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Solving Water Issues for CSP Plants

Periodic Reporting for period 1 - SOLWARIS (Solving Water Issues for CSP Plants)

Reporting period: 2018-05-01 to 2019-10-31

The electricity production from concentrated solar thermal power (CSP) has to cope with two main challenges, the reduction of the water consumption, since a high insolation often occurs in locations with a lack of water resources, and also the improvement of the cost-effectiveness of the CSP technology.

To obtain an efficient electrical power generation, the turbine condenser must be cooled efficiently. Wet cooling is the traditional solution, despite its high-water requirements, representing up to 90% of the total water used in a wet cooled CSP plant. Moving to a dry cooled power block avoids this high-water usage but reduces turbine efficiency compared to a wet cooled system. Indeed, as assessed in the case study CSP Plant in Ma’an in Jordan , for equal electricity productions, implementation of dry cooling technology compared to wet one increases the investment cost by 16.4% and the LCOE by 16.1%. For those reasons, Engineering, Procurement, and Construction (EPC) contractors turn to dry cooling only when local regulations on the water use force them to do so. Therefore, by reducing the amount of water used for solar field cleaning, steam generation and for wet cooling, and by addressing the lack of efficiency of dry cooled CSP plants, SOLWATT project will actively support a significant reduction in water usage in CSP plants and improve efficiency of dry ones.

The overall purpose of the SOLWATT project is to upscale, implement and demonstrate cost-effective technologies and strategies that bring about a significant reduction of water of CSP plants while ensuring excellent performance of electrical power production. The SOLWATT approach proposed will tackle all segments of water consumption in a CSP plant by:
• 90 % for reduction of cleaning operations;
• 15 to 28 % for cooling of turbine condenser;
• 90 % for recovery and recycling of water;

Then, a total reduction of water consumption by:
• 35 % for a wet cooled CSP plant
• 90 % for a dry cooled CSP plant
Reduction of water cleaning operations
The activities performed on innovative soiling sensors were the electronic design and mechanical enclosure definition. 30 soiling sensors are being manufactured and will be installed in La Africana’s solar field.
Ultrasound cleaning prototype is able to reduce drastically the water consumption. SOLWARIS has designed and analyzed the best configuration in order to install it on cleaning truck to test it on the solar field mirrors. SOLWARIS has already designed the device and started the tests in a solar tower power plant. Other relevant result of SOLWARIS is an anti-soiling coating. This development is able to slow down the process of fouling the reflectors and receivers of solar field. It has been tested in a laboratory under accelerated conditions and is now ready to be tested in real weather conditions. Last prototype designed is a dust barrier. This barrier has been designed taking into account the shape, material and location.

Delayed cooling of turbine condenser
The thermocline cold Thermal Energy Storage (cTES) has been assessed with different shapes and sizes to be able to select the most effective for the cooling circuit process of the plant. Five operation modes have also been studying taking into account that day and night modes are different.
Finally, SOLWARIS has defined the shape, size and operation mode to validate them in a real plant.

Water recovery technologies
The water recovery system can recover wastewater of the plant with plant’s own waste energy. In this case, SOLWARIS is decreasing the consumption and cost of water thanks to an evaporator integrated in the process. The water recovery system can purify the wastewater to reuse it in the internal process.
SOLWARIS has finished the final design of water recovery system and its integration in La Africana plant.

Plant operation optimizer including soiling rate forecast
SOLWARIS project also pretends to upscale the developments and test the solutions in real plant conditions. Once the developments will be integrated in normal operation of the plant, SOLWARIS wants to optimize the operational modes and forecast the next configurations to achieve the maximum performance. That is why the inputs and outputs of prototypes have been identified, creating a database. The forecast tool will be able to select the best operation mode at any time taking into account the new integrated innovations.

Socio-economic and environmental studies
SOLWARIS project is also assessing the social, economic and environmental impact of a CSP plant in different locations where CSP plants are built. The project wants to ensure that the developments will improve these relevant aspects.
Along of SOLWARIS life the key characteristics affecting the livelihood of local population close to CSP plants are being assessed. In addition, an economic modelling is being implemented to introduce the project as a responsible innovation with the environment as well as a way to reduce costs.

Demonstration and validation of project technologies
SOLWARIS project has selected the best locations for each development and scheduled the activities to integrate and validate all of them within La Africana CSP plant during a relevant period.
The SOLWARIS project is expected to reduce the total water consumption at CSP facility by 35% for a wet cooled and by 90% for dry cooled CSP plants. Attached table shows detailed information on water savings (estimated for La Africana CSP plant) according to individual SOLWARIS technologies. These figures are based on preliminary tests and estimations performed by the project partners in order to validate the primary concept. F

Economic impact
The growth of installed CSP capacity, which is expected not only in Europe but also in other world regions such as the Middle East and North Africa (MENA), will provide SOLWARIS with tremendous opportunity for market penetration. Since transition to new technologies is the least financially and technologically challenging during the phase of design and planning, SOLWARIS has the biggest added value specifically during this time. Due to this fact, various proposed SOLWARIS solutions are primarily designed for future CSP plants, which offers an alternative to solutions currently available on the market. However, several technologies included in SOLWARIS (e.g. innovative cleaning technologies, soiling rate forecast and O&M optimizer) can be applied to existing plants as well, which also increases the chance for success on the market.

Environmental and social impact
One of the SET-plan initiatives (European Industrial Initiative on solar energy - Concentrating solar power) identified the demonstration of the competitiveness and readiness for mass deployment in the near future as most challenging task in the field of CSP. SOLWARIS proposes to contribute to this objective by improving the CSP water management and increase of the cost-effectiveness of the CSP technologies. By reducing the unfavourable environmental impact SOLWARIS will be a powerful tool to demonstrate sustainability of CSP technology and to further increase its social acceptance. SOLWARIS will also enable stakeholders to extend the technology to new locations without hampering environment and societal considerations. SOLWARIS carries out a comprehensive analysis of the impact of a CSP plant on the local inhabitants and their livelihoods. T