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Grid-Scale Gravity Energy Storage | Earth Wise

September 19, 2023 By EarthWise Leave a Comment

As wind and solar energy play a growing part in our energy system, the need for grid-scale energy storage is growing as well. An historic form of energy storage and still the largest in installed capacity is pumped hydro storage, which makes use of the potential energy contained in having water sitting at a higher elevation where it can be released downward to operate turbine generators. This is an effective system but is limited to places where geography cooperates.

For the past five years, a company called Energy Vault has been developing a system that uses the same principle to generate electricity but instead of pumping water to a higher elevation, it uses mechanical devices to lift heavy objects such as concrete blocks to an appropriate height. Lowering the blocks back to the ground drives generators.

To date, Energy Vault has only built demonstration systems with a fraction of the storage capacity needed for grid-scale operation. Their EV1 Tower in Switzerland was successfully grid interconnected in 2020 and demonstrated round-trip efficiency (the fraction of the energy stored that was produced by the generators) above 75%. Their improved EVx system is expected to do better than 80%.

This year the company, along with partners Atlas Renewable and China TIanying, is now in the first phases of commissioning a grid-scale system located outside of Shanghai, China. The 25-MW system is built adjacent to a wind farm and a national grid interconnection site

This is the first grid-scale gravity energy storage system and is expected to be fully online in the fourth quarter of this year. A second, similar system is now under contract to be built elsewhere in China.

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First grid-scale gravity energy storage system undergoes commencement in China

Photo courtesy of Energy Vault.

Earth Wise is a production of WAMC Northeast Public Radio

Coastal Land Reclamation | Earth Wise

April 3, 2023 By EarthWise Leave a Comment

People are artificially expanding the coastlines of cities by extending industrial ports and creating luxury residential waterfronts. Major cities have added 900 square miles to their coastlines just since 2000.

A recent study published in the journal Earth’s Future made use of satellite imagery to analyze land changes in 135 cities with populations of at least 1 million. But population growth is not the only driver of coastal land reclamation. It is popular in places that are eager to enhance their reputation and promote revenue growth.

At present, coastal land reclamation is most common in the Global South, where many economies are growing. In the past, the Global North dominated the use of coastal land construction.

The largest additions to land area occurred in China, Indonesia, and the United Arab Emirates. Port extension is the most common reason for development. Shanghai alone has added 135 square miles of land.

New land is typically created by piling sediments in the ocean, building cement sea walls and structures to contain sediments or cement, or sometimes filling in wetlands and other shallow areas of water near the coast. The ecological impacts of reclamation are immense and, unfortunately, are not always considered. Projects affect both the local ecosystems as well as those of the places where fill materials are obtained.

Industrialization and the need for urban space have driven much coastal reclamation. Some projects, such as the palm-tree-shaped artificial islands of Dubai, are essentially for prestige. Some cities, including Shanghai, are building new land in consideration of future sea level rise.

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New Land Creation on Waterfronts Increasing, Study Finds

Photo, posted October 15, 2010, courtesy of Werner Bayer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Sea Level Rise And Global Security | Earth Wise

March 22, 2023 By EarthWise Leave a Comment

Recently, United Nations General Secretary Antonio Guterres addressed the U.N. Security Council on the issue of the security threats created by rising sea levels. In the past, some members of the Security Council – notably Brazil, China, Russia, and at times, India – have argued that the U.N.’s climate program should address such issues and that the Security Council doesn’t have a mandate or the expertise to consider the issue. The underlying problem is that by addressing the security issues created by rising seas, other sensitive geopolitical issues might come to the forefront.

Guterres’ speech focused on the real possibility that rising seas could disrupt and destabilize global societies unless there is an organized international effort to get ahead of the problem. Major cities facing serious impacts from rising seas include Cairo, Lagos, Bangkok, Jakarta, Mumbai, Shanghai, Copenhagen, London, Los Angeles, New York, and Buenos Aires, among others.

In all, Guterres said that the danger is most acute for about 900 million people living in low-lying coastal areas. Some countries, particularly small island developing countries, could disappear entirely.

The world is already facing refugee crises related to politics, warfare, and extreme weather. The flood of refugees created by rising seas could be biblical in magnitude.

The confluence of climate change and global security is growing steadily. As the global body primarily responsible for maintaining international peace and security, the U.N. Security Council cannot duck this issue much longer. It has a critical role to play in building the political will required to address the security challenges looming from rising seas.

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Sea Level Rise Could Drive 1 in 10 People from Their Homes, with Dangerous Implications for International Peace, UN Secretary General Warns

Photo, posted July 19, 2021, courtesy of Face of the World via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon From 25 Cities | Earth Wise

September 10, 2021 By EarthWise Leave a Comment

There are roughly 10,000 cities in the world, defined as places with at least 50,000 inhabitants with a sufficient population density. Roughly half the world’s population lives in cities.

Urban carbon emissions are one of the world’s biggest problems with respect to the climate. A new study has determined that just 25 cities globally are responsible for 52% of urban greenhouse gas emissions.

The study gathered data on greenhouse gas emissions in 167 cities in 53 countries. The results were that megacities in Asia, such as Shanghai and Tokyo, were among the biggest total emitters, and that major cities in Europe, the US, and Australia tended to have larger per capita emissions. Several Chinese cities, however, matched levels seen in developed countries. Researchers tracked emissions over time in 42 of the cities studied. Some cities saw declining emissions in the period between 2005 and 2016. These included Oslo, Houston, Seattle, and Bogota. Others saw large increases, including Rio de Janeiro, Johannesburg, and Venice.

The largest sources of emissions are power generation, industry, and transportation. In a third of the cities, road transportation alone accounted for over 30% of emissions. (Railways, waterways, and aviation combined only accounted for less than 15% of total emissions).

Half of the world’s population lives in cities, but cities are responsible for more than 70% of greenhouse gas emissions. Thus, cities have a big responsibility for the decarbonization of the global economy. Of the 167 cities in the study, 113 have set emission-reduction targets. But as the study shows, cities have much more work to do to meet the goals of the Paris Climate Agreement.

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Two Dozen Large Cities Produce 52 Percent of Urban Carbon Emissions

Photo, posted December 1, 2017, courtesy of Hector Galbis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Rising Seas Will Erase Cities

December 18, 2019 By EarthWise Leave a Comment

According to new research, climate-driven sea level rise could affect three times more people by 2050 than previously thought. This sobering assessment means some of the world’s great coastal cities, including Bangkok, Shanghai, Mumbai, Basra, Alexandria, and Ho Chi Minh City, could be in big trouble.

Scientists have always relied on land elevation data to determine the effects of sea level rise over large areas. But standard elevation measurements using satellites struggle to differentiate the true ground level from the tops of trees or buildings. The authors of the paper developed a more accurate way to calculate land elevation by using artificial intelligence to determine the error rate and to correct for it. The new findings revealed that 150 million people – three times more than previously thought – are now living on land that is projected to be below the high-tide line by the middle of this century.

Eight Asian nations – China, Bangladesh, India, Vietnam, Indonesia, Thailand, the Philippines, and Japan – account for about 70% of the people living on at-risk land.

More than 20 million people in Vietnam, including much of Ho Chi Minh City, live on land that will be inundated by 2050. In Thailand, more than 10% of its citizens, including much of Bangkok, currently live on land imperiled by projected sea level rise.

This new research was produced by Climate Central, a New Jersey-based science organization, and was recently published in the journal Nature Communications.

Sea level rise is clearly not just an environmental problem. It’s a humanitarian crisis.

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