Designing co-located wind, solar, and storage systems, referred to as hybrid power plants (HPPs), has emerged as a key research area in enabling demand-driven and dispatchable renewable electricity. This work investigates the technical and economic feasibility of configuring such systems to serve a constant power output. The scope focuses on understanding the extent to which variability in wind and solar generation can be mitigated through co-location and storage integration, and on identifying the storage requirements and technology choices needed to achieve different levels of supply firmness.

The core contribution of this work lies in the development of an optimization-based framework to simulate both the design and operation of HPPs for demand-driven power output. The model is structured to reflect the operating conditions, where the HPP acts as a price-taker in the electricity market, participating in the spot market while simultaneously attempting to meet predefined constant demand. The goal is to identify an optimal plant design serving a constant load, incorporating a balanced assessment of both technical feasibility and economic performance.

The study includes multiple case studies across geographically diverse locations, capturing variations in wind and solar resource availability and energy market conditions. This allows for a systematic evaluation of the role of resource complementarity and market price in plant design and operation. Furthermore, a comparative assessment of battery and hydrogen-based storage configurations is performed to meet demand requirements.

The analysis also aims to identify a techno-economically viable indicative share of constant demand that co-located wind and solar systems can meet, with storage or a combination of storage technologies, depending on resource complementarity. Beyond this range, storage system costs become critical, leading to a higher levelized cost of energy. Battery systems could be efficient and cost-effective for short-term balancing and intra-day variability, while hydrogen-based storage aids long-term balancing and higher levels of firmness. However, hydrogen systems currently face challenges related to lower round-trip efficiency (around 30-45%), higher capital costs, and system complexity, although they offer advantages in scalability and long-term energy storage.

The major conclusions highlight that while a fully constant renewable-based supply is technically achievable, it is economically viable only under specific conditions involving overcapacity and hybrid storage solutions. A balanced combination of wind, solar, batteries, and hydrogen storage, along with flexible demand or grid support, could provide the most practical pathway. Continued advancements in storage technologies and system integration will be crucial in improving the feasibility of demand-driven renewable power systems.

Hence, this work contributes to the broader goal of efforts to decarbonize power systems while ensuring reliability and flexibility. As power systems transition toward higher shares of renewables, understanding how to design integrated systems capable of meeting firm demand - is essential for grid planning, market design, and investment decisions.