Assessing the implications of RES technology mix on curtailments, storage requirements and system economics

This paper investigates the development of wind and solar photovoltaic (PV) technologies for achieving renewable energy sources (RES) penetration levels of ∼80 %, focusing on renewable curtailment mitigation, system economics, storage needs, and RES investments' financial viability when exposed to market prices. Three growth trajectories are evaluated: prioritizing PV, prioritizing wind farms, and a balanced PV-wind development approach. For each scenario, combinations of batteries and closed-loop pumped-hydro capacities are also assessed to determine the optimal storage configurations that minimize system costs. Analysis reveals that RES curtailments primarily occur during midday peak PV generation, regardless of the level of installed PV capacity. Storage effectively mitigates these curtailments; however, complete elimination would necessitate excessive storage capacities, which are not economically justifiable. Although a wind-dominated renewable mix has the potential to effectively reduce curtailments, a cost-minimization approach identifies a balanced RES development combined with strategically selected storage capacities as the most favorable option. Minor adjustments within the balanced RES development scenario could favor the moderate precedence of PVs against wind installations, yielding similar system costs. Additionally, prioritizing a specific RES technology in the mix cannibalizes its spot market revenue, paving the way for other renewable technologies to harvest boosted income. Nonetheless, not all renewable technologies in the mix can achieve financial viability solely through market revenue. Additional support mechanisms are necessary to incentivize investments in these technologies and facilitate progress towards more ambitious decarbonization objectives.