Characteristics of Solar Panels
Characteristics of Solar Panels


Open circuit voltage Voc can be defined as maximum output voltage at zero output current which means whole current flows through the diode (R is infinite). Short circuit current Isc can be defined as maximum output current at zero output voltage which means whole current flows through the load (R is zero). As we can see in figure 1,2 and 3 that Isc varies linearly in proportion with the illumination and Voc varies logarithmically with illumination. On the other hand Isc varies little with temperature and Voc is inversely proportional to temperature.
Continue reading
    Share:

ICICI Lombard General Insurance made an announcement today that solar park developers can now be covered under the insurance scheme and stated 
" The standalone insurance product gives comfort to lenders and investors and is a perfect solution to support project finance. The product will be distributed through the company’s branches and affiliated agencies. "

Alok Agarwal, Executive Director, ICICI Lombard General Insurance told that " The viability of solar power projects depends largely on the performance of solar modules. Also, the risks associated with this industry are different compared to the conventional power generation sources, such as thermal power plants. Thus, a comprehensive solar panel insurance product would help in covering the various risks associated with developing, building, operating, owning and investing in solar power projects. "

With the increase in Solar Industry all across the country to achieve the target of 100 GW solar energy by 2022, this insurance scheme will contribute a lot.

Agarwal added " This is a long-term product in which a solar park developer is protected for at least 15 years from the start date of commercial operation of solar parks. This will make the energy transition cheaper and generate more economic value. To enable this transition, we must frame the right policies, and must embrace the new era of solar power and uphold our promise to provide a cleaner environment for our future generations. "
Key problems such as degradation of PV modules, material ageing and under performance of PV modules will be covered in this scheme.
Continue reading
    Share:

Target of 100 GW Solar energy by 2022 is set up by Government of India, motivating Indian solar PV panel manufacturers but but cheaper chinese solar modules have created a burden on these companies and have risked the employment of thousand of workers. Due to this pressure continuity on Indian manufacturers we may see increase in bad loans next year.

Continue reading
    Share:
Occupational Safety and Health Administration (OSHA) is an agency for safety and health legislation and have specified certain mandatory measures for ensuring safety at work place. OSHA is an act passed by United States in 1970. Many countries including India follows safety measures provided by OSHA.

Guidelines of OSHA are divided into four categories :

1) Eye and face protection.

2) Head protection

3) Hand Protection

4) Foot Protection

Thus employers are the one who are responsible for providing safe and healthful workplace to their workers by following OSHA guidelines.
Continue reading
    Share:


What is Net Metering ??
    
Net Metering is an agreement signed by the system owner and utility which allows the owner to buy or sell the energy from utility using Net Meter which tracks energy exchange.


An Example

During early morning or evening hours when there is no sun, energy required to fulfill the load is taken from the utility grid and net-meter moves forward. While in day time, during peak sun hours the load is less and energy generated is in excess. This excess energy is fed back to the grid and net-meter moves backward.
NOTE- Electricity generated needs to be fed in real time as electricity travels with speed of light.


Advantage of using Net Meter

1) Financial Benefits - Per unit cost of excess energy generated is paid to the user by utility.

2) No need of battery backup - Excess energy from PV panels need not to be stored in battery as it can be fed directly to grid. Thus there is no battery capital cost and maintenance cost.

Feasibility of Net Metering System

Usually DISCOM that are active in your area do a feasibility check of your system under certain guidelines such as - The total capacity of solar plant to be installed should not be more than 30% capacity of the distribution transformer.
      Other guidelines vary as  per local DISCOM's criteria.



       
Continue reading
    Share:
For the past few years, much research has been conducted regarding standalone and grid-connected Renewable Energy (RE) sources all over the world. The HOMER tool has been used to analyze a hybrid electric supply system (hydro/PV/wind/ biomass) and to find the optimum sizing of components for a diesel-based RE system. The name HOMER is an abbreviation of “Hybrid Optimization Model for Electrical Renewable” and it is developed by U.S. National Renewable Energy Laboratory (NREL). HOMER Pro allows simulation of various combinations of Solar PV modules, Wind turbines, and Biomass-based generators. Proper functioning of HOMER requires an understanding of its three core capabilities – 

       Simulation: At its core, HOMER is a simulation model. HOMER simulates a viable system for all possible combinations of the equipment that is to be considered. Depending on the problem, HOMER may simulate hundreds or even thousands of systems.

     Optimization: The optimization step follows all simulations. HOMER sorts all the simulated systems and filter them according to criteria defined by a user so that the best possible fits can be observed.

    Sensitivity analysis: This is a step that HOMER allows to model the impact of variables that are beyond our control, such as wind speed, fuel costs, etc., and see how the optimal system changes with these variations.

     HOMER PRO is a good tool........ DO check it out.
     
     To get familiar below is a screenshot of HOMER PRO home screen.


Continue reading
    Share:
Government announce various schemes to provide continuous power supply to rural India. Still, hundreds of villages use chimney lamps. ‘Electrified’ villages still waiting for power. In many villages, electricity poles have been installed, but lines have not been laid. In order to improve energy security in such places  we need “DC Solar Micro Grid” for providing free electricity which will be free upto a particular limit and then chargeable. Energy is a strategic research priority and we must be committed to deliver solutions to the global energy challenge.

 Smart Grids is a broad concept that covers the entire electricity supply chain and is characterized by the use of technologies to intelligently integrate the generation, transmission and consumption of electricity. We define the concept of Smart Grids as one that embraces all measures in support of immediate and future integration of automation and control technologies into local, national or regional electricity infrastructure. The concept aims to optimize grid systems and their operation, integrate high levels of renewable energy penetration, and improve the reliability and efficiency of electricity supply. In addition to being smart, this system guarantees access to modern energy services without marginalizing the poor.

Concept :
The concept aims to optimize grid systems and their operation, integrate high levels of renewable energy penetration, and improve the reliability and efficiency of electricity supply. In addition to being smart, effective and economical measures will be taken in order to guarantee access to modern energy services without marginalizing the poor.

Applying the Concept :



Distribution Design : Distribution using smart sensors, flexible and intelligent switches and interrupters at critical points on distribution circuits will minimize the extent of outages and increase the speed of restoration, while keeping cost increases at a minimum. Smart distribution technologies will be especially important for addressing rural electrification needs and minimize connection costs.

DC Micro Grid : Cost is further reduce through the implementation of (DC) micro‐grids. While losses can be reduced through saving layers of DC/AC power conversion, the more expensive protective devices required for fault management and control, such as coordinated power converters, add complexity and outweigh some of the potential savings.

Demand Side Management : This usually affects the poorest electricity consumers the most. The DC load such as LED Bulb, LED Tube, DC Fan, DC TV each with 12V rating will be used which is of lower wattage rating, thus reducing the demand. This could also encourage people to adopt energy efficient practices for peak times, either because of higher tariffs or dependency on batteries.

Charging Through Prepaid System : While rural electrification is a priority, millions of people live near the grid but cannot afford a connection. For these people, charging stations ensure a minimum level of access to electricity services. For eg. Anyone can got to the recharge shop and ask for electricity and can buy it if its free daily consumption is over.
Continue reading
    Share:

Before understanding Tilt Angle, we should get familiar with Latitude and Longitude.

Latitude and Longitude are imaginary lines that are drawn on maps for locating different places on earth. Latitude is the distance toward north or south of the equator and longitude is the distance toward east or west of prime meridian. Both equator and prime meridian can be seen in the figure below.


Tilt angle is the latitude of the destination where you want to install the solar plant. In summer when sun is available for longer duration, Tilt Angle is Latitude - 15 degree.
And in winters when sun is available for shorter duration the Tilt Angle is Latitude + 15 degree.

If you live above the equator line then you should point your panels due south. If you live below equator line then your panels should be pointed north.
Continue reading
    Share:
1. Solar PV Panel
It converts sun’s rays into electricity by exciting electrons in silicon cells using the photons of light from sun. 

2. Battery Bank
For Solar plant lead acid deep-cycle storage batteries are used for storing the energy generated by PV panels for providing backup to the system when sun is not present.  DOD is the complement of State of Charge (SOC). It describes the degree to which a battery is emptied relative to its total capacity. This affects the length of the battery’s operational life, as well as the total number of kilowatt-hours it will be able to store over its lifetime. DOD should be taken as 50%. If a lead-acid battery is discharged 100% every time its electrolyte will quickly degrade compared to if it were only discharged to a maximum of 50%. 
3. MPPT Charge Controller
Maximum Power Point Tracker (MPPT) is a kind of charge controller that utilizes the solar panel power to its maximum potential. The MPPT fools the panels by giving output with different voltage and current which will allow more power to go into the batteries. Output voltage and current from the solar panel is monitored by MPPT and operating point that will deliver that maximum amount of power to the batteries will be determined. MPPT can accurately track the always-changing operating point where the power is at its maximum, thus the efficiency of the solar cell will be increased. Many algorithms have been developed for tracking maximum power point of a PV generator such as Perturb and Observe (P&O), Incremental Conductance, and fuzzy logic based tracking techniques. These algorithms vary in effectiveness, complexity, convergence speed, sensors required and cost.
4. Power Converter
HRES that contains both AC and DC elements requires a converter. It acts as both rectifier and inverter accordingly. 
Continue reading
    Share:

1. First Generation Wafer Based Silicon Cells
 Silicon wafer based technology is the oldest and most popular due to its highest power efficiency. First generation solar cells are of two types Mono-crystalline and Polycrystalline solar cell.

1.1. Mono-crystalline Solar Cell
Mono-crystalline cells are made by cutting a block of silicon that has been grown from a single crystal.  These are oldest technology based solar cells. Efficiency of these cells varies from 14% to 17.5%. Performance of these cells is not good at high temperatures but occupies significantly less volume to produce same amount of power. These are two times more expensive when compared to thin film solar cells. Area required for 1 kW solar panel is 6 to 9 m2 .

1.2. Poly-crystalline Solar Cell
 Polly-crystalline cells are made by cutting from multifaceted silicon crystal This technology is comparatively an economical choice. Efficiency of these cells varies from 12% to 14%. Similarly as in Mono-crystalline solar cell performance is not good at high temperatures but occupies significantly less volume to produce same amount of power. It is also two times more expensive when compared to thin film solar cells. Area required for 1 kW solar panel is 8 to 9 m2 .

2. Second Generation Thin Film Solar Cell
 Second Generation Thin Film Solar Cell cells are much more economical when compared to first generation silicon wafer solar cells. Thin film solar cells are not made up of any crystal. They are made by depositing a thin layer of silicon that is deposited on a base material like metal or glass. Light absorbing layer of silicon wafer cell is around 350 m thick while light absorbing layer of thin film solar cell is quite thin .

2.1. Amorphous Silicon Thin Film Solar Cell
 Amorphous Silicon thin film solar cells are comparatively less costlier and easily available all around. “Amorphous” means there is no definite arrangement of atoms or no definite structure. Temperature performance of these cells is good at both low as well as high temperatures and efficiency of these cells varies from 4% to 8%. These cells require less installation time and require much larger space. Area required for 1 kW solar panel is 13 to 20 m2 .

2.2. CdTe Thin Film Solar Cell

 For making a practically economically viable PV system Cadmium Telluride (CdTe) as it is 50% less costlier than conventional silicon cell and it’s efficiency varies from 9% to 11% . Area required for 1 kW solar panel is 11 to 13 m2. This cell technology is toxic due to the presence of Cd which is a heavy metal and toxic. Thus manufacturing is limited due to environmental hazards associated with Cd..


3. Third Generation Solar Cells         
It is the new technology that has evolved in the market now-a-days but are not studied deeply.

3.1. Nano Crystal Based Solar Cell
 These are generally known as Quantum Dots (QD). QD refers to the crystal having small size of the order of nano meters such as porous Si. Efficiency of these cells varies from 7% to 8%. These cells have excellent thermal stability and offer a wide range of product designs. It is also 50% less expensive than Si cells and requires less installation time and large space.

3.2. Dye Sensitized Solar Cell
Many studies are going on Dye Sensitized solar cell (DSSC) for improving it’s performance efficiency. These cells use dye molecules between different electrodes. These cells consists of four components – semiconductor electrode, a dye sensitizer, redox mediator and counter electrode. Efficiency of these cells is around 10% and performance is not good at high temperature conditions.

3.3. Polymer Solar Cell
Polymer solar cells (PSC) are flexible in nature because of the presence of polymer substrate. Efficiency of these cells varies from 3% to 10% and performance of these cells is not good at high temperatures. Due to its flexibility it offers wide range of product designs and requires less installation time.

3.4. Concentrated Solar Cell
In Concentrated solar cell (CSC) technology large amount of solar energy is concentrated over a tiny region of a solar cell. The principle of this technology is based on optics. When solar radiations are concentrated on a point, ample amount of heat energy is generated and converted into electricity using integrated power generator. Efficiency of this cell is 40% and offers excellent thermal stability.
Continue reading
    Share:


Circuit of solar cell consists of current source (Ish) in parallel with a diode. As in practical conditions no solar cell is ideal, so a shunt resistance and a series resistance is considered in the circuit as shown in figure. RS is the series resistance and RSH is the parallel resistance and ID is the diode current.When terminals are short circuited, the output voltage becomes zero and the short circuit current (Isc) becomes equal to current source (Iph). When we open circuit the terminals output current becomes zero and source current (Iph) becomes equal to diode current (Id).
                       I = Iph – Io(  - 1) = Iph – Id                                        
                                              Iph = qA x efficiency x photon flux                                                    
                                                          Voc =  ln (  – 1)                                                
Where,
I = output current,
Iph = photo current,
V = output voltage,
q = electron charge,
k = Boltzman contant,
T = operating temperature (kelvin),
Id = diode current,
Io = reverse saturation current of diode,
A = collector area.
Continue reading
    Share:

Solar cells are of tiny sizes and produce approximately one watt power. Figure (a) represents solar cell which produces voltage around 0.5V to 0.6V. As the voltage of solar cells is quite low so these cells are connected in series for getting sufficient output voltage. The series connection of solar cells is called solar module which is shown in figure (b). The voltage of solar modules are usually multiple of 12 V so that they can be readily used based on the system requirements as shown in figure (c). The resultant voltage of solar array is called system voltage. 
Continue reading
    Share:

Looking into the history Alexandre-Edmond Becquerelin 1839 witnessed the first observation of Photovoltaic effect. Russel Ohl in 1946 invented the first modern solar cell made up of silicon. “Photo” means pertaining to light and “Voltaic” means producing voltage. After 100 years of research, the conversion of sunlight to electricity is not just an experiment but much more. Latest PV technologies are based on the electron-hole creation principle in each cell having two different material layers (P-type and N-type) semiconductor which are separated by a junction. As seen in the figure, when a photon from sunlight strikes the semiconductor, free electrons and holes with higher energies are created. An electric field is required for inducing these higher energy electrons and holes to flow out of the semiconductor and do the useful work. In solar cells, this is done by using p-n junction as it is known that an electric field exists across p-n junction and by this electrons are swept in one direction and holes in another.
Continue reading
    Share: