PHOTOVOLTAIC POWER

Photovoltaic Power: Viability as a National Energy Source

Brian Rasmussen

4039351

EVSP320

Energy and Resource Sustainability

Dr. Daniel Reed

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PHOTOVOLTAIC POWER

Photovoltaic Power: Viability as a National Energy Source

INTRODUCTION

Photovoltaic (PV) power is one of the most viable and sustainable resources that are

available to our economy today. Powered by the sun, this resource is unlimited and does not

destroy or take away from other natural processes. The earth receives about 1,000 watts of

solar energy per square meter from the sun (Nersesian, 2010, p327). Plants have been

harnessing this technology since the dawn of time.

ELECTRICITY PRODUCTION

Electricity production is the primary focus of the photovoltaic or solar power although it

can be used for heating. The basic principle behind a PV electricity panel is that the solar

cell is made up of two semiconductor layers that is exposed to sunlight (Bent, Baker, Orr,

2002). One layer has a large portion of electrons and the other has a deficiency of electrons

(Nersesian, 2010, p325). When the two materials are put together and exposed to sunlight it

creates a direct current (DC) that is finally converted to alternating current (AC) and

transferred to a power grid (Nersesian, 2010, p325).

How PV Works

How photovoltaic energy works is that the PV can be either stand alone or be connected to a

grid to generate electricity (Goetzberger, & Hoffmann, 2005). There are also three different

generations of PV cells as well as many innovations that can be used to increase the efficiency of

those cells. One of the innovations of optical to electrical onsite power generation that is in the

works is using concrete integrated dye-synthesized PV (Hosseini, Flores-Vivian, Sobolev,

Kouklin, 2013).

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First Generation PV is a single junction cell that works by using screen printed single or

multi-crystal silicon wafers. The single crystal PV will produce at about 18-21% efficiency and

cost more than the multi-crystal version. The multi-crystal version accounts for about 63% of

the world market and costs less. The drawback with these is that they only work at about 7-14%

efficiency rates (Nersesian, 2010, p329). The lower overall costs make this type of cell more

attractive at about four dollars per Watt and costs continue to decrease as production streamlines.

Cost concerns in both material and costs resulted in the invention of second generation PV

designs. This type uses amorphous SI, Culn (Ga)Se2, CdTe/CeTES, or polycrystalline-Si

mounted on low-cost glass or similar surfaces (Bagnall & Boreland, 2008). The fabrication costs

decrease compared to first-generation and efficiencies increase to around 18.4%.

There is a third generation PV which uses triple junction thin film and produces energy at up

to 32% efficiency (Bagnall & Boreland, 2008). This type is expensive and used mainly on space

craft or satellites.

Large scale PV arrays can be designed to track the sun to maximize sun exposure which

increases photon exposure by 20% (Bagnall & Boreland, 2008). Arrays designed without

tracking mechanisms can incorporate specially designed nanostructured glass to improve

efficiency by about 10% (Bagnall & Boreland, 2008). This increases costs, but as printing

options continue to improve, these costs will soon fall to become more feasible. These

technologies and others could be available within the next 1-5 years that would significantly

increase efficiencies and decrease costs (Bagnall & Boreland, 2008).

Panel Alternative: Concrete

Another alternative to the traditional panels is PV concrete. This would be more in line with

large buildings that use large amounts of decorative concrete. This could be done using TiO2

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impregnated dyes to impregnate photo-catalytic concrete (Hosseini, Flores-Vivian, Sobolev,

Kouklin, 2013). This technology is still in the development phases, but has had successful proof

of concept experiments conducted. This technology would incorporate batteries into the

structure of the buildings to store energy for use during the night (Hosseini, Flores-Vivian,

Sobolev, Kouklin, 2013). This technology is also used in paints and can have efficiencies of up

to around 10%. This technology incorporates a junction between the conductive carbon

nanotube and the TiO2. This is still an improving technology and the team points to

incorporating thin-film in lieu of the dye to improve efficiency and lower costs (Hosseini, Flores-

Vivian, Sobolev, Kouklin, 2013).

Issues

There are two major issues that are affixed to PV power. First is operating at night. The issue

of operating at night is not hard to fix as a heat absorber can collect enough heat in six hours to

sufficiently heat water at 212 degrees for either or both a steam turbine and water tank that

would power a generator for the other 18 hours (Gonzales, 2012, p36).

The second is storing electricity during seasonally less sunny days. Batteries main issue here

is that they self-discharge. This is able to be overcome by using a hydrogen system that uses an

electrolysis unit to split water atoms and store the hydrogen and oxygen separately in pressurized

containers over the sunny summer months that can be later recombined or the hydrogen can be

used separately to be used as fuel during limited sun days to power a generator. The waste heat

can be used to heat the home or structure as well in the winter months (Voss, & Musall, 2012,

p22). This added benefit reduces the draw on any local power grid and opens the door to the use

of hydrogen power to increase overall efficiency of a hours or building (Nersesian, 2010, p347).

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IMPACTS

Environmental Impacts

Major costs associated with solar panels include silicon, aluminum, and steel (Bent,

Baker, Orr, 2002). These materials must be mined or recycled. The process to obtain these

materials can include strip-mining or other intrusive forms of acquisition. The recycling

alternative is the least impactful and would be better overall for the environment as it reduces the

total amount of waste that is put into dump sites. The PV cell once installed does not exude any

emissions (Bent, Baker, Orr, 2002).

Solar power can be used as either an electrical resource or as a thermal source . Thermal

solar energy can be used as passive systems, ventilation, water and other area heating, as well as

provide hybrid lighting to light building’s interior areas. Furthermore, the U.S. has the greatest

potential for solar energy harnessing of industrialized nations (Gonzales, 2012, 39).

Social Impacts

With the lack of major negative environmental impacts, including lack of greenhouse

gasses being produced, this seems to be a viable option for the United States as a major part of an

integrated alternative energy plan. The question is not why solar power, but why is it not a more

prevalent form of energy in the U.S.? From the 1950’s to the 1980’s the U.S. government did

not support the technological improvement of solar power as they chose to support nuclear

proliferation instead (Gonzales, 2012, p 39). This choice was due in most part to the focus on

weaponizing nuclear energy or focusing on improving fossil fuel technologies as opposed to

harnessing the solar potential. Other social impacts of limiting oil reliance include a reduced

footprint in the Middle East or other oil exporting countries (Gonzales, 2012, p61).

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This limited push in the past has created a situation that will require immense funding to

properly outfit buildings with sufficient PV sources to power the sprawled urban environment

that has been created in the United States. To assist in this, the government has given several tax

incentives as well as a 30% grant that was authorized by the Energy Policy Act of 2005

(Nersesian, 2010, p322).

Tax breaks and incentives are important as it takes about $16,000 to install a 2 kW panel

array that would be needed to power a single 2,000 foot home (Nersesian, 2010, p332). These

rebates may help the economics of the installation. If the rebate covered half of the cost and the

consumer was able to generate $16,000 over a 25 year period due to saved grid electrical

expenses, then that would equate a 2.8 percent return on that consumer’s investment. Money is

usually the deciding factor in either the business or consumer sector. By proving that there is a

profit or savings to be made it will assist in gaining the necessary support and momentum from

the population.

ANALYSIS

Photovoltaic power is definitely a sustainable option for use as a fossil fuel alternative. It

has been proven in places like Germany and Spain where they have build major subdivisions that

are entirely powered by solar power (Nersesian, 2010, p331).

This being said, PV is better suited for different parts of the country like places that get a

lot of sun like deserts, the Midwest, and large cities. This technology currently is best utilized as

a localized energy source and can be collected on every rooftop or in larger arrays that are tied to

a grid. The only constraints to this are limits due to capital, construction, manufacturing, or

power storage. Technology has come a long way to bridge the gap of efficiency as well as to

streamline the manufacturing processes that closes the difference in cost per Watt. The limited

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exposure to harmful fumes in the manufacturing processes can be mitigated through safety

procedures.

The lack of greenhouse gas emissions is an additional plus as there is no major

environmental impact after the panel is initially made until it is taken out of service and either

recycled or disposed of. Since the sun is the source of the energy, therefore, the resource is in

limitless in supply.

The positive impacts outweigh the negative impacts of this resource and it should be used

in more new construction and subsidies should be continued to support the retrofitting of older

buildings to reduce the draw on the existing power grid. The benefits are many; some of these

include the reduction of power draw to the conventional grid, the ability to supplement existing

power grids, and ability to be modular and scalable (Nersesian, 2010, p330). Since they are

small and self-contained, they can be set up in remote areas that are not feasible to support a new

power grid.

Pros

Unlimited clean resource that does not emit greenhouse gasses

High efficiency rate over time: many types of panels retain up to 92% efficiency

after 10 years and up to 80% efficiency after 25 years of use (Anonymous, 2011).

There are many government subsidies to offset the initial cost

Can be integrated into many forms of construction. Examples include concrete,

roof tiling, on building panels, etc.

There are flush fitting solar panels to be used in roofing that are also easy to

install by builders and attractive additions to homes (Anonymous, 2011).

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The use of photovoltaic concrete can offset the amount of land needed to support

buildings by reducing the need of external generating plants or the need of large

scale solar farms (Hosseini, Flores-Vivian, Sobolev, Kouklin, 2013).

Not able to be weaponized and is not able to be dominated or controlled by a few

parties as opposed to nuclear or fossil fuels that are able to be used (Gonzales,

2012, p8).

Cons

More expensive than fossil fuels

Large amount of funding needed to retrofit buildings

Needs large footprint for major generation farms (Bent, Baker, Orr, 2002).

Secondary emissions of toxic gasses during construction and disposal phases

(Bent, Baker, Orr, 2002).

CONCLUSION

Photovoltaic power has been proven in many places across the world. This is a limitless

resource that emits no greenhouse gasses and can produce enough electricity to power individual

buildings. New technologies in PV have reduced the cost to return ratio and coupled with its

modularity, making it a viable and growing resource that will reduce our reliance on fossil fuels.

This is an essential shift in focus that is being embraced by the government and utility companies

across the nation. The reduction in greenhouse gasses that will result in this shift will help

stabilize the air quality. Photovoltaic power will prove to be a key piece in the nation’s

alternative energy strategy.

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References

Anonymous. (2011). Photovoltaic Solar Roofing System. Chicago: Cygnus Business Media.

Accessed at http://search.proquest.com.ezproxy2.apus.edu/docview/857734253?pq-

origsite=summon

Bagnall, D. M., & Boreland, M. (2008). Photovoltaic technologies. Energy Policy, 36(12), 4390-

4396. doi:10.1016/j.enpol.2008.09.070. Accessed at

http://www.sciencedirect.com.ezproxy2.apus.edu/science/article/pii/

S0301421508004552

Bent, Robert, Baker, Randall, & Orr, Lloyd (eds). (2002). Energy: Science, Policy, and the

Pursuit of Sustainability. Accessed at http://site.ebrary.com/lib/apus/reader.action?

docID=10064667

Gonzalez, G. A. (2012). Energy and Empire : The Politics of Nuclear and Solar Power in the

United States.(pp 8, 36, 39, 61). Ithaca, NY, USA: State University of New York Press.

Accessed at http://site.ebrary.com/lib/apus/reader.action?docID=10622362

Hosseini, T., Flores-Vivian, I., Sobolev, K., & Kouklin, N. (2013). Concrete Embedded Dye-

Synthesized Photovoltaic Solar Cell. Scientific Reports, 3, 2727. Accessed at

http://www.nature.com/srep/2013/130925/srep02727/full/srep02727.html

Nersesian, R. L. (2010). Energy for the 21st Century : A Comprehensive Guide to Conventional

and Alternative Sources (2nd Ed).(pp 322, 325, 327, 329-332, 347). Armonk, NY, USA:

M.E. Sharpe, Inc.. Accessed at http://site.ebrary.com/lib/apus/reader.action?

docID=10425389

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Voss, K., & Musall, E. (2012). Net Zero Energy Buildings: International Projects of Carbon

Neutrality in Buildings. Basel, CHE: DETAIL. Accessed at

http://site.ebrary.com/lib/apus/reader.action?docID=10831575

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