Water is one of our most vital sources on the planet. It’s all around us; 70% of the human brain is water, and there are roughly 326 million trillion gallons of water on Earth! As one of our most important resources, and with growing populations and more and more need for water everyday, it is vital that we protect this shared resource for future generations.
One of our partners here at Filters.com is Suez Environment, a world leader in water treatment. They recently put together a really inspiring YouTube video about how they’re working to revolutionize and digitize the way that we clean water. Watch the video below to hear them talking about why they love their work, but more important what its impact has on the water supply in the world. We are so excited that our filters are used by Suez and that we are a part of making the world’s water supply cleaner!
An off-grid desalination technology that combines membrane distillation with light-harvesting nanophotonics is being developed by the Centre for Nanotechnology Enabled Water Treatment (NEWT) at Rice University.
Video: NEWT Centre will use nanotechnology to transform water treatment.
NEWT’s ‘nanophotonics-enabled solar membrane distillation’ technology, or NESMD, is described in an article in the Proceedings of the National Academy of Sciences (PNAS).
Direct solar desalination
More than 18,000 desalination plants operate in 150 countries, but NEWT says its desalination technology is unlike any other used today.
“Direct solar desalination could be a game changer for some of the estimated 1 billion people who lack access to clean drinking water,” says Rice scientist and water treatment expert Qilin Li, a corresponding author on the study. “This off-grid technology is capable of providing sufficient clean water for family use in a compact footprint, and it can be scaled up to provide water for larger communities.”
The oldest method for making freshwater from salt water is distillation, the research team explains. Salt water is boiled, and the steam is captured and run through a condensing coil. However, distillation requires complex infrastructure and is energy inefficient due to the amount of heat required to boil water and produce steam. More than half the cost of operating a water distillation plant is for energy.
Membrane distillation is an emerging technology for desalination. Hot salt water is flowed across one side of a porous membrane and cold freshwater is flowed across the other. Water vapour is naturally drawn through the membrane from the hot to the cold side. Because the seawater does not need to be boiled, the energy requirements are less than for traditional distillation, but still significant because heat is continuously lost from the hot side of the membrane to the cold.
“Unlike traditional membrane distillation, NESMD benefits from increasing efficiency with scale,” explains Rice’s Naomi Halas, a corresponding author on the paper and the leader of NEWT’s nanophotonics efforts. “It requires minimal pumping energy for optimal distillate conversion, and there are a number of ways we can further optimise the technology to make it more productive and efficient.”
NEWT’s new technology builds upon research in Halas’ lab to create engineered nanoparticles that harvest as much as 80% of sunlight to generate steam. By adding low-cost, commercially available nanoparticles to a porous membrane, NEWT has essentially turned the membrane into a one-sided heating element that heats the water to drive membrane distillation.
“The integration of photothermal heating capabilities within a water purification membrane for direct, solar-driven desalination opens new opportunities in water purification,” says Yale University ‘s Menachem ‘Meny’Elimelech, a co-author of the new study and NEWT’s lead researcher for membrane processes.
In the PNAS study, researchers offered proof-of-concept results based on tests with an NESMD chamber about the size of three postage stamps and just a few millimetres thick. The distillation membrane in the chamber contained a specially designed top layer of carbon black nanoparticles infused into a porous polymer. The light-capturing nanoparticles heated the entire surface of the membrane when exposed to sunlight. A thin half-millimetre-thick layer of salt water flowed atop the carbon-black layer, and a cool freshwater stream flowed below.
Li says the water production rate increased greatly by concentrating the sunlight. “The intensity got up 17.5 kW/m2 when a lens was used to concentrate sunlight by 25 times, and the water production increased to about 6 l/m2 per hour.”
The NEWT team has already made a much larger system that contains a panel that is about 70 cm by 25 cm. Ultimately, they hope to produce a modular system where users could order as many panels as they needed based on daily water demands.
“You could assemble these together, just as you would the panels in a solar farm,” Li says. “Depending on the water production rate you need, you could calculate how much membrane area you would need. For example, if you need 20 l/hr, and the panels produce 6 l/hr per m2, you would order a little over 3 m2 of panels.”
In conventional membrane distillation (top image), hot saltwater is flowed across one side of a porous membrane and cold freshwater is flowed across the other. Water vapour is naturally drawn through the membrane from the hot to the cold side. In NEWT’s nanotechnology-enabled solar membrane distillation (lower image), a porous layer of sunlight-activated carbon black nanoparticles acts as the heating element for the process. (Image courtesy of P. Dongare/Rice University.)
Risk of Power Outages: Today’s electricity grid is increasingly vulnerable to threats from nature, terrorists, and accidents. Millions of American families and businesses are victimized by outages (both sustained and monentary) each year. Power outages cost as much as $130 billion annually, while hitting the job-creating commercial and industrial sectors the hardest.
Saving Consumers Money: Sixty million Americans in thirteen states plus Washington, DC are saving money because energy storage systems are providing frequency regulation in PJM territory (the power transmission operator in the mid-Atlantic region). PJM has projected that a 10-20% reduction in its frequency regulation capacity procurement could result in $25 million to $50 million savings to consumers. Energy storage can also let customers avoid premium pricing that utilities charge during times of peak demand. That’s like getting a cheap airline flight on Thanksgiving or a rush-hour subway pass at an off-peakprice.
Clean Energy Integration and Energy Independence: Energy storage supports the integration of renewable energy generation. Energy storage can also help cut emissions as it takes more of the load off fossil-fuel generation. Peaking generation is one of the most costly and wasteful aspects of the grid, so making existing generation go further and avoiding capital and resource-intensive new facilities would make a significant contribution to our environmental priorities. By supporting an all-of-the-above energy strategy, storage will also help accelerate our drive to energy independence.
Economy and Jobs: In addition to reducing economic losses from major and minor annual outages, experts say that energy storage will be a critical technology in the electricity grids of the future. They also predict that the long term-health of the U.S. economy, and tens of thousands of future U.S. jobs, depend in no small part on the ability of U.S. companies to at least remain competitive, if not to become leaders, in this critical technology.
Compressors use off-peak electricity to fill the cavern with compressed air. For peak demand, the compressed air is withdrawn from the cavern and used to power a wind turbine. Credit: Ridge Energy Storage & Grid Services LP Read more at: http://phys.org/news/2010-03-compressed-air-energy-storage-renewable.html#jCp
Is energy storage clean?
Yes. Energy storage has no direct emissions. It requires no pipelines. Its systems typically require a minimal footprint. It recycles electricity. But energy storage will also help cut emissions as it takes more of the load off traditional generation.
How big is the energy storage market?
Energy storage systems currently make up approximately 2% of U.S. generationcapacity. That percentage is growing significantly, especially with the advent of more renewable energy. Pumped hydroelectric power has played an important part of our electricity grid since the 1930s. Yet today, electricity from wind, solar and other ‘intermittant’ sources have created urgent needs for additional energy storage.
World-wide demand for grid-scale energy storage is estimated to reach over 185.4 gigawatt-hours (GWh) by 2017 – which is approximately the amount of electricity New York City consumes in 17 days. That represents a $113.5 billion incremental revenue opportunity for an industry that currently generates sales of $50-60 billion a year.
Advanced-adiabatic compressed air energy storage (AA-CAES) is an evolution of traditional CAES, designed to deliver higher efficiencies via a zero-carbon process. Operation is similar to traditional CAES in that energy is stored by compressing air with turbomachinery and storing in an underground cavern. The difference lies in the treatment of the heat of compression.