Geothermal energy is increasingly recognized as a vital renewable energy source with significant economic and environmental benefits, contributing to the global transition to cleaner energy. This paper examines the economic feasibility and environmental impact of geothermal energy development, focusing on the high initial costs of drilling and infrastructure, which are offset by low operational costs and long-term sustainability. Although geothermal projects require substantial upfront investment, particularly in drilling, they offer a reliable, low-maintenance energy solution with operational lifespans of 20 to 50 years. The paper analyzes cost–benefit dynamics, comparing the levelized cost of electricity (LCOE) of geothermal power with other renewables such as wind and solar, showing that geothermal is competitive in regions with high resource potential. In addition to cost considerations, it discusses geothermal energy’s environmental advantages, emphasizing its low greenhouse gas emissions and carbon intensity, which make it one of the most sustainable energy sources. Reducing emissions is crucial for addressing climate change and meeting global carbon-reduction targets. The paper also highlights the importance of resource management to avoid overexploitation and depletion. Strategies such as fluid reinjection and the development of enhanced geothermal systems (EGS) are presented as ways to ensure long-term viability. Furthermore, it presents successful case studies from California, Alberta, the Philippines, and the United Kingdom, where abandoned oil, gas, and exploration wells have been repurposed for geothermal energy production. These case studies demonstrate the cost-saving and environmental benefits of using existing infrastructure, reducing the need for new drilling and minimizing environmental impacts. By leveraging advanced technologies and innovative approaches, geothermal energy can provide a sustainable, low-carbon energy source that addresses both economic and environmental challenges. The paper concludes by underscoring geothermal energy’s potential to contribute significantly to global energy sustainability, offering a reliable, eco-friendly solution for the future.