Rooftop Solar Power Installations
Rooftop solar power installations have assumed a lot of importance over the past few years, due to the increasing awareness about the need for renewable energy.
In India, the Government at the Center as well as the state levels knows the importance of solar power. Many schemes and activities have been started to promote solar power installation in India.
It is anticipated that by the year 2100 the temperature on the earth would have risen on an average by 1.8 degrees Celsius. In the worst possible case scenario, it could rise by 4 degree Celsius. High Carbon dioxide emissions cause immense damage to the environment.
In India, the Power sector in itself contributes around 50% of all emissions. A major part of the power generating activities relates to Non-renewable sources like Coal and Gas. With a population of 1.2 billion, we are the highest contributors of greenhouse gasses.
Regular power cuts, fluctuations, rising charges of non-conventional energy source make living tough here in India. However, the Sun is an enormous and unending source of renewable energy and India with a significant geographical presence on globe enjoys its riches.
What are Rooftop Solar Power Installation ???
Rooftop Solar Power installations are also known as Rooftop solar power systems or Rooftop Photovoltaic Power Systems. These are designed for roofs of commercial and residential establishments.
Types of rooftop solar power systems
There are mainly three types of Rooftop PV systems as listed below:
- On-Grid System
- Off-Grid System
- Hybrid System
On-Grid System: It is the most commonly used system and is also called the Utility Interconnected system. This allows the user to use both solar energy and electricity provided through the grid. This system has the provision of Net-Metering, where surplus solar power produced by cells, is redirected to the grid. The benefit of this is received in the electricity bills at predetermined rates. On cloudy days when solar cells are not able to produce electricity, the power from the Grid is used.
Off-Grid System: In this system Generators substitute the grids in the case of shortage in production of electricity. Electric generators are added as a part of the whole system. These generators act as power backups and provide electricity when solar cells are not able to meet the requirement due to cloud cover or excess load.
Hybrid System: These systems are an upgrade of the On-Grid systems. Here the user gets the benefit of storage also and can enjoy environment-friendly energy all the time. An inverter is added into the system. Instead of sending excess electricity back to the Grid, it is first stored in this inverter. Once the storage capacity is met, left over power is then directed to Grid.
Various Components involved in a rooftop solar system
The solar photovoltaic system is a fairly simple one. Following are the major components:
- Photovoltaic Panels
- Mounting equipment
- DC to AC inverters
- Wiring and fuse box connection
- Utility Power meter
Working of the rooftop solar installations
Photovoltaic cells are the primary and fundamental building part of a solar energy system. These cells are made of semiconductor material, like silicon. A Glass covers these silicon cells on top, allowing sunlight to pass through them on silicon cells.
- In a panel, these cells are connected in parallel circuits.
- Parallel connection helps in yielding better and higher current.
- The process of generating electricity using sunlight through this phenomenon is called ‘photoelectric effect.’
- Sunlight with a particular wavelength is the only possible source through which power is generated
- Every day, on an average we receive approximately 5.5 hrs of undisturbed solar light.
- This light hit these photons in PV cells on rooftop systems. These photons are converted into electrons of direct current (DC).
- These electrons are then transferred through wires into a DC to AC inverter.
- Here in the inverter, the ‘DC’ power commonly used in batteries is converted into AC (Alternate current).
- We use AC power in our homes and workplaces to run electronic appliances. Through a fuse box using power cables this AC power is distributed.
- A Utility Power meter acts as a manager of this system. It keeps track of all the power produced by solar energy. These meters are specially designed with the capability of backward spinning.
At night or at the time of a cloud cover solar cells reduce or stop generating electricity. At this stage, we use electricity from the standard grid and are billed in utility bills accordingly. When there is excess surplus power, these meters redirect them to the grid, resulting in the backward spinning of the meter.
The reverse spinning of meter helps in reducing energy bills. In Utility bills, net consumption is considered. That is why these meters are also called ‘Net Energy Meters’ and process of charging at net usage is called ‘Net Metering.’
Some Major advantages of rooftop solar installations:
- Uninterrupted power supply
- Environment friendly
- Reduced electricity bills
- Less maintenance
- Easily transportable
- One time investment
- Renewable energy source
- Government policies promoting solar rooftops
In 2015 through the Intended National Determined Contribution (INDC) as many as 162 countries including India submitted the steps they would be initiating at various levels to limit global warming. As part of these initiatives, India committed to generating 40% of its electricity through renewable sources of energy by the end of 2030.
Some of the policies are highlighted below:
- MOU signed between MNRE and NABARD for the promotion of SOLAR HOME LIGHTING SYSTEMS in rural India. It would be carried out under Jawaharlal Nehru National Solar Mission (JNNSM) with a target of 20000mw of solar power production by 2022.
- Both the centre and state governments are offering subsidies and support for solar energy projects.
- An easy to use mobile app ‘ARUN’ (Atal Rooftop solar User Navigator) has been launched to promote installation of Rooftop solar power installations.
- 7000 railway stations to receive electricity through solar energy.
Rooftop Solar Power Installations are set to become the major energy source in the coming years. And rightly so – with an unending energy source in the form of the Sun and other major advantages, we stand to gain in the form of high returns on the investment made in these projects.