Electrification Through Alternative Energy Sources - Solar

Solar home system

After the formation of AEPC in 1996 under the Ministry of Environment, Science and Technology, solar energy has been gaining popularity as an alternative source of energy in Nepal. It is best suited for remote areas where electrification through grid becomes difficult. The solar energy is utilized to generate electrical energy which is then stored and used later to power simple electrical appliances such as light bulbs and heaters. If large solar modules are used, a considerable amount of power can be generated and modern appliances such as refrigerators can also be used.

Components of a solar home system

The schematic diagram of a solar home system with all the necessary components is shown below.

A solar home system is designed to convert solar energy into electrical energy for performing basic daily household activities. The major components of a solar home system are described as follows.

Solar panels

Solar panels consist of one or more photovoltaic modules which convert sunlight into electrical energy. They are mounted either on fixed or movable metal structures which tilt them appropriately to face the sun. The modules are connected either serially and/or in parallel to meet the required voltage and current demand. The PV panels can cost between 2.40 US dollars to 5 US dollars per watt and their efficiency usually lies between 15% - 16%.

Charge controller

A charge controller, also known as a charge regulator, is a circuit responsible for limiting the rate at which the battery is charged and discharged. Overcharging of a battery reduces its lifespan or performance and may pose a safety risk as well. A charge controller prevents the battery from overcharging and may also protect the battery from overvoltage. Similarly, it also prevents the battery from being drained completely (also known as deep discharging) or performs a series of controlled discharges to protect battery life.

Battery bank

A battery bank contains one or more batteries connected in series or in parallel depending on the voltage level or current requirement. It gets charged as the solar panel receives sunlight and is discharged whenever an electric load is connected to it. Generally, lead-acid batteries are used.

Inverter

An inverter is an electronic circuit which converts the DC power stored in the batteries into AC power. It is required whenever AC appliances are to be powered from the solar system. Sensitive electronic loads require a very good form of sinusoidal power which in turn requires a quality inverter. An inverter is one of the costly equipment and its quality shouldn't be compromised with if sensitive electronic loads are to be powered.

AC and DC loads

These are the electrical appliances which are powered by the solar system. DC appliances can be directly powered by the battery bank whereas appliances that consume AC power require the installation of an inverter.

In addition to these components, a solar home system may also contain a utility meter if the solar home system is to be connected to the distribution grid.

Advantages of solar home system

Some of the numerous advantages of the solar system are listed below.

1. Solar lights are a smoke-free, clean and excellent form of energy source for students in rural areas. They can also be used to power light bulbs during adult literacy classes at night times.
2. The solar home system is safe as there is no risk of fire or electric shocks.
3. The solar home system reduces the use of kerosene lamps and candles which make it an environment-friendly option of the light source.
4. Solar cooking is clean and reduces indoor air pollution significantly which in turn reduces respiratory disease occurrences.
5. Solar home systems can be tied up to the national grid and electrical energy can be sold to various utilities which can yield a reasonable profit.
6. Generation of electrical energy has a fixed routine as we will be aware of when the sun rises and sets. Hence, we can plan our electrical energy demanding activities accordingly.

Disadvantages of solar home system

There are not many disadvantages of a solar system. The few that exist are listed below.

1. Solar systems cannot generate electricity during night times. So in case large amount of power is required during night times, an additional source of power or a connection to the grid is required. Energy generated is also very less during cloudy or rainy days.
2. Solar home systems can be expensive for large ratings.
3. In case a solar system is connected to a grid, the inverter used in the system can produce harmonics which may require complex filters for elimination or cancellation.

References

1. Home Power. (2016).Solar Electricity Basics. Retrieved fromhttp://www.homepower.com/
2. John Wiley & Sons, Inc. (2016). The Basic Components of a Solar Home System. Retrieved fromhttp://www.dummies.com/

The image was taken from

1. http://lifefreeenergy.com/home-solar-system/