CNN — As the US endeavors to reduce its reliance on fossil fuels and transition to cleaner energy sources, experts are looking to big-box stores and shopping malls as a potential solution. These retail giants, such as Walmart, Target, and Costco, have vast amounts of rooftop and parking lot space, which currently go unused. By harnessing this space for solar power, these stores have the potential to reduce US dependency on foreign energy, decrease emissions, and save millions of dollars. For example, IKEA’s store in Baltimore cut its energy costs by 57% from September to December 2020 by installing solar panels on its roof and parking lot. As of February 2021, IKEA had installed solar arrays across 90% of its US locations. A report from nonprofit Environment America and research firm Frontier Group states that big-box stores and shopping centers have enough roof space to generate half of their annual electricity needs from solar power. Leveraging this potential could generate enough electricity to power nearly 8 million homes and reduce emissions equivalent to taking 11.3 million gas-powered cars off the road. Despite the potential, only a small fraction of big-box stores in the US have implemented solar power. Roadblocks, such as regulations, labor costs, and concerns about structural integrity, have hindered widespread adoption. However, advocates argue that a solar revolution in these retail establishments would not only address the climate crisis but also stimulate local economic growth and benefit marginalized communities. Walmart, with its extensive rooftop potential, could make the biggest impact. The company has over 5,000 US stores and more than 783 million square feet of rooftop space, enough to power over 842,000 homes. Walmart has invested in renewable energy projects but has not focused primarily on rooftop solar installations. Environment America has urged the company to commit to installing solar panels on its stores. Target, on the other hand, ranked number one for on-site solar capacity in 2019 and has currently installed rooftop solar in a quarter of its stores. Home Depot and Kroger also have some solar installations but face challenges related to aging rooftops and feasibility. Challenges for retail companies and the power sector in expanding solar power include labor costs, incentives, and complex regulations. Experts argue that incentivizing and streamlining the process could lead to greater progress in solar installations.