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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

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

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

Much more energy storage for New York

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As solar and wind power play an ever-growing role in the electricity grid, the need for energy storage also grows.  Even if sun and wind can provide more energy than is needed at a particular time, they can’t provide it at all times.  The ability to store excess energy waiting in reserve for when the sun and wind are not providing it is essential to avoid the need for burning fossil fuels to take up the slack.

The New York State Public Service Commission has announced that it has approved a new framework for the state to have in place a nation-leading six gigawatts of energy storage by 2030.  This represents at least 20% of the peak electricity load of New York State.

An extensive set of recommendations to expand New York’s energy storage programs describe cost-effective ways to unlock the rapid growth of renewable energy across the state as well as to bolster the reliability of the grid.  The buildout of storage deployment is estimated to reduce projected future statewide electric system costs by nearly $2 billion.  New York has previously established goals to generate 70% of its electricity from renewable sources by 2030 and 100% zero-emission electricity by 2040.

The new roadmap includes programs to procure an additional 4.7 gigawatts of new energy storage projects across large-scale, retail, and residential energy storage sectors across the state.  These future procurements, when combined with the 1.3 gigawatts already being procured or under contract, will allow the State to achieve the 6-gigawatt goal by 2030.

Energy storage plays a critical role in decarbonizing the grid, reducing electricity system costs, and improving the reliability of the electricity system.

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New York approves plan to add six gigawatts of energy storage by 2030

Photo courtesy of NineDot Energy.

Earth Wise is a production of WAMC Northeast Public Radio

Clean energy investment at record levels

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According to a new study by the International Energy Agency, global clean energy investment will be nearly twice that of fossil fuels this year.  The surging funding for clean energy is being driven by a combination of lower costs for renewable energy and by improving supply chains.

In 2024, the world’s investments in energy are expected to surpass $3 trillion dollars for the first time.  About $2 trillion of that will be directed at green technologies that include renewable power sources, grids, and energy storage; electric vehicles; low-emission fuels; nuclear power; and heat pumps and efficiency improvements.  The remaining amount of just over $1 trillion will fund oil, gas, and oil projects.

The record growth in clean energy investments is taking place in spite of challenging economic conditions related to high interest rates, which demonstrates the momentum behind the global energy transition.

The IEA report does caution that there are big imbalances and shortages in energy investment in various places around the world.  For example, there is a low amount of green energy spending in developing and emerging economies outside of China.  Countries like Brazil and India are leading the way for this sector by having investments in excess of $300 billion.

More money is currently going into solar power development than all other electricity generation technologies combined.  In 2024, solar photovoltaic power investment is set to grow to $500 billion as the falling price of solar modules spurs new investments.

The largest renewable investments will come from China at $675 billion, followed by Europe and the U.S. at $370 billion and $315 billion, respectively.

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Global Clean Energy Investment Will Nearly Double That of Fossil Fuels in 2024: IEA Report

Photo, posted October 2, 2015, courtesy of John Englart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

California renewable energy

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California has aggressively pursued the use of renewable energy, particularly solar and wind power.  Last year, renewables supplied 54% of the state’s electricity needs.  This year, California has been achieving some remarkable milestones with its renewable energy.

As of May 26th, California had produced more than 100% of its electricity demand with wind, solar, and hydropower for parts of 51 straight days and 75 out of 81 days.  On May 25th, California’s grid ran entirely on renewable energy for 10.1 straight hours and renewables provided 83% of the state’s electricity for the entire 24-hour period.  California uses more electricity than any other state apart than Texas, which uses more than half its energy for operating refineries and petrochemical plants.

Excess power in California is either exported to other states or is used to charge up the state’s growing arrays of energy storage batteries.  California has the largest grid-connected battery storage facility in the world, located in Kern County.  The facility can store nearly 3,300 megawatt-hours of energy.

The ability to produce more power than the state needs occurs during the day when the sun is shining, and when many people are not at home.  At night, demand goes up and solar power is not available.  But as the quantity of energy storage available continues to grow along with additional solar installations, California will ultimately be able to wean off of the gas-fueled power plants it predominantly uses at night.

According to some experts, California may operate entirely on renewables and battery storage as soon as 2035. 

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California exceeds 100% of energy demand with renewables over a record 30 days

Photo, posted January 11, 2016, courtesy of Jared Eberhardt via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Gravity storage on the grid

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For the past several years, the Swiss-based company Energy Vault has been developing an energy storage system based on the principle of using mechanical devices to lift heavy concrete blocks into stacks using power generated by wind turbines or other renewable sources.  When energy is needed, the blocks are lowered back to the ground, spinning generators in the process.

The principle of storing energy in the form of gravitational potential energy is the most widely used form of energy storage in existence but usually works by pumping water into a reservoir at higher elevation and then letting the water come back down when energy is needed.

Energy Vault has built a grid-scale 100 MWh gravity storage system in Rudong China.  It has now been successfully tested with charging and discharging and has been commissioned. Pending final provincial and state approvals, it will be the world’ first commercial, utility-scale non-pumped hydro gravity energy storage system.

The Rudong project teamed Energy Vault with environmental management company CTNY and Atlas Renewable.  Energy Vault has extended its license agreement with Atlas Renewable to 15 years.  CTNY has announced plans for eight additional deployments of the Energy Vault gravity storage system across China, representing more than 3.7 GWh of energy storage.

Energy Vault’s technology has attracted a fair amount of skepticism from parts of the energy community based on the environmental burdens of concrete as well as durability issues.  It appears the technology will have significant real-world testing in China, which should provide unambiguous answers to everyone’s questions.

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Energy Vault Announces Successful Testing and Commissioning of First EVx 100 MWh Gravity Energy Storage System by China Tianying, Extension of Atlas Renewable Licensing Agreement to 15 Years

Photo, posted December 21, 2018, courtesy of Nancy Winfrey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A giant underground battery

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Two up-and-coming energy technologies are coming together near a tiny town in central Utah.  Outside of the town of Delta, population 3,600, two caverns, each as deep as the Empire State Building, are being created from an underground salt formation to be used to store hydrogen gas.  The gas will be used as a fuel in a new electricity generation plant.

The plant will replace an aging local coal-fired power plant.  The new plant will burn a mixture of natural gas and hydrogen – green hydrogen produced without emitting greenhouse gases. To produce the hydrogen, the facility will operate 40 giant electrolyzers that will use excess solar and wind power generated at times of low demand to split water molecules into hydrogen and oxygen.

The caverns were created by a process called solution mining in which high-pressure water is pumped down into salt deposits that are dissolved. The resulting caverns are 200 feet in diameter and 1,200 deep and lie 3,000 to 4,000 feet below the surface.  Hydrogen cannot escape through the thick salt layers.

The amount of energy that can be stored in the form of hydrogen fuel in these caverns is massive – far more than all the battery storage installed in the U.S. to date.  Chevron has a majority stake in one of the projects and will supply the natural gas.  The facility is expected to go online in 2025.

While this will produce far fewer emissions than existing coal plants, it is not carbon-free.  Currently, turbine technology cannot operate with pure hydrogen fuel.  The Delta plant will run on only 30% hydrogen.  The hope is that turbine technology will improve in the future and permit operation on pure hydrogen.

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A Huge Underground Battery Is Coming to a Tiny Utah Town

Photo, posted September 9, 2013, courtesy of Scott via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Sodium-ion batteries

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The transition away from fossil fuels is driving a rapidly increasing need for batteries.  Both electric vehicles and energy storage for the electric grid are enormous consumers of batteries.  At present, lithium-ion batteries are almost universally used for these purposes.  They have been getting better all the time and cheaper all the time and are likely to be the answer for the foreseeable future.  But they are not perfect.

Lithium is only found in a relatively small number of places and mining and extracting it is fairly expensive and environmentally unfriendly.  Lithium-ion batteries also frequently contain cobalt, which has its own set of problems.  There are also safety issues related to the flammability of lithium-ion batteries. 

As a result, there continue to be numerous efforts to identify and develop alternative battery technologies.  One of these is sodium-ion batteries, which are similar in many ways to lithium-ion batteries but in which sodium replaces lithium as the cathode material.

Sodium is extremely common – it’s found in ordinary salt – and sodium-ion batteries have a high energy density and are easy to produce.  They should have a long lifetime and have a more benign environmental impact than lithium-ion.  Many companies and researchers are working on sodium-ion batteries and are making good progress.

A study by Chalmers University in Sweden looked at the potential for sodium-ion batteries and found that the batteries are particularly promising for use in energy storage even in their current state of development and could eventually be used in cars.  Whether sodium-ion batteries can be good enough and cheap enough quickly enough to give lithium-ion a run for its money remains to be seen.

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Resource-efficient and climate-friendly with sodium-ion batteries

Photo, posted March 12, 2013, courtesy of Chris Hunkeler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Powering Britain with sun and wind

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The United Kingdom is quite small in size compared with the US, but its population of 67 million makes it a fairly large country with substantial energy needs.  A recent study by Oxford University looked at the ability of wind and solar power to provide for those energy needs over the course of time.

According to the study, Britain’s energy needs could easily be met entirely by the two sources of clean power.  Wind and solar can provide significantly more energy than the highest energy demand forecasted for 2050 and nearly 10 times the current electricity demand. 

Britain currently requires 299 TWh per year.  The Oxford study found that wind and solar could generate as much as 2,896 TWh per year. Furthermore, the researchers stated that these estimates are intentionally conservative, taking into account concerns around land use and the visual impact of installations.

The analysis assumes that offshore wind would produce nearly three-quarters of the energy required.  Onshore wind would contribute about 7%, while taking up only 0.07% of the country’s land.  Utility-scale solar would add about 19% of the power.  The small remainder comes from rooftop solar.  The researchers do point out that the power grid would require significant upgrades to handle all this renewable energy and that there would need to be appropriate quantities of energy storage. 

According to the authors of the study, achieving these results is a question of ambition rather than technical feasibility.  So far, the UK government has not been aggressive in making the transition to renewable energy.

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Wind and solar power could significantly exceed Britain’s energy needs

Photo, posted November 4, 2021, courtesy of Steve Knight via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Geologic Hydrogen | Earth Wise

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There is great interest in the potential use of hydrogen as a fuel or an energy storage medium.  Unlike hydrocarbon-based fuels, pure hydrogen combustion produces nothing but water as an emission.  But most hydrogen used at present is made by reforming natural gas, which is a process that results in carbon dioxide emissions.  Thus, the search goes on for cost-effective and energy-efficient ways to make “green hydrogen” that doesn’t result in greenhouse gas emissions.

Researchers at Colorado University Boulder are investigating the potential effectiveness of coaxing hydrogen from subterranean rocks – a commodity known as geologic hydrogen.

When water mixes with iron-rich minerals deep in the earth’s crust, ensuing chemical reactions can generate pockets of hydrogen gas. 

The questions are whether it is possible to bring these deposits up to the surface without harming the environment or human communities in the process and whether they can be extracted in large enough quantities to meet growing global energy demands.

The Colorado researchers will conduct experiments both in the lab and hundreds of meters below the earth’s surface to see if it is possible to induce the subterranean rock to make more hydrogen than it normally does.  If the hydrogen-producing reactions can be accelerated, then geologic hydrogen could become a clean and abundant energy source.

Geologists have known about hidden underground deposits of hydrogen for a long time, but recent research has found that there may be a lot more of it than once thought.  According to a 2022 report by the US Geological Survey, there may be enough hydrogen below ground to supply humanity’s need for fuel for hundreds of years.

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Can rocks produce abundant clean energy? New project to explore

Photo, posted December 26, 2013, courtesy of Juozas Šalna via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Storing Energy In Abandoned Mines | Earth Wise

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An international study led by researchers from Austria has developed a novel way to store energy by transporting sand into abandoned underground mines.  The technique is called Underground Gravity Energy Storage or UGES.

As the world deploys growing amounts of wind and solar energy, it is increasingly important to find ways to accessibly and efficiently store that energy to eliminate the inherent variability of the generation.  There are many ways to store energy on a short-term basis – most commonly in batteries – but cost-effective long-term storage is still in its early stages.

The UGES technique generates electricity by lowering sand into an underground mine thereby converting the potential energy of the sand into electricity by the same regenerative braking effect used in hybrid and electric cars.  The lowering sand operates a generator.   Storing energy is accomplished by lifting the sand from the mine with electric motors to an upper reservoir where it is ready for the next cycle.  By its nature, this storage technique has an indefinite duration, unlike batteries, for example, which lose energy to self-discharge.

The main components of UGES are the mineshaft, motor/generator, sand storage sites, and mining equipment.  The deeper and broader the mineshaft, the more power can be extracted from the plant, and the larger the mine, the more energy can be stored. Mines generally already have the basic infrastructure needed and are connected to the power grid.  The researchers estimate that there is global potential of 7 to 70 TWh of storage. Total global generating capacity is currently at the lower end of that range.

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Turning abandoned mines into batteries

Photo, posted October 21, 2020, courtesy of Christine Warner-Morin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Big Year For Rooftop Solar | Earth Wise

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The global capacity of rooftop solar power grew by 49% in 2022.  Overall, the installed amount of rooftop solar grew from 79 gigawatts to 118 gigawatts last year and it is projected to reach 159 gigawatts by the end of this year.  By comparison, a typical nuclear power plant can produce 1 gigawatt; a gas-powered power plant is typically half a gigawatt.

Rooftop solar constitutes a relatively small fraction of the total global installed solar capacity, which is dominated by utility-scale solar arrays.  Total installed solar capacity rose from 950 gigawatts to 1,177 gigawatts last year and is projected to reach 1,518 gigawatts this year.  That is enough power to meet more than half the electricity demand of the European Union.

The rapid growth of solar power can only continue if there is more energy storage put in place to manage the peaks and troughs in solar output.  Countries will also need to upgrade their power grids to be able to transport excess solar power from where it is generated to where it is needed.   Bottlenecks in the grids of most of the leading solar-producing nations are already interfering with further solar development.

The overall potential for rooftop solar is based on the number of rooftops that would be suitable for solar power, which depends on the size, shading, orientation, and location of the roofs.  According to the National Renewable Energy Laboratory, rooftops in the United States have the potential for more than 1,000 gigawatts of solar capacity. Currently, only about 4% of US homes have rooftop solar. 

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Rooftop Solar Grew Nearly 50 Percent Globally Last Year

Photo, posted November 16, 2022, courtesy of Oliver Knight via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Geothermal Energy Storage | Earth Wise

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About 12% of the energy consumed by humanity is used to heat and cool homes and businesses.  A study by researchers at Lawrence Berkeley National Laboratory and Princeton University looked at a novel approach to making use of underground water to maintain comfortable temperatures and reduce consumption of natural gas and electricity.

The idea is to use aquifer thermal energy storage (known as ATES) to provide both heat in the winter and cooling in the summer.  The concept leverages the heat-absorbing property of water and natural geological features.  The idea is to pump up water from existing underground reservoirs and heat it at the surface using environmental heat or even excess energy from solar or wind generation.  Then the warm water is pumped back down. It stays warm for a long time – even months – because the earth is a good insulator.  When the water is pumped back up in the winter, it is much hotter than the ambient air and can be used to supply heat to buildings.

Alternately, water can be pumped up and cooled in the winter and then put back down underground and stored until cooling is needed in the summer months.

This technology has not been used much in the US, but it is gaining recognition internationally, particularly in the Netherlands.  It can perform very well in areas with large seasonal fluctuations.

The research study used modeling and various simulations to estimate how much energy ATES could save on the US grid.  The results showed that adding ATES to the grid could reduce consumption of petroleum products for heating and  cooling by up to 40%.  The system could also help prevent blackouts by reducing high power demand during extreme weather events.

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Underground Water Could be the Solution to Green Heating and Cooling

Photo, posted February 19, 2012, courtesy of Sanjay via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Minimizing The Impact Of EVs On The Grid | Earth Wise

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Two current trends are the increasing reliance on renewable sources in the electric grid and the increasing use of electric vehicles.  According to some projections, these trends could lead to the need for costly new power plants to meet peak loads in the evening when cars are plugged in to charge.  Overproduction of power from solar farms during the daytime would require expanded energy storage capacity so as not to waste all that generating capacity.

A new study by MIT researchers has found that it is possible to mitigate or eliminate these problems without the need for advanced technological systems and complex infrastructure.  The key elements of the strategy are the strategic placement of charging stations and the practice of delaying the onset of home charging.

Better availability of charging stations at workplaces could help to soak up peak power being produced at midday from solar power installations.  In general, placing of charging stations in strategic ways, rather than letting them spring up just anywhere, could make a big difference.

Delaying home charging to times when there is less electricity demand could be accomplished with the use of a simple app that would estimate the time to begin the charging cycle so that it finishes charging just before the car is needed the next day.  Since different people have different schedules and needs, by delaying the onset of charging appropriately, not everyone will be charging at the same time, and therefore the peak in demand would be smoothed out.

There are substantial government funds earmarked for charging infrastructure and creating that infrastructure in suitably strategic ways could make a big difference in supporting EV adoption and supporting the power grid.

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Minimizing electric vehicles’ impact on the grid

Photo, posted July 2, 2020, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

An Iron-Air Battery Plant | Earth Wise

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Lithium-ion batteries are the standard energy source for electric vehicles, and they are also the dominant technology for storing energy in the electric grid.  However, they are not the only game in town.  There are other battery technologies that have various potential advantages over lithium-ion and some of them are getting the chance to show what they can do.

One is the iron-air battery.  Unlike lithium-ion batteries that require expensive and strategically challenging materials like lithium, cobalt, nickel, and graphite, iron-air batteries make use of one of the most common elements in the earth’s crust.

Iron-air batteries operate on a principle known as “reversible rusting”.  When discharging, the battery takes in oxygen from the air and converts iron into rust.  While charging, electrical current converts rust back into iron and the battery releases oxygen.  Batteries consist of a slab of iron, a water-based electrolyte, and a membrane that feeds a controlled stream of air into the battery. 

A Massachusetts-based company called Form Energy is building a $760 million iron-air battery storage facility in the city of Weirton in West Virginia.  Investment financing along with a $290 million government incentive package is paying for the facility. 

The facility is designed to address the need for long-duration energy storage and will be capable of storing electricity for 100 hours at competitive prices.  The battery modules will be about the size of a side-by-side washer/dryer and will contain a stack of 50 3-foot-tall cells.  Such batteries are too big and heavy for use in cars but will be cheaper and higher-capacity than equivalent lithium-ion battery systems.

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Form Energy selects West Virginia for its first iron-air battery plant

Photo credit: Form Energy

Earth Wise is a production of WAMC Northeast Public Radio

Green Steel | Earth Wise

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The Inflation Reduction Act provides $369 billion in investments to ramp up renewable energy generation and manufacturing of solar panels, wind turbines, energy storage, and electric vehicles. 

Every megawatt of solar power deployed requires 35 to 45 tons of steel.  Every megawatt of wind power uses 120 to 180 tons of steel.   Estimates are that it will take 1.7 billion tons of steel just to build all the wind turbines needed to reach net zero emissions by 2050.

This is a big problem because steel production accounts for roughly 10% of global carbon emissions and is one of the most carbon-intensive industries in the world.

Making steel is a complex and age-old process that hasn’t changed much over time.  Green steel is steel made with little or no carbon emissions.  There are a few ways to do it.  One is called the direct reduced iron method that uses green hydrogen instead of fossil fuel gas to produce iron and then a renewable-powered electric arc furnace to make the steel. 

Molten Oxide Electrolysis is an alternative green steel approach that doesn’t depend on having a green hydrogen infrastructure.  It uses electrolysis, powered by renewable energy, to separate the bonds of iron ore and produce liquid metal while releasing only oxygen in the process.

Green steel solutions rely on the availability of renewable energy, but the ultimate success of renewable energy will depend on the success of green steel.  The U.S. steel industry will leverage about $6 billion under the Inflation Reduction Act to make progress on it.

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Building tomorrow’s clean energy systems on green steel

Photo, posted October 30, 2008, courtesy of Paul Bica via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Pumped Hydro Storage In Switzerland | Earth Wise

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Pumped hydro energy storage is still by far the largest form of energy storage in the world, representing more than 90% of storage capacity worldwide.  The theory behind it is simple.  Water is pumped into an upper reservoir (that is, one at a higher elevation), and when electricity is needed, the water is allowed to flow downhill to power turbines and then is collected in a lower reservoir.   When there is excess electricity, it is used to pump water back uphill for use later.

Pumped hydro installations can’t be built just anywhere.  Geography and hydrology have to be suitable, which means high voltage transmission lines need to be constructed to link electricity sources like wind and solar farms with the storage location.  But in those situations where pumped hydro makes sense, it is a great solution to the energy storage problem.

Switzerland has just completed one of the largest pumped hydro facilities in the world.  The Nant de Drance installation makes use of the Emosson reservoir, which is an artificial lake built high in the Alps near the French border.  Over the past 14 years, 10 miles of tunnels have been dug into the mountains to connect the Emosson reservoir to the Vieux Emosson reservoir to the south.

In between the two reservoirs is a giant underground cavern where six of the largest water-driven turbines in the world are spun from the water rushing down from above.  The turbines have a capacity of 900 megawatts, making Nant de Drance one of the most powerful generating plants in Europe.  In terms of storage capacity, the installation has a maximum capacity of 20 gigawatt-hours, and can store that energy indefinitely, which is challenging for other storage technologies.

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14 Years In The Making, 20 GWh Pumped Hydro Storage Facility Comes To Switzerland (With Video)

Photo, posted September 7, 2009, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Lithium-Sulfur Batteries | Earth Wise

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The growing use of electric vehicles as well as energy storage systems has created a major focus on the batteries for these applications.  Lithium-ion batteries dominate these applications and the demand for the materials needed to manufacture them continues to grow.

The raw materials for these batteries include not only lithium, but also can include nickel, manganese, and cobalt. 

Sulfur has been a desirable alternative for use in lithium-based batteries for quite a while because it is an abundant element and can be extracted in ways that are safe and environmentally friendly.  However, previous attempts to create lithium batteries that combine sulfur cathodes and the standard carbonate electrolytes used in lithium-ion batteries have not been successful because of irreversible chemical reactions between intermediate sulfur products and the electrolytes.

A group of chemical engineers at Drexel University has now found a way to introduce sulfur into lithium-ion batteries that solves the stability problem and also has major performance advantages.  The new batteries have three times the capacity of conventional lithium-ion batteries, and last more than 4,000 recharges, which is also a substantial improvement.

The new battery technology involves creating a stable form of sulfur called monoclinic gamma sulfur by depositing the sulfur on carbon nanofibers.   Previously, this sulfur phase was only observed at high temperatures and was only stable for 20 or 30 minutes.  This chemical phase of sulfur does not react with carbonate electrolytes and therefore produces a battery that is chemically stable over time.

 Incorporating this sulfur into battery cathodes results in a better battery that doesn’t need any cobalt, nickel, or manganese.  It could be the next big thing in electric vehicle batteries.

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Breakthrough in Cathode Chemistry Clears Path for Lithium-Sulfur Batteries’ Commercial Viability

Photo, posted April 5, 2022, courtesy of Oregon Department of Transportation via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Record Renewable Use In California | Earth Wise

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California, the most populous state, is the second largest electricity user.  Only Texas, the second most populous state, uses more energy, in part because it consumes large amounts in refining fossil fuels. Overall, California uses about 8% of the electricity generated in the U.S.

Thus, it was a significant milestone when briefly, on April 3, a record 97.6% of the energy on California’s statewide grid came from renewable energy resources.  (The previous record of 96.4% was set just a few days earlier).

Renewable energy’s share of the power typically peaks in the spring when mild temperatures keep demand relatively low and higher sun angles drive greater solar energy production.

On April 8, a record peak solar power production was set at 13,628 megawatts just after noon.  On March 4, the state set an all-time wind generation record of 6,265 megawatts. 

California now has over 15,000 MW of grid-connected solar power and 8,000 MW of wind.  Another 600 MW of solar and 200 MW of wind are coming online by June.  The state also has about 2,700 MW of energy storage online and that will climb to 4,000 MW by June.

In 2020, 34.5% of the state’s retail electricity sales came from wind and solar sources.  Adding in hydropower and nuclear power, nearly 60% of the state’s electricity came from non-fossil fuel.  Despite the effects of drought on hydropower generation and the impact of the pandemic on the pace of renewable energy projects, California continues its dramatic transition to sustainable energy.

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Solar and wind notched records as renewables met California’s energy demand

Photo, posted September 20, 2016, courtesy of Tom Brewster Photography / BLM via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)