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Help from elephants in cooling buildings

September 15, 2025 By EarthWise Leave a Comment

Elephant ears play a crucial role in keep the giant animals cool. Elephants don’t have significant sweat glands. Instead, they rely on their large ears to regulate body temperature. Their ears make up 20% of their body’s surface area. The ears act like a natural air conditioner, making use of a network of blood vessels close to the surface that help dissipate heat when it’s hot and absorb heat when it’s cold.

Researchers at Drexel University have developed a new approach to passive heating and cooling that has the potential to make buildings more energy efficient. The idea, published in the Journal of Building Engineering, embeds the equivalent of a vascular network within cement-based building materials. The network, when filled with paraffin-based material, can help passively regulate the surface temperature of walls, floors, and ceilings.

Building energy demand contributes almost 40% of the production of greenhouse gas from energy use, and about half of building energy use is spent maintaining comfortable temperatures.

The new temperature regulation method puts a grid of paraffin-filled channels in the surface of building concrete. When temperatures drop, the paraffin transitions from liquid to solid and releases heat energy. When ambient temperatures rise, the paraffin absorbs heat energy, producing a cooler surface. This is essentially the same way elephants as well as jack rabbits regulate their temperatures with their large ears.

The Drexel study was a proof-of-concept effort, but the results are promising enough to warrant further work. With additional testing and scaling, it has the potential to make a significant contribution to ongoing efforts to improve the energy efficiency of buildings.

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Drexel Engineers Want to Make Buildings More Energy Efficient by Making Walls, Floors and Ceilings More Like Elephant Ears

Photo, posted September 1, 2016, courtesy of Nane Kratzke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A surprising drop in renewable power

March 28, 2024 By EarthWise Leave a Comment

Renewable power – which includes wind farms, solar farms, and hydroelectric dams – constitutes over 21% of the country’s utility-scale electricity generation, behind only natural gas power plants at 43%. Nuclear power provides nearly 19% of our electricity and coal, which is gradually diminishing, is at 16%.

Both solar and wind power capacity have been growing rapidly in recent years and will be providing an increasing percentage of our electricity. That being said, it turns out that utility-scale renewable electricity generation actually decreased slightly in 2023 as a result of weather-related issues.

Utility-scale renewables generated about 894,000 gigawatt hours of energy last year, which was 0.8% less than the record amount generated in 2022.

The reasons? The biggest factor was slower wind speeds in the Midwest during the warmer weather months. In 2023, there were fewer warm fronts and cold fronts passing through the region. The passage of fronts is often associated with wind and precipitation.

The other factor affecting renewable generation was a 5.9% drop in hydropower in 2023. The main reason for the decrease was a drop in water levels at many hydroelectric dams in areas experiencing drought.

Experts explain that there is no reason to overreact to a one-year blip in renewables generation. All three major sources of power – sun, wind, and hydroelectric – are tied to natural forces and all of them fluctuate over time. Putting aside minor variations year-over-year, renewable electricity is on pace to more than double by the end of this decade.

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Federal Data Reveals a Surprising Drop in Renewable Power in 2023, as Slow Winds and Drought Took a Toll

Photo, posted July 5, 2014, courtesy of Patrick Finnegan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record renewable energy in Scotland

March 1, 2024 By EarthWise Leave a Comment

The Scottish government recently announced that in 2022, renewable technologies in that country produced the equivalent of 113% of Scotland’s electricity consumption.

Fossil fuels still supplied electricity in Scotland, helping to fill in gaps in renewable power, but the government figures showed that the growing amount of Scottish renewable generation can easily generate more power than the country uses. Scotland has seen significant growth in wind power as well as a small drop in overall electricity consumption.

Scotland, with a population of only 5.5 million, aims to produce enough renewable power to both meet its own demand and export clean electricity to other countries. The U.K. is the obvious potential customer, but it will need to upgrade its national power grid and develop enough capacity to store up surplus wind and solar power.

The U.K. itself is drawing less power from natural gas and coal than it has at any point in the last 66 years. Fossil fuels supplied only 33% of British electricity in 2023 while renewables supplied 43%.

Fossil power use in Britain peaked in 2008. Since then, power from natural gas has fallen nearly in half while coal power has dropped by 97%. The U.K. has aggressive decarbonization goals in place, but the current Conservative government under Prime Minister Sunak has recently set about weakening British climate policy.

Meanwhile, the Scottish government is talking about becoming a global renewables powerhouse and is making investments aimed at achieving it.

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Record renewable energy output

Photo, posted July 21, 2010, courtesy of Martin Abegglen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The slow decline of coal

January 25, 2024 By EarthWise Leave a Comment

Despite the fact that coal is the dirtiest and most climate-harmful energy source we have, the global demand for it hit a record high in 2023. The demand for coal grew by 1.4% worldwide, according to an analysis by the International Energy Agency.

Coal use grew by 5% in China and 8% in India. The two countries are the world’s largest producers and consumers of coal. Meanwhile, coal use in the U.S. and the European Union fell by 20%.

Despite this discouraging news, the IEA forecasts that coal use will decline over the next two years. There have been declines in coal demand a few times before, but they were driven by unusual events such as the collapse of the Soviet Union and the Covid-19 crisis. But the IEA says that the forthcoming decline is different. It will be driven by the formidable and sustained expansion of clean energy technologies.

According to the IEA, global coal demand will fall by 2.3% by 2026 even in the absence of new policies to curb coal use. Forces at play will be increased hydropower in China as it recovers from drought and puts new wind and solar projects online. China is responsible for more than half of global coal demand, but it is also responsible for more than half of the planned renewable power projects coming online over the next three years. Experts believe that with these forthcoming projects, Chinese emissions may have peaked in 2023.

The projected drop in coal demand is still far short of what is required for the world to avoid catastrophic warming. Much greater efforts are needed to meet international climate targets.

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After a Record 2023, Coal Headed for Decline, Analysts Say

Photo, posted August 25, 2015, courtesy of Jeremy Buckingham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

EV battery costs continue to drop

January 10, 2024 By EarthWise Leave a Comment

Electric vehicles have historically been more expensive than their gas-powered counterparts primarily because of the cost of the batteries that power them. Today’s EV battery packs range in size from about 40 kWh to as much as 200 kWh, where kWh measure the amount of energy stored in pack.

The batteries in EVs are lithium-ion batteries, the same technology used to power cell phones, tablets, and computers. A decade ago, the batteries averaged $668 per kilowatt-hour and packs as large as those in some of today’s vehicles were simply unthinkable from a price standpoint.

Over the years, government subsidies, increased competition, higher volume, improvements in battery technology, and reductions in the cost of raw materials such as lithium have combined to drive continuous and dramatic reductions in battery costs. By March 2022, the average price for lithium-ion batteries was $146 per kWh. This past August, battery costs broke the $100 per kilowatt-hour barrier.

Industry analysts have long maintained that once the $100 barrier has been reached, EVs could achieve price parity with their fossil-fuel counterparts. Electric cars would no longer be more expensive to buy than equivalent gas cars.

Projections are that battery prices will continue to fall by something like 10% a year for the rest of this decade. All else being equal, EVs should be cheaper to buy than gas cars. Of course, they have already been cheaper to operate for a long time.

None of this means that car prices will go down in general. That will depend on trends in inflation and those are pretty hard to predict.

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EVs Set to Match Gas Guzzlers in Price as Battery Costs Plummet

Photo, posted May 9, 2018, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Large Drop In U.S. Greenhouse Gas Emissions | Earth Wise

December 29, 2020 By EarthWise Leave a Comment

Greenhouse gas emissions in the U.S. in 2020 are on track to be at their lowest level in nearly 30 years as a result of the COVID-19 pandemic. U.S. emissions haven’t been this low since 1983, when the economy was not even 40% of its current size.

According to a new study by the research group BloombergNEF, U.S. emissions for the year will be 9% lower than they were in 2019, which will be the largest yearly drop on record. The report also anticipates that whatever happens in the pandemic, 2021 emissions will be well below pre-COVID levels as well.

The pandemic has inadvertently put the U.S. back on track to meet its original commitments to the Paris Climate Agreement, despite the fact that we have pulled out the agreement. The incoming administration plans to return the U.S. to the pact.

Overall, U.S. emissions have been trending downward since 2008, primarily as a result of the lower dependence of the power sector on coal. The report estimates that in the absence of the pandemic, 2020 emissions would have been 1% lower than last year’s.

The dramatic drop in emissions is not really a great cause for celebration. Achieving significant emission reductions through massive economic hardship and societal disruption does not point the way towards making progress on climate change. The economic upturn that will undoubtedly occur when the pandemic loses its grip on the world will lead to rebounding levels of greenhouse gas emissions. But as is the case with all major crises, the current situation does present a chance to turn this temporary downturn in emissions into a more permanent one by making appropriate investments and policy changes.

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Due to COVID-19, 2020 greenhouse gas emissions in the U.S. are predicted to drop to lowest level in three decades

Photo, posted January 13, 2013, courtesy of Onnola via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Another Way To Make Solar Cells

March 21, 2019 By EarthWise Leave a Comment

Millions of rooftops now contain solar panels and the majority of the solar cells that make up those panels today are made from silicon. Silicon solar cells require expensive, multi-step processing conducted at very high temperatures in special clean room facilities. Despite these complications, the price of solar panels has continued to drop dramatically over the years.

But even as the price of solar cells gets lower and lower, there are still widespread efforts to find even better ways to make them. One of those ways is with perovskite solar cells. Perovskites are materials with a characteristic crystal structure and are quite common in nature. Perovskites can be formed with a wide range of elements and can exhibit a variety of properties.

They were first used to make solar cells about 10 years ago and those first cells were unimpressive in most respects. However, there has been steady progress since that time. The potential advantages of perovskite solar cells are that they can be made from low-cost materials and can be manufactured using liquid chemistry, a far cheaper process than what is used to make silicon cells.

Researchers at MIT and several other institutions have recently published the results of research on how to tailor the composition of perovskite solar cells to optimize their properties. What used to be a trial-and-error process can now become much more engineered and should lead to perovskite solar cells with performance that could exceed that of silicon cells.

Silicon solar panels are a huge, worldwide industry and displacing them in favor of an alternative technology is a tall order. But if perovskite cells can be optimized for large-scale manufacturability, efficiency and durability, they could definitely give silicon a run for its money.

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Unleashing perovskites’ potential for solar cells

Photo courtesy of Ken Richardson/MIT.

Earth Wise is a production of WAMC Northeast Public Radio.