Comparative seasonal assessment of hybrid solar-biomass cogeneration for sustainable year-round energy: Technoeconomic, and life cycle approaches

• Comparative seasonal assessment of a hybrid solar–biomass cogeneration system. • Constant 100 kW electricity and ∼595 kW heat achieved via dynamic biomass adjustment and TES. • System efficiency varies from 34.6% to 44% across seasonal solar conditions. • LCOE ranges from 0.219–0.238 €/kWh and summer IRR reaches 35.8%, highlighting economic viability. • Environmental impact ranges from 0.247–0.522 kg CO 2 -eq/kWh. Delivering reliable low-carbon electricity in regions with variable solar resources remains a major challenge for off-grid and decentralized systems. This study presents a seasonally resolved assessment of a hybrid solar–biomass cogeneration system integrated with thermal energy storage, designed to deliver a constant 100 kW net electrical output and approximately 595 kW of useful heat throughout the year. Seasonal operation is achieved by adjusting biomass input and thermal energy storage management based on solar availability. Simulations based on five years of solar radiation data for Salamanca, Spain, were conducted to evaluate the system’s energy performance, technoeconomic feasibility, and life cycle environmental impacts within a gate-to-gate operational boundary. The results show that the overall CHP efficiency varies from 34.6% in summer to 44% in winter, with an annual average efficiency of 39.2%. Summer operation provides the most favorable economic performance, with the lowest levelized cost of electricity (0.219 €/kWh), the lowest levelized cost of heat (0.0369 €/kWh), and the highest net present value (€2.06 million), while winter operation ensures higher system efficiency at the expense of increased biomass consumption, higher electricity generation costs, and greater environmental burdens. Climate change potential ranges from 0.247 to 0.522 kg CO 2 -eq/kWh across seasons. The results demonstrate that solar–biomass hybridization combined with thermal energy storage can provide stable, dispatchable, and low-carbon cogeneration under strong seasonal variability, offering a promising solution for decentralized renewable energy supply.