Efficiency, Wattage, and Why Engineering Matters
The evolution of solar energy has consistently grappled with two central concerns: cost and efficiency.
Over the years, this has resulted in engineers and developers walking a tightrope between maximizing space, savings, and wattage. Of course, solar's growing popularity and potential means understanding efficiency and why it matters is more important than ever.
Indeed, those pushing back against the renewable transition often use perceived deficits in efficiency and high upfront costs as reasons to stick with more traditional energy sources. However, the truth is that solar’s efficiency has increased dramatically. In fact, renewables are now the cheapest energy option out there.
Such misinformation hurts public awareness of solar energy's viability, especially when it comes to promoting the benefits of utility-level solar over commercial or home setups. The irony is that more utility-level projects are precisely what will increase efficiency and further reduce costs.
“It’s problematic,” says Aaron Burkhart, VP of Doman Energy Group. “Solar efficiency and capacity keep going up, but much of the public remains convinced that’s not the case. For instance, in the 90s, we were looking at 150-watt modules, and those were a big deal. Today, we’re looking at 650 or 680-watt modules – these huge projects with drastically increased power output.”
As with any fast-moving technology, education is key to fighting back against both bad faith and accidental misinformation. To that point, it’s a good idea to examine just how far solar has come and how companies like Doman are pushing its capabilities even further.
A Brief History of Solar Efficiency
Many people are surprised to learn that the first solar cell was invented in 1883. Back then, when Charles Fritts demonstrated his new device, it boasted a modest 1-2% efficiency. So, while the concept of being able to derive energy from the sun proved true, the technology couldn’t be seen as anything more than a novelty, even considering 1880s energy needs.
Decades later, no less than Albert Einstein would win a Nobel Prize for work related to the photovoltaic effect. Through his theories on the quantum nature of light, Einstein laid the groundwork for the future operation of photovoltaic cells. In 1954, Bell Labs developed the first practical silicon solar cell. Although this new cell only had an efficiency level of around 6%, its invention proved enough to kick off a race among solar developers to see who could increase efficiency the most.
By the 1960s, solar cell efficiency had already more than doubled to 14%. Then, during the energy crisis of the 1970s, solar again received public attention and funding, pushing efficiencies up even further. The 1990s and 2000s introduced more efficient architectures like multi-junction cells. They also saw a dramatic rise in commercial solar availability. Even then, solar investment was mainly dominated by early adopters and those who could claim government subsidies. But that was enough to provide proof of concept. More importantly, it created a cash incentive for outside investors to treat it like a business.
The 2010s marked the introduction of Passivated Emitter and Rear Cell technology and the first bifacial modules. As of 2023, mid-range solar panels boast an efficiency rate of around 22-24%, while high-end panels backed by state-of-the-art R&D are pushing 28-30%. This means modern panels can convert nearly 1/3rd of the sunlight hitting them into electricity.
Compare that to traditional coal-fired power plants, which have an average efficiency of about 33% to 40%, then remember that nothing happens to the extra solar energy; it’s just sunlight. With coal, the remaining 60% that didn’t result in energy production still contributes to the carbon problem.
“We’re approaching the ‘break-even point’ where renewable efficiency meets the efficiency of carbon-intensive methods,” Burkhart says. “Solar is already the cheapest option for energy. And with new concepts like perovskites and tandem solar cells, that affordability will only improve.”
The Relationship Between Size and Efficiency
One of the biggest misconceptions about solar panels is the relationship between size and efficiency. For instance, when engineers talk about efficiency, they’re referring to how well a solar panel can convert sunlight into electricity. This figure is usually expressed as a percentage, indicating the portion of sunlight that can be converted into usable electrical energy. Meanwhile, the size, specifically the surface area, determines how much sunlight the panel can potentially absorb at any given time.
The final part of the equation, and arguably the most important for promoting solar’s capabilities, is power output. “There’s a direct relationship between the size of a solar panel and its potential wattage output,” Burkhart says. “Larger panels have more surface area to absorb sunlight, which can increase the total electrical power they generate. But if you have a smaller panel that’s more efficient, you could produce more wattage per square foot or meter.”
This means that fewer high-efficiency panels may be needed for a given area (or for a given power output requirement) compared to lower-efficiency panels. But depending on space and budget restrictions, one might be easier or cheaper to build than the other. “Think of it as having an Olympic-sized swimming pool as opposed to a 5000-foot-deep well,” Burkhart says. “They can both hold the same amount of water, but the pool is far more viable.”
High-efficiency panels often come at a higher cost per panel due to the advanced materials and technology required to achieve higher efficiency rates. However, the reduced number of panels needed for a given power output can offset the higher cost per panel, especially in space-constrained applications. In utility-scale projects, these cost differentials can add up quickly.
Ultimately, it’s easy to think of solar panels in relatively static terms. But in reality, every installation is completely unique, and maximizing wattage output while still considering space and cost is no easy task. “Efficiency is something you have to plan for,” Burkart says. “That sort of efficiency in engineering is what Doman is all about.”
Why Efficiency Maximization Still Matters
As crucial as technology improvements are for solar as a concept, they don’t erase the need for each project to maximize its own efficiency. “You can’t just sit back and expect the technology to do the work,” Burkhart says. “In the end, the one or two efficiency percentage points can add up to millions of dollars over the life of a project.”
This type of oversight is precisely what Burkhart and Doman Energy Group hope to help their clients avoid. Doman has been working in the solar industry since the 1990s and has completed dozens of large-scale projects all across the United States. The aforementioned “tightrope” between module size, savings, and wattage is where they thrive. This is because the Doman team has spent years refining and standardizing their process to maximize efficiency for their customers.
“We typically see conductor and wire usage go down by 20, maybe 30% over preliminary designs by other firms, clients attempting to handle the job internally, and automated layout software,” Burkhart says. “In fact, the bigger the project, the bigger the savings.”
However, those savings are not only the result of increased efficiency but also Doman’s embrace of the partnership model. “The number of hands involved in a single solar installation project can be overwhelming,” Burkhart says. “As the ball gets passed from firm to firm, there are often delays, miscommunications, and other issues. After years of seeing this happen repeatedly, Doman decided to adopt a partnership model, where we oversee the project from beginning to end.”
As more and more companies, factories, and commercial properties embrace the potential of solar power, more engineering firms will enter the space. However, Burkhart firmly believes that those projects with the best potential to meet compliance and get up and running fast will be the ones that incorporate engineering from start to finish.
“We thrive in this space not only because we understand the engineering, but how to make that engineering more efficient,” Burkhart says. “Still, we also understand the construction, construction mechanisms, regulation, permitting, and all the things required to produce a utility-scale project. By partnering with our clients for the life of their project, they get continual access to the best aspects of our business.”