solar energy basics.pdf

7/29/2019 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


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.


SUITE 200

HOUSTON, TX 77070


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.



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.


SUITE 200

HOUSTON, TX 77070


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


PH:713-259-3301

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