In this era of an environmental crisis which is constantly calling for higher usage of eco-friendly and sustainable means of producing electricity, the installation of solar panels and inverters for power generation is one of the best ways to contribute towards the betterment of the environment.
What are solar inverters?
A solar inverter is one of the most crucial elements of any solar energy system. It allows the conversion of direct current (DC) into alternating current (AC), thus making the energy usable for a wide variety of residential, commercial as well as industrial applications such as powering various instruments ranging from commercial and regular home appliances like refrigerators, TVs and microwaves to huge industrial equipment. Not only do solar inverters play a pivotal role in making eco-friendly energy applicable for the majority of electrical appliances, but they also help in monitoring the performance of the entire solar system and provide diagnostic data required to identify and fix any technical failures. Additionally, with inverters, users can also store excess energy in batteries or feed it back to the main power grid.
Role of solar inverters in solar PV systems
A solar inverter primarily plays the following roles in a solar power system:
- Conversion of DC to AC power
- Maximization of energy production
- Ensuring safe system operations
- Improved grid assistance capabilities
- Efficient tracking of power output
Applications and advantages of various types of solar inverters
The suitability and application of various types of solar inverters vary depending upon a number of criteria. Following are different types of solar inverters available in India along with their applications, advantages and other important details:
String inverters
They are directly connected to the grid and mostly do not come with the facility of battery back-up. These are the most commonly used solar inverters, for both business and household purposes. They generally have a 25-year design life along with a 5-year warranty.
Applications
This type of inverters are most suitable for residential as well as commercial purposes as it covers the ambit of small utility installations that generally fall under 1 MW. String inverters are best suitable for homeowners who are looking for lower-cost PV systems or properties with roofs that are uncomplicated and get consistent sunlight throughout the day.
Advantages
- Reliable technology
- Easiest to maintain as they are installed in easy-to-access locations
- Availability of 3 options of phases
- Pocket-friendly
- Highly efficient
- Lower installation cost as no specialized tools or equipment are needed
- High design flexibility
- Low power consumption
Central inverters
These solar inverters are highly efficient while being compatible with distinct features of the grid-like — fluctuation management, balancing, etc. This type of solar inverters are generally very huge and have their own storage room, exhaust system, etc. They are generally available with a capacity of 400 KW or more.
Applications
Central inverters are generally used for large commercial installations, industrial facilities or utility-scale solar farms as central inverters support uniform and consistent production throughout. They are generally not preferable for residential requirements as their much smaller counterpart — string inverters — are sufficient for fulfilling household energy requirements.
Advantages
- Centralised control leading to ease of management
- Optimised per watt cost
- Highly efficient
- Easy installation
Micro-inverters
As the name suggests, they are relatively smaller in size and capacity when compared to string inverters and generally come with a capacity in the range of 200-350 W. They are comparatively costlier yet more effective for areas with partial shading. They are installed individually on the back of each panel so the conversion from DC to AC is done for the specific panel to which it is connected.
Applications
These are best suitable for residential and commercial arrangements wherein the solar panels face different directions, hence combating inefficiencies created due to shading. It is costlier than string inverters but is the perfect solution for installations where there is a disparity in the amount of sunlight received by individual solar panels.
Advantages
Higher production of solar energy
Combats shade issues
Most suitable for solar panels facing different directions
Generally offered with a 25-year warranty
Trackability of each panel individually
Off-grid inverters
They are also known as stand-alone inverters because they are totally independent of syncing with a solar panel. Off-grid inverters receive energy for conversion from batteries that are charged with the help of photovoltaic arrays. This type of solar inverters are most commonly used in remote areas, where people wish to live completely off the grid.
Applications
Off-grid inverters are most suitable for remote or rural areas where the power grid is situated far away from the solar inverter and connecting the inverter with the power grid would be impractical and uneconomical.
Advantages
- Self-sustainable system of energy without requiring connectivity to a power grid
- Pocket-friendly
- Easy installation in rural areas where the grid is situated at far-off locations
- Functions regardless of any shutdowns or grid failures
- Reliable due to storage of power in batteries
In India, the prices of various solar inverters vary depending upon their type, phase as well as capacity. The capacity of off-grid inverters generally vary from 500 VA to 50 KVA and are available in various phase options ranging from 12V/1 Phase to 360V/3 Phase. Their costs typically vary between Rs 3500 and Rs 3,20,000.
Grid-tied inverters
It is a type of solar inverter that is capable of feeding the converted energy into the main power grid by matching their corresponding phase and frequency. These inverters are also capable of automatically shutting down for safety reasons as they are connected to the utility grid.
Applications
They are most suitable for homes and offices in urban areas which have access to power connections and lines to connect to the utility grid. Solar users who do not want to invest in batteries should opt for grid-tied inverters.
Advantages
- Easy feeding of energy into the power grid
- Easy installation
- Cost-effective
- Combats high electricity demand
The capacity of grid-tied inverters available in India generally varies from 1 KW to 50 KW and comes in 2 different phase variants — single-phase and three-phase. Their costs typically fall in the range of Rs 19,000 to Rs 2,30,000.
Battery-based inverters/Hybrid solar inverters
This type of solar inverters are a combination of off-grid and grid-tied inverters as they give you full independence from the grid while simultaneously syncing with the grid for days with low sunlight or high power consumption. They use a technique called ‘DC Coupling’ by which the battery is interfaced with the inverter.
Applications
This type of inverters are ideal for users who want to cut costs by utilizing energy produced from sunlight during daytime as well as store the same in batteries to support energy usage after sunset. Hybrid solar inverters are a perfect choice for buyers who are encountering frequent power outages, faults and excessive load-shedding.
Advantages
- Reduced power consumption from the grid
- Continuity in power supply
- Effective load management
- Low maintenance cost
- Efficient energy management as it facilitates the use of stored energy at times of high energy requirement
The capacity of hybrid solar inverters generally available in India varies in the range of 3 KW to 50 KW and come with various phase options which vary between 48V/1 Phase and 240V/3 Phase. Their costs typically are in the range of Rs 71,500 to Rs 7,90,000.