Solar power’s growth has become unstoppable for all the right reasons.It’s been a tough past few days for First Solar (FSLR 2.25%) shareholders. And understandably so. Investors suspect pro-oil President-elect Donald Trump could also prove unsupportive of renewable energy. Iin fact, most clean energy stocks are down since his Nov. 5 election on this very worry. First Solar has been no exception to the industrywide sell-off.This weakness, however, is also a buying opportunity for anyone interested in owning a piece of the solar panel maker, or in adding exposure to the solar industry as a whole. The solar power movement is too big and too well-developed for Donald Trump to bring to a halt now.First Solar is also well-positioned to sidestep one of the few meaningful actions the president-elect could take to disrupt the solar industry’s growth.Solar is just too competitive to stop nowDon’t misunderstand. Trump certainly has enough authority to rattle the solar power business. He can’t end it, though. He’ll even be hard-pressed to slow its current growth.See, contrary to a common assumption, solar power is no longer leaps and bounds more expensive than more common forms of energy production. Data gathered by Wood Mackenzie and reported by the U.S. Department of Energy indicates that utility-scale solar power is now in line with the cost of natural gas and coal-fired power, in fact.That’s a key reason the Solar Energy Industries Association says the United States’ solar power production capacity grew a record-breaking 32.4 gigawatts last year. Indeed, for the first time ever, solar accounted for over half the country’s expansion of its electricity-generating potential. This growth has continued to accelerate through 2024 too, despite economic headwinds.The irony? Largely because it’s the cheapest means of adding utility-scale power production there, solar is growing like wildfire in several states like Texas, Oklahoma, and Kansas that picked Trump to be president during the recently ended election cycle. To the extent voters picked Trump for economic reasons, they’ll certainly appreciate cheaper electricity and its positive impact on the economy.Legally limited, with little incentive to stand in its way anywayThe 2022 passage of the Inflation Reduction Act is admittedly fueling much of this growth, by offering taxpayers a tax credit of up to 30% of the cost of a solar power system. The IRA also incentivizes utility-scale solar power projects as well as the manufacturing of solar panels themselves.And this raises an important detail about solar power’s future. That is, while Trump can undo any of President Biden’s executive orders that may promote renewable energy (such as Biden’s goal of making the federal government’s fleet of vehicles 100% zero-emission by 2035), he can’t unwind voted-upon legislation — like the IRA — without new legislation to repeal or replace it. And there doesn’t appear to be enough political will at this time to undo a law b