How can renewable energy effectively power a desalination plant?

In my opinion thermal desalination with thermal or mechanical re-compression would be the best option to separate salt from sea-water. One can also use the temperature differential at various depths of the sea as a low-temperature option.

Though reverse osmosis is favored by desalination science, it requires more water and energy to operate than it produces. In contrast, high-performance concentrated solar panels (CSP) technology collects solar radiation to generate heat from a petroleum distillate to a multi-effect evaporator. The evaporator makes steam by heating contaminated water to recover freshwater. A heat pump recovers waste steam to increase efficiency and productivity, while a thermal storage system supplies electricity produced by the solar arrays to provide energy for facility operations and outsourcing to surrounding users. Thus, CSP can produce phenomenal amounts of freshwater daily, making solar desalination possibly the most effective treatment available.

Desalination technologies, crucial for fresh water supply, mainly include thermal and membrane methods. Thermal desalination, relying on evaporation and condensation, is highly energy-intensive. Membrane desalination, particularly reverse osmosis (RO), is less so, making it more suitable for pairing with renewable energy sources like solar or wind. This compatibility offers a sustainable approach to addressing water scarcity, especially in areas with abundant renewable energy potential.

Compared to reverse osmosis (RO) seawater desalination, using concentrated solar power (CSP) is about 25% of the cost. CSP technology is available and has been successfully tested, implemented, and operated at megascale capabilities worldwide. Since CSP is derived from basic solar-still technology, it works equally well at smaller scales, like single-family homes. A completely passive solar-powered desalination system developed by MIT researchers provides more than 1.5 gallons of fresh drinking water per hour for every square meter of solar collecting area. Such systems could potentially serve off-grid coastal areas to provide an efficient, low-cost water source and equally inland regions with high levels of agricultural irrigation run-off.

Integrating renewable energy with desalination plants varies based on energy source availability and desalination technology. There are three main integration modes: direct, indirect, and hybrid coupling. Direct coupling directly powers the plant with renewable energy, ideal for small-scale, off-grid setups but subject to energy source variability. Indirect coupling, suitable for large-scale, grid-connected plants, involves grid or battery systems but needs extra infrastructure. Hybrid coupling, blending conventional with renewable sources, fits medium-scale, remote applications but slightly diminishes the environmental advantages of renewables. Each mode balances benefits with challenges, tailored to specific needs and contexts.

Using renewable energy to power desalination plants improves affordability and stimulates innovation. An example is MIT’s 2023 advanced single-stage design, consisting of a thin box topped with a dark material to absorb the sun’s heat efficiently. The device separates water flow through its top half by heat and evaporation and funnels the water vapor to the bottom half, where a condensing layer air-cools the vapor into freshwater. The device is tilted within a larger vessel, with a tube attached from the top to the bottom, and is floated in saltwater. As water naturally pushes up through the tube, it swirls to eliminate salt settling and clogging. The prototypes show that operational costs are less than tap water production in the US.

En realidad no estoy deacuerdo, parte de una propuesta que llame la teoría de arquitectura renovable hace más de 20 años. es replicar las adaptaciones existentes, mejorándolas y optimizándolas con la tecnología y materiales actuales. Se sorprenderán de los resultados. Y no son costosos comparándolos con los inmensos beneficios. Para que tratar de cambiar algo que lleva millones de años evolucionando? El problema no radica en las soluciones sino en la falta de apoyo. aunque una solución de estas, cambiaría el mundo mejorándolo notoriamente. Al no generar rentabilidad se vuelve invisible. esto señores es la única limitante para su difusión.

Integrating renewable energy into desalination faces challenges and offers transformative opportunities. The intermittent nature of solar and wind power poses a reliability challenge for consistent desalination processes. Advanced energy storage systems are crucial to store excess energy during peak production, ensuring a continuous power supply. The high cost of renewable infrastructure is a financial hurdle, but long-term benefits and reduced environmental impact make a compelling business case. The opportunities are substantial. Diversifying the energy mix enhances energy security and reduces dependence on fossil fuels. Decentralizing desalination facilities, particularly in remote areas, promotes water independence and reduces losses.

HydroRevolution is a concentrated solar power (CSP) demonstration engineered for the Panoche Water and Drainage District. It produces affordable freshwater for California's central valley farmlands. Their Aqua4™ technology ensures the consistent delivery of freshwater, regardless of seasonal conditions, for agri-businesses and other commercial water users by using any treatable water source—irrigation surface run-off or saltwater. Though intended to treat spoiled freshwater, Aqua4™ also treats seawater. The technology uses concentrated solar stills to evaporate and distill water at 30 times the efficiency of natural evaporation. A single 160' x 40' module generates 65,000 gallons of freshwater per day—equivalent to 70 acre-feet per year.

Alignment of available predominant renewable energy sources with specific climatic conditions can overcome unstable renewable energy services for powering desalination plants. For example, wave motion or wind turbine technology can triumph over poor solar access. Yet, solar access is usually sufficient in most inhabited parts of the world. The National Renewable Energy Laboratory states by 2035, seven percent or less of the land area in three mid-sized states will generate most of the country’s electricity from solar and wind. Moreover, from water harvesting to on-site solar powered desalination systems, every project can produce freshwater with today's available technology, especially at smaller scales.