This prospective describe the Howard Solar
Farm Alternative (HSFA). The HSFA is a project
to decrease the cost of utilities by 12 million
dollars annually at Howard. Presently, Howard
University purchases approximately 15-18
million dollars of energy per year which varies
depending on the winter. The solution is a
2.25 megawatt solar farm combining both on
campus rooftops and a two megawatt solar
farm in Beltsville, MD. The projected cost of
such a farm is between 85¢ to 65¢/Watt. The
approximate cost would be $29 million, this
figure takes in consideration the cost of energy
storage and conversion. Solar Panels generate
energy for about 6 hours daily. So for 24 hour
system the energy generated would be four
fold or $12 million/year. These are very
conservative numbers.

In July 2016, Mayor Muriel Bowser signed
the initial Renewable Portfolio Standard
Expansion Amendment Act of 2016. Under
the act, DC must procure 50% of its electricity
from renewable energy by 2032 and the solar
requirement is now 5%. If the utilities
companies don’t meet theses standards a
penalty of $500 per megawatt hour (MWh) is
assessed and is passed on to the consumer via
the Alternative Compliance Fee. This penalty is
commonly called the Solar Renewable Energy
Credits (SREC). DC customers paid over $15
million extra because of the shortfall in DCbased
solar facilities in 2016. The amount of
land required for a two mega watt facility
varies from 9-12 acres depending on the solar
cell technology. The plant typically has a 25
year life cycle. We are proposing both a grid
connected captive system and a sale of power
generated to 3rd party (alumni).

Solar power is radiant light from the sun that can
be converted into thermal and/or electrical energy.
The conversion directly into electrical energy is by
way of photovoltaic (PV) cells. Such a PV system
is active and will be the focus of this primer. Solar
is one of the cleanest sources of energy and is
renewable. Solar energy is measured in watt-hour
(the amount of solar energy in the world is
estimated at 173,000 terawatts that strikes the
Earth continuously). That is more than 10,000
times the world’s total energy consumption.
Photosynthesis in which solar energy is converted
by green plants into chemical energy which
creates the bio-mass that makes fossil fuels.
Expanding solar power is key to meeting the
climate and weather goals. According to the
International Energy Agency solar energy is the
fastest growing energy sector, will projections of
“more than 10% of the global electricity market by
2050”.

Photovoltaics cells commonly called solar cells
were first invented at Bell Laboratories in 1954.
The New York Times April 26,1954 proclaimed,
“ The beginning of a new era, leading eventually
to the realization of one of mankind’s most
cherished dreams — the harnessing of the
almost limitless energy of the sun for the uses
of civilization.” The Space industry has been
employing this technology since the 1960s to
power spacecraft and terrestrial satellites.The
oldest such satellites has just logged over 6
billion miles around the earth.

The Sun produces a spectrum of light on Earth
commonly referred to as the Solar irradiance
spectrum. This radiation is close to that of a
black body (thermal electromagnetic radiation
surrounding a body) at a temperature 5800 ºK.
The sun emits radiation over the most of the
electromagnetic spectrum from X-rays to
ultraviolet to radio waves. The Earth
atmosphere filters out so of the light and
protected us from some of the harmful radiation.
I have enclosed the spectrum solar radiation on
the Earth to understand the spectrum
completely.

Solar irradiance spectrum above atmosphere and at
surface. Extreme UV and X-rays are produced (at left of
wavelength range shown) but comprise very small
amounts of the Sun’s total output power.

How do Photovoltaics Cells Work?

Photovoltaics is the only way of conversing the
suns energy directly to light. A number of
materials absorb light particles (photon) and
release negative charge particles (electrons).
These type of materials exhibit the photoelectric
effect. During the energy crisis in the 1970s,
photovoltaic technology gained recognition as
an important source of power for earth
applications and several solar cell goals cost
goals were outlined, mainly, least than a dollar/
watt. Shown below is a map of the mean total
sunshine hours provided by the National
Solar Primer

Oceanic and Atmosphere Administration
(NOAA). Presently, according to the
Department of Energy, there is enough
capacity to power the equivalent of 5.7 million
average American homes.

Solar (PV) cells are made from semiconductor
materials, such as silicon used in the
nanotechnology/microelectronic industry. Thin
film solar cells use layers of semiconductor
materials only a few micrometers thick. Thin
film technology has made it possible for PV
cells to now double as rooftop shingles or roof
tiles. When light stokes this material electrons
are released from the semiconductor material
and these electrons can be capture and used
to power a lot, such as a light or a tool.This is
illustrated in the diagram shown above.

A number of the PV cells are electrically
connected to each other and mounted to a
support structure or fame commonly called a
photovoltaic module. The modules are design
to provide a known voltage typically 12 or 24
volts. The modules are wired together to form
an array. This array produces direct current
(dc) electricity. The cells can be single junction
or multi-junction. The multi-junction cells are
more efficient in conversing sunlight into
energy and convert more of the energy
spectrum of light to electricity.

The PV system comes in two favors; flat plate
and or concentrator. Both can utilized to
generate electricity. The flat-plate flavor just
covers the Earth with PV cells. The
concentrator approach focuses the light to a
spot, uses a smaller PV cells and a tracking
system. (Remember the magnifying glass you
got as a toy in CrackerJacks and focused it
down to a spot and burned ants, that similar to
the concentrator approach.) A comparative
manufacturing cost analysis of the two types of
systems is always considered. But for most
application the flat plate approach is more cost
effective.

Much of today research focuses on advance
multi-junction cells made from materials like
gallium arsenide and gallium indium phosphide
tunnel junction cells (also called tandem cells).
Such multi-junction cells have reached
efficiencies of around 35% under concentrated
sunlight. There is also a cheap PV cell
approach using multi-junction devices
employing amorphous silicon and copper
indium diselenide.
Total global solar energy generation capacity
averaged 40 percent annual growth from 2000
(1.5 GW) to (208 GW and 343 GW) by 2016
Solar is the fastest growing source of
renewable electricity in the world and in the
United States.

Recommended Articles
1. The Silicon Solar Cell Turns 50, by John
Berlin, http://www.nrel.gov/docs/fy04osti/
33947.pdf
2. Solar Cells: Operating Principles,
Technology, and System Applications,
Martin A Green, ISBN-13:
978-0138222703, Prentice-Hall, 1982
3. Third Generation Photovoltaics: Advanced
Solar Energy Conversion, Martin A. Green,
ISBN-13: 978-3540265627, Springer
Series in Photonics, 2005
4. Journal: Progress in Photovoltaics:
Research and Applications