The usage of fossil fuel in the energy sector is the primary factor for global GHG emissions, so it is crucial to better utilize RE sources. One way to do that is to hybridize RE technologies to make up for their deficiencies while enabling a more synergistic power production. This study utilizes such an approach to hybridize the KZD-2 Geothermal Power Plant (GPP) with CST and biomass in the southwest region of Turkiye. The main motivation is to address the two main issues of GPPs—excess turbine capacities happening over the operating years and decreasing performance during hot summer months—while also increasing the flexibility of KZD-2. A topping cycle of CST–biomass is added utilizing a PTC field as the CST technology and olive residual biomass combustion as the biomass technology. The hybrid plant is simulated on TRNSYS, and the energetic data show that it is possible to generate more than 20 MW_e of additional power during sunny and clear sky conditions while also increasing the Capacity Factor (CF) from 69% to 74–76%. Moreover, the financial results show that the resulting LCOAE is 81.19 USD/MWh, and the payback period is five or nine years for using the YEKDEM incentive or the spot market prices, respectively.

The efficient operation of a solar field is an essential factor for the commercial operation of a concentrating solar power (CSP) plant. In addition to predictive control for the highest possible constant outlet temperature at high mass flow, efficient operation also includes early detection of defective components and heat losses. This work presents a method for non-invasive heat loss detection as a strong indication for vacuum losses, based on measured operational data of Andasol III, an operating 50 MW parabolic trough collector (PTC) plant located in southern Spain. To detect vacuum losses via this method, mass flow rate and temperature reduction are determined separately for each individual loop via the analysis of a short-term temperature rise of the heat transfer fluid (HTF) during preheating. While the temperature reduction was measured directly, the mass flow was determined via the thermal time-of-flight (ToF) method using the same installed temperature sensors. By measuring thermal step responses during the preheating of the solar field at nighttime operation, the influence of fluctuating direct normal irradiance (DNI), misalignment of the absorber tubes and an offset in collector focus was circumvented. In the scope of the presented work, single loops were detected, which show a higher heat loss at lower mass flow rate and therefore have an increased probability of a higher vacuum loss. Better localization and early detection of these vacuum losses would allow the corresponding absorber tubes to be renewed at the economically and environmentally best time, improving the efficiency of the solar field and thus the entire CSP plant.

While Geothermal Power Plants (GPPs) can be a reliable renewable energy source, this reliability can decrease over the years due to brine mass flow declining. This reduced mass flow causes extra capacity unused in the GPP turbines. This problem can be overcome by hybridizing GPPs with CST and biomass. These three thermal technologies can, in theory, complement each other if all the resources are present at the exact location. This is the scenario for this study, as the location for the case study is the Kızıldere 2 (KZD2) GPP in Denizli, Turkiye, operated by Zorlu Energy. This region has sufficient potential for all three technologies: CST, geothermal, and biomass. Furthermore, by building a topping cycle using CST and biomass, it is possible to generate additional power. This study utilizes a topping steam Rankine cycle run equally by CST and biomass, and, as a result, the 20% excess capacity in the GPP turbine is used while generating an additional 20 MWe of power.

In this work, an innovative CSP plant concept comprising a combined Brayton and Organic Rankine Cycle (ORC) and a stratified Thermal Energy Storage (TES) is investigated. A dynamic model of the plant is developed and used to perform annual simulations to investigate the plant at different locations under a variety of DNI levels and demand conditions. The focus of the study is on the dynamic behavior, in terms of response time to the demand profile and changing the operation mode, for example, from charging to discharging (dispatchability). Annual yield and LCOE calculations are performed for every scenario. Results show two optimization opportunities, in the first one, by means of a sensitivity analysis the design is adjusted and it is possible to increase 10% of the electricity production. A second analysis shows the possibility of including an operational mode that maximizes the use of TES and increases electricity production by 11%. The application of both strategies results in a 21% increase in electricity.

An innovative small-scale CSP tower plant, developed within the European research project POLYPHEM, was technically and economically evaluated and a benchmarking study was carried out including competing solutions to cover electricity demand of two remote locations with no existing access to national grid. First of all, this study shows that the POLYPHEM technology is able to deliver electricity at the target cost for this project. Regarding the cost of electricity per technology, the LCOE of POLYPHEM was higher than the PV+BESS solution, competitive with grid expansion, and significantly lower than diesel generators. Some additional relevant improvements such as the ability of delivering heat and integration of water desalination system, necessary for such a system to expand its competitiveness, were identified towards developing a roadmap to bring small-scale CSP projects to market within another study. In this study, the benchmarking is solely based on electricity production.