Title: Ancillary Services in Power System Transition Toward a 100% Non-Fossil Future: Market Design Challenges in the United States and Europe Show Chinese title

Title: 电力系统向100%非化石未来转型中的辅助服务：美国和欧洲的市场设计挑战

Abstract: The expansion of variable generation has driven a transition toward a 100\% non-fossil power system. New system needs are challenging system stability and suggesting the need for a redesign of the ancillary service (AS) markets. This paper presents a comprehensive and broad review for industrial practitioners and academic researchers regarding the challenges and potential solutions to accommodate high shares of variable renewable energy (VRE) generation levels. We detail the main drivers enabling the energy transition and facilitating the provision of ASs. A systematic review of the United States and European AS markets is conducted. We clearly organize the main ASs in a standard taxonomy, identifying current practices and initiatives to support the increasing VRE share. Furthermore, we envision the future of modern AS markets, proposing potential solutions for some remaining fundamental technical and market design challenges. Show Chinese abstract

Abstract: 变量发电的扩展推动了向100%非化石能源电力系统的转型。 新系统需求对系统稳定性提出了挑战，并表明需要重新设计辅助服务（AS）市场。 本文针对工业从业者和学术研究人员，全面而广泛地回顾了应对高比例可变可再生能源（VRE）发电水平的挑战和潜在解决方案。 我们详细阐述了推动能源转型并促进辅助服务（AS）提供的主要驱动因素。 对美国和欧洲的辅助服务（AS）市场进行了系统性回顾。 我们清晰地组织了标准分类中的主要辅助服务，识别了当前实践和旨在支持不断提高的VRE份额的举措。 此外，我们展望了现代辅助服务（AS）市场的未来，提出了某些剩余基本技术和市场设计挑战的潜在解决方案。