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Inverter Replacement Practices

Repowering Your Legacy Solar Sites: Think Ahead for Inverter Replacement

Solar inverter plays a critical role in the entire solar system. While solar panels usually last for 25 to 30 years, most inverters come with a life-expectancy of approximately 10 years. When it comes to the point of its lifespan with fatal inverter failures, oftentimes you’ll face a dilemma of replacing or repairing it. We will suggest you to seriously consider replacement when the following happens to you:

  • Cost of acquiring spare parts for repair is unreasonably high
  • Long lead time for service call to take place
  • Spare part becomes obsolete and unavailable

We are proud to announce we have viable solutions to replace your grandfathered central inverters. The first option is by adopting a wide-range MPPT  inverter. Solar panels’ efficiency degrades from year to year.  It is highly likely that your strings aren’t producing as much when it comes to the day for replacement, which potentially creates a problem of not being able to bring enough voltage to feed the new 1,000V inverter. Kehua’s 50kW and 60 kW inverters have a wide MPPT voltage range from 300V – 950V and are able to yield without the voltage boost from optimizers. However, we still advise you to discuss with installers to tackle the grounding issue that can’t solely be resolved by transformerless inverters. We will discuss the considerations for such method in following series. Figure 1 explains the scope of work from such replacement.

Figure 1 Above: Scope of work from replacing central inverter with string inverters

The second way is to introduce optimizers to marry the old 600Vstrings to the new 1,000V inverter. Optimizers are able to not only boost the voltage to new inverter’s operating voltage range but also solve the grounding issues caused by the replacement of new transformeless inverter. Learn more from Alencon ‘s “PV Retrofits in the Age of Transformerless Inverters

Figure 2 Above: A Typical 600 Volt PV Plant with its original inverter (Source: Alencon)

Lastly, we want you to consider replacing the 600V central inverters with hybrid central inverters. It will not only save your investment on reworking the cables and wires but also bring you a huge advantage by adding energy storage systems which allow you to store excessive production from solar as well as arbitrage and mitigate the peak demands. Most importantly, you are eligible to claim federal investment tax credit and California state SGIP incentives for your extension to energy storage systems. Figure 3 demonstrate the concept of replacement with hybrid inverters.

Figure 3 Above: Replacement with hybrid inverters

Overall, it is important to compare your return on investment when replacing old inverters. Your eligibility for incentives and considerations for new technology can affect your project economics. No matter what, we’ve got your back.