An inverter is essential for a solar panel system. Its job is to convert the Direct Current (DC) generated by the solar panels into alternating current (AC). It is necessary to make solar energy usable for day-to-day activities. There are different types of inverters in the market but central inverters and string inverters are the most talked about. You also came here to know between Central Inverter vs String Inverter which is better. Well, let’s find that out in this blog. But before that let’s try to establish a basic understanding of what is a Central Inverter and what is a string inverter.
What is a Central Inverter? What is a String Inverter?
Typically, central inverters are large, box-shaped devices. They are installed in the central location of the solar energy system. They usually range from several kW to 100 MW. They are used in larger solar energy systems, like the ones installed in utility-scale solar farms, and commercial, or industrial buildings.
A string inverter is an inverter that is connected to the solar array that uses multiple strings for connection and supply of current. There are multiple and different ways of attaching a string of solar panels. A common solar array comprises of 250Wp each for around 15 solar panels. Each solar panel featured to be is joined to the string inverters in series. The inverter combines the direct current and converts it into an alternating current. The input voltage rating of the inverter is directly propositional to the number of connections in a string inverter.
Central Inverter vs String Inverter: What’s the Difference?
When you will compare the central inverter vs string inverters you will find that there are many differences such as a string inverter having a much smaller capacity than a central inverter. String inverters are designed to be modular and scalable. They are built in such a way that they are connected together to get a higher output of AC energy.
Single-string inverters provide a much lesser capacity than a central inverter. They are called the Central inverter because they tend to incorporate long PV strings, other than the spread-out architecture seen with string inverters.
The capacity of each type of inverter is varying and shifting toward the middle as central inverters have been narrowing in size and now range in size from a larger inverter as 4.5MW to a tinier one as 700kw and you will also see the size increase of a string inverter and ranges between 1kw to around 300kw or 350kw each.
Central inverters have higher efficiency in regard to converting DC electricity to AC electricity. On the other hand, string inverters are not as efficient as central inverters.
Central inverters are used in utility-scale solar or large-scale commercial installations. On the contrary, a string inverter is used in smaller commercial or residential solar installations.
Central inverters are more expensive and have more maintenance demands in comparison to string inverters.
What is the Advantage of Central Inverter and String Inverter?
Another major question people ask before choosing between central and string inverters is in regard to their advantages. So, let’s find out what is the advantage of a central inverter and string inverter through these points-
These inverters provide many profits to both the owners and the providers so let me tell you what is the advantage of central inverters through these brief points:
- Lower costs
- Capable of producing much higher power
- It provides credibility due to its presence for a long time and its use in the market.
- It is reliable as central inverters are placed in protective environments.
Also See: How to Connect Hybrid Inverter to Grid?
After seeing the advantages of the central inverter let’s have a look at the advantages of the string inverter, they are as follows:
- Less expensive most cost-effective.
- An efficiency rate of up to 98% for converting DC energy into AC energy
- Easy maintenance
- String inverters are easy to scale down or up to satisfy the needs of the business.
What is the Disadvantage of Central Inverter and String Inverter?
Well, there is nothing in this world that can claim to have zero disadvantages, the same is the case with both these inverters. So, let’s find out what is the disadvantage of central inverters and string inverters through these points.
The disadvantage of central inverters are as follows-
- Higher replacement cost
- It can have a problem of a single point of failure but it affects the performance of the entire system.
- It has a higher risk factor which could lead to a serious problem for both the owners and operators.
Also Read: What are Enphase Micro Inverter Problems?
Now let’s check on the disadvantages of the string inverters and they are as follows:
- String inverters offer you the capability of limited performance monitoring. They do not allow you to track the level of the individual panel which makes it difficult to identify the performance of each panel.
- One panel of the string inverter affects the entire performance and functioning of the entire inverter thus reducing the results of energy production. It gives you the highest risk of failure.
- String inverters are not made for limited-space businesses as essentially they need more space for installation.
Central Inverter vs String Inverter Which is Better?
Now that you are aware of both the central inverter and string inverter so let’s see if the central inverter vs string inverter which is better? First of all, I will advise you to do a detailed study of both the string inverter and the central inverter according to your uses, temperature around, and cost before you install. Based on all information provided, I would suggest that the central inverters will have an overall lower yield of around 2-4% per annum where as the String inverters will provide you with an average of around 2-5% per annum.
With an answer to this, basically what you are looking at is a choice between a higher ROI and higher yield or lower CAPEX over time. In general, the string inverter produces a lower LCOE, which results in the recovery of money that you have spent on CAPEX as it produces more efficient power.
The central inverters have a single MPPT thus resulting in efficiency losses and significant performance due to module mismatch so, providing the advantages of string inverters over central inverters. But on the other hand, it is advisable to use the central inverter on flat terrain but there is also no loss in using string inverters. If you are using these inverters then you will be aware of the black start capability, these string inverts do not have that facility but the modern central inverters have this feature which makes it one of the best choices.
The most important is its maintenance cost. While looking at the central inverters they are quite high as it requires regular filter replacement, oiling, and cooling mechanisms. The cost of central inverters is also generally a little higher than compared string inverters and the maintenance cost of the string inverter is also low in comparison as it does not require regular checkups but it has a higher rate of failure as it has increased no of inverters so rate of failure increase, so owners are advised to keep a spare or new inverter in case of sudden failure.
In this blog, I have given a detailed study of the central inverter vs string inverter and it is true that the higher MPPT density of the string inverters will be best when it is used with single-axis trackers and bifacial modules. So, before installing go through all the features according and make the best use of your inverters.
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