power grid

Powering Britain with sun and wind

November 8, 2023 By EarthWise Leave a Comment

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

A Huge American Lithium Discovery | Earth Wise

October 12, 2023 By EarthWise Leave a Comment

Human history has often been described in terms of a succession of metal ages: the copper age, the bronze age, and the iron age. In many ways, we have now entered the lithium age. The light metal goes into the batteries that power smartphones, electric vehicles, and massive storage banks for the power grid. Lithium has become a critical strategic resource.

As it stands now, the U.S. gets most of its lithium from imports from Australia and South America. Major lithium sources are not commonplace; in 2022 there were only 45 lithium mines in the world. Many of the known deposits are not in North America but in Chile, Bolivia, Argentina, China, and Australia. The current largest known lithium deposits lie beneath the salt flats of Bolivia.

Lithium Americas Corporation, a company dedicated to advancing lithium projects to the stage of production, funded research over the past decade that has identified vast deposits of lithium-rich clay in a dormant volcanic crater along the Nevada-Oregon border. The McDermitt Caldera is estimated to hold between 20 and 40 million tons of lithium, which would make it the largest deposit in the world.

There are many questions still to answer. It is not clear how easy it will be to extract lithium from the clay, in particular how expensive or carbon-intensive it will be. There are also political complexities since the area where the lithium deposit was found is considered to be unceded ancestral land for both the Paiute and Shoshone tribes.

Apart from a dearth of domestic sources of lithium, the US also lags well behind China in lithium processing capabilities. The country has catching up to do in the new lithium age.

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America Just Hit the Lithium Jackpot

Photo, posted April 19, 2020, courtesy of Ken Lund via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Storing Energy In Abandoned Mines | Earth Wise

October 10, 2023 By EarthWise Leave a Comment

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

July 19, 2023 By EarthWise Leave a Comment

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

Minimizing The Impact Of EVs On The Grid | Earth Wise

May 4, 2023 By EarthWise Leave a Comment

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

Solar Power At Night | Earth Wise

March 16, 2023 By EarthWise Leave a Comment

The use of solar power has grown tremendously in recent years as it has declined in price and become far more competitive with other forms of electricity generation. Its fundamental drawback, of course, is that it only works when the sun is shining. Solar panels don’t produce any power at night. That is, until now, apparently.

A team of engineers at Stanford University have developed a new kind of solar cell that is capable of generating at least some electricity at night. Published in the journal Applied Physics Letters, the research describes a device that can be a continuous renewable power source for both day and nighttime.

The device incorporates a thermoelectric generator that produces electricity from the small difference in temperature between the ambient air and the solar cell itself. The amount of power produced is far less than the solar cell generates from sunlight, but the device can provide nighttime standby lighting and power in off-grid and mini-grid applications.

Mini-grid applications are independent electricity networks that are used for small populations that may be too isolated to be connected to the main power grid. Nearly 600 million people in Africa currently live without access to electricity, primarily in rural areas. A standalone solar system operating independently of any power grid can meet many electricity needs such as phone charging and lighting, but such systems may not be able to handle large electrical need such as powering machinery and agricultural equipment. Mini-grids are larger installations that can provide power to a small rural community.

With innovations like the new Stanford device, a solar mini-grid may be able to keep running at some level even at night.

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Solar panels that can generate electricity at night have been developed at Stanford

Photo, posted December 15, 2021, courtesy of Pete via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Solar-Powered Target Store | Earth Wise

April 26, 2022 By EarthWise Leave a Comment

Many companies have made sustainability commitments of various types. Environmental organizations have urged big-box and grocery stores to install solar panels on their rooftops and parking lots thereby reducing their energy usage and expanding the country’s supply of renewable energy. These places occupy large areas and therefore are capable of supporting large solar arrays.

According to a report by two environmental advocacy groups, rooftop solar panels on retail stores could generate enough electricity to power the equivalent of nearly 8 million U.S. homes.

Target Stores are one of the retailers that has been making an effort to be a greener company. Target has installed solar panels on about 25% of its approximately 1,900 stores. The Target store in Vista, California, about 40 miles north of San Diego, is the company’s most sustainable store. It already had solar panels on its rooftop, powering a portion of the store.

But now it has installed massive carports topped with solar panels high above its parking lot. With these panels, this Target can now produce enough renewable energy to power the entire store, from its refrigeration to its heating and air conditioning. Adding in some of the other energy-saving features of the store, Target expects to produce 10% more energy than the store needs, which it will return to the local power grid. This is Target’s first net-zero energy store.

Target is not the only big retailer going solar. Home Depot, Lowe’s, and Walmart all have been installing solar panels on some of their rooftops. Even some restaurants are trying to reach sustainability goals with solar panels. This is a trend that hopefully will continue to grow.

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Target looks to massive solar panels in a California parking lot as a green model to power its stores

Photo, posted June 30, 2014, courtesy of Mike Mozart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

What’s The Best Way To Reduce Emissions? | Earth Wise

April 1, 2021 By EarthWise Leave a Comment

A carbon tax is a fee imposed on the burning of carbon-based fuels, like coal, oil, and gas. It’s one way to make the users of carbon fuels pay for the climate damage caused by releasing carbon dioxide into the atmosphere.

According to a new study by researchers at Ohio State University, putting a price on producing carbon is the cheapest and most efficient policy change that legislators can make in order to reduce climate change-causing emissions.

The case study, which was recently published in the journal Current Sustainable/Renewable Energy Reports, looked at the impact that a variety of policy changes would have on reducing carbon dioxide emissions from electricity generation in Texas. The researchers found that assigning a price to carbon, based on the cost of climate change, was most effective.

The study did not look at how policy changes might affect the reliability of the Texas power system, an important consideration after the failure of the state’s power grid following winter storms in February.

But the study did examine other policies and found that they were either more expensive or not as effective, including mandates that a certain amount of energy in a portfolio come from renewable sources. Subsidizing renewable energy sources was also found to be less effective.

According to researchers, market-based solutions have previously proven effective combating environmental issues. For example, a cap-and-trade approach was used to reduce levels of sulfur dioxide, one of the chemicals that causes acid rain.

For the sake of the climate, we should probably tax carbon.

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Want to cut emissions that cause climate change? Tax carbon

What’s a carbon tax?

Photo, posted June 5, 2011, courtesy of John Englart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Floating Solar Fuel Farms

September 20, 2019 By EarthWise Leave a Comment

Limiting global warming will require a massive reduction in CO2 emissions from fossil fuel burning. Renewable energy sources are playing a growing role in the power grid and electric cars are becoming increasingly popular. Despite all this, carbon-based liquid fuels will continue to dominate our energy use for the foreseeable future.

Researchers in Norway and Switzerland have described a potential scheme that would help remove CO2 from the atmosphere and produce a valuable liquid fuel.

The idea is to create floating islands containing large numbers of solar panels that convert carbon dioxide in seawater into methanol, which can fuel airplanes and trucks.

A combination of largely existing technologies would be the basis of these floating islands, which would be similar to present-day floating fish farms. The researchers envision clusters each composed of 70 circular solar panels that in total cover an area of roughly half a square mile. The solar panels would produce electricity, which would split water molecules and isolate hydrogen. The hydrogen would then react with carbon dioxide pulled from seawater to produce usable methanol.

The technology already exists to build the floating methanol islands on a large scale in areas of the ocean free from large waves and extreme weather. Suitable locations are off the coasts of South America, North Australia, the Arabian Gulf, and Southeast Asia.

A single floating solar farm could produce more than 15,000 tons of methanol a year – enough to fuel a Boeing 737 airliner for more than 300 round-trip flights across the country. Floating energy islands would not be a magic bullet for limiting the effects of climate change, but they could well be an important part of an overall strategy.

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