What Is a Grid Tied Inverter? Benefits, Uses and How to Choose One
In grid-connected solar systems, solar panels generate electricity, whilst the grid-tied inverter ensures that the electricity is usable, grid-compatible and manageable. It is widely used in residential rooftop solar installations, commercial rooftops, industrial and commercial premises, and large-scale solar power stations, and is suitable for projects with a stable grid supply that aim to reduce electricity bills and maximise solar energy utilisation. As a manufacturer of photovoltaic inverters, Sunways offers grid-tied inverter solutions for residential, commercial and large-scale projects, helping users to build efficient and reliable grid-connected solar systems.
What Is a Grid Tied Inverter?
A grid-tied inverter, also known as a grid-tie inverter or on-grid inverter, is a key component of grid-connected photovoltaic (PV) systems. It converts the direct current (DC) generated by photovoltaic modules into alternating current (AC) that can be used by homes, commercial buildings and the public grid. It also feeds surplus electricity back into the grid where permitted by local regulations. The US Department of Energy also regards this conversion process as the fundamental function of a solar inverter.
How Does a Grid Tied Inverter Work?
System Flow
Solar Panels → DC Power → Grid Tied Inverter → AC Power → Home / Business Loads → Utility Grid
Step 1: Solar Panels Generate DC Power
Photovoltaic modules first generate direct current, or DC power. However, homes, factories and commercial buildings use alternating current, or AC power. Therefore, solar panels cannot directly power most loads. A solar grid-tied inverter is required to act as an intermediary.
Step 2: The Grid-Tied Inverter Converts DC into AC
A grid-tied inverter converts DC power into AC power. High-quality inverters not only perform this conversion but also regulate the output voltage, frequency and power quality.
Taking some of Sunways’ grid-tied models as an example, their product specifications include THDi <3%, MPPT efficiency of 99.9%, rated AC frequency of 50/60 Hz, and anti-islanding protection, amongst other features. These parameters directly affect grid stability and long-term power generation quality.
Step 3: AC Power Is Used by Loads First
The converted AC power is supplied to local loads as a priority. Examples include household appliances, office equipment, factory lighting and production machinery. This is also the most direct benefit of a grid-connected PV project. You can prioritise the use of your own solar power, thereby reducing the amount of electricity drawn from the grid.
Step 4: Excess Power Can Be Sent to the Grid
When PV generation exceeds current electricity demand, the surplus power can be fed into the public grid, subject to local policies and the grid operator’s approval. Grid connection requirements vary across different countries, regions and grid operators.
Step 5: The Inverter Monitors Grid Safety
A reliable grid-tied inverter continuously monitors the state of the grid, including voltage, frequency, current, temperature and safety protection status. Should any grid anomalies occur, the inverter must respond promptly. This protects both the equipment and the grid, ensuring the long-term stable operation of the grid-connected system.
Why It Matters for Your Project
For residential rooftop PV projects, the inverter determines the stability of day-to-day power generation. For commercial rooftop or industrial and commercial power stations, the inverter also affects operational and maintenance efficiency as well as return on investment.
For installers and EPCs, choosing a reliable grid-tied inverter is critical for system efficiency, grid compliance and long-term operation.
If you are planning a residential, commercial or industrial solar project, Sunways can help you select the appropriate grid-tied inverter solution based on your system capacity, grid type and installation environment.
How Does a Grid Tied Inverter Work?
Grid Tied Inverter vs Hybrid Inverter vs Off-Grid Inverter
| Inverter Type | Grid Connection | Battery Required | Backup Power | Best For |
|---|---|---|---|---|
| Grid Tied Inverter | Yes | No | Usually no | Grid-connected solar projects |
| Hybrid Inverter | Yes | Optional / Yes | Yes | Solar + battery systems |
| Off-Grid Inverter | No | Yes | Yes | Areas without stable grid access |
Grid-Tied Inverter
A grid-tied inverter, also known as a grid-tie inverter, is suitable for photovoltaic projects with a stable grid. Its core function is to convert the DC electricity generated by photovoltaic modules into AC electricity that can be fed into the grid.
However, it should be noted that a standard grid-tied inverter is not a backup power supply. It typically requires the grid as a synchronisation reference. NREL’s description of grid-following inverters also notes that this type of inverter operates by tracking the measured grid voltage.
Hybrid Inverter
A hybrid inverter is suitable for projects where battery storage is required. If you wish to use solar power during the day and battery power at night, or to maintain power supply to critical loads during a power cut, then a hybrid inverter is the more appropriate choice.
It can connect PV modules, battery storage, the grid and backup loads. This type of system is better suited to users with high demands for continuity of power supply. Examples include detached houses, clinics, small businesses, farms and areas with an unstable grid. Systems equipped with solar off-grid capability and battery storage can provide emergency power to critical loads in the event of a grid failure.
Off-Grid Inverter
An off-grid inverter is suitable for areas without a grid or where the grid is extremely unstable. It does not rely on the public grid. The system usually requires a battery and may even be paired with a diesel generator. It is suitable for remote areas, island projects, off-grid buildings and so on.
Can a Grid-Tie Inverter Be Used Off-Grid?
No. A standard grid-tie inverter is not designed to operate independently off-grid. Standard grid-tie inverters require grid voltage and frequency as a reference. When the grid malfunctions or there is a power cut, they typically cease output to prevent power from being fed back into the faulty grid. This type of anti-islanding protection is a key safety feature in grid-connected PV systems.
Therefore, if you require backup power, please choose a hybrid inverter. If you require fully off-grid operation, please choose an off-grid inverter.
Benefits of Using a Grid Tied Inverter
If your project has a stable grid connection, a grid-tied inverter is usually the most straightforward and cost-effective option. High-efficiency power generation, priority for self-consumption, safe grid connection, and reduced system costs.
a. Lower Electricity Costs
The biggest benefit of a grid-tied inverter is lower electricity costs. During daylight hours, the solar system will prioritise supplying your on-site loads—such as household appliances, office equipment, factory lighting or production machinery. This means you can reduce the amount of electricity you purchase from the grid.
b. No Battery Required
Grid-tied solar systems generally do not require a battery. This directly reduces the initial investment. Batteries increase system costs, installation space requirements and maintenance complexity.
Therefore, if the project’s objectives are grid-connected power generation and reducing electricity bills, prioritise grid-tied inverters. Only consider hybrid inverters when customers require backup power, night-time electricity consumption or peak-valley arbitrage.
c. High Solar Energy Conversion Efficiency
Inverter efficiency impacts long-term returns. Do not underestimate a 1% difference in efficiency. For 100 kW, 500 kW or MW-scale projects, the long-term difference in power generation will be magnified.
For example, some of Sunways’ grid-tied models achieve maximum efficiencies of 98.1%–98.8%, with MPPT efficiency of 99.9%. Such parameters have a direct impact on power generation and system performance.
d. Grid Synchronisation and Safety Protection
Grid-tied inverters must remain synchronised with the grid. They need to match the grid’s voltage, frequency and power quality. Furthermore, they must be equipped with safety protection features.
Several of Sunways’ grid-tied series are equipped with protection functions such as DC/AC surge protection, anti-islanding, over-temperature, short-circuit and over-voltage protection, whilst also supporting RS485/WiFi/GPRS/LAN communication and remote firmware updates.
e. Suitable for Residential, Commercial and Utility PV Projects
The advantage of grid-tied inverters lies in their wide range of applications. They can be used for small residential rooftops as well as large-scale commercial and industrial power stations.
Sunways’ grid-tied inverters comprise the single-phase STS series and the three-phase STT series, with a product range covering multiple power ratings required for residential, commercial, industrial and large-scale PV projects.
Where Are Grid Tied Inverters Used?
- Residential Rooftop Solar Systems
Suitable for domestic rooftops, detached houses and small-scale residential PV systems. You can use a residential grid-tied inverter to prioritise the supply of rooftop solar power to your home’s electrical loads, thereby reducing the amount of electricity purchased from the grid. For this type of project, Sunways single-phase grid-tied inverters are better suited to low-power residential applications, offering simple installation and convenient day-to-day monitoring.
- Commercial Rooftop PV Systems
Suitable for the roofs of factories, warehouses, schools, office buildings and shopping centres. Commercial buildings typically have high electricity consumption during the day, which coincides perfectly with the period when solar power is generated. In such cases, choosing a commercial grid-tied inverter can help you increase the proportion of self-consumption and reduce long-term electricity costs.
- Industrial Solar Projects
Suitable for larger-capacity industrial and commercial solar projects. You need to consider not only power output but also features such as multiple MPPT channels, a wide voltage range, compatibility with high-power modules, thermal management design and remote O&M capabilities. - Utility-Scale Solar Plants
Suitable for large-scale ground-mounted power stations and centralised solar projects. These projects place greater emphasis on grid stability, generation efficiency and project-level operations and maintenance. Choosing a reliable three-phase grid-tied inverter can help you reduce system risks and enhance long-term returns.
How to Choose the Right Grid Tied Inverter？
1. Match the Inverter Power Rating with the PV System
You need to first confirm the capacity of the PV system before selecting a grid-tied power inverter in the appropriate power range. Residential projects typically range from 3kW to 10kW, small commercial projects from 10kW to 30kW, whilst commercial and industrial rooftop projects may require 30kW to 100kW or even higher.
| Project Type | Common Inverter Range |
|---|---|
| Home rooftop solar | 3kW–10kW |
| Small commercial PV | 10kW–30kW |
| C&I rooftop project | 30kW–100kW |
| Large commercial / utility PV | 100kW+ |
2. Choose Single-Phase or Three-Phase
Residential rooftop projects typically use single-phase grid-tied inverters, whilst commercial rooftops, factories and large-scale projects are generally better suited to three-phase grid-tied inverters. If your project has a higher load and greater grid-connected power, a three-phase solution is usually more stable and suitable for long-term operation.
3. Check MPPT Design and Voltage Range
The MPPT design affects the power generation performance of the PV system. If the project roof features multiple orientations, partial shading or a complex module layout, you need to pay particular attention to the number of MPPT channels and the MPPT voltage range. An insufficient MPPT configuration can result in power generation losses.
4. Confirm Maximum Input Current for High-Power PV Panels
High-power modules are becoming increasingly common, and module currents are also higher. You therefore need to confirm that the inverter supports sufficient maximum input current and short-circuit current.
5. Review Efficiency and Thermal Design
High efficiency translates to greater power generation returns, whilst good thermal management ensures more stable long-term operation. For commercial and industrial projects, efficiency and thermal management should not be overlooked.
6. Check IP Rating and Protection Functions
Grid-tied inverters are typically installed in outdoor or semi-outdoor environments, so the IP rating and protection functions are crucial. Common features include: IP65/IP66, lightning protection, anti-islanding protection, overtemperature protection, residual current protection, short-circuit protection and overvoltage protection.
Need Help Choosing a Grid-Tied Inverter?
Not sure which grid-tied inverter is right for your project?
Send us your project capacity, grid type and country. Sunways will recommend a suitable grid-tied inverter solution.
FAQs About Grid Tied Inverters
Q1. Is a Grid-Tied Inverter the Same as a Grid-Tie Inverter?
Yes. Grid-tied inverter and grid-tie inverter generally refer to the same type of product: inverters used in grid-connected photovoltaic systems. Their function is to convert the direct current (DC) generated by photovoltaic modules into alternating current (AC) and synchronise it with the public grid.
Q2. Are Grid Tie Inverters Legal?
Grid tie inverters are legal in many markets provided they are certified, correctly installed and approved for grid interconnection. However, you cannot simply consider whether the product is capable of grid connection. You must also verify local electrical regulations, utility company requirements and grid connection agreements. IEEE 1547 also explicitly sets out the technical requirements for the interconnection of distributed energy resources with the grid.
Q3. Are Plug-in Grid-Tie Inverters Legal?
Plug-in grid-tie inverters may not be accepted in many markets. Whether such products comply with regulations depends on local certifications, electrical standards and utility company requirements. Grid-connected solar projects should use certified equipment and be installed by a qualified installer in accordance with local grid connection procedures. The US Department of Energy also notes that grid-connected systems typically require an interconnection agreement to be signed with the electricity supplier.
Q4. Can a Grid-Tie Inverter Be Used Off-Grid?
A standard grid-tie inverter is not designed to operate independently off-grid. It typically requires a stable grid as a reference for voltage and frequency. In the event of a grid anomaly, the inverter will cease output to avoid the risk of islanding.
Q5. Can I Use 2 Grid-Tie Inverters?
Yes, provided that the system design, electrical wiring, monitoring configuration and grid approval all permit it. Multiple grid-tie inverters are commonly found in larger-capacity residential, commercial or industrial projects. You will need a qualified installer or EPC contractor to verify the AC-side capacity, protection configuration and grid connection requirements. Do not simply connect two inverters in parallel.
Q6. How Do I Choose the Right Grid-Tied Inverter?
When selecting a grid-tied inverter, you should focus on system capacity, grid type, MPPT design, maximum input current, conversion efficiency, protection rating, communication methods and local grid connection compliance. For commercial and EPC projects, low price should not be the primary criterion. Stable grid connection, remote operation and maintenance, and long-term power generation returns are more important. Standards such as UL 1741 are also commonly used for the testing and certification of grid-connected equipment.
Start Your Project
