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Faster electric vehicle charging

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One concern that people have in replacing gas-powered vehicles with electric vehicles is the time it takes to charge them.  Charging an EV at home from an ordinary 110V electrical outlet is a slow process; installing a 220V outlet speeds things up considerably but it still can take all night to fully charge a car.  The driving range of electric cars has increased over the years so that now there are many cars that can go 300 miles or more on a charge. For most people, so-called range anxiety is mostly gone.  But on long road trips, charging time can be a real issue.

There are increasing numbers of high-speed chargers along or adjacent to major highways that can provide 200 miles of driving range in less than half an hour.  But people want more charge, and they want it faster.

There are multiple efforts in improving EV batteries and charger technology aimed at transforming a visit to a public charger to an experience comparable to filling up at a gasoline station.

Researchers at the University of Waterloo have designed a new kind of lithium-ion battery that will be able to go from zero battery power to 80% in just 15 minutes. This technology would certainly enhance the capabilities of today’s electric cars.  However, it is quite possible that other technologies that surpass this performance will emerge in the near future.  There is talk across the industry of cars that can charge up in 5 or 10 minutes.   There is also the prospect of many cars that can drive 500 miles on a charge.  These features would address the needs or desires of all but a very small number of drivers.

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From zero to 80 per cent in just 15 minutes

Photo, posted May 7, 2022, courtesy of Sharon Hahn Darlin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Giant batteries in the Earth

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The wind and the sun are inexhaustible sources of energy, and we are tapping into them to produce electricity at a growing rate around the world.  But neither of them is always available when we need them.  When the sun isn’t shining and the wind isn’t blowing, they don’t work.

An opposite problem also exists.  When our energy needs are low, but it is sunny or windy, solar and wind power are all dressed up with nowhere to go.  Energy storage is the answer to both of these problems.   When there is excess generation, store the energy for later use.  When there is need for energy and not enough is being generated, tap into the energy that is stored.

Giant banks of lithium-ion batteries are the rapidly growing form of energy storage, and they are increasingly providing resilience in the electric grid.  But battery storage is short-term energy storage.  Even the largest battery banks can only provide a few hours of electricity. 

So, there is a real need for “long-duration energy storage” – systems that provide at least 10 hours of backup power and sometimes much more – for the grid to be fully reliable.

Pumped hydro storage, which uses water from elevated reservoirs to drive turbines, has been around for a long time.  Historically, this is the largest form of energy storage in the world.  Other methods include pumping compressed air into underground caverns or lifting massive blocks into elevated positions.  All of these techniques use excess electricity to place things like water, air, or cement into a position where they can be used to drive electrical generators.

The grid of tomorrow will store energy in giant battery banks, but also in the ground, in reservoirs, and in large structures.

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How giant ‘batteries’ in the Earth could slash your electricity bills

Photo, posted March 21, 2024, courtesy of Sandra Uecker/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Hydrogen-powered aviation

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The transportation sector is responsible for about a quarter of human-generated greenhouse gas emissions.  Most of the energy used by transport systems comes from fossil fuels.  The transition to electric vehicles – cars, trucks, and buses – is making a real difference.  However, the emissions from the aviation industry have continued to grow faster than those of other forms of transportation.  There have been increased efforts to develop hydrogen-powered aircraft, but the challenges are substantial.

Hydrogen can be used for aviation both as a directly combusted fuel, or to power electric fuel cells.  Its advantages are that its use produces no carbon dioxide, and, in fact, hydrogen produces more energy per pound than jet fuel.

A study by researchers at MIT looked at the prospects for hydrogen use in aircraft and what needs to be done to make it practical.  The biggest issue is that the extra bulk of a hydrogen fuel tank and fuel cells in a plane would have to be offset by weight reductions elsewhere, such as reducing payload (cargo or passengers).  This would mean there would need to be more flights, thereby reducing the gains made.  The researchers argued that improvements in fuel cell power and more weight efficient fuel systems could eliminate the need for additional flights.

The bigger challenge is the infrastructure for generating and distributing hydrogen.  There needs to be green hydrogen – hydrogen produced without carbon emissions – and the infrastructure for getting it to planes where it is needed has to also not produce substantial emissions.

The study suggests that the rollout of hydrogen-based aviation should start at locations that have favorable conditions for hydrogen production.

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Fueling greener aviation with hydrogen

Photo, posted December 20, 2016, courtesy of Dylan Agbagni via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Capturing hot carbon dioxide

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Decarbonizing industries like steel and cement is a difficult challenge.  Both involve emitting large amounts of carbon dioxide both from burning fossil fuels and from intrinsic chemical reactions taking place.  A potential solution is to capture the carbon dioxide emissions and either use them or store them away.  But this sort of carbon capture is not easy and can be quite expensive.

The most common method for capturing carbon dioxide emissions from industrial plants uses chemicals called liquid amines which absorb the gas.  But the chemical reaction by which this occurs only works well at temperatures between 100 and 140 degrees Fahrenheit.  Cement manufacturing and steelmaking plants produce exhaust that exceeds 400 degrees and other industrial processes produce exhaust as hot as 930 degrees.

Costly infrastructure is necessary to cool down these exhaust streams so that amine-based carbon capture technology can work. 

Chemists at the University of California, Berkeley, have developed a porous material – a type of metal-organic framework – that can act like a sponge to capture CO2 at temperatures close to those of many industrial exhaust streams.  The molecular metal hydride structures have demonstrated rapid, reversible, high-capacity capture of carbon dioxide that can be accomplished at high temperatures.

Removing carbon dioxide from industrial and power plant emissions is a key strategy for reducing greenhouse gases that are warming the Earth and altering the global climate.  The captured CO2 can be used to produce value-added chemicals or can be stored underground or chemically-reacted into stable substances.

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Breakthrough in capturing ‘hot’ CO2 from industrial exhaust

Photo, posted March 3, 2010, courtesy of Eli Duke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Artificial plants to clean indoor air

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The average American spends about 90% of their time indoors breathing the air in our workplaces, homes, or schools.  The quality of this air affects our overall health and well- being.  Indoor air quality is an issue because many sources can generate toxic materials, including building materials, carpets, and more.  But high levels of carbon dioxide are a health hazard themselves. Indoor CO2 levels can often be 5 to 10 times higher than the already heightened levels in the atmosphere. 

Many of us make use of air purification systems, which can be expensive, cumbersome, and require frequent cleaning and filter replacements.

Researchers at Binghamton University in New York are working to develop artificial plants that consume carbon dioxide, give off oxygen, and, as a bonus, generate a little electricity. These artificial plants make use of the artificial light in the indoor environment to drive photosynthesis.  They achieve a 90% reduction in carbon dioxide levels, which is far more than natural plants can achieve.

The Binghamton researchers had been working on bacteria-powered biobatteries for various applications, but they repurposed the work into a new idea for artificial plants.  The artificial plants have “leaves” containing a biological solar cell and photosynthetic bacteria.  Their first plant had five leaves and demonstrated promising carbon dioxide capture rates and oxygen generation.  It also produced a little electricity.  If its generating capacity can be improved, it might also be useful for charging cell phones or other practical applications.

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Binghamton researchers develop artificial plants that purify indoor air, generate electricity

Photo, posted October 13, 2012, courtesy of F. D. Richards via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A better way to extract lithium

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Lithium is the critical component in the batteries that power phones and computers, electric cars, and the systems that store energy generated by solar and wind farms.  Lithium is not particularly rare, but it is difficult and often environmentally harmful to extract from where it is found.

Traditional ore sources are increasingly difficult and expensive to mine.  The largest known deposits of lithium are in natural brines – the salty water found in geothermal environments.  These brines also contain other ions like sodium, potassium, magnesium, and calcium, and efficiently separating out the lithium is extremely challenging.

Traditional separation techniques consume large amounts of energy and produce chemical waste, particularly hazardous chlorine gas.  These techniques typically suffer from poor selectivity; that is, the process is interfered with by the other ions present in natural brines.

A team of researchers at Rice University has developed a three-chamber electrochemical reactor that improves the selectivity and efficiency of lithium extraction from brines.  The middle chamber of the reactor contains a specialized membrane that acts as a barrier to chloride ions, preventing them from getting to the electrode area where they can form chlorine gas.

The new reactor has achieved a lithium purity rate of 97.5%, which means the setup can effectively separate lithium from other ions in the brine and allow the production of high-quality lithium hydroxide, the key material for battery manufacturing. 

The Rice University reactor design has the potential to be a game changer for lithium extraction from geothermal brines.

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‘Game changer’ in lithium extraction: Rice researchers develop novel electrochemical reactor

Photo, posted October 21, 2023, courtesy of Simaron via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The race for fusion power

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The sun is powered by fusion energy.  Hydrogen atoms fuse together into helium atoms, liberating vast amounts of energy in the process.  Our understanding of this process emerged early in the 20th century and by the 1950s, research efforts were underway trying to replicate the process on Earth.  If it could be done, fusion would be a source of almost unlimited clean energy.  But there has been a cynical saying going around for half a century:  fusion power is the energy source of the future, and it always will be.

However, in recent years, there has been progress in developing fusion power.  Extraordinarily expensive and colossal machines have produced fusion energy albeit consuming more energy than they make.  However, for a brief moment in 2022, a fusion reactor at Lawrence Livermore National Laboratory did produce more energy than it took to run the machine.

Despite the less than encouraging history, there are now multiple start-up companies dedicated to developing fusion energy and they are optimistic that there will be significant progress over the next few years.

One such company, Commonwealth Fusion Systems, located 40 miles northwest of Boston, is building a fusion reactor called SPARC, that they claim will be producing net energy in 2027.  They say that their next machine, called ARC, will generate electricity for paying customers in the early 2030s.

A handful of other companies, including Type One Energy, Thea Energy, Realta Fusion, Zap Energy, General Fusion, and Helion Energy are also pursuing fusion reactor designs and also expect to have machines running over the next 5 to 10 years.

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The Quest to Build a Star on Earth

Photo, posted April 21, 2015, courtesy of John Spiri via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Limiting global warming

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A pressing question from the recently concluded 29th annual United Nations Climate Change Conference in Azerbaijan is how to transition away from fossil fuels and speed up climate mitigation in line with the 1.5 °C global warming target.

Keeping global average temperatures below 1.5 °C above pre-industrial levels is crucial to avoid the most severe impacts of climate change, including extreme weather, rising seas, biodiversity loss, and disruptions to food and water security. 

According to a new study by researchers from Stockholm University, Chalmers University of Technology, and Uppsala University in Sweden, it is still possible to limit global warming to 1.5 °C.  But the study found that the United States, the European Union, and 16 other countries will have to exceed their own current targets in order to achieve this global goal.  

The study, which was recently published in the journal Nature Communications, introduced an “additional carbon accountability” indicator, which quantifies countries’ responsibility for mitigation and carbon dioxide removal in addition to achieving their own targets.

The study identified 18 countries that should be accountable for increasing their ambitions to stay within their equal per capita share of the global carbon budget for 1.5 °C.  Additional carbon accountability is highest for the United States and China, and highest per capita for the United Arab Emirates, Russia, Saudi Arabia, and the U.S.

Failure to limit global warming risks catastrophic impacts of climate change.

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COP29: Possible to limit climate change to 1.5°C – if EU and 17 other countries go beyond their own targets

Photo, posted December 27, 2015, courtesy of Gerry Machen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Electric vehicles and health

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Much of the discussion about the benefits of electric vehicles centers about the climate impact of not burning fossil fuels as well as about reduced operating costs.  A new study by the University of Toronto looked at the health benefits of large-scale adoption of electric vehicles.

The Toronto researchers used computer simulations to show that widespread electrification of the U.S. vehicle fleet when coupled with significant use of renewable energy to power the fleet could result in health benefits worth between $84 and $188 billion dollars by 2050.  Expressing these benefits in dollar terms is a way to quantify those benefits, but clearly what is most important is people’s health.

Carbon dioxide coming out of tailpipes is what is most harmful to the climate, but there is much more than CO2 vehicle exhaust.  There are many air pollutants that have a significant, quantifiable impact on human health.  These include nitrogen oxides, sulfur oxides, and small particles known as PM2.5. 

The study simulated levels of air pollution across the United States under various scenarios of adoption of EVs and the use of renewable energy.  The simulations clearly showed that the combination of widespread use of electric vehicles and the greening of the power grid would result in huge cumulative public health benefits.  But these benefits will take time to accrue.  The internal combustion vehicles being sold today will still be on the roads for many years and will continue to spread pollution everywhere there are roads.

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New research reveals how large-scale adoption of electric vehicles can improve air quality and human health

Photo, posted May 7, 2020, courtesy of Mark Vletter via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Lithium in Arkansas

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Lithium is the critical raw material in the batteries that power electric cars as well as cell phones, computers, and other gadgets.  The stuff has been nicknamed “white gold” for good reason.  Chile and Australia are the world’s largest producers of the metal, which is mostly extracted from brine in evaporation ponds.  The majority of it is then processed in China.  The energy industry has been increasingly working to produce the raw materials needed to produce lithium-ion batteries in the United States and process those materials domestically.  There are multiple projects at various stages across the country.

Researchers at the US Geological Survey and the Arkansas state government recently announced that they have discovered a vast trove of lithium in an underground brine reservoir in Arkansas.

With a combination of water testing and machine learning, the researchers determined that there could be 5 to as much as 19 million tons of lithium in the geological area called the Smackover Formation.  This is more than enough to meet all the world’s demand for it.

Several companies – including Exxon Mobil, which is covering its bets on the future of oil as an energy source – are developing projects in Arkansas to produce lithium.  If these companies can develop and scale up economical new ways to extract lithium from salty water, the region in Arkansas could become the lithium capital of the world.

Energy and mining companies have produced oil, gas, and other natural resources in the Smackover Formation, which extends from Texas to Florida.  The same brines have long been the source of other valuable substances. 

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Arkansas May Have Vast Lithium Reserves, Researchers Say

Photo, posted May 22, 2020, courtesy of the European Space Agency via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon levies for shipping

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The global shipping industry is responsible for 90 percent of world trade.  The ships crossing the world’s oceans emit nearly 3% of the global greenhouse gas emissions caused by human activity that are contributing to climate change.  Among the effects of climate change are sea level rise, which is threatening the very existence of small island nations.

One such nation is Tuvalu, which is a group of islands in the South Pacific.  Tuvalu has a total landmass of just 10 square miles, and sea level there is rising 1.5 times faster than the global average.  Predictions are that within 50 to 100 years, low-lying islands like those of Tuvalu could be fully submerged by the ocean.

Representatives from six Pacific Island states and a growing number of Caribbean nations known as the 6Pac+ Alliance are urgently calling upon the International Marine Organization to enact a mandatory universal levy of $150 per ton of shipping emissions from large commercial vessels. 

Most marine vessels typically run on highly polluting heavy fuel oil.  Burning really filthy fuel is the cheapest way to cross the oceans.  There are alternatives including entirely carbon-free technologies, but they will be expensive to implement and utilize.  The cost of shipping would undoubtedly go up and be especially felt by small island nations and in developing countries where most food is imported.

The idea behind putting a price on ships’ carbon emissions is to both provide a financial incentive for the shipping industry to reduce its emissions and provide revenue for countries that incur costs from dealing with rising seas.

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Pacific and Caribbean Island Nations Call for the First Universal Carbon Levy on International Shipping Emissions

Photo, posted November 23, 2006, courtesy of Stefan Lins via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Extreme geothermal power

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Krafla is one of the most explosive volcanoes in Iceland, which is home to many active volcanoes, including one recently in the news near Reykjavik that hadn’t erupted for 800 years .  Krafla is the site of the Krafla Magma Testbed, which may end up being for geoscientists what the Large Hadron Collider has been for particle physicists. 

For over a decade, researchers have been drilling straight into the ground at Krafla to study what goes on deep beneath an active volcano.  Ten years ago, they encountered an unexpected magma chamber a little over a mile down.  Their equipment was destroyed but the researchers decided that they had uncovered a unique opportunity to study magma dynamics and potentially be able to tap into a significant new energy source.

The plan is to use the tremendous heat energy contained in magma to dramatically improve the production of geothermal energy.  Krafla is already the site of a geothermal energy plant that makes use of the heat beneath the surface to boil water that then drives turbines to generate electricity.

Forthcoming drilling projects will make use of new equipment that can handle the harsh conditions that will be encountered in the magma chamber.  The goal is to tap directly into the magma to produce superheated steam that could produce ten times more power than conventional geothermal systems.  Conventional systems access temperatures around 200 to 300 degrees; the magma is at 1,800 degrees.

It will take a few years to complete the project, but if it is successful, it could have implications well beyond Iceland.  There are many active volcanoes all over the world.

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Drilling into magma: Risky plan takes geothermal to supercritical extremes

Photo courtesy of Landsvirkjun.

Earth Wise is a production of WAMC Northeast Public Radio

A giant solar project for Google

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One of the largest solar projects in the US has recently come online in Texas.  Three solar farms built side-by-side in Buckholts, Texas by SB Energy can provide 875 megawatts of electricity, nearly the size of a typical nuclear power plant.  The project will supply the largest solar energy purchase ever made by Google and the electricity generated will be used to power its new operations in the area.  Google will use about 85% of the project’s solar power for data centers in Ellis County and for cloud computing in the Dallas Region.

In total, Google has contracted with clean energy developers to bring more than 2,800 megawatts of new wind and solar projects to Texas.  Google expects to spend $16 billion through 2040 to purchase clean energy for its global operations.

According to the International Energy Agency, data centers’ total electricity consumption could reach more than 1,000 terawatt-hours in 2026, which is more than double the amount used in 2022.  One terawatt-hour is enough energy to power 70,000 homes for a year.  So, it is not surprising that large technology companies are investing heavily in energy technologies.

Google, Amazon, and Microsoft have all recently announced investments in nuclear energy to power data centers.  These companies all have made commitments to seek sources of carbon-free electricity to power their data centers and their increasing efforts in artificial intelligence.  Because of the rise of artificial intelligence, the large companies are not meeting their commitments to reduce their carbon emissions and are needing to greatly increase their efforts to obtain clean power.

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One of the largest solar projects in the US opens in Texas, backed by Google

Photo, posted March 27, 2016, courtesy of Ben Nuttall via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

New approaches to nuclear power

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The US is the world’s largest user of nuclear power.  Its 94 reactors supply nearly 19% of the country’s electricity. But the number of U.S. reactors has steadily fallen over the past 30 years and new nuclear power plants are a real rarity.  The reasons are a combination of perceived dangers following several nuclear accidents and the increasing costs associated with building plants that can meet a growing number of regulatory requirements.

There are recent developments associated with new advanced reactor technologies that may lead to a resurgence in the use of nuclear power.  Bill Gates’ energy company TerraPower is developing nuclear reactors that use sodium instead of water for cooling.  Such reactors operate at lower pressures and higher temperatures.  

Meanwhile, Kairos Power, a California-based energy company, has entered into an agreement with Google to build multiple small modular nuclear reactors that will supply electricity to that giant tech company.  The modular reactors use a molten-salt cooling system combined with a ceramic, pebble-type fuel in order to transport heat to a steam turbine to generate power.  The novel design of these reactors can reduce construction timelines, allow deployment in more places, and make final project delivery more predictable.

Surveys indicate that a majority of Americans favor the use of nuclear power, which has the advantages that it doesn’t create greenhouse gas emissions and can run 24-7.  But traditional nuclear power plants are too expensive and have too many potential problems.  These new nuclear power technologies may be the answer for allowing nuclear power to play an important role in the future energy system.

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New nuclear clean energy agreement with Kairos Power

Photo, posted May 16, 2016, courtesy of Steve Jurvetson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The bloated carbon footprint of LNG

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According to the U.S. Department of Energy, the United States is the world’s largest producer of natural gas.  In fact, natural gas supplies approximately one third of the United States’ primary energy consumption, most of which is used to heat buildings and to generate electricity.  While most natural gas is delivered in its gaseous form in this country, the demand for natural gas in international markets has given rise to the use of natural gas in a liquified form. 

Liquified natural gas (LNG) is natural gas that has been cooled to a liquid state, at about -260° Fahrenheit, for easier storage and transportation.  The volume of natural gas in its liquid state is about 600 times smaller than its volume in its gaseous state, which makes it possible to transport it to places pipelines do not reach.

Liquified natural gas is considered a clean fossil fuel because burning it produces less emissions than coal and oil.  However, according to a new study by researchers from Cornell University, LNG imported from the U.S. actually has a larger climate impact than any other fossil fuel—including coal – once processing and shipping are taken into account. 

The study, which was recently published in the journal Energy Science & Engineering, found that LNG leaves a greenhouse gas footprint that is 33% worse than coal when emissions are analyzed over a 20-year time frame. 

According to the research team, there is no need for LNG as an interim energy source because the transition requires massive infrastructure expenditures.  Instead, those financial resources should be used to “build a fossil-fuel-free future as rapidly as possible.”

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Liquefied natural gas carbon footprint is worse than coal

Photo, posted November 17, 2017, courtesy of Colin Baird via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reducing emissions from cement

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Cement production accounts for about 7% of global carbon emissions.  It is one of the most difficult challenges for emissions reduction.  The emissions associated with producing cement come from both the energy used to provide heat for the process and from the chemical reactions that take place in the formation of cement.  Cement is an essential building block of society, and its use is not expected to decline over time.

A German company called Heidelberg Materials is embarking on an ambitious project to reduce carbon emissions from a cement plant in Norway.  They are building a facility to use absorbent chemicals to capture large quantities of carbon dioxide emitted through cement production.  More than half a ton of carbon dioxide arises from every ton of cement produced at the plant.

Once the carbon dioxide is captured it will be chilled to a liquid, loaded onto ships, and carried to a terminal farther up the Norwegian coast.  From there, it will be pumped into undersea rocks located 70 miles offshore and a mile and a half below the bottom of the North Sea.

With all of this complicated process going on, cement from the plant is likely to be quite expensive.  It might even be two or three times the price of ordinary cement.  Heidelberg Materials is counting on customers’ willingness to pay much more for cement that comes with green credentials. 

Can this be economically viable?  Heidelberg estimates that cement accounts for only about 2% of the cost of a large building project but as much as 50% of the emissions.  As a result, using carbon-free cement could be a relatively inexpensive way for builders to reduce emissions.

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Cement Is a Big Polluter. A Plant in Norway Hopes to Clean It Up.

Photo, posted May 7, 2016, courtesy of Phillip Pessar via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

South American drought

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Vast areas of South America have been gripped in drought conditions for months.  Rivers in the Amazon basin fell to record-low levels in October.  The drought has amplified wildfires, parched crops, disrupted transportation networks, and interrupted hydroelectric power generation in parts of Brazil, Bolivia, Colombia, Ecuador, Peru, and Venezuela.

The drought is related to the impact of the El Niño that was present for the latter part of 2023 and the first half of this year.  El Niño typically shifts rainfall patterns in such a way that there is reduced rainfall in the Amazon.  This is especially true during the dry season months of July, August, and September.

Forecasts earlier in the year warned that there would be extreme fire conditions during the dry season.  Indeed, the Pantanal region that spans parts of southern Brazil, Paraguay, and Bolivia has experienced one of its worst fire seasons in decades.  The lack of rainfall, low soil moisture, and drawdowns of groundwater helped to amplify fires and caused them to spread faster and farther.

The drought has strained power supplies in Brazil and Ecuador because hydroelectric power stations are producing less electricity.   Snarled transportation networks with impassible rivers have left some communities struggling to get supplies. 

Brazil’s National Center for Monitoring and Early Warning of Natural Disasters has called the current drought the most intense and widespread Brazil has ever experienced.  Late October saw 293 Brazilian municipalities facing extreme drought.

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Intense, Widespread Drought Grips South America

Photo, posted August 13, 2010, courtesy of Colm Britton via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

How much energy storage is needed?

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Energy storage is a critical aspect of modern energy systems as they move towards heavy dependence on renewable sources such as solar and wind that don’t produce energy at the same rate all the time.  Excess energy generated by solar power needs to be stored for when the sun isn’t shining; excess wind energy needs to be stored for when the wind isn’t blowing.  But how much storage capacity does the energy system need to have?

Researchers at North Carolina State University have developed a model that can be used to project what a system’s storage needs would be if it were to shift entirely to renewable sources.

The model accounts for how energy production from renewable sources would change during different times of day and different times of the year.  For example, there is much more solar energy generation in the summer when the days are longer, and it is sunny more often.

There is also the issue of short-term vs. long-term energy storage.  Short-term energy storage does not refer to how long a storage device can store the energy.  It refers to how long it can provide power at its rated level.

The study focused on Italy’s energy system, which has suffered in recent years because it had difficulties in obtaining natural gas from Russia due to the invasion of Ukraine.

As the world moves increasingly towards renewable power sources, energy systems need to be able to account for the variability of those sources.  The new model offers policymakers critical information for use in energy system planning.

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Model Projects Energy Storage Needs for Fossil Fuel-Free Energy System

Photo, posted October 28, 2016, courtesy of Daxis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Progress towards electric school buses

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The U.S. has nearly half a million school buses providing daily transportation for about 20 million students.  Most of these buses are powered by diesel engines which not only dump greenhouse gases into the atmosphere but also fill kids’ lungs with harmful fumes.

Thanks to various federal and state incentive programs, this situation is starting to change.  School districts all over the country are beginning to swap out old diesel buses for emissions-free electric-powered school buses.

Electric school buses are finding their way into school districts of all sizes and demographics.  The first district in the country to go fully electric was in Martinsville, Texas, which last year converted its 4-bus fleet.  The first large urban district to go all-electric was the 74-bus fleet in Oakland, California this summer.

The EPA’s $5 billion Clean School Bus program and many state initiatives are providing incentives for the transition.  Five years ago, there were less than 1,000 electric school buses in the U.S.  Now there are about 5,000 and more than 7,000 additional buses are in the pipeline.

Apart from the climate implications, there is urgency to replacing diesel school buses from a health perspective.  Diesel exhaust is classified as a carcinogen by the World Health Organization, and it contains fine particles and nitrogen oxides, both of which are well-documented asthma triggers.

Electric buses are more expensive than diesel buses, but they are much cheaper to operate. School districts need to put in place charging infrastructure.  The transition is not so easy to accomplish, but it is an important step, and more and more school districts are taking it.

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Slowly but Surely, U.S. School Buses Are Starting to Electrify

Photo, posted May 5, 2021, courtesy of California Energy Commission via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar-powered desalination

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People in remote, low-income regions far from the ocean often need to meet their water needs from groundwater and groundwater is becoming increasingly saline due to climate change.  Desalination of brackish groundwater is a huge and largely untapped source of drinking water, but there are challenges in making the process efficient and reliable.

Engineers at MIT have developed a solar-powered desalination system that requires no batteries or external power sources and is capable of producing large quantities of clean water despite the variations of sunshine throughout the day.

The system is based on the process of electrodialysis and consists of water pumps, an ion-exchange membrane stack, and a solar panel array.  What is unique about it is that it makes use of sensors and a control system that predicts the optimal rate at which to pump water through the system based on the output of the solar panels.  As a result, it uses nearly all of the electricity generated to produce clean water and does not need stored or grid-based energy.

The MIT engineers tested a community-scale prototype on groundwater wells in New Mexico over a six-month period.  The system harnessed on average over 94% of the electricity generated by its solar panels and produced as much as 5,000 liters of water per day despite large variations in weather and sunlight.

The new renewable-powered, battery-free system could provide much-needed drinking water at low cost, especially for communities where access to seawater and to grid power are limited.  The team plans to further test and scale up the system so it can supply larger communities and even whole municipalities with low-cost drinking water.

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Solar-powered desalination system requires no extra batteries

Photo courtesy of Shane Pratt.

Earth Wise is a production of WAMC Northeast Public Radio

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