Photovoltaic cell seems to be Greek to many, but solar cell is a layman’s term. A PV (photovoltaic) cell converts solar energy into electricity. An invention from the 1950s, it promised the cleanest renewable energy source. It has come a long way from silicon wafers. Made like computer chips, PV cells absorb and convert sunlight into electricity. They reduce the cost of energy required to light up your homes or companies. These cells are arranged into solar panels on open spaces like rooftops. Definitely, the solar cell is one with many benefits, such as:
• use of the most abundant and available renewable energy source
• saving your annual electricity bills
• low-cost maintenance
• zero waste and pollution
• long lasting source of energy for residential and industrial purposes
All these assurances, yet, have another side. Certain drawbacks follow PV cells, like:
• need for a wide-open space with the most sunlight for higher production of energy
• high initial installation charges
• power variation during times when the sunlight is low
• production of a large number of solar cells is not that environmentally friendly
• pretty difficult to dismantle and re-install at another location
Besides, solar panels have become the vogue for the past few years. They ensure clean energy for homes and offices.
Types of PV Systems
PV systems are divided into three based on configuration:
- Grid-tied system: This is a basic PV installation with an inverter. It is without a battery storage unit. It is cost-effective and has a simple design suitable for homes. It can lower your electricity bills, but will not work without a power supply.
- Grid-hybrid system: This is a suitable PV system for places with power outage. It has a battery back-up that enables the system to work even without power. But it is costlier and less efficient as compared to the grid-tied system.
- Off-grid system: This is suitable to power up places that are far off from the grid. Yet, it has to be designed to cover the entire load of the system as it is preferred in remote locations. As it has more components, it is costly as well.
Performance Trends in Solar Cells
With technological advancement, solar cells and panels have become essential for sustainable energy. It all began with Passivated Emitter Rear Cell to enhance the electron movement. It was substituted by HeteroJunction Technology, which improved panel efficiency. With Half-Cell Technology, power loss during energy absorption and consumption is minimized. By the 2010s, Bifacial Solar Panels were introduced that improved the efficiency by 40%. The popularity of solar energy came to its peak with Building-Integrated Photovoltaics.
An example is a rooftop solar panel in the form of a light-weight and durable solar shingle. It adds an extra sophisticated hue to buildings. Later, Concentrated Photovoltaic Cells with optical lenses or mirrors were invented. They absorb more concentrated sunlight. Further research has introduced Multi-Junction Solar Cells. All these developments have made solar energy available for everyone.
Solar energy has paved the way for various and a large number of industries. They depend upon it for their day-to-day functions. The average intensity of solar energy reaching the atmosphere is about 1360 W per sq.km. So, one sq.m of a solar panel can produce 700 – 800 W of energy. For instance, if a given solar panel produces 250 W, one requires 15 solar panels to run a 5HP motor.
The average American home needs around 20 solar panels to produce a month’s energy, which is about 850 kWh. For industrial purposes, solar farms or photovoltaic power stations are installed in open spaces. The average annual growth of them over the past decade has been 50%: the largest one spreads across 13,000 acres. As of today, more than 125,000 megawatts of electricity are produced in the country through solar power.
A 1MW solar power plant can produce 4000 units of electrical energy per day. This requires the plant to be ground mounted, unlike the rooftop solar shingles. It usually costs $1 for solar panel installation per watt. Yes, it is definitely costly. But in the long run, you are in for cost-effective, environmentally friendly energy consumption.
Furthermore, the federal solar tax credit enables one to claim 26% of the total cost of one’s solar system installation. Solar taxes reduce the tax that one owes as long as one is a homeowner with a solar panel system. If what one owes is less than the credit earned, the tax credit rolls over and can go on for up to five years.
Faults in the System
Like any device or system, solar panels are subject to faults. They can be:
• permanent, or
Permanent errors are caused by electrical or mechanical problems. These cannot be corrected. The only solution is often to get the faulty panel replaced as soon as possible. The temporary errors arise from problems with the wiring, inverter or modules. Even a cloudy day can affect the performance of the system. These faults must be detected on time and should be corrected, else one is sure to cause energy loss.
Performance of PV System
The photovoltaic performance is measured based on:
• the climate conditions
• configuration of the PV system
• the equipment used.
Various methods are used to find out the faults in the system as well as to monitor its performance in general. Performance alerts can be set in most systems to get notifications on time through messages or emails. This, along with a data acquisition unit, makes it easy for one to check the performance of the PV solar systems. Issues like temperature overload can be addressed with the aid of inverters.
These inverters are capable of alerting the owner or installer about the issues. Other data acquisition units are available that are not directly linked to the inverter. Such a generic data logging solution is cost-effective. Yet, the current trend is software-based portals that work through direct data connections.
Solar energy has revolutionized the energy utilization concepts of people around the world. Solar panels are used to channelize this energy. And various devices and technologies have emerged based on this invention.
• Solar water purifiers are far more affordable and efficient. Solar-powered desalination ensures clean drinking water for a large number of people.
• Installing floating solar farms on water bodies for more solar energy.
• Means of transport that run only on solar power will be available.
• Solar skins are soon to cover the rooftops: an ideal substitute for solar shingles.
And solar panels have been undergoing tremendous changes to make them more affordable and effective. More solar innovations are being introduced into our lives, enabling us to have a clean energy supply.