gravity

Gravity storage on the grid

June 4, 2024 By EarthWise Leave a Comment

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

Protecting coastal areas with tidal range electricity generation

February 13, 2024 By EarthWise Leave a Comment

Tidal range electricity generation uses the water level difference between high and low tides to operate generator turbines. The method requires the construction of barrages and sluices to capture water during high tides and then release it during generation at low tide. Tidal range generation is predictable renewable energy driven by the gravitational pull of the moon and sun.

It is only a practical scheme in those places that have large tidal ranges. The largest tidal range in the world is in the Bay of Fundy in Canada. The second largest is the Severn Estuary, in the UK. Tidal ranges are large in many places around Britain’s coasts. But they are also vulnerable to flooding and surges from rising seas.

A new study by Lancaster University in the UK has found that the environmental and economic benefits are huge because tidal range barrages can protect coastal areas from flooding and sea level rise. With two-way generation and pumping, the full range of existing tides can be maintained to protect and support low-lying intertidal areas such as saltmarshes and mudflats. High tides can be limited to existing levels simply by closing sluices and running turbines and low tide levels can be maintained by pumping. The study determined that with modern technology and operating procedures, these so-called estuarine barrages may be the only practical way to protect vital coastal habitats.

Earlier work by the researchers found that tidal range projects under commercial consideration in the UK can produce about 5% of the country’s electricity use and additional projects are feasible for 4 or 5 times as much generation.

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How tidal range electricity generation can protect coastal areas from flooding

Photo, posted August 17, 2014, courtesy of Andrea via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Disappearing Glaciers | Earth Wise

February 20, 2023 By EarthWise Leave a Comment

Glaciers are massive bodies of slowly moving ice. Glaciers form on land, and represent the snows of centuries compressed over time. They move slowly downward under the influence of their own weight and gravity.

Most of the glaciers on the planet are found in the polar regions, including Antarctica, the Canadian Arctic, and Greenland. Glaciers can also be found closer to the equator in mountain ranges, such as the Andes Mountain range in South America. Glaciers are always changing, accumulating snow in the winter and losing ice to melting in the summer. But in recent times, the melting has been outpacing the accumulation.

A new international study led by researchers at Carnegie Mellon University’s College of Engineering has produced new projections of glacier loss through the century under different emissions scenarios. According to the projections, the world could lose as much as 41% of its total glacier mass this century – or as little as 26% – depending on climate change mitigation efforts.

In a future with continued investments in fossil fuels (sometimes referred to as the “business as usual” scenario), more than 40% of the glacial mass will be gone by 2100, and more than 80% of glaciers by number could disappear. Even in a best case scenario where the increase in global mean temperature is limited to 1.5° degrees Celsius relative to pre-industrial levels, more than 25% of glacial mass will be gone, and nearly 50% of glaciers by number will disappear.

Glaciers take a long time to respond to changes in climate. A complete halt to emissions today would take anywhere from 30 to 100 years to be reflected in glacier mass loss rates.

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Team projects two out of three glaciers could be lost by 2100

Ice, Snow, and Glaciers and the Water Cycle

Photo, posted August 13, 2010, courtesy of Kimberly Vardeman via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Major Funding For Novel Energy Storage | Earth Wise

October 21, 2021 By EarthWise Leave a Comment

The accelerating adoption of wind and solar energy is driving a growing interest in energy storage technologies. An electric grid dominated by intermittent power sources will need large-scale energy storage. Grid-scale energy storage is expected to increase at least 10 times over the next decade and this will require nearly $300 billion in investments over that time period.

Much of the effort in energy storage has focused on battery storage. But there are other storage technologies that are attracting attention and investment.

Energy Vault is a Swiss-based company specializing in gravity and kinetic energy-based energy storage. Their technology uses a multi-headed crane to store energy generated by renewable sources by stacking heavy blocks made of composite material into a tower, capturing potential energy from the elevation gain of the blocks. To produce electricity, the crane lowers the blocks to the ground, driving generators in the process. The company has just raised $100 million in funding from investors.

Malta, Inc. is an energy storage company based in Cambridge, Massachusetts that is developing an electro-thermal energy storage system. Energy generated from renewable (or other) sources drives a heat pump to create thermal energy producing both hot and cold reservoirs. The heat is then stored in molten salt while the cold is stored in a chilled liquid. To generate electricity, the temperature difference between the two reservoirs is used to drive a heat engine. Malta has recently raised $60 million in new funding including significant support from Chevron Energy Ventures.

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Energy Vault Raises $100 Million In Series C Funding

Chevron backs long-duration thermal energy storage developer Malta

Photo, posted October 16, 2019, courtesy of Jonathan Cutrer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Giant Jellyfish | Earth Wise

August 28, 2020 By EarthWise Leave a Comment

There have been recent news stories about giant jellyfish washing ashore from Maine to the south coast of Massachusetts. These stories have claimed that some of these lion’s mane jellyfish have been the largest on record and even might be the largest animals in the ocean.

The truth of these accounts is rather suspect. For one thing, it is rather difficult to measure the size of a jellyfish when it is out of the water. Gravity compresses and spreads out the bell portion of the animal, and that makes up the bulk of its mass. For example, a jellyfish bell that measures four feet across on the beach would appear to be much smaller if the animal was floating in the water.

Some claims that lion’s mane jellyfish are larger than blue whales date back a full century and are very much disputable. The claimed size certainly included the animal’s long tentacles, and such things hardly compare with a blue whale.

In any event, the current spate of jellyfish sightings is not necessarily that unusual. Many factors influence jellyfish populations, including water temperature and food supply. It is possible that warming water temperatures may be influencing the jellyfish population this year, but there is not enough data to know for sure.

People do need to be cautious around lion’s mane jellyfish. They do sting and while their stings are not as bad as those of a number of other species, they can be a problem for people who have allergic reactions. Furthermore, the stinging cells remain active in a jellyfish that has washed ashore.

Sightings of these animals are continuing, and reports of larger specimens continue as well, even if they don’t compare with blue whales.

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Jellyfish larger than blue whales?

Photo, posted September 13, 2015, courtesy Derek Keats via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Storing Energy With Rocks

June 2, 2016 By WAMC WEB

Energy storage is hot topic because more and more electricity is being generated from renewable sources like solar power and wind power that can’t operate all the time because the sun doesn’t always shine and the wind doesn’t always blow. So we need ways to store surplus energy when it is produced and be able to use it later when it is needed.