# Techno-Economic Assessment of an Innovative Small-Scale Solar-Biomass Hybrid Power Plant
## 4 Conclusions  
The present study constitutes a techno-economic analysis of a 2 MW CSP-biomass hybrid plant. The uniqueness of the analyzed plant lies in the fact that the thermal energy from the solar field, consisting of parabolic trough collectors, is complemented by biomass combustion through a mixed configuration (Figure 5). Thus, the mixed hybridization consists of both a series scheme (Boiler 1), aiming to improve the quality of generated steam, and a parallel scheme (Boiler 2), designed to absorb solar resource fluctuations. This study highlights the attractiveness of CSP-biomass hybrid systems for dispatchable power generation from 100% renewable resources, especially in regions that, like the one analyzed, combine high levels of availability of both resources. In fact, in cases with BFF = 100%, the power generated by the steam turbine was completely independent of the available DNI value at any given moment (Figure 7). Furthermore, the annual balance of consumed forest biomass by the proposed 2 MW hybrid power plant was compatible with the availability in the analyzed area. Specifically, the highest annual biomass consumption corresponded to the case with BFF = 100%, SM = 0.5, and no limit on biomass contribution, estimated at 15.8 kton/year, representing 10.8% of the annual production within a 25 km radius of the plant location (146 kton/year). Considering more realistic scenarios where biomass contribution was limited to 50%, the biomass consumed by the configuration with the lowest LCOE (BFF = 50% and SM = 1.5) was 4.2 kton/year, representing 2.9% of the available quantity within a 25 km radius. In addition to the advantage mentioned regarding plant dispatchability, the proposed hybrid scheme improves profitability compared to traditional CSP plants. Therefore, the proposed mixed hybridization enhances the profitability of the plant by reducing the LCOE compared to the value corresponding to traditional CSP plants. It was observed that the most attractive scenarios in terms of minimizing the LCOE corresponded to situations where production was predominantly achieved through biomass combustion. In fact, for cases where biomass contribution was not limited, the LCOE of the hybrid plant tended to reach values similar to those of conventional biomass plants. On the other hand, it was found that in contexts with limitations on biomass contribution, opting for the BFF = 50% configuration is more cost-effective (Figure 13). However, it was demonstrated that the existence of limits on biomass contribution negatively impacts the resulting LCOE. Considering the realistic scenario where biomass contribution was limited to 50%, an optimal configuration (SM = 1.5 and BFF = 50%) was identified where the LCOE reached a value of cEUR 27.93/kWh, which is very high compared to market values. Figure 14: LCOE (cEUR/kWh) as a function of gross output (MW) for a 50% biomass contribution limit for the two considered values of BFF (SM = 1.5). Based on the aforementioned results, the concept of CSP-biomass hybridization proposed in this study would only be economically viable in a context where, due to the use of 100% primary energy sources, there are no limits on biomass contribution and the remuneration for production equals or exceeds the obtained LCOE values. This is because the viability of such hybrid power generation systems should not be evaluated solely based on economic profitability criteria but should also be assessed for their potential to replace conventional fossil-fuel-based generation systems. In addition to the renewable nature of the production, the proposed scheme stands out for its ability to dispatch production, decoupling it from the available solar resources, which positively impacts the quality of the electrical system. Finally, it should be noted that the considered plant size (2 MW gross) also contributed to the high LCOE values obtained.