Weather-record adequacy for renewable portfolio and storage planning: A 25-year solar-wind assessment for Türkiye

Planning studies often compress multi-decadal weather chronology to a few representative years, yet short records can distort both event statistics and planning decisions. This study develops a decision-adequacy framework using 25 years of hourly ERA5 data for 81 provinces in Türkiye, linking compound solar-wind droughts, constrained conditional value-at-risk (CVaR) portfolios, record-length tests, and cyclic storage screening. With q20 thresholds fixed from 2001 to 2025, the 2020–2024 record yields 4.8 widespread-drought days/year versus 6.28/year over the full record; re-estimating thresholds within 2020–2024 would give 6.8. At a 0.18 mean-output target, only 47.6% of five-year windows are feasible, whereas all tested windows are feasible at targets up to 0.175. Daily-CVaR reduces tail shortfall by 5.9% and mean shortfall by 8.5% relative to expected-output planning. Deterministic tie-breaking leaves short-window allocation differences largely unchanged, but near-optimal analysis shows that exact weights are weakly identified, so performance and feasibility are emphasized over L1 distance alone. Under cyclic storage, diversified portfolios require 96 MWh/MW at a 0.15 target, while none meets the 0.1% energy-not-served criterion within 600 MWh/MW at a 0.17 target under the baseline storage-power limit.