Although developers design solar projects to stand for decades, even the best panels and components degrade over time.
The average solar project experiences less than 1% degradation in performance annually. It might not sound like much, but those small performance declines compound over time. Often, solar panel performance is the main topic, mostly because they’re what’s generating the electricity. However, they’re only one part of a larger ecosystem, of which any component can become a failure point.
For example, solar panel racking should outlast the panels, but can suffer from mechanical issues. This is especially true for single- and double-axis trackers that rely on motors to point panels at the sun throughout the day.
Similarly, inverters often have shorter lifespans than other components, with manufacturers offering only 5- to 15-year warranties. When inverters fail, it can lead to performance declines, system damage, and outages. In this scenario, the project doesn’t produce as much – or any – power, leading to lost revenue and potential penalties.
Even something as benign as photovoltaic (PV) wire can fail in the field. This is why teams perform regular partial discharge (PD) and insulation resistance tests on AC and DC systems, respectively. Tests like these quickly identify insulation defects on the wire that could lead to shorts or component failure.
To combat failures and lost return on investment, solar operators are looking to solar repowering for their projects. This process allows operators to replace worn parts, boosting efficiency and extending the project’s lifespan while reducing part failures.
What is Solar Repowering?
Solar repowering involves upgrading older, worn, or underperforming parts like panels, inverters, wire, racking, and more with new ones. Repowering, unlike decommissioning and building new, utilizes the same land and good parts to improve efficiency, integrate new technology, and increase a project’s lifespan.
In general, it’s less expensive to repower a solar site than to decommission it and build a new one. New sites require new permits, taxes, and land leases, but repowered sites work with what the site already has. The project infrastructure is already in place, functional, and connected to the grid — all it needs is sprucing up. That often means smaller project scopes, timelines, and costs, with higher upsides once the job is complete.
Generally, the amount of savings repowering provides depends on project scope, materials, and the system’s current condition. As solar projects age, the cost to refresh the site increases. Projects with less wear and tear are usually less expensive to replace, since there’s less to worry about.
Another benefit of repowering versus building new is that it gives operators opportunities to employ new solar energy technology. This means investing in more efficient panels, improved inverters, and adding battery energy storage systems (BESS) to store power.
What Are the Pros and Cons of Repowering?
Though repowering can come with plenty of upside, not every project is a candidate.
For example, projects nearing the end of their usable lifespans may not benefit from a full retrofit. In other cases, the benefits of repowering may not offset project costs and lost production. Conversely, efficient projects that still perform well may not need upgrades yet.
But for many projects, repowering can turn back the hands of time.
Why Repowering Makes Sense
The process is more cost-effective than building a new site.
Compared to leasing land, filing for permits, dealing with tax incentive concerns, and buying all-new parts, fixing what you have is a bargain.
The overall cost depends on the extent of upgrades, and some parts are easier/cheaper to replace than others. For example, replacing PV wire or inverters is much less expensive than purchasing new panels.
Plus, as previously mentioned, the critical infrastructure is already in place, including roads and interconnection points. This also applies to several other site-specific expenses, including land purchases, initial permits, and taxes.
Smaller scopes make for faster timelines.
Unlike starting from scratch, replacing worn parts reduces overall scope, timeline, and cost.
Racking is a great example of a component that can withstand the test of time. Fixed-tilt racking that is still stable, corrosion-free, and secure likely doesn’t need replacement. However, single- or double-axis racking systems may require new trackers at some point.
PV wire is another component that might not need replacement during a repowering project. If workers installed the wire correctly and the insulation is undamaged, PV wire can operate safely for decades.
Repowering sites improves performance.
Solar site repowering isn’t always about replacing broken parts; it’s about utilizing new technologies and components we didn’t have before. Today’s solar panels are much more efficient than they were only 10 years ago. But even a small uptick in performance pays dividends over the life of the project.
It also allows companies to add on emerging technology, including advanced monitoring systems, automated processes, and BESS. These upgrades make the site a more consistent power generator while prolonging the project’s lifespan.
Helps operators honor power purchase agreements (PPAs).
When independent power producers (IPPs) sign PPA agreements with utilities, they may agree to produce a certain amount of power. If they fail to reach those benchmarks, they may face penalties or other fines.
Though repowering causes temporary performance dips at sites, systems perform much better once the work is done. Completed projects generate power above the agreed threshold, preventing costly fines or buying supplemental electricity.
Why Companies Might Reconsider Repowering
Some critical components may be obsolete or unavailable.
For smaller, older sites, this may mean replacing central inverters with new string inverters. While central inverters were popular for early projects, those parts have fallen out of favor for improved designs. On top of that, the manufacturer may no longer produce those components — or even exist.
Older solar projects also face the problem of operating at lower voltages than current sites. For example, they may operate at 600V DC when the industry has pushed ahead with higher working voltages.
Replacing one component might start a cascade of changes.
Sometimes, changing out one outdated or weak component may lead to other, more expansive, updates across the site.
Using the central inverters as an example, replacing them with new string inverters also means updating grounding systems to support them. The work might also trigger further changes to interconnection processes or even require reengineering aspects of the project.
More changes also mean higher project costs. Although operators typically build operations and maintenance budgets into a solar project’s lifespan, repowering is a curveball and large-scale repowering jobs may damage the site’s ROI.
The National Electrical Code (NEC) for renewable energy projects has likely changed.
A lot can change over the course of a decade, especially for the burgeoning solar industry. As solar technology improves and matures, the NEC has kept pace, updating NFPA 70 several times — most recently for 2026.
The NEC governs every facet of electrical systems, including updates to technologies, power outputs, and safety features. In past iterations, we’ve seen Articles 690 (Solar Photovoltaic System Requirements), 705 (Interconnection of Power Production Sources), and 706 (Energy Storage Systems) go through significant changes. Our current codebook, NEC 2026, has fewer large-scale changes and more tweaks to existing rules.
If developers decide to upgrade older solar sites, they may run into code issues. Bringing a site up to 2026 standards may mean additional expenses and a larger project scope than initially expected.
Recycling is still an issue we’re trying to solve.
Solar panels, wind turbines, and batteries are becoming mainstream, but they still face several challenges, including recycling. PV panels in particular have become a sore spot for solar site operators, mainly because of their composition.
Solar panels contain several high-value critical minerals, including silicon, copper, silver, and more. Recycling these materials keeps the minerals and metals in circulation and maintains stocks, reducing the need for new mining. But while companies CAN recycle panels and other components, it can be difficult or unprofitable.
The silver lining is that renewable energy recycling is increasing in the United States. As the industry matures, more panels can avoid landfills while we recover critical minerals.
We still have to be cognizant of the environment around us.
Like new-build projects, repowering may damage land and habitats if crews aren’t careful. Teams should perform all work on any repowering site as carefully and cleanly as possible to limit potential issues.
However, repowering projects also allow developers and operators to improve the environment around their solar sites. For example, early projects often didn’t employ native flora for beauty or protection.
Native flowers, shrubs, grasses, and other plants offer solar sites plenty of benefits. With help from a local horticulturalist, they promote natural habitats and pollinator growth while preventing soil erosion. It takes several years for the plants to mature, but once established, they improve a site’s beauty and functionality.
Repowering Offers Operators Another Option
Aging is inevitable, but operators and developers don’t have to sit helplessly watching their sites fade over time.
Repowering processes offer a crucial third option beyond leaving sites to fall into obsolescence or building from scratch. Partial builds cost less than starting over, and the scope leads to shorter downtimes. Companies also avoid delays caused by permitting, approvals, and other procedural work.
But as with a new build, solar operators need to know what they’re getting into. What might look like a simple upgrade to one component can quickly cascade, turning into a larger, more expensive job. Additionally, as the scope increases, so does the risk of running afoul of updated NEC codes.
Despite the risks, solar site repowering is a worthwhile way to keep projects performing better for longer. Once back online, those sites will produce reliable, clean energy for years to come.






