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Solar-Powered Desalination | Earth Wise

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About 1% of the world’s population is dependent on desalinated water to meet daily needs, but water scarcity is a growing problem that experts believe will affect 14% of the world’s population within the next five years.

Desalination takes much more energy than, for example, transporting fresh water over large distances.  In general, desalination costs are much higher than those associated with fresh water, but beyond costs, freshwater is simply not always available.

Researchers at MIT and Shanghai Jiao Tong University in China have developed a completely passive solar-powered desalination system that could provide more than 1.5 gallons of fresh drinking water per hour for every square meter of solar collecting area.   Such a system could provide an efficient, low-cost water source for coastal areas that are off the grid.

The system uses multiple layers of flat solar evaporators and condensers topped with transparent aerogel insulation.  The key to its efficiency is the way it uses each of its multiple stages to desalinate water.  At each stage, heat released by the previous stage is harnessed instead of wasted.  The proof-of-concept device, which was tested on an MIT building rooftop, produced more than twice as much water as the record amount produced by any previous passive solar-powered desalination system.

The researchers plan further experiments aimed at optimizing the choice of materials and configurations and to test the system under realistic conditions.  The hope is to have a technology that can play a role in alleviating water scarcity in parts of the world where electricity is scarce, but seawater and sunlight are abundant.

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Simple, solar-powered water desalination

Photo courtesy of MIT/researchers.

Earth Wise is a production of WAMC Northeast Public Radio.

Figuring Out Photosynthesis | Earth Wise

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Plants have been harnessing the sun’s energy for hundreds of millions of years. Algae and photosynthetic bacteria have been doing the same for even longer, all with remarkable efficiency and resiliency. 

People have used the energy of the sun in one way or another for millennia, but only recently have we gotten sophisticated about it by using devices like solar panels and sensors.  And we still have a long way to go to get anywhere close to the efficiency of plants. It’s no wonder, then, that scientists have long sought to understand exactly how photosynthesis works.

Scientists from the U.S. Department of Energy’s (DOE) Argonne National Laboratory, and collaborators at Washington University in St. Louis, recently solved a critical part of the age-old mystery of photosynthesis, studying the initial, ultra-fast events through which photosynthetic proteins capture light and use it to initiate a series of electron transfer reactions.  Electrons in plants have two possible pathways to travel but only use one.   

But as a result of their efforts, the scientists are now closer than ever to being able to design electron transfer systems in which they can send an electron down a pathway of their choosing. 

By gaining the ability to harness the flow of energy, it may be possible to incorporate new design principles in non-biological energy systems. This could allow us to greatly improve the efficiency of many solar-powered devices, potentially making them far smaller. Understanding the intricacies of photosynthesis creates a tremendous opportunity to open up completely new disciplines of light-driven biochemical reactions, perhaps even ones that haven’t been envisioned by nature.

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Scientists unravel mystery of photosynthesis

Photo, posted June 14, 2017, courtesy of Alex Holyoake via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Clouds And Global Warming | Earth Wise

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Recent climate models from multiple organizations project that the amount of warming that doubling atmospheric carbon dioxide would cause would be much more than previously estimated.  And one of the significant changes to the models relates to the role of clouds.

Clouds have long been a major uncertainty in climate calculations.  Clouds can shade the earth and thereby provide cooling.  But clouds can also trap heat.  Which effect dominates depends on how reflective the clouds are, how high up they are, and whether it is day or night.  The dynamics of clouds are complicated.

If you fly across the ocean, you will see blankets of low clouds extending for hundreds of miles.  These marine stratus and stratocumulus clouds predominantly cool the Earth.  In fact, they shade roughly a fifth of the oceans and reflect 30-60% of the solar radiation that hits them back into space.

Recent studies indicate that as global temperatures rise, these clouds are likely to become thinner or burn off entirely, leaving more clear skies through which the sun may add another degree Celsius or more to global warming.

The concerns about clouds are part of the larger issue about feedbacks in warming the world.  It has long been clear that the greenhouse effect of doubling CO2 levels in the atmosphere would raise global temperature.  But there are amplifying feedback effects.  Melting large areas of snow and ice reduces reflectivity and allows the land and oceans to absorb more heat.  More water vapor entering the atmosphere traps more heat.  And now clouds are another concern.

Overall, these effects are leading to climate models predicting much larger global temperature increases, which is a scary prospect for the world.

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Why Clouds Are the Key to New Troubling Projections on Warming

Photo, posted September 10, 2006, courtesy of Nicholas A. Tonelli via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Extreme Heat From Solar Power | Earth Wise

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Renewable sources are playing a growing role in meeting our energy needs, but one place where they have continued to fall short is in industrial processes that require extreme heat.  These include the cement, steel, and glass industries, among others.  These industries account for a significant amount of CO2 emissions because the most effective way to reach the necessary temperatures continues to be combustion of fossil fuels.  The cement industry alone accounts for 7% of global emissions and the need for cement continues to grow.

A previously stealthy startup company backed by Bill Gates and fellow billionaire Soon-Shiong has made a breakthrough in the area of using solar energy to achieve high temperatures.  The company, called Heliogen, has created a solar oven that is capable of generating heat above 1800 degrees Fahrenheit, which is enough for high-temperature industrial processes.

The Heliogen technology uses concentrated solar power to generate heat.  Concentrated solar power uses arrays of mirrors to reflect sunlight and focus it to a single point.  That technology is not new;  there are systems that use it to produce electricity and, to some extent, heat for industry.  But it could not achieve high enough temperatures for producing cement or steel.

The new system uses computer vision software, automatic edge detection and other sophisticated technologies to focus the sun’s rays far more finely than ever before and thereby generate far higher temperatures at the focal point.

Heliogen is now focused on demonstrating how the technology can be used in a large-scale application, such as cement-making.  The selling points to industry are that not only will there be no emissions generated, but that the fuel needed to obtain their extreme heat will be free.

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Secretive energy startup backed by Bill Gates achieves solar breakthrough

Photo courtesy of Heliogen.

Earth Wise is a production of WAMC Northeast Public Radio.

A Possible Storage Breakthrough: Solar Energy | Earth Wise

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Solar energy is a nearly unlimited resource, but it is only available to us when the sun is shining.  For solar power to provide for the majority of our energy needs, there needs to be a way to capture the energy from the sun, store it, and release it when we need it.  There are many approaches to storing solar energy, but so far none have provided an ideal solution.

Scientists at the Chalmers Institute of Technology in Sweden have developed a way to harness solar energy and keep it in reserve so it can be released on demand in the form of heat—even decades after it was captured. Their solution combines several innovations, including an energy-trapping molecule, a storage system, and an energy-storing laminate for windows and textiles.

The energy-trapping molecule is made up of carbon, hydrogen, and nitrogen.  When hit by sunlight, the molecule captures the sun’s energy and holds on to it until it is released as heat by a catalyst.  The specialized storage unit is claimed to be able to store energy for decades.  The transparent coating that the team developed also collects solar energy and releases heat.  Using it would reduce the amount of electricity required for heating buildings.

So far, the team has concentrated on producing heat from stored solar energy.  It is unclear whether the technology can be adapted to produce electricity, which would be even more valuable.  In any event, the team does not yet have precise cost estimates for its technology, but there are no rare or expensive elements required, so the economics seem promising.  There is much more work to be done, but this could be a very important technology for the world’s energy systems.

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An Energy Breakthrough Could Store Solar Power for Decades

Photo courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Turning CO2 Into Rock

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As the world continues to struggle to find ways to reduce carbon emissions, there is increasing attention being paid to so-called negative emission technologies (NET), which remove and permanently sequester carbon dioxide from the atmosphere.

The University of Victoria in British Columbia has brought together an international team of experts to explore the possibilities of permanently and safely sequestering CO2 as rock beneath the ocean floor.  The Solid Carbon Project seeks to extract carbon dioxide directly from the air and then, using deep-ocean technology powered by offshore solar and wind energy, inject it into sub-seafloor basalt, where it would mineralize into solid carbonate rock.

When CO2 is injected into porous basalt, a type of volcanic rock, it reacts relatively quickly with minerals to form solid carbonate, thereby permanently removing it from the atmosphere.  Because 90% of the planet’s basalt is located beneath the ocean floor, the deep ocean is the place to do this kind of carbon sequestration.

The team includes experts in ocean science, carbon mineralization, renewable energy, engineering design, and oil-and-gas drilling/injection operations. Other experts are focusing on the social and legal implications of the NET technology.

Over the next four years, the Solid Carbon Project will assess the integration of multiple existing technologies that will be needed to successfully develop this kind of carbon storage.  One of these is the direct air capture technology itself, which will need to be adapted to a renewable energy-powered offshore platform.  The best outcome technologies explored by the project will be selected for a real-world demonstration at Ocean Networks Canada’s observatory site, 9,000 feet underwater in the Cascadia Basin, off the coast of British Columbia.

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A rock-solid solution for CO2

Photo courtesy of the University of Victoria.

Earth Wise is a production of WAMC Northeast Public Radio.

More Solar And Wind Power In The U.S.

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According to the U.S. Energy Information Administration, both wind and solar power are contributing more and more to total electrical generation in the United States.  For the first 8 months of 2019, the combination of wind and solar power accounted for almost 10% of U.S. electrical generation.

Solar, including small-scale PV systems on home rooftops, grew by almost 14% compared to the first eight months of 2018 and accounted for more than 2.7% of total electrical output.  In fact, small-scale solar generation increased by 19% and provided nearly a third of all the solar power in the country. 

Wind energy in the U.S. increased by 4.4%, accounting for almost 7% of the country’s electricity.

Overall, renewable energy sources – which include biomass, geothermal, hydropower, solar, and wind – accounted for 18.49% of net domestic electrical generation during the first 8 months of 2019.  The non-hydro renewable sources actually accounted for over 11% of total electricity production and saw a year-over-year growth of 6%. 

Outside of renewables, nuclear-generated electricity declined by 0.6% and coal power dropped by almost 14%.  Much of the coal generation was replaced by natural gas, which grew by 6.5% compared to the previous year.

Renewables now accounting for nearly 20% of overall electricity generation in the US represents significant progress.  But the variations by state continue to be substantial.  For example, while Vermont gets 99% of its power from renewables, Ohio gets only 2%. 

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Solar and wind energy provide almost 10 percent of total generation in the US in 2019

Photo, posted April 8, 2019, courtesy of City of St. Pete via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Solar And Wind Energy And Groundwater

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The use of both solar and wind farms has been expanding all over the country as a way of lowering carbon emissions from the electric power sector.   According to a new study led by Princeton University, these renewable energy sources have another important benefit:  they keep more water in the ground.

The study focused on drought-prone California where both solar and wind power have been expanding dramatically.  California is the largest agricultural producer in the United States and has also experienced one of the most severe droughts on record between 2012 and 2017.

The study determined that increased solar and wind energy can reduce the reliance on hydropower, especially during times of drought. 

The study looked at multiple scenarios in order to determine how much solar and wind energy should be used to maximize economic revenue and to see how solar and wind power could ensure groundwater recovery.  They created a framework to quantify the optimal pathways for maximizing hydroelectricity and agricultural income while avoiding groundwater depletion.

During the long drought, California’s agriculture industry relied heavily on tapping into groundwater stores, which is an unsustainable practice.  With more droughts likely to occur in California as well as increasing water demand from the growing California population, the burden on the state’s groundwater supply will only grow.

According to the researchers, it is far more practical to impose further regulations on groundwater use if sufficient solar and wind power is deployed.   They caution that these resources need to be deployed long before groundwater aquifers are depleted, or it will be too late for them to do any good.

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Solar and Wind Energy Preserve Groundwater for Drought, Agriculture

Photo, posted December 11, 2014, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Potential For Offshore Wind

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According to a new report from the International Energy Agency, offshore wind technology has vast potential for meeting our energy needs.  In total, offshore wind has the potential to generate more than 420,000 terawatt-hours of electricity each year, which is more than 18 times the global electricity demand that exists today.

Based on current policy targets and plummeting technology costs, offshore wind could increase 15-fold by 2040, becoming a $1 trillion industry and eliminating 5 to 7 billion tons of carbon dioxide emissions annually.

Offshore wind today generates just 0.3% of the world’s electricity, but its’ use is growing rapidly.  The industry has grown nearly 30% a year since 2010, and 150 new offshore projects are currently in development around the world.  The leading countries are in Europe – especially in the UK, Germany, and Denmark – but China is greatly expanding its offshore capacity and the US, India, Korea, Japan, and Canada are also expected to make large investments in offshore wind going forward.

Offshore wind is in a category of its own because it is considered a variable baseload power generation technology.  This is because the hourly variability of offshore wind is much lower than solar power or onshore wind.  Offshore wind typically fluctuates far less from hour-to-hour than the other variable energy sources.

Technology improvements and industry growth are driving steep cost reductions for offshore wind.  The cost of offshore wind is expected to be cut in half in the next five years, dropping to $60 per megawatt-hour, which is on par with solar and onshore wind and cheaper than new natural gas-fired capacity in Europe.

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Offshore Wind Has the Potential to Fulfill Global Electricity Demand 18 Times Over

Photo, posted August 9, 2016, courtesy of Lars Plougmann via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Reducing Emissions From Natural Gas Processing

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Qatar, a small country in the Middle East with a population of about 2.5 million has the highest per capita income of any country in the world.  This is largely a result of being one of the world’s top producers of natural gas.  The upshot of that is that the tiny country has the dubious honor of being the world’s leading emitter of CO2 per capita.

Texas A&M University has a campus in Qatar and researchers there in collaboration with colleagues at the main campus in College Station, Texas have developed a new reactor technology that can help Qatar process its wealth of natural gas while reducing the country’s carbon footprint.

The technology processes natural gas and captured CO2 to produce both syngas – which is a valuable precursor for many products – and high-quality carbon nanotubes, all without releasing CO2 into the atmosphere.

Natural gas reforming is a process by which syngas – a feedstock for liquid hydrocarbons and ultraclean fuels- is produced.  The process requires lots of heat and emits CO2.  The new technology adds a novel CARGEN (or CARbon GENerator) reactor that advances the natural gas reforming process and includes a catalyst that captures the CO2 emissions and produces nanotubes.  The reactor can be driven by either electric or solar power, eliminating the need to burn fuel that ordinarily results in more carbon emissions.

The result is that Qatar’s CO2 emissions would be converted into two products that are important to its economy.  In particular, carbon nanotubes are very expensive and extremely versatile, and can be used to manufacture products such as computers and other high-quality materials.

The next step for the researchers is to partner with industry collaborators to further scale up the technology.

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Qatar Researchers Develop Natural Gas Processing Technology That Could Reduce Qatar’s Carbon Footprint

Photo, posted September 30, 2012, courtesy of Jimmy Baikovicius via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Stranded Coal Assets In Japan

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Japan is facing a looming financial problem as a result of heavy investments in coal technology that may quickly become stranded assets as renewable energy sources become increasingly inexpensive.

Japan is gradually adding more ambitious policies with regard to climate change including goals to reduce emissions and to have renewables become the main source of power over the next three decades.  But despite these policy efforts, Japan is still investing heavily in coal power.  Japan currently has 21 new coal projects with over 11 GW of under-construction, permitted or pre-permitted coal capacity.  But these tens of billions of dollars in assets would have to be closed prematurely in order to remain consistent with the goals of the Paris Climate Agreement.

According to a new report by the Carbon Tracker Initiative, a financial think tank, and the University of Tokyo, offshore wind power will be cheaper than coal in Japan by 2022, new solar cheaper by 2023, and onshore wind less expensive by 2025.  The price of offshore wind is already comparable to existing coal power in Japan.  Japan had a total of 55.5 GW of solar capacity last year and has the potential to reach 150 GW by 2030.

The report notes that 42% of the global coal fleet likely became unprofitable last year and this could rise to 72% by 2040.  The authors contend that building coal power today equals high-cost power and financial liabilities tomorrow.  The planned and operating coal capacity in Japan is partially protected by regulations that give coal generators an unfair advantage in the marketplace.  Ultimately, the stranded coal assets are likely to be passed down to consumers through higher power prices.

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Land of the Rising Sun and Offshore Wind

Photo, posted April 25, 2019, courtesy of Jen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Hydrogen From The Ocean

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Hydrogen is frequently touted as an excellent source of clean energy that could be used as a fuel in vehicles, or as a storage medium for energy generated by wind and solar power.  The challenge is that hydrogen is rather difficult and expensive to attain, and the most economical methods are not clean and green.

Most industrial hydrogen is produced by reforming natural gas, which has the drawback that carbon dioxide is generated in the process.  The environmentally friendly way to produce hydrogen is via electrolysis, in which a chemical reaction is triggered by a catalyst enabling electricity to split water into its constituent elements of oxygen and hydrogen.

The best performing catalyst for electrolysis is platinum, but its high price is a big drawback for the economics of making hydrogen.  Researchers at the Pacific Northwest National Laboratory have found a pairing of minerals that may solve the problem.  Testing a molybdenum-phosphide catalyst with wastewater in a small reactor called a microbial electrolysis cell revealed that the new catalyst actually worked better than platinum.

Even better, the molybdenum-phosphide catalyst worked well with seawater.  If hydrogen can be produced using seawater, there would be a pretty much unlimited resource for making it.  By eliminating the use of platinum catalysts, it may be possible to reduce the cost of hydrogen made by electrolysis to a competitive level.

Hydrogen as a vehicle fuel currently costs about twice as much as gasoline on an energy-equivalent basis.  Given that running cars from batteries is considerably cheaper than using gas, the cost of hydrogen needs to come down considerably for it to be a viable vehicle fuel.

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Ditching Platinum for the Ocean Could Make Hydrogen Cheap

Photo, posted July 19, 2011, courtesy of Heather Paul via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Geoengineering And Volcanoes

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Solar geoengineering is a theoretical strategy for curbing the effects of climate change by introducing aerosol particles in the upper atmosphere to reflect some of the Sun’s radiation back into space and thereby cool the planet.  It would basically be intentionally tinkering with the climate system on a global scale.

The concept is fraught with the danger of unintended consequences and most experts consider the idea almost unthinkable.  But there are those who see it as a last resort if all our other efforts to mitigate the effects of climate change are unsuccessful.

Proponents of the idea like to describe the technique as being like a human-made volcano.  Major volcanic eruptions spew ash particles into the atmosphere which can linger for as long as a few years.  The result is cooler temperatures, sometimes across much of the globe.  The Krakatoa eruption of 1883 lowered average Northern Hemisphere temperatures by more than 2 degrees and created chaotic weather patterns until about 1888.

Researchers at the Carnegie Institution and two Chinese research institutions used sophisticated modeling techniques to compare the effects on the climate of a volcanic eruption with long-term geoengineering deployment.

They found that the volcanic eruption created a greater temperature difference between the land and sea than the geoengineering and resulted in very different precipitation scenarios.  In both cases, there would be less available water for people on land.

Overall, the study demonstrated that volcanic eruptions are imperfect analogs for geoengineering and that scientists should be very cautious about extrapolating too much from them.  It is important to evaluate geoengineering from an informed position, but the truth is that it represents a great and perilous unknown.

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Geoengineering Versus A Volcano

Photo, posted November 1, 2002, courtesy of the NASA Goddard Space Flight Center via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Removing Dams Restores Ecosystems

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In many parts of the country, dams that sometimes date back as much as 100 years are being removed and are giving way to the revival of migratory fish and their river ecosystems.  Since 1912, more than 1,600 dams have been removed in the U.S., but the pace of dam removal has greatly picked up in recent years.  2017 and 2018 were the highest years ever with 91 and 99 dams removed, respectively.

When dams are removed, the response from migratory fish can be almost immediate.  A large dam removal project on the Penobscot River in Maine in 2012 opened up 1,000 miles of habitat with a quick return of shad and alewives, followed by salmon.

In 2022, four large dams across the Klamath River will be removed.  The dams, which are located at the California and Oregon border, were facing an expensive re-licensing process and, because of their age, could no longer be run at a profit.

Re-licensing the dams along the Klamath was going to cost as much as $400 million.  On the other hand, uncapping the Klamath River has tremendous commercial and tourism potential.  Two states, tribal nations, and other stakeholders have all seen the virtues of restoring the landscape to its original form.

Opposition to dam removal is typically driven by aesthetics or recreational preferences.  But dam economics are getting increasingly worse.  Now that electricity can be produced far more cheaply with wind and solar power, many American dams have become artifacts of an older manufacturing era.  Meanwhile, rural towns near decommissioned dams are likely to now have more robust fishing industries.

In rivers big and small, migratory fish and river ecosystems surge back to life as old energy structures are taken down.

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Take Down That Dam: River Ecosystems Bounce Back As Removals Soar

Photo, posted June 11, 2016, courtesy of the Bureau of Land Management via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Amazon And Climate Change

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Online shopping giant Amazon has unveiled a Climate Pledge, committing to meet the goals of the Paris climate agreement ten years ahead of schedule, and to be carbon neutral by 2040. This is the company’s most ambitious push yet to reduce its carbon footprint, which currently rivals that of a small country.  In fact, Amazon is responsible for 48.9 million tons of carbon dioxide last year, which is about 85% of what Switzerland typically emits in a year. 

Amazon, which ships more than 10 billion items a year on fossil fuel-intensive planes and trucks, has ordered a fleet of 100,000 electric vans that will start delivering packages to doorsteps in 2021.  The vans will be made by Rivian, a Michigan-based company that Amazon invested in earlier this year. 

Amazon plans to get 100% of its energy from solar and other renewable sources by 2030.  Currently, it gets about 40% of its energy from renewables. 

Amazon is also investing $100 million in nature-based climate solutions and reforestation projects around the world in order to remove carbon from the atmosphere. 

While announcing these initiatives recently at the National Press Club in Washington, D.C., Amazon CEO Jeff Bezos said the company needs to be a leader on the climate change issue:

We want to say look, if a company of Amazon’s complexity, scale, scope, physical infrastructure, delivering 10 billion items can do this, so can you.

After revealing Amazon’s Climate Pledge, Bezos said he would talk with CEOs of other large companies to try to get them to also sign it.  You can find a link to Amazon’s progress on its commitments by visiting this website.

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‘Middle of the herd’ no more: Amazon tackles climate change

Amazon: Committed to a sustainable future (track progress here)

Photo courtesy of Amazon.

Earth Wise is a production of WAMC Northeast Public Radio.

Compressed Air Energy Storage

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The increasing use of solar and wind power has created a growing need for technology to store up the energy they generate for use when it is most needed.

Historically, pumped hydropower has provided the largest amount of storage capacity, but it is limited to only certain geographic locations.   Battery energy storage has been growing rapidly, with the technology becoming better and cheaper over time.  But there are various other ways to store energy that have potential and may well find their place in the changing energy infrastructure.

One of these is compressed air energy storage, which has been around for more than a century.  It has been used as a backup method for restarting power plants.  But to date, the economic viability of using it at a large scale has been lacking.

A Canadian startup company called Hydrostor is developing compressed air energy storage technology that it believes can be used on a utility scale.

The way it works is excess renewable energy is used to run compressors that compress air.  Compressing the air heats it up and the heat is captured and stored in insulated hot water tanks.  The compressed gas is then injected into underground caverns.  When energy is needed, the compressed air is released, the stored heat is added, and the warmed gas is run through turbines to generate electricity.  Additional features improve the system’s efficiency.

Hydrostore has built a 1 MW pilot project in Ontario, Canada and is now commissioning a 2MW system as well.  It is funded to build a 5 MW system in Australia next year and it is bidding for 300 MW and 500 MW systems in North America.  The company has received equity funding from Baker Hughes, a large oil-and-gas services and equipment company.

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Storing energy in compressed air could finally become cheap enough for the big time

Photo courtesy of Hydrostor.

Earth Wise is a production of WAMC Northeast Public Radio.

Pulling Water From The Air

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A couple of years ago, we reported on the early development of a device that harvests water from the air that even works in the low humidity environment of a desert.  Since then, the researchers from UC Berkeley have continued to improve the device and it is now 10 times better than it was two years ago.

The harvester is based on a porous water-absorbing material called a metal-organic framework, or MOF.  The latest version can pull more than five cups of water from low-humidity air per day for every kilogram of the improved MOF material and that is more than enough water to sustain a person.  The harvester cycles around the clock and is powered by solar panels and a battery.

Previous techniques for condensing water from air at low humidity required cooling down the air to temperatures below freezing, which is not economically practical.  The MOF-based device does not require any cooling.

The Berkeley researchers have formed a startup company – Water Harvester, Inc. – which is now testing and will soon market a device the size of a microwave oven that can supply 7 to 10 liters of water per day, which is enough drinking and cooking water for two or three adults.

An even larger version of the harvester, which would be the size of a small refrigerator, would provide 200 to 250 liters of water per day, enough for a household to drink, cook, and shower.  The new company envisions a village-scale harvester that would produce 20,000 liters per day, still running off of solar panels and a battery.

Water Harvester believes the water needs for many people can come out of the thin air.

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Water harvester makes it easy to quench your thirst in the desert

Photo courtesy of Grant Glover (University of South Alabama) via UC Berkeley.

Earth Wise is a production of WAMC Northeast Public Radio.

Solar-Powered Desalination

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Turning seawater into drinking water is an energy-intensive process and is therefore pretty expensive.  Worldwide, one third of people don’t have reliable access to safe drinking water and they are the least able to afford expensive ways to get it.   By 2025, half of the world’s population is expected to live in water-stressed areas.

At a newly-constructed facility in Kenya, a nonprofit company called GivePower has built a desalination system that runs on solar power.  The system started operating in the coastal area of Kiunga in July 2018 and can create nearly 20,000 gallons of fresh drinking water each day – enough for 25,000 people.

GivePower started in 2013 as a nonprofit branch of SolarCity, the solar-panel company that ultimately merged with Tesla in 2016.  However, GivePower spun off as a separate enterprise shortly before that.

GivePower mostly focuses on building solar-energy systems to provide electricity across the developing world. 

Desalination technology is not new, but it is notoriously energy-intensive because it requires high-power pumps.  The GivePower system is integrated with a solar microgrid that makes use of Tesla batteries to store energy for when the sun is not shining. 

Local residents pay about a quarter of one cent for every quart of water from the system.  The Kiunga community has faced ongoing drought and before the GivePower system was installed, was forced to drink from salt water wells, which present serious health risks.

The GivePower system cost $500,000 to build and is expected to generate $100,000 a year, to be eventually used to fund similar facilities in other places.

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A solar-powered system can turn salt water into fresh drinking water for 25,000 people per day. It could help address the world’s looming water crisis.

Photo courtesy of GivePower.

Earth Wise is a production of WAMC Northeast Public Radio.

Agrivoltaics

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A new study by Oregon State University has found that the most productive places on Earth for solar power are farmlands.   In fact, if less than 1% of agricultural land was converted to solar panels, it would be sufficient to fulfill global electricity demand.

The concept of co-developing the same area of land for both solar photovoltaic power and conventional agriculture is known as agrivoltaics.

The synergy between agriculture and solar power is not surprising.   People have been growing crops around the planet for at least 8,000 years and, long ago, farmers found the best places to grow them which turn out to also the best places to harvest solar energy.  The needs for solar panels are pretty similar to those of food crops.  The efficiency of the panels decreases if they get too hot.  Barren land is hotter than cropland, so the productivity of solar panels is less in such places.

The Oregon State Study analyzed power production data collected by Tesla, which had installed five large grid-tied, ground-mounted solar electric arrays owned by Oregon State.  The researchers monitored air temperature, relative humidity, wind speed, wind direction, soil moisture, and incoming solar energy.  With the data, they developed a model for the best conditions for solar panel productivity and they coincide with excellent conditions for agriculture.  Solar panels are kind of like people with regard to the weather:  they are happier when it is cool and breezy and dry.

Previously-published research shows that solar panels actually increase crop yields on pasture or agricultural fields.

These new results have implications for the current practice of constructing large solar arrays in deserts.  Agricultural lands may be a much better option for both solar production and crop production.

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Installing solar panels on agricultural lands maximizes their efficiency, new study shows

Photo, posted April 20, 2011, courtesy of U.S. Department of Agriculture via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Floating Solar Fuel Farms

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Limiting global warming will require a massive reduction in CO2 emissions from fossil fuel burning.  Renewable energy sources are playing a growing role in the power grid and electric cars are becoming increasingly popular.  Despite all this, carbon-based liquid fuels will continue to dominate our energy use for the foreseeable future.

Researchers in Norway and Switzerland have described a potential scheme that would help remove CO2 from the atmosphere and produce a valuable liquid fuel.

The idea is to create floating islands containing large numbers of solar panels that convert carbon dioxide in seawater into methanol, which can fuel airplanes and trucks.

A combination of largely existing technologies would be the basis of these floating islands, which would be similar to present-day floating fish farms.  The researchers envision clusters each composed of 70 circular solar panels that in total cover an area of roughly half a square mile.  The solar panels would produce electricity, which would split water molecules and isolate hydrogen.  The hydrogen would then react with carbon dioxide pulled from seawater to produce usable methanol.

The technology already exists to build the floating methanol islands on a large scale in areas of the ocean free from large waves and extreme weather.  Suitable locations are off the coasts of South America, North Australia, the Arabian Gulf, and Southeast Asia.

A single floating solar farm could produce more than 15,000 tons of methanol a year – enough to fuel a Boeing 737 airliner for more than 300 round-trip flights across the country.  Floating energy islands would not be a magic bullet for limiting the effects of climate change, but they could well be an important part of an overall strategy.

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Giant Floating Solar Farms Could Make Fuel and Help Solve the Climate Crisis, Says Study

Photo courtesy of PNAS.

Earth Wise is a production of WAMC Northeast Public Radio.

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