To address the insufficient flexibility of 100% renewable energy export systems, a two-stage coordinated planning approach is proposed in this paper for long- and short-duration energy storage based on daily energy and intra-day power requirements. The method enables effective matching between system regulation capability and the multi-timescale variability of renewable generation. In the first stage, at the daily timescale, long-duration energy storage and hydrogen load power and capacity are configured based on the daily renewable energy generation. In the second stage, at the intra-day timescale, short-duration energy storage capacity is configured using modified typical scenarios of renewable output fluctuations, resulting in a coordinated planning scheme for both long- and short-duration storage. Furthermore, the additional grid-integration costs of renewable energy are quantified from both the supply and demand sides. Operational simulations are conducted to comprehensively and effectively evaluate the economic performance and renewable energy accommodation efficiency of the proposed planning scheme. Finally, case studies are conducted using data from a 100% renewable energy base connected to the Zhangxiong UHV substation in Zhangjiakou. The results indicate that the proposed approach effectively balances renewable accommodation and system economics. It exhibits strong adaptability and stability across different typical scenarios, meeting diverse planning requirements with enhanced flexibility.