We covered how many solar panels it would take to replace a nuclear reactor (hint: it’s a lot), but a more feasible exercise would be building a solar project to supplant a micro nuclear reactor. To replace their output with solar would require tens of thousands of solar panels on the low end, or hundreds of thousands of panels to replace a higher production microreactor.
The difference, as you’d imagine, is one of scale. A nuclear reactor is a massive installation, a large, site-built power plant that typically generates hundreds to over a thousand megawatts of electricity. These huge power generators sit on large, dedicated sites surrounded by supporting civil works, including containment buildings, cooling towers, and extensive safety systems.
A micro nuclear reactor is a much smaller production. They’re factory built units intended to be transported on trucks or similar vehicles, and as such produce significantly less power (usually in the neighborhood of 10 to 20 megawatts of electricity). They’re often deployed for modular or temporary use at sites like remote communities, mines, industrial sites, microgrids, or to assist during disaster response. The U.S. Army, for example, is reportedly developing such a microreactor that would weigh in at around 40 tons and be transportable by C-17 Globemaster III aircraft.
Replacing a nuclear microreactor with solar
Much like replacing a full nuclear reactor with wind turbines, the sheer scale of such a project is daunting. And while replacing the output of a microreactor is significantly more feasible, it’s wholly dependent on the output of the reactor, which can vary broadly. Microreactor output generally ranges from one to 20 megawatts, with many designs in the five to 10 range.
The other consideration is that, while a reactor can run at almost full power continuously, a solar panel’s efficiency depends on weather, cloud cover, location, panel wattage, and several other variables. Planners typically use a 20% capacity factor for solar panels in sunny locations to estimate the number of panels required. Using widely available, common residential solar panels at 550W at 20% capacity factor, you’d need around 41,000 panels to replace a 5 megawatt microreactor (around 22.5 MW of solar), or 82,000 to replace a 10 megawatt model (45 MW of solar). Scale the panels up to industrial 750W versions and you could reduce those numbers to 30,000 and 60,000, respectively. And even then, that’s before considering the different maintenance requirements for solar panels, and the panels that may need to be fixed or switched out over time.