even generate electricity in remote areas that are not connected to the

national electric grid such as those solar powered satellites in space. Installations in these areas

can be cost effective rather than laying down several high voltage wires. [5] However one major

challenge affecting the widespread usage of solar power is that solar energy can only be

harnessed when it is daytime and sunny; cloudy skies can reduce its effectiveness. The solar

resource is both “variable”, showing predictable pattern, and “intermittent”, showing

unpredictable pattern i.e. the output generated is from solar insolation which cannot be manually

changed and depends upon the climate and weather. [7] This “variability” poses a threat to the

system stability and reliability. The intermittency issue can only be resolved through advanced

technologies such as demand responsiveness and improved energy storage capabilities but these

come with an added cost. [6] Moreover, since the panels’ job is to absorb sunlight, they cannot

be sheltered and therefore, sudden, harsh weather conditions such as thunderstorms or gale may

damage the panels and/or reduce their efficiency. [5] The solar panel output is maximized when

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the panels are directly facing the sun. Thus, panels in a fixed location is a disadvantage. The

panel need to be of movable type, changing angles to absorb light wherever it sets upon nearest.

[8] The inefficiency of solar panels due to weather and intermittency can lead to greater space

requirements. Larger and stronger panels may need to be developed which is too costly for an

average consumer. The availability of land becomes an extra problem for solar power generation.

A large-scale solar project need to operate on a large piece of land. Several acres of land may be

required per megawatt of electricity that can be produced. For example, “Apple’s 40 MW Data

Center Solar Farm in Maiden, NC, covers 200 acres of land while 125 MW of Arlington Valley

solar project covers some 1,160 acres of land” [4]. The large areas of land are required to

capture the sun’s energy since the solar installations generate a relatively less amount of energy

per unit land. Increasing the efficiency of solar power can reduce land requirements. The

technologies for making the panels effective are already available and are expected to develop in

the coming future. [7]. Along with careful site planning, locating solar projects on degraded land

can help minimize the land required. For example, “47 acres of former new York Freshkills

landfill on Staten Island, NY – once the largest landfill in the world – is being turned into a 10

MW solar farm” [4]. As for household solar panels, these can be placed on rooftop which

minimizes the need for required space for installation. [5]

Social:

The solar panels require little maintenance, since after installation and optimization, they are

very reliable as they actively produce electricity without the aid of any mechanical parts that

could fail. The PV panels may not fail mechanically, however, debris and dirt can reduce their

efficiency. In case of unexpected failures, maintenance costs can be very high. Solar panels are

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silent producers of energy, which can minimize disturbances in neighborhoods where residents

have problems with repetitive noises [8].

Environmental:

Solar Energy is almost 100% non-polluting since gases or harmful products are not emitted

during generation of electricity from the sun compared to generating electricity through burning

fossil fuels. The manufacturing of solar panels may involve emission of such pollutants but the

PV panels itself never emit any carbon dioxide or other gases for that matter. Moreover, the

emissions from solar manufacturing plants do not matter to the people as these plants may be

located far from neighborhoods but solar panels located near heavily polluted areas such that

those fossil fuel plants can affect the panel’s efficiency. [5] The panels use water minimally

whereas almost all power plants that generate power trough steam such use large quantities of

water. The panels, however, contains material that need to be disposed of carefully These may be

hydrochloric acid, sulfuric acid, nitric acid or hydrogen fluoride. The non-silicon solar cells

contain materials more toxic that traditional solar cells such as gallium arsenide, copper-indium-

gallium-diselenide. In order to keep these solar materials out of landfills, there have been several

developing recycling programs where End-of-life recycling approach is used. Many American

solar manufactures adopt this approach. Large solar project requires large areas of land which

means the developments of large solar manufacturing plants may pose a risk to plant and animal

habitats around. They can also pose risk to cultural and archaeological sites which need to be

preserved. The large plants also requires longer transmission lines which have their own

detrimental effect to the environment. [4]

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Discussion:

The solar energy advantages heavily outweighs its disadvantages. The solar panels employing

this energy are increasingly being used for residential purposes. This energy does not pollute,

neither emitting gases nor toxic substances in the process as in fossil fuels where carbon dioxide

is exhausted during burning of fossil fuels leading to the greenhouse effect resulting in increased

global warming. The greenhouse effect consequences are more serious than the toxic materials

that may be contained within the PV cells. The solar energy is available in infinite quantities for

an infinite time compared to the diminishing quantities of fossil fuels. Compared to this infinite

amount and time, the intermittency and variability of PV due to weather is negligible. The solar

energy is completely free to harness for electricity compared to the machinery needed to burn

fossil fuels to generate electricity. It may be expensive to purchase, install and maintain the PV

panels though but the prices are steadily going down due to favorable policies. The carbon tax is

soon going to make solar power competitive with fossil fuels as solar prices are going down. The

federal government began funding for the research and development of renewable energy that

included solar upon realizing the wrath unleashed by the oil spills and the adverse effects of

global warming

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Conclusion:

The future of Solar Energy usage seems bright in the U.S. Despite numerous issues with solar

power generation for electricity, the country possesses a key to a successful and prosperous solar

industry. There have been great increase in solar technology over the years that are bringing the

prices lower and making panels more efficient. Currently the solar cells can only convert 20

percent of sun’s energy to electricity. [4] This number is likely to increase with the increasingly

technological progress. Solar energy will the prime option once world’s oil reserves finish in an

estimated 30 to 40 years.

Figure 6: Solar Panels [4]

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References:

[1] "How Electricity Is Generated through Solar Power." EDF Energy. EDF Energy, n.d. Web.

27 Nov. 2014. <http://www.edfenergy.com/energyfuture/solar-generation>.

[2] "Solar Thermal Heating & Water Heating | How It Works." Solar Panels Plus. Solar Panels

Plus, n.d. Web. 28 Nov. 2014. <http://www.solarpanelsplus.com/all-about-solar/how-

solar-heating-works/>.

[3] Lawrence, Craig. "Why Is Solar Power in the US Less Common than Europe? -." Quora.

Quora, n.d. Web. 28 Nov. 2014. <http://www.quora.com/Why-is-solar-power-in-the-

US-less-common-than-Europe>.

[4] Rogers, John, and Laura Wisland. "Solar Power on the Rise." Solar Power on the Rise

(2014): n. pag. Union of Concerned Scientists. Union of Concerned Scientists, Aug.

2014. Web. 28 Nov. 2014. <www.ucsusa.org/solarpowerontherise>.

[5] Bratley, James. "Pros & Cons of Solar Energy." Clean Energy Ideas. Clean Energy Ideas, 29

Oct. 2014. Web. 25 Nov. 2014. <http://www.clean-energy-ideas.com/solar/solar-

energy/pros-and-cons-of-solar-energy>.

[6] Skarboe, Bjorne, Chris Azeredo, and Nate Ehsani. "The Future of Residential Solar PV." The

Future of Residential Solar PV (2010): n. pag. Texas A&M University, 10 Dec. 2010.

Web. 28 Nov. 2014. <http://energy.ece.tamu.edu/solarprimer/reports/G10.pdf>.

[7] Baker, Erin, Meredith Fowlie, Derek Lemoine, and Stanley S. Reynolds. "The Economics of

Solar Electricity." Annual Review of Resource Economics 5.1 (2013): 387-426. Apr.

2013. Web. 28 Nov. 2014. <http://energy.ece.tamu.edu/solarprimer/reports/G10.pdf>.

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[8] "Advantages and Disadvantages of Solar Power, Facts about Solar Power." Alternative

Energy. University of Minnesota, n.d. Web. 27 Nov. 2014.

<http://www.tc.umn.edu/~dama0023/solar.html>.