SolarCity made headlines earlier this month when they announced that they had created “the world’s most efficient solar panels.” In independent laboratory tests by the Renewable Energy Test Center, SolarCity’s new solar panels received a rating of 22.04% efficiency. Given that full production of these panels won’t start until 2017, it’s understandable that solar shoppers are wondering if they should wait until then to buy the most efficient solar panels possible. Before you decide to wait to go solar, there are a few factors you should consider.
The future of financial incentives for solar is unclear
The federal investment tax credit (ITC) for solar, which lowers the cost of installing a solar energy system on your property by 30%, is set to expire at the end of 2016.There’s no guarantee that Congress will choose to extend the ITC, and even if they do, it’s likely that they will reduce the percentage in response to increased adoption of solar across the country. If you’re considering installing solar panels on your home, the value of accessing the ITC now is certainly much larger than the value of any efficiencies gains you could achieve from more efficient solar panels in 2017. (Update: On December 18, 2015, Congress extended the solar tax credit for homeowners through 2021. Learn more about the extension.)
State and local financial incentives are also being reduced or disappearing altogether. Some programs, like NV Energy’s SolarGenerations and the California Solar Initiative, have tiered rebates that decline in value (or “step down”) as more solar is installed. Property owners are also facing the possibility of receiving lower credits from their utilities for the electricity that their solar panels generate. Hawaii just became the first state to close its retail net metering program to new applicants in favor of a program that credits solar homeowners at the wholesale rate of electricity, and California may be the next to follow.
Efficiency ratings are estimates, not guarantees
Lab tests can provide a good starting point for understanding solar panel efficiency, but until the panels are operating on a large scale there’s no way of knowing exactly how well they will perform. Even Peter Rive, the co-founder and CTO of SolarCity, acknowledged that 22% efficiency is “on the high end” of their test results, and that most of their panels test closer to 21.8%. Some variation in solar panel efficiency is not uncommon – manufacturing and testing conditions can impact measured production efficiency. However, Rive’s comment is a reminder that, until the technology reaches the marketplace and is installed at scale, it remains to be seen whether SolarCity’s new product is actually “the world’s most efficient solar panels.”
That isn’t to say that uncertainty around solar panel efficiency ratings will inevitably result in a lower score. Solar panel performance can actually be higher than manufacturers indicate: SunPower has been producing panels for the past two years that are rated at 21.5% efficiency, while the company reports that the majority of those panels actually exceed 22% efficiency once installed!
Module efficiency is only one component of solar panel system performance
While there is definite value to solar panels with a higher efficiency, panels are one of many components that impact the long-term performance of your solar energy system. This is why it is key to compare quotes from multiple installers and find the optimal equipment setup for your property’s needs. By taking into consideration the overall design of your solar energy system, including panel and inverter efficiency, warrantees, and production guarantees from your installer, you can better determine the impact that more efficient solar panels will have on overall system performance.
In some cases, a higher efficiency solar panel module could be the only way for you to “go solar.” For example, if the roof of your home is particularly small, or if you have gables or skylights that take up significant roof space, you might not have enough space to install a useful system unless you choose the most efficient solar panels possible.
Solar technology is constantly evolving
SolarCity’s announcement has been heralded as a remarkable development in solar technology, but the truth is that the increase in efficiency is relatively small when compared to what’s already available on the market. Analogous to Moore’s Law, there will always be more efficient solar technology coming down the line. If you wait until 2017 to install SolarCity’s new high efficiency solar panels, there will surely be new reports of companies working to create even more efficient panels at an even lower cost.
The bottom line? If you’re considering going solar, don’t wait for the most efficient solar panels to hit the market – start exploring your options now. Get an instant estimate or register your property today to find out how much you can save by comparison shopping for solar online through the EnergySage Solar Marketplace.