solar energy basics.pdf
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Renewable energy is the future of energy and covers a range of natural energysources including wind, wave and solar. These types of energy are available without
resorting to burning fossil fuels or creating nuclear reactions. Renewable energy production
methods are by definition sustainable with the aim of having no negative impact upon
earths environment. MIB has concentrated on solar power in particular as part of our
business services as we believe this offers the most cost effective renewable energy solution
for non-utility clients.
Solar power is the ability to capture energy directly from the Suns rays as they reach the
ground or building roof. There are two forms of solar power available today for the small
business or the residential user both are fundamentally different from each other and both
give significant cost savings. Solar energy collection systems, more commonly referred to as
solar water heaters, are incorporated as part of the hot water system to preheat the water
before conventional heating, such as gas or oil completes the heating cycle until the desired
operating temperature is reached. These systems generally do not replace the house water
heater but rather they aim to reduce the overall running costs and increase efficiency.
Savings of 75% on monthly fuel costs are possible with this type of system even when other
heat reduction methods such as improved insulation materials are not also installed.
MIB Engineers20333 STATE HIGHWAY 249, SUITE 200, HOUSTON, TX 77070
www.mibengineers.com
MIB Engineers20333 STATE HIGHWAY 249, SUITE 200, HOUSTON, TX 77070
www.mibengineers.com
MIB Engineers20333 STATE HIGHWAY 249
SUITE 200
HOUSTON, TX 77070
www.mibengineers.com
PH:713-259-3301
Solar Electricity or Photovoltaic (Solar PV) systems are the second solar collection method
available today. These systems provide electrical energy directly from the suns rays. They
do this by using special semiconductors or cells that convert the light energy striking them
into electrical current. The cells are arranged into modules (panels) and these in turn are
mounted in arrays, usually on the property roof, to give the required power.
Both types of solar systems, Solar Heating and Solar PV, have a common drawback, that
without the light from sun during the day they are ineffective. This means that during the
night or during overcast days when electrical power or heat is required by the user, someother energy source must be used and there are several ways that this problem is
overcome. The remainder of this paper discusses only Solar PV systems and their use. For
more information on Solar Heating systems contact MIB Engineers.
The majority of Solar PV systems must use some means to store the energy that isnt used
immediately by the system load or to provide a supply when the sun is not available. There
are two principle ways that this is done, firstly by using batteries on the premises which is
called off grid solar or secondly by using the electricity supply company local grid
connection which is called grid tie. The majority of residential systems installed today are
grid tie systems mainly because costly batteries are eliminated.
MIB Engineers20333 STATE HIGHWAY 249
SUITE 200
HOUSTON, TX 77070
www.mibengineers.com
PH:713-259-3301
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A basic Off-Grid Solar PV system layout is shown on the diagram below:
The diagram above illustrates the basic elements of a system that is independent of the
electricity grid. This type of system is common on boats, RVs and remote buildings for
example hunting cabins or wilderness refuges, that need rudimentary electricity for lights,
radios and small appliances.
MIB Engineers20333 STATE HIGHWAY 249, SUITE 200, HOUSTON, TX 77070
www.mibengineers.com
A typical off-grid solar
system
A typical grid tied solar system
The most common type of residential installation is shown in the above block diagram.
This type of system does not have any form of storage on the property, instead any excess
power is fed back to the electricity company. These systems must use special meters to
allow a net billing or payment by the consumer. The exact type of meter arrangement can
vary from state to state. This type of system does have a major drawback because in the
event of a grid supply interruption the consumer cannot operate his system.
Additional systems using combinations of Solar PV, wind turbines and generators can be
designed and built but these more complex systems are beyond the scope of this shortdiscussion. Solar arrays are generally placed on the property roof as this generally gives
the most unobstructed view of the sun. This arrangement results in an added benefit of
shading the roof below which can significantly reduce the heat load particularly with single
story buildings in the summer months.
MIB Engineers20333 STATE HIGHWAY 249
SUITE 200
HOUSTON, TX 77070
www.mibengineers.com
PH:713-259-3301
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System Economics
There are several incentives to consider when choosing Solar PV installations. The most
compelling reason is that a location that requires electricity has no existing supply of power
and connection to the utility company will cost thousands of dollars. The only viable
alternative in these situations is wind turbines or engine driven generators. The justification
for Solar Power becomes more difficult when the case must be made and an existing utility
supply is already available. In the case of older properties the decision may be more difficult.
Installed costs for off grid solar are approximately (2011) $12/watt of peak generation
capacity. Average homes are in the 3-4Kw range yielding an total installed cost of around
$36-48k. Grid-tied systems are about 20% less costly because no batteries are required.
Provided that applicable federal and state tax credits are utilized this initial cost can be
reduced by up to 35% or higher and the remaining cost would normally be financed over 20
or 25 years. When the effects of net metering are taken into account the consumer would
expect no net outlay per month for electricity or even a slight profit.
The costs of Solar PV are usually spread out over a period determined by the projectfinancing arrangements. The figure below indicates how the costs of a typical off-grid Solar
PV system are modified over time from the installation.
Costs in Year 1 Costs in Year 20(based on 1993 do not include finance charges)
The costs of solar equipment continue to reduce from year to year and it expected thatviability of residential and small commercial systems will continue to improve. Accurate
system costs can easily be calculated and presented to each client before installation begins,
as many factors including array placement, current electricity usage and local credits and
tariffs vary with every installation. MIB can assist customers with cost benefit analysis for
each installation.MIB Engineers20333 STATE HIGHWAY 249
SUITE 200
HOUSTON, TX 77070
www.mibengineers.com
PH:713-259-3301