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Energy droughts

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With new ways of doing things, there are always new problems.  Our energy systems are increasingly dependent upon solar and wind power.  These energy sources are free to take and aren’t going to run out, but they also depend on natural processes that are out of our control.  In particular, the sun doesn’t always shine, and the wind doesn’t always blow.

Fortunately, the two sources of energy are typically not in sync and often when one is diminished, the other can take up the slack.  But it is possible for both sun and wind to not be present, and it can even happen for an extended period of time.  This is known as a compound energy drought. There are some parts of the country where these energy droughts can last for nearly a week.

Researchers at the Pacific Northwest National Laboratory studied the phenomenon and its potential impact on the electric grid.   Looking at 40 years of weather data, the study found that the longest energy drought occurred in California for 6 days; the longest in Texas was 37 hours.

The study further investigated the possible connection between energy droughts and energy demand, again mapping historical data over the past 40 years.  The impact of an energy drought depends on how much demand for energy exists at the time.

The data from the study will provide critical insights into the design and management of multi-day energy storage facilities that can provide the resilience of the electric grid that is required.  Clearly, the storage needs in a place like California will be substantially greater than those in Texas.  As more and more of the grid depends on wind and solar power, appropriately designed and operated storage facilities will be essential.

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“Energy Droughts” in Wind and Solar Can Last Nearly a Week, Research Shows

Photo, posted February 10, 2023, courtesy of Guilhem Vellut via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Recycling solar panels

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The use of solar energy has been growing by leaps and bounds in recent years. It is the fastest growing source of energy in the U.S.   Solar panels have a useful life of about 25 to 30 years and there are growing numbers that have been around that long.  They contain valuable materials, including silver, copper, and aluminum, as well as some hazardous materials, so just committing them to landfills is a bad idea from many perspectives.

Recycling solar panels is a relatively new but increasingly important business.  At the present time, roughly 90% of panels that have lost their efficiency due to age or that are defective end up in landfills because that is much cheaper than recycling them.  The best option is to reuse them where their reduced efficiency is acceptable.  This includes in developing nations or in other places that are able to make use of the lower power in exchange for lower installation cost.

Estimates are that the area covered by solar panels in the U.S. that are due to retire by 2030 would cover about 3,000 football fields.   The amount of potential waste contained in all of those panels is quite substantial.

There are new companies dedicated to solar panel recycling such as one called SolarCycle that are trying to change this situation.  It is much more expensive to have SolarCycle take away solar panels than to send them to landfills, but it is difficult to find landfills that accept panels and many clients want to minimize the environmental impact of their old panels.

Only 10% of retired solar panels are currently recycled. That that is likely to change as economics and regulations continue to evolve.

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As Millions of Solar Panels Age Out, Recyclers Hope to Cash In

Photo, posted November 23, 2024, courtesy of Mussi Katz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

AI and energy

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MIT recently hosted a symposium on the subject of artificial intelligence being both a problem and a solution for the clean energy transition.

AI-powered computing centers are expanding rapidly, creating an unprecedented surge in electricity demand.  Electricity demand in the US had been relatively flat for decades but now these computing centers consume about 4% of the nation’s electricity.  Some projections say that this demand could rise to 12-15% in the next five years. 

The power required for sustaining some of the AI large-language models is doubling every three months.  The amount of electricity used by a single ChatGPT conversation is as much as it takes to charge a phone and consumes the equivalent of a bottle of water for cooling. 

The MIT symposium focused on the challenges of meeting these growing energy needs but also on the potential for AI to dramatically improve power systems and reduce carbon emissions. 

Research shows regional variations in the cost of powering computing centers with clean electricity.  The central United States offers lower costs due to complementary solar and wind resources but would require massive battery deployments to provide uninterrupted power.

Because of data center demand, there is renewed interest in nuclear power, often in the form of small modular reactors, as well as efforts in long-duration storage technologies, geothermal power, or hybrid approaches.

Artificial intelligence offers both great promise and great peril.  It will take real intelligence to steer it in the right direction.

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Confronting the AI/energy conundrum

Photo, posted August 31, 2024, courtesy of Jefferson Lab via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Geothermal energy may be safe

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The Trump Administration is outwardly hostile to renewable energy, especially solar and wind power.  Federal support for these energy sources that are by far the most rapidly growing energy sources across the globe is being gutted while fossil fuels are being propped up.

There is also renewed enthusiasm for nuclear power and, somewhat surprisingly, geothermal heat.   Geothermal is a renewable and clean energy source that has long been mostly overlooked and underfunded.  The main reasons are its expense and the fact that its large-scale use is unproven. 

Historically, geothermal energy has relied upon naturally occurring features such as hot springs and shallow underground heat sources.  However, technological breakthroughs that began in 2013 have led to enhanced geothermal systems, or EGS.  EGS makes use of the fact that if you drill deep enough into the earth pretty much anywhere, you will encounter substantial amounts of heat.  EGS plants pump water three miles down or more where it encounters rock that reaches over 500 degrees.  The piping hot water is then brought to the surface where it spins turbines to generate electricity.

Several companies are developing EGS in the U.S.  financed by tech companies seeking power for their AI activities, the Defense Department, and even by fossil fuel companies who use comparable drilling technology for fracking.

The so-called Big Beautiful Bill passed by Congress in July that eliminates tax credits for wind and solar energy preserves tax credits for geothermal projects.

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Why U.S. Geothermal May Advance, Despite Political Headwinds

Photo, posted September 30, 2019, courtesy of Stephen D Strowes via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar power in Europe

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In June, solar power was the largest source of electricity in the European Union for the first time.  Solar supplied a record 22% of the power for the 27-country bloc.  At least 13 of the countries produced new monthly highs for solar power in June.  The Netherlands got more than 40% of its electricity from solar power and Greece 35%.  Other countries with record solar generation included France, Germany, and Sweden.

These solar records are for the most part a result of continuing installations of solar power in recent years as well as long stretches of hot and sunny weather.

Across the EU, nuclear power was the second largest source of electricity, followed by wind, natural gas, and hydropower.  Coal generated only 6% of the EU’s electricity, a new monthly low.  In fact, 15 countries in the EU don’t use any coal to generate electricity at all, including Austria, Belgium, and Ireland, which shut down its last coal plant in June.  All fossil fuels combined generated less than 24% of EU electricity in June, just a little more than the record low of 22.9% set in May, 2024.  Natural gas generation was somewhat higher than last year because of lower levels of hydro and wind generation.

Europe has been grappling with brutal heatwaves with triple-digit temperatures in multiple countries.  The heatwaves were, of course, accompanied by plentiful sunshine, which at least provided abundant solar power at midday, when there was the greatest demand for air conditioning.  This helped to take some of the pressure off the grid and helped to prevent blackouts.

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In a First, Solar Was Europe’s Biggest Source of Power Last Month

Photo, posted May 28, 2025, courtesy of Mike Popp via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Coexisting birds and solar energy

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Floating photovoltaic systems – known as floatovoltaics – are becoming increasingly popular.  These are arrays of solar panels installed over artificial water bodies such as irrigation ponds, wastewater treatment plants, and reservoirs.  These projects maximize the space for producing clean energy while not taking up natural lands.

Wherever there are bodies of water, there are waterbirds.  A recent study by researchers at the University of California, Davis looked at the potential impact of floating solar projects on birds and other wildlife. 

Birds face many threats from habitat loss, climate change, pollution, and disease.  Many bird populations are in decline.  So, it is important to consider the effects of floating solar projects on birds. 

The researchers have observed birds resting on floating solar structures before dawn, birds jockeying for favorable sites on the structures, and some nesting under the panels.  These are positive interactions.  On the other hand, it is possible that pollutants could be released or leached from floating solar infrastructure.  Such risks must be mitigated.

Floating solar on irrigation ponds and reservoirs can reduce evaporation and reduce algae growth, which benefits both humans and wildlife.

The researchers will continue to monitor bird behavior at floating solar installations using expertise in ecology and energy system science to identify risks and solution pathways so that negative impacts are avoided, and potential ecological benefits are realized.  It is important that as floating solar continues to become more popular, it and waterbirds can coexist.

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Helping Birds and Floating Solar Energy Coexist

Photo, posted February 28, 2019, courtesy of Renee Grayson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar on farmland

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New studies have found that devoting a small percentage of U.S. farmland to producing solar power would benefit both the country’s energy system and its farmers.

Currently, about 46,000 square miles of farmland – about the area of Pennsylvania – is being used to grow corn to make ethanol.  One study looked at the impact of using some of this land for solar power instead of corn ethanol.

Not much of all this farmland is close enough to electrical transmission lines to be practical for utility solar power.  In fact, only about 1,500 square miles fits the bill.  But if even this small fraction of the corn growing land was used instead for solar power, it would generate as much energy each year than from all of the farms growing corn for fuel.

Solar installations on farms are helpful for farmers as well.  The land beneath the panels can be used to grow wildflowers that attracts the bees, wasps, and other insects needed to pollinate crops in the nearby fields.  In addition, the solar arrays provide a steady income stream for farmers.

In some places, farmers can earn substantially more from leasing their land for solar than from growing crops.  But a study of farms in California suggests that the best option is to do both.  Farmers who both grow crops and host solar arrays can have more financial security than those who do just one or the other.  The income from solar arrays is pretty predictable and is paid throughout the year.  Income from crops can drop off from, for example, a seasonal drought, or from extreme weather events.

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To Help Growers and the Grid, Build Solar on Farmland, Research Says

Photo, posted June 9, 2016, courtesy of Matt Lavin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Saharan dust and solar power

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The world is a big place but even things that are far away can have serious local consequences.  The effects of distant Canadian wildfires on air quality in Florida is a good example.

Europe is increasingly becoming reliant on solar energy to meet its targets for climate change mitigation and energy security.   According to new research by four Hungarian universities, mineral dust carried on the wind from the Sahara Desert is not only reducing electricity generation from solar power across Europe but it is also making it harder to predict what gets generated.

The Sahara releases billions of tons of fine dust into the atmosphere each year.  Tens of millions of tons reach European skies where the tiny particles scatter and absorb sunlight, reduce the amount of light reaching the surface, and even promote cloud formation.   All of these things reduce the output of photovoltaic systems.

In addition, conventional weather forecasting tools don’t consider the effects of Saharan dust events, so that scheduling of solar power for the energy system becomes less reliable.  Incorporating these events into new forecast models will be essential.

Apart from the atmospheric effects of the dust, there are also long-term impacts due to dust contaminating and eroding the physical infrastructure of solar panels thereby further reducing their efficiency and increasing maintenance costs.

Over time, south-to-north transport of Saharan dust is likely to become more pronounced due to a steeper thermal gradient.  Currently, the quantities of atmospheric dust, the dynamics of its transport, and the physical properties of the dust itself are not very well understood.  Understanding these things will be crucial for Europe’s energy future.

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The shadow of the wind: photovoltaic power generation under Europe’s dusty skies

Photo, posted March 11, 2023, courtesy of Mark Wordy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Recycling lithium-ion batteries

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Lithium-ion batteries are used to power computers and cellphones and, increasingly, vehicles.  The batteries contain lithium as well as various other valuable metals such as nickel, cobalt, copper, and manganese.  Like other batteries, lithium-ion batteries have a finite lifetime before they can no longer perform their intended function.

Recycling lithium-ion batteries to recover their critical metals is an alternative to mining those metals.  A recent study by Stanford University analyzed the environmental impact of obtaining those metals using lithium-ion battery recycling compared with mining.  They found that the recycling process is associated with less than half of the greenhouse gas emissions of conventional mining.  The process uses about one-fourth of the water and energy of mining new metals.  North America’s largest industrial-scale lithium-ion battery recycling facility is Redwood Materials, located in Nevada, which uses a clean energy mix that includes hydropower, geothermal, and solar power.

These calculated advantages are associated with recycling batteries that have been in use.  The advantages are even greater for recycling scrap:  defective material from battery manufacturers.

The advantages of recycling are dependent on the sources of electricity at the recycling plant and the availability of fresh water. 

At present, the U.S. recycles about half of its available lithium-ion batteries.  By comparison, 99% of lead-acid batteries (like those found in cars and trucks) have been recycled for decades.  As the supply of used lithium-ion batteries continues to increase, it is important for the availability of industrial-scale battery recycling to keep pace. 

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Recycling lithium-ion batteries delivers significant environmental benefits

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

Earth Wise is a production of WAMC Northeast Public Radio

The green grab for land

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Solar and wind farms are spreading rapidly around the world.  Many economists believe that solar power has crossed the threshold where it is generally cheaper than other ways to make electricity and will become the dominant energy source in the next couple of decades.  As a result, both solar and wind farms are gobbling up more and more land around the world.  Estimates are that they will take up around 30,000 square miles by mid-century.

One concern is whether we are entering an era of trading food for energy.  Land conflicts seem inevitable since solar power operates best in unshaded areas with gentle winds and moderate temperatures, which are the same conditions favored by many crops.

China is installing more solar farms than the rest of the world combined.  Many of these are in the Gobi Desert, where there is no competing need for the land.  But some are in eastern China, in densely populated grain-growing areas.

There are a number of strategies that reduce the impact of solar farms on land use.  One approach is to put them on old industrial or brownfield sites that are otherwise unusable.  Another is floatovoltaics:  putting solar panels on the surface of lakes and reservoirs.  And then there is agrivoltaics, where solar panels are installed above crop fields or where livestock graze between or even beneath solar arrays.  China has more than 500 agrivoltaic projects that incorporate crops, livestock, aquafarming, greenhouses, and even tea plantations.

Green energy has both environmental and economic benefits to offer, but it must conserve nature and not excessively grab land needed for people, wildlife, and ecosystems.

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‘Green Grab’: Solar and Wind Boom Sparks Conflicts on Land Use

Photo, posted May 25, 2011, courtesy of Michael Mees via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A record year for solar and batteries

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According to a recent forecast from the U.S. Energy Information Administration, solar panels and batteries will account for more than 80% of new power capacity installed in the U.S. this year.  The record growth of these technologies is hastening the decline of coal power in this country.

Solar power alone will account for more than half of the country’s new power capacity and most of it will be in Texas and California.

Wind power is expected to provide only 12% of new capacity this year.  Wind is facing rising costs, lengthy permitting, public backlash, and clear opposition from the Trump administration which is determined to stifle its growth.

As renewable energy grows, coal power continues to decline.  The U.S. will retire twice as much coal power this year as it did last year, closing about 5% of the country’s capacity.  Not only are older coal plants shutting down; the remaining plants are generating less power.

One of the most significant changes in technology over the last few decades has been the massive drop in the cost of clean energy.  Solar photovoltaic costs have fallen by 90% in the past decade, onshore wind by 70%, and batteries by more than 90%.  The connection between cost reduction and volume has been very strong:  costs of these technologies have fallen by around 20% every time global cumulative capacity doubles.   Over the past 40 years, solar power has transformed from one of the most expensive electricity sources to the cheapest in many countries.  That trend is likely to continue.  Setting politics aside, market forces generally are the strongest driver.

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U.S. Solar and Batteries Headed for Record Year

Photo, posted December 16, 2024, courtesy of Bureau of Land Management California via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Clean energy in New York

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The New York State Energy Research and Development Authority – NYSERDA – recently issued a report on clean energy progress in the state during 2024.  The report highlighted continued and increased growth in heat pumps, electric vehicles, and solar energy.

Heat pumps, which provide both heating and cooling, have outsold gas furnaces countrywide for three straight years.  Air source heat pumps outsold gas furnaces by 37%.  This does not include ground source heat pumps, also known as geothermal heat pumps. New York offers Clean Heat rebates to offset the cost of installing heat pumps.

2024 was a good year for electric vehicles in New York with 90,221 new registrations.  More than 60 car models are eligible for New York’s Drive Clean state rebates.

New York achieved its Climate Act goal of having 6,000 MW of distributed solar power in October.  The state is expected to have more than 10,000 MW of distributed solar by 2030.

Nationwide, solar energy represented 64% of all the new electricity generation capacity installed in 2024, up from 55.5% in 2023.  Utility-scale solar generation in the lower 48 states was 36% higher in the summer of 2024 than in summer 2023.

NYSERDA’s report points out that converting to clean energy technologies can bring multiple benefits that include energy efficiency, cost savings, and reduced greenhouse gas emissions and air pollution.

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Heat Pumps, Electric Vehicles, and Solar Scale Up Through 2024

Photo, posted April 6, 2017, courtesy of Stephen Yang / The Solutions Project via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reliability of renewable energy

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Naysayers about renewable energy often claim that it is unreliable.  It is true that the sun sets every night and sometimes the wind doesn’t blow.  But with the growing use of battery banks to store excess power generated by renewables, the lack of reliability of renewable energy is turning out to be a myth.

A new study published in the journal Renewable Energy looked at the deployment of renewable energy in California last year.  From late winter to early summer, renewable sources supplied 100% of the state’s electricity demands for up to 10 hours on 98 out of 116 days.  There were no blackouts during that time thanks in part to the presence of battery backup power.  During peak generation periods, the renewables provided as much as 162% of the grid’s needs. 

The main finding of the study is that the electricity grid can be kept stable even as it adds more and more renewables.  Beyond that, every major renewable energy source – geothermal, hydroelectric, wind, and especially solar – is on average lower in cost than fossil fuels.

Despite the low cost of renewable energy, Californians pay the second highest rates for electricity in the country.  Part of the reason is that electrical equipment from utilities has set off wildfires, notably the 2018 Camp Fire that devastated the town of Paradise and killed 85 people.  California’s utilities are now passing the costs that come from lawsuits and from burying transmission lines to their customers.  Overhead power lines are especially prone to falling in high winds and igniting fires.

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California just debunked a big myth about renewable energy

Photo, posted December 16, 2024, courtesy of EDF Renewables / Bureau of Land Management California via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A big year for battery storage

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A decade ago, the ability of utilities to store large amounts of electricity in batteries was basically nonexistent.  In the past several years, growth in battery storage systems has exploded.  As of the end of November, the US had about 24 gigawatt-hours of storage capacity in place.  This is 71% more than just a year ago.  Nearly half of the battery storage in the US is located in California.  Texas, Arizona, and Nevada are also leaders in deploying battery storage.

Battery storage allows solar and wind generating plants to keep operating when there is reduced demand for their output and have the electricity that they produce be available later when demand rises.  Storing this excess electricity essentially extends the hours of the day when clean energy can be used.

Equally important, the existence of battery storage reduces the need for peaker plants, the fossil-fueled power plants that only turn on at times of peak demand, such as during hot afternoons.

There are 1,000 peaker plants in the US and they are generally heavily polluting, inefficient, and expensive to operate.  Some 63 million people live within a three-mile radius of one of them and are exposed to harmful pollutants like nitrogen oxides and sulfur dioxide.  Peaker plants also release more greenhouse gases than other power plants do for every unit of electricity they generate.

Many battery storage facilities are co-located with, or otherwise support, solar energy plants.  The amount of solar energy in the US is growing rapidly and surpassed the 100-gigawatt mark in 2024.  As solar power continues to expand, so will battery energy storage.

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Battery projects soared again in 2024

Photo, posted August 3, 2024, courtesy of the Bureau of Ocean Energy Management via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A solar peaker plant

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Peaker plants are power plants that the grid makes use of during times of particularly high electricity demand.  The power they supply is typically high in cost and usually high in greenhouse gas emissions.  When operating the electricity grid, power sources are generally called upon in order of marginal cost.  Only when demand is very high do grid operators make use of the highest-cost assets that tend to be fossil-fueled power plants that can start and ramp up quickly. 

For years, there has been the idea that solar-powered peaker plants could eventually replace the polluting fossil-fueled ones.  Recently, the renewable energy developer, owner, and operator Arevon Energy began commercial operations of the Vikings Solar-plus-Storage Project in Imperial County, California.  It is the first utility-scale solar peaker plant in the United States.

The plant utilizes a 157-megawatt solar array combined with 150 MW and 600 MWh of battery energy storage.  It can shift low-cost daytime solar energy to higher-cost peak demand periods.  The result is a lowered cost of electricity for nearly one million customers of San Diego Community Power.

The project contradicts the often-held notion that renewable energy is inherently unreliable.  It can provide carbon-free electricity at specific times of critical need.  Typical hybrid solar + storage plants provide electricity during daylight hours and store only excess generation in their battery systems.  The Vikings project is specifically designed to shift the entirety of its generation from solar hours to the peak demand period.

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Arevon fires up the first solar + storage peaker plant in the U.S.

Photo, posted October 15, 2024, courtesy of Jay Inslee 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

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

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

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

Renewables progress

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According to a new report by the International Energy Agency, the world is on track to produce nearly half of the electricity it uses from renewable sources by the end of this decade.  The report also finds that in nearly every country, large wind and solar plants are the cheapest forms of new power.

Between now and 2030, countries will add more than 5,500 gigawatts of new renewable capacity.   That is as much as China, India, the U.S., and the EU combined have at present.  Most of the new capacity will come from solar power.

China is aggressively pursuing renewable power installations with massive solar and wind projects.  By 2030, China will account for nearly half of the world’s renewable power capacity.

This year’s UN Climate Change Conference, held in the United Arab Emirates, established the goal of tripling renewable energy capacity worldwide by 2030. 

The growth in solar power continues to outperform industry expert projections as manufacturing ramps up.  India and the U.S. are both expected to triple their solar manufacturing capacity by the end of this decade.  Manufacturing, largely based in China, is already outstripping demand.

By 2030, solar and wind power are expected to account for about 30% of global electricity generation, hydropower about 13%, and other renewables such as geothermal power about 5%.

These estimates are based on existing policies and market conditions.  Governments could speed up the shift to clean energy by cutting red tape and by making it cheaper for poorer countries to finance solar and wind projects.

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Renewables 2024

Photo, posted November 23, 2023, courtesy of Rick Obst via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

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