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Decontaminating Drinking Water | Earth Wise

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At least two billion people around the world often drink water that is contaminated with disease-causing microbes.  Waterborne diseases are responsible for two million deaths each year, mostly among children under the age of five.

There are various ways to decontaminate water, including chemicals that can themselves produce toxic byproducts as well as using ultraviolet light, which takes fairly long to disinfect the water and requires a source of electricity. 

Scientists at Stanford University and the SLAC National Accelerator Laboratory have recently invented a low-cost, recyclable powder that kills thousands of waterborne bacteria every second when the water containing it is exposed to ordinary sunlight.  The discovery of this ultrafast disinfectant could be a tremendous benefit to the nearly 30% of the world’s population with no reliable access to safe drinking water.

The new disinfectant is a harmless metallic powder that works by absorbing both ultraviolet and high-energy visible light from the sun.  It consists of nano-sized flakes of aluminum oxide, molybdenum sulfide, copper, and iron oxide.  The key innovation is that when these four metallic ingredients are immersed in water, they all function together by reacting with the surrounding water and generating chemicals that quickly kill bacteria. The chemicals themselves don’t last long.  They quickly break down in the water leaving completely safe drinking water.

The nontoxic powder is recyclable.  It can be removed from water with a magnet.  It can also be reused at least 30 times.  Apart from its uses in less developed parts of the world, it could be valuable for hikers and backpackers who want to drink water from natural sources of unknown quality.

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New nontoxic powder uses sunlight to quickly disinfect contaminated drinking water

Photo, posted February 27, 2013, courtesy of Petras Gagilas via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Giant Farming Robots | Earth Wise

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Farmers are perpetually engaged in a battle against weeds, which can strangle crops and destroy their yields.  There are basically two ways to fight weeds:  spraying herbicides that are bad for the environment and human health or using human labor to pull the weeds by hand. 

Both choices are increasingly undesirable.  Herbicide resistance is a growing problem facing farms around the world and widespread labor shortages in the agricultural sector are making it increasingly difficult to use human resources to combat weeds.

A startup company called FarmWise founded by an MIT engineering alumnus is providing a third option for farmers.  The company has developed giant autonomous weeding robots that use artificial intelligence to cut out weeds without damaging crops.

The company’s first product is called the Titan.  It looks like a large tractor without a driver’s seat.  It uses machine vision to distinguish weeds from crop plants like leafy greens, cauliflower, artichokes, and tomatoes.  It snips off the weeds with sub-inch precision.

Fifteen titan robots have been roaming the fields of 30 large farms in California and Arizona for several years.  A newer robot, called the Vulcan, is more lightweight and is pulled by a tractor.  FarmWise continues to add new crops to its database so that the robots can be used to fight weeds in more and more kinds of farms.

Weed problems are especially acute for farmers of specialty crops, which grow on smaller farms than corn and soybeans, and have unique growing practices, which limit the effectiveness of chemical and technical solutions. 

The overall goal of FarmWise is to turn artificial intelligence into a tool that is as reliable and dependable as GPS is now in the farming industry.

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Titanic robots make farming more sustainable

Photo, posted August 23, 2021, courtesy of Carol VanHook via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Clean Energy From North Africa | Earth Wise

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Europe is hungry for clean energy.  The war in Ukraine has amplified Europe’s desire to end its reliance on Russian natural gas.  Increasingly, Europe is pushing to install giant solar energy farms in sunny North Africa and transport the energy through underwater cables.

Solar panels in sunny North Africa generate up to three times more energy than those in Europe.  As a result, solar farms and wind farms as well are proliferating south of the Mediterranean Sea.  Morocco’s Noor and Egypt’s Benban solar farms are among the largest in the world.  Many of these farms were initially built to boost domestic power supplies and reduce dependence on coal.  But now these farms are increasingly supplying green energy to industrial neighbors in Europe.

Morocco has signed deals with the European Union to expand power exports.  Egypt is considering proposals for cables to link to Greece.  Another planned cable would link new solar farms in Tunisia to Italy’s grid.  These projects would certainly bring money and jobs to North African countries, but it isn’t all good news.

There are growing concerns about the environmental impacts of Europe outsourcing its energy needs.  Desert ecosystems could be greatly compromised.  And much of this development is likely to happen with only minimal community consultation or ecological assessment.  Half of Africa’s population does not have access to reliable power grids. Electricity becoming a major export is not likely to improve this situation.

Europe has long obtained many resources from the developing world.  Now it is tapping into the sunshine and wind in other lands.  It remains to be seen if North Africa’s countries will achieve the large potential gains those resources can offer them.

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In Scramble for Clean Energy, Europe Is Turning to North Africa

Photo, posted October 17, 2019, courtesy of Richard Allaway via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Computing With Honey | Earth Wise           

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Researchers are always working to develop faster and more powerful computers.  Some of them believe that the future of computing lies with neuromorphic computers, which are systems designed to mimic the neurons and synapses found in the human brain.

The human brain has more than 100 billion neurons with more than 1 quadrillion synapses or connections among them.  These numbers far exceed anything people have built.  There have been some neuromorphic computer chips made that have the equivalent of more than 100 million neurons per chip, but this is still far less than the number in the brain.  Despite all its complexity, the brain uses vastly less power than a powerful computer.  Some supercomputers use tens of millions of watts to operate; the brain uses around 10 to 20 watts.

Many researchers are searching for biodegradable and renewable ways to make neuromorphic computing components.  Researchers at Washington State University have demonstrated a way to make them using, of all things, honey.  The honey is used to form a memristor, which is a component similar to a transistor that can both process and store data in memory.  The device uses honey processed into a solid form and sandwiched between two metal electrodes.  The organic device is very stable and reliable over a long time.

So far, these devices are on a micro scale – about the size of a human hair.  The researchers want to develop them on a nanoscale, which is about 1/1000 the width of a human hair, and then bundle many millions or even billions together to make a neuromorphic computing system.  Such a honey-based system would be renewable and biodegradable – which, pardon the pun, would be really sweet.

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Honey holds potential for making brain-like computer chips

Photo, posted January 28, 2008, courtesy of Dino Giordano via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Avoiding Blackouts With Renewable Energy | Earth Wise

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There are some people who worry that an electric grid heavily dependent upon intermittent sources like solar and wind power may be more susceptible to blackouts.  According to a new study by Stanford University, these fears are misplaced.

The study, published in the journal Renewable Energy, found that an energy system running on wind, water, and solar, when combined with energy storage, avoids blackouts, and lowers energy requirements and consumer costs.  In addition, implementing such a system would create millions of jobs, improve people’s health, and reduce land requirements.

The study focused on the stability in all U.S. grid regions as well as individual states based on the requirement that all electricity is provided by clean and renewable sources. No fossil fuel use, bioenergy, blue hydrogen, or even nuclear power were included in the modeling.  Critics of such a shift in the energy system point to grid blackouts during extreme weather events in California in 2020 and Texas in 2021 as evidence that renewable sources can’t be trusted.  But in both cases, renewable energy was not found to be any more vulnerable than other sources.

The study looked at the costs of the transition – which would be substantial – but found that it would pay for itself fairly quickly based on energy cost savings alone.

A significant finding of the study was that long-duration batteries were neither necessary nor helpful for grid stability.  That stability could be obtained by linking together currently available short-duration batteries.  Interconnecting larger and larger geographic regions would make the power system smoother and more reliable.  Overall, intelligent management of the electric grid can result in a reliable and clean power system.

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Stanford researchers point the way to avoiding blackouts with clean, renewable energy

Photo, posted October 17, 2016, courtesy of B Sarangi via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Cutting The Cost Of Energy Storage | Earth Wise

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The cost of both solar and wind power continues to drop making the two renewable energy sources the cheapest way to make electricity in more and more places.  Given the virtually inexhaustible supply of both wind and sun power, these clean electricity sources can in principle meet all our energy needs.  The hang up is that both of them are intermittent sources – the wind doesn’t blow all the time and the sun doesn’t shine all the time.

The solution to the intermittency problem is energy storage.  If energy produced by wind and sun can be stored so it can be made available for use at any time, then the goal of having 100% clean energy can be realized.

Energy storage technology has continued to improve over time and to get cheaper.  The Department of Energy recently announced a new initiative aimed at accelerating both of these trends.

The new program – called Long Duration Storage Shot –  has the goal of reducing the cost of grid-scale, long-duration energy storage by 90% within this decade.

Long-duration energy storage is defined as systems that can store energy for more than ten hours at a time.  Such systems can support a low-cost, reliable, carbon-free electric grid that can supply power even when energy generation is unavailable or lower than demand.  With long-duration storage, solar-generated power can be used at night.

The program will consider multiple types of storage technologies – electrochemical (that is: batteries), mechanical, thermal, chemical carriers, and various combinations thereof.  Any technology that has the potential to meet the necessary duration and cost targets for long-term grid storage are fair game for the program.

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DOE announces goal to cut costs of long-duration energy storage by 90%

Photo, posted October 16, 2017, courtesy of UC Davis College of Engineering via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sunlight As A Cash Crop

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It isn’t so easy to be a farmer these days.  Farming has always involved long hours, hard work and the uncertainties of weather and yield.  The 21st Century has added new and unique challenges such as increasingly unpredictable weather, insect infestation and disease, and low commodity prices.  Add in sudden tariffs and farmers struggle even more to make ends meet.  The default rate for farmers’ loans is the the highest in at least nine years.

One thing that remains reliable for farmers is the sun.  It rises in the morning and goes down at night.  The sun can be trusted, unlike politicians, rain, or commodity prices.  These days, many farmers are taking advantage of the dependability of the sun to make money from a new cash crop: solar energy.

The trend is spreading.  North Carolina has been a leading solar energy state for several years and a 2017 report found that solar energy generates 30% of the income of many farms.  Typical annual rent payments for farmland by solar companies range from $500 to $1,400 per acre in North Carolina.

A growing list of states have clean energy mandates targeting 100% use of renewable energy.   These mandates provide incentives for farmers that make installing solar a financially smart decision and falling prices for solar installations make it an even better deal.

Solar works well when co-located on a farm and can be built in ways that minimizes impact.  It is quiet, uses almost no water, doesn’t pollute, and if it is decommissioned, the land can go back to its previous use.  If the solar facilities are raised up, the same land can be used to graze livestock or grow shade-tolerant crops.

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Harvesting the sun is the new cash crop

Photo, posted December 25, 2017, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Solar Plus Storage In The Caribbean

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The Caribbean is home to nearly 30 island nations and more than 7,000 individual islands with a combined population of around 40 million.  All of the islands are susceptible to disasters such as hurricanes that can leave residents without electrical power for extended periods of time.

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Geothermal Power For LA

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Los Angeles has a tremendous thirst for electric power and is always trying to find new sources.  On December 1, the Los Angeles Department of Water and Power began buying all the power generated by the brand-new 24 MW Tungsten Mountain geothermal power plant located in Churchill County in Nevada’s Great Basin region.

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Tidal Turbines Set An Energy Record

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Two turbines in the Pentland Firth in Scotland recently set a world record for monthly energy production from a tidal stream power station.  In August, the MeyGen installation off the Caithness coast of Scotland produced 700 MWh of electricity, enough to power 2,000 homes.

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Too Much Of A Good Thing

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Germany has continued to be the most aggressive adopter of renewable energy among large industrial nations.  The country has the goal of shifting to 100% renewables by 2050.  Its continuing embracing of solar and wind generation resources over the past decade has resulted in renewables supplying a third of the country’s power on average.

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