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MOdular high concentration SolAr Configuration

Periodic Reporting for period 2 - MOSAIC (MOdular high concentration SolAr Configuration)

Reporting period: 2018-02-01 to 2019-05-31

MOSAIC focuses on developing the next generation technologies of renewable electricity, through the development of a new CSP concept with a high potential for energy cost reduction. It aims to deliver cheap and dispatchable green energy thanks to its intrinsic storage capability. MOSAIC could allow to introduce large amounts of predictable and grid friendly energy allowing larger amounts of other variable output renewable sources in the grid. MOSAIC plants would produce green energy while other non-dispatchable green energies like PV and wind could also enlarge its penetration. This mix will be cost competitive with fossil fuel sources and will allow for a 100% carbon free electricity generation. MOSAIC aims to develop and validate in relevant environment this configuration for CSP plants and all relevant components required to implement the concept, thus clearing possible uncertainties and risks.
To assure Sustainable Development and tackle global climate and energy challenges, Energy Sector must be transformed towards carbon neutrality. To get it, renewable energy technologies must become the keystones of the energy system. MOSAIC support key actions of tge SET Plan, notably action 1 and action 2 aiming to accelerate the decarbonisation of the energy system. Although Renewable energies have experienced an impressive development that makes them already competitive in many scenarios, they still need further improvement to assure secure supply of energy at affordable prices.
Moreover, Europe needs to maintain global leadership in renewable energy technology and in particular in the CSP. This requires developing more “affordable” technologies and solutions, thus further reducing LCoE (Levelized Cost of Energy), that enable European companies to compete in the global market and sustain its technological and economic leading position.
MOSAIC will be validated at a relevant environment moving up to TRL5-6. In that aim, the specific objectives in the project are:
• Development of an innovative low cost fixed solar field with high concentration ratio
• Development of a high temperature receiver tailored for the flux distribution generated by this solar field
• Development of a cheap closed-loop controlled tracking system for the receiver.
• Integration, test and validation of the whole MOSAIC module
• Design the modular plant approach.
Main challenge is to reach the highest concentration ratios using systems that can be manufactured, installed, operated and maintained at low cost.
MOSAIC concept develops a cost-effective fixed hemispheric semi-Fresnel reflector lighting up a high temperature actuated receiver in an efficient modular plant configuration with the objective of achieving the lowest LCoE. It targets:
• Advanced and innovative components, such as the fixed spherical mirrors for the concentrator, the concentrator configuration (fixed hemispherical semi-Fresnel mirror), the high temperature solar receiver unit and the accurate, low-cost tracking system of the receiver, in order to remarkably reduce the capital cost of the whole system while improving the whole efficiency of the system to achieve lower LCoE.
• Reducing construction and O&M costs via optimized fixed solar field configuration easy to assemble, suitable for low cost mass production and for easy maintenance thanks to its improved accessibility. It also includes a considerably smaller number of driving systems thus improving reliability
• Improved plant control and operation by means of an advanced tracking control which is obtained by a closed loop tracking control.
• Innovative modular plant configuration, providing an optimum in terms of efficiency (very high concentration like that of Power Tower systems could be achieved at each MOSAIC module avoiding problems such as the atmospheric attenuation), cost effectiveness, better land use, and operability (power block is directly driven by a central Thermal storage).
Hence, a significant reduction in the LCoE is expected from a reduction in both CAPEX and OPEX.
Two milestones have been achieved:
• The preliminary design of the MOSAIC concept has been finished including module definition and overall plant configuration.
• A validation prototype that can validate the concept at a relevant environment has been also defined.
This includes the design of all relevant components that could be grouped in three main systems:
• The Fresnel type solar field configuration has been defined. It consists of a number of sections of different spheres sharing a single central point. Definition of the system includes; the number, curvature and size of each sphere, the tilt angle, the structure to support the mirrors, the civil works and foundations required to support that structures, etc.
• The tracking system able to move the receiver from sunrise to sunset all along the year. It includes the tracking systems as well as the required structures and a preliminary design of the clamping systems and interfaces. Moreover, a non-contact system to close the control loop has been also defined.
• The receiver tailored for this extremely irregular and high flux as well as the thermal loop to operate the system has been defined. The prototype will include a different heat transfer fluid in order to reduce operation risks during characterization and testing so two different systems have been designed.
The whole design process have been driven by cost reduction, efficiency enhancement and reliability. Therefore, once a complete set of targeted requirements was defined, practical evaluation criteria (technical, operating and economical) were analyzed in order to define practical constraints to ensure the achievement of a techno-economically balanced design.
In the coming weeks the effort will be focused on the detailed design of the prototype sub-systems, to its manufacture, check and further installation as well as to the detailed definition of the test plan.
More detailed and updated information about the project development, consortium, etc. is available at project website.
Spherical concentrators allow to reach high concentration ratios with fixed solar fields. That is a very interesting due to the potential cost reduction on the solar field. On the other hand, the receiver must be mobile, which introduces challenges that are not completely solved.
Spherical concentrators have been proposed in the past, but no industrial development has been done so far, mainly due to:
• Large concentrators lead to huge civil works, so high costs
• Large concentrators require expensive drives and structures that can rigidly support them
• No tailored receivers have been developed to take full advantage of the high and progressive concentration ratios
This project overcomes these limitations since:
• The optimized semi-Fresnel solar field proposed reduce the solar field cost.
• A low-cost driving system has been proposed that could lead to affordable mobile receivers.
• A tailored receiver adapted to the progressive high 3D concentration assures better efficiencies and high temperatures.
The proposed modular design allows the development of both; distributed applications adapted to niche markets, and large mass electricity production facilities.
MOSAIC project pursues to deliver affordable and dispatchable green energy thanks to its intrinsic storage capability.