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Storing CO2 Underground | Earth Wise

February 19, 2020 By EarthWise Leave a Comment

Capturing the carbon dioxide emitted from power plants and factories and safely storing it so it can’t enter the atmosphere has long been an attractive and desirable goal. Even though the use of renewable energy sources has been expanding rapidly, it will still be a long time before fossil fuel plants go away entirely.

The most widely considered method of carbon capture and storage is underground storage. The idea is to send the carbon dioxide through a pipeline to a place where underground rock formations can store it safely and permanently. Typically, it would be pumped deep underground – often more than half a mile down – and the site would be monitored to make sure the CO2 doesn’t leak back up to the atmosphere or into the water table.

A new study looked at how much carbon dioxide the suitable geological formations on Earth can store. The conclusion of the study is that drilling about 12,000 carbon storage wells globally could provide enough capacity to store 6 to 7 billion tons of CO2 a year by 2050. That is about 13% of global emissions.

Drilling 12,000 wells is equivalent to the amount of oil and gas drilling that has taken place just in the Gulf of Mexico over the last 70 years. The study identified locations worldwide that could handle the pressures associated with storing injected carbon dioxide.

So far, less than two dozen projects exist that capture and store carbon dioxide from fossil fuel plants. In total, these plants can capture about 36 million tons a year, which is far less than what is needed. But the new study at least shows that finding places to put captured carbon is not a problem.

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Ample Geological Capacity Exists to Store Large Quantities of Captured CO2

Photo courtesy of Equinor.

Earth Wise is a production of WAMC Northeast Public Radio.

A New Way To Remove CO2 From The Air

December 13, 2019 By EarthWise Leave a Comment

Researchers at MIT have developed a new way of removing carbon dioxide from a stream of air that could be a powerful tool in the battle against climate change. The new system can pull carbon dioxide out of almost any concentration level of the gas, even including the roughly 400 parts per million level currently found in the atmosphere.

The technique is described in a new paper in the journal Energy and Environmental Science and is based on passing air through a stack of electrochemical plates. The device is essentially a large battery that absorbs carbon dioxide from the air passing over its electrodes as it is being charged up, and then releases the gas as it is being discharged.

To use it, the device would simply alternate between charging and discharging. Fresh air or some other feed gas would be blown through the system during the charging cycle and then pure, concentrated carbon dioxide would be blown out during discharging.

The specialized battery uses electrodes coated with a compound called polyanthraquinone, which is composited with carbon nanotubes. These unique electrodes have a binary affinity to carbon dioxide, which means that they either strongly want to capture carbon dioxide or not at all, depending upon whether the device is charging or discharging.

Carbon dioxide is important in many industries such as soft drinks and greenhouse agriculture. With this device, the stuff could literally be pulled out of the air. And, of course, in power plants where exhaust gas is dumped into the air, these novel electrochemical cells could be used to prevent the emission of CO2 into the atmosphere. At the right price, this could be a game changer.

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MIT engineers develop a new way to remove carbon dioxide from air

Photo, posted August 9, 2007, courtesy of William Clifford via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Air Quality In The U.S.

November 13, 2019 By EarthWise Leave a Comment

Globally, poor air is a serious problem. According to the World Health Organization, exposure to air pollution is linked to the premature deaths of an estimated 7 million people every year. In fact, 91% of the people on the planet live in places where air pollution exceeds WHO guideline limits.

In the United States, air pollution has dramatically improved over the last four decades due in large part to federal regulations put in place under the Clean Air Act of 1970. Fine particulate matter (known as PM2.5) and other pollution, including ozone, sulphur dioxide, and nitrogen dioxide, have all decreased during this time span.

But according to recent research, this trend has unfortunately done an about-face. New data reveals that air pollution has increased nationally since 2016. An analysis of Environmental Protection Agency data by researchers at Carnegie Mellon University found that, on average, fine particulate pollution increased 5.5% across the country between 2016 and 2018.

This increase in fine particulate pollution was associated with nearly 10,000 additional premature deaths in the United States during that time period.

According to researchers, there are several factors likely causing this uptick in unhealthy air, including increases in both driving and the burning of natural gas. Wildfires out west are also thought to be a major contributor.

The researchers also suggest that a decrease in enforcement of the Clean Air Act may also be playing a role. The law put in place strict air pollution standards for vehicles, factories, power plants, and other sources, and is credited with saving hundreds of thousands of lives.

It’s time for clean air to be recognized as a basic human right.

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America’s Air Quality Worsens, Ending Years of Gains, Study Says

Photo, posted April 6, 2007, courtesy of Brett Weinstein via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Compressed Air Energy Storage

October 23, 2019 By EarthWise Leave a Comment

The increasing use of solar and wind power has created a growing need for technology to store up the energy they generate for use when it is most needed.

Historically, pumped hydropower has provided the largest amount of storage capacity, but it is limited to only certain geographic locations. Battery energy storage has been growing rapidly, with the technology becoming better and cheaper over time. But there are various other ways to store energy that have potential and may well find their place in the changing energy infrastructure.

One of these is compressed air energy storage, which has been around for more than a century. It has been used as a backup method for restarting power plants. But to date, the economic viability of using it at a large scale has been lacking.

A Canadian startup company called Hydrostor is developing compressed air energy storage technology that it believes can be used on a utility scale.

The way it works is excess renewable energy is used to run compressors that compress air. Compressing the air heats it up and the heat is captured and stored in insulated hot water tanks. The compressed gas is then injected into underground caverns. When energy is needed, the compressed air is released, the stored heat is added, and the warmed gas is run through turbines to generate electricity. Additional features improve the system’s efficiency.

Hydrostore has built a 1 MW pilot project in Ontario, Canada and is now commissioning a 2MW system as well. It is funded to build a 5 MW system in Australia next year and it is bidding for 300 MW and 500 MW systems in North America. The company has received equity funding from Baker Hughes, a large oil-and-gas services and equipment company.

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Storing energy in compressed air could finally become cheap enough for the big time

Photo courtesy of Hydrostor.

Earth Wise is a production of WAMC Northeast Public Radio.

Cleaner Air Saves Lives

September 25, 2019 By EarthWise Leave a Comment

A new study by Columbia University has concluded that lower air pollution levels saved an estimated 5,660 lives in New York State in 2012, compared to 2002 mortality levels.

The study looked at New York State levels of the specific type of pollution known as fine particulate matter, referred to as PM2.5. These microscopic particulates are a mixture of solid particles and liquid droplets that either come from burning fuel or are formed in the atmosphere as a result of complex reactions of chemicals such as sulfur dioxide and nitrogen oxides from power plants, industries, and automobiles.

Long-term exposure to PM2.5 can lead to respiratory and cardiovascular problems.

The study looked at extensive amounts of data to analyze trends in PM2.5 levels across New York State. The data showed that PM2.5 levels dropped by 28 to 37% between 2002 and 2012. This was a result of continued progress in cleaner vehicles, the reduction of high sulfur-dioxide emitting coal-burning power plants, and other air pollution reduction programs. They calculated that this amount of reduction in PM2.5 reduced the air pollution mortality burden for New York State residents by 67% – from 8,410 premature deaths in 2002 to 2,750 deaths in 2012.

The study provides evidence that emission controls on air pollutants – which were initiated by the Clean Air Act of 1970 and later expanded in 1990 – have improved public health across New York State. According to the researchers, the study is a key step to documenting the health benefits from cleaner air.

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Air Pollution Cuts Are Saving Lives in New York State

Photo, posted June 29, 2014, courtesy of Paul Comstock via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Falling U.S. Carbon Emissions

September 16, 2019 By EarthWise Leave a Comment

Reducing carbon emissions is a goal embraced by nearly every country in the world, but actually accomplishing it isn’t easy. It is true that renewable energy sources are playing a growing role in energy systems, but counterbalancing that trend is growing energy demand, especially in developing countries.

Here in the US, energy-related CO2 emissions actually went up nearly 3% in 2018 compared with 2017. But the US Energy Information Administration is now forecasting a 2% drop in emissions this year.

The main reason energy-related emissions are headed lower at this point is coal-fired power plant retirements. More than 90% of the coal used in the US goes toward electric power and utilities are increasingly turning away from coal.

The rapid shift away from coal has mostly been due to the increasing use of natural gas. Natural gas is not actually a clean and green fuel, but it is definitely less carbon-intensive than coal. Overall, the total installed capacity of renewable sources – hydropower, wind, solar, geothermal, and biomass – has now actually surpassed the capacity of coal plants. Given that renewables have in many places become the cheapest power option, there is little chance that coal has much of a future, despite efforts by the current administration.

The electric power sector is gradually moving away from all carbon-emitting sources – a trend that is being reinforced by legislation in many states. The real CO2 emissions leader is petroleum, which accounts for nearly half of the total. We have a long way to go to reduce emissions from the use of petroleum. There are over 250 million cars and trucks on US roads and only a little over a million of them don’t burn fossil fuels.

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Photo, posted November 6, 2017, courtesy of Cindy Shebley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Meeting Climate Goals With Current Energy Infrastructure

September 2, 2019 By EarthWise Leave a Comment

The Paris Climate Agreement set forth a goal to keep global warming below 2 degrees Celsius as well as a more optimistic (and preferable) goal of keeping the temperature rise to less than 1.5 degrees. Reaching either of these goals requires getting to net-zero emissions by the middle of the century.

A new paper, published in Nature, looks at the issue of whether existing power plants and other fossil-fuel-burning equipment (including vehicles) can continue to operate until they age out of functionality, or whether they need to be retired early.

The results of the study are that future emissions from existing facilities would take up the entire carbon budget needed to limit warming to 1.5 degrees Celsius and almost 2/3 of the budget needed to keep warming below 2 degrees over the next 30 years.

So, the good news is that we can still avoid a 2-degree rise without having to shut down all the existing power plants early. But we would definitely have to stop building new things with smokestacks and tailpipes that dump CO₂ into the atmosphere.

That good news is tempered by the fact that the number of fossil fuel-burning power plants and vehicles in the world has increased dramatically over the past decade, spurred by rapid economic and industrial development in China and India. In fact, China is predicted to produce more than 40% of all the carbon emissions over the next 30 years.

The 2-degree climate goal is not at all the most desirable result. The 1.5-degree target would be far better for the climate. But if the world is to achieve it, there will be dramatic changes needed in the existing infrastructure – either shutting it down or retrofitting it to drastically reduce emissions.

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Two-Degree Climate Goal Attainable Without Early Infrastructure Retirement

Photo, posted March 5, 2010, courtesy of Tennessee Valley Authority via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Shutting Down Minnesota Coal Plants

July 8, 2019 By EarthWise Leave a Comment

One of the largest utilities in the United States, Xcel Energy Inc., announced that it will close its remaining coal-fired power plants in the Upper Midwest a decade ahead of its previously-announced schedule. In addition, the company will add 3,000 megawatts of new solar capacity by 2030.

The Allen S. King plant in Oak Park Heights, Minnesota and the Sherburne County Generating Station in Becker, Minnesota are the plants in question. The transition away from coal is a difficult challenge for such small communities. The plant in Becker, for example, employs 300 people in a town of 4,500 and provides 75% of the city’s tax base. Towns like this realize that coal is inevitably going away and must find ways to move beyond their dependence upon it. The Becker plant will not completely close until 2030, but parts will now only run seasonally, and one of the 3 units will close permanently in 2023

Xcel Energy, based in Minneapolis, serves more than 3.3 million electricity customers in 8 states. Last December, the company announced that it would deliver 100% clean, carbon-free electricity by 2050 and would achieve an 80% carbon reduction from its 2005 levels by 2035. It is the first major US utility to set such a goal.

Xcel will increase its investment in energy efficiency measures, bring 1,850 megawatts of new wind capacity online in Minnesota by 2022, and keep its Monticello Nuclear Generating Station operating until 2040, a decade later than planned. The company’s stepped-up clean energy strategy is part of a new legal settlement between the company, environmental organizations, and labor groups that involves Xcel’s proposed $650 million purchase of a 760-megawatt natural gas plant.

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A Major U.S. Utility Is Closing Its Coal-Fired Power Plants a Decade Early

Photo, posted January 3, 2016, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Giant Solar Farm In Dubai

June 26, 2019 By EarthWise Leave a Comment

Like many places in the Middle East, Dubai made its fortune from oil. But the Emirate’s oil resources are limited, and its economy has evolved in other directions. Today, oil provides less than 5% of Dubai’s revenues; its economy relies on revenues from trade, tourism, aviation, real estate, and financial services.

Dubai is also away from fossil fuels to meet its energy needs. A monumental construction project is underway deep within Dubai’s desert interior which will be the largest solar energy facility in the world.

The Mohammed Bin Rashid Al Maktoum Solar Park – named after Dubai’s ruler – has been under development for 7 years. Total investment in the project will be nearly $14 billion when it is completed in 2030. It will have a total capacity of 5,000 megawatts, enough to power 1.3 million homes. Only some large hydroelectric power plants, the largest nuclear power plants, and a couple of Asian coal plants have more generating capacity.

Phases one and two of the project are already complete and feature more than 2 million solar panels. Phase three – well along the way in construction – will add another 3 million solar panels and should be completed next year.

Phase four will not involve solar panels but instead will make use of the world’s tallest concentrated solar power tower. It will use mirrors to focus sunlight at the top of the tower to heat up molten salt that will power steam turbines to generate electricity and will be able to operate long after the sun goes down.

Currently, the Tengger Desert Solar Park in China is the largest photovoltaic park in the world, but a colossal farm in India will take its place in a few years. Big solar is getting bigger all the time.

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$13.6B record-breaking solar park rises from Dubai desert

Photo, posted December 15, 2018, courtesy of Anoop S. via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Coal Isn’t Even Cheap Anymore

May 15, 2019 By EarthWise Leave a Comment

Coal has historically been very cheap compared with many other energy sources and the reason is that it is so plentiful. The United States has especially abundant quantities of the stuff – perhaps a quarter of the world’s estimated recoverable reserves. Estimates are that at the rate at which we are currently using coal here, the remaining reserves would last about 325 years.

That would be great, of course, if the use of coal was not relentlessly destructive to the environment, hazardous to human health, and a major driver for global warming. Despite all of that, the Trump administration is a big booster of coal.

But coal has little chance of holding on to its current status, much less having some kind of renaissance. According to a new report from renewables analysis firm Energy Innovation, nearly 75% of coal-fired power plants in the United States generate electricity that is more expensive than local wind and solar resources. Wind power, in particular, can at times provide electricity at half the cost of coal.

Wind and solar power are growing by leaps and bounds. The Guardian reported that by 2025, enough wind and solar power will be generated at low enough prices in the U.S. that it could replace 86% of the entire U.S. coal fleet with lower-cost electricity.

It has been known for some time that there are places where the so-called coal crossover has already taken place. But this is actually far more widespread than previously thought. Substantial coal capacity is currently at risk in North Carolina, Florida, Georgia and Texas. By 2025, Indiana, Michigan, Ohio, and Wisconsin will join their ranks.

The biggest threat to coal is not regulators or environmentalists; it is economics.

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Renewables Cheaper Than 75 Percent of U.S. Coal Fleet, Report Finds

Photo, posted May 1, 2011, courtesy of Alan Stark via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Lots Of Renewable Energy In Germany

April 29, 2019 By EarthWise Leave a Comment

As the contributions to the electrical grid from renewable sources continue to rise, people have expressed concerns about what might happen as sources like wind and solar energy become dominant. Not many years ago, there was a common concern that if wind and solar contributed more than about a quarter of the energy mix, the grid might become unstable or unreliable. Theoretical models looked at this situation but there hadn’t been much real-world data to look at.

One place where there is now real-world data on a large scale is Germany. Germany has been aggressively deploying both wind and solar energy for years as part of a national initiative called the Energiewende or energy transition. Germany recently increased its renewable energy goal from 55% to 65% by the year 2030. The increased share of renewables takes into account the decommissioning of aging nuclear and coal power plants.

A demonstration of the feasibility of such a goal occurred in the first week of March when renewable sources actually supplied nearly 65% of Germany’s electricity. Wind power alone provided nearly half of the country’s power. As a result, fossil fuel plants ran at a minimum output and nuclear facilities were shut down at night.

Germany has a very large domestic coal industry and indeed lignite coal generated an average of 24% of the country’s power last year. However, recently that share was down to just 12%. During that first week of March, solar power contributed more than 5% of Germany’s electricity, biomass 7.6%, and hydropower 3.5%.

While the week with 65% renewable set a record, the ongoing trend is very positive as well. In 2018, renewable energy generated an average of more than 40% of Germany’s electricity.

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Renewables Generated a Record 65 Percent of Germany’s Electricity Last Week

Photo, posted April 28, 2012, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Growing Rocks To Store Carbon

April 24, 2019 By EarthWise Leave a Comment

The US Geological Survey recently published a comprehensive review of geological carbon storage in sedimentary rocks through carbon mineralization. That is the process by which carbon dioxide becomes a solid mineral, such as a form of carbonate. Certain rocks undergo a chemical reaction when exposed to carbon dioxide and turn into different minerals as a result.

The idea is to use carbon mineralization as a way to permanently store carbon dioxide that has been captured from power plant emissions, other industrial activities, or even directly from the atmosphere.

Two basic approaches are injecting the CO2 deep underground or exposing it to crushed rocks at the surface. The two types of rock best suited for mineralization through injection are basalt and various ultramafic rocks. Pilot studies have shown that injection into basalt can lead to mineralization in under two years.

Exposing carbon dioxide to crushed rock at the surface generally makes use of crushed mining waste. Mineralization can be much faster in this case because there is more surface area on the crushed rock where mineralization occurs. (However, the quantities of rock available at the surface are much less than what exists deep underground).

Like all carbon capture and storage approaches, the key consideration is cost. The USGS study estimates that underground injection would cost around $30 per metric ton of CO2. The crushed rock approach might only cost $8 per metric ton, but that assumes the crushed rock is already available. If it must be newly mined, the costs would obviously go up significantly. To put this into perspective, a typical car produces around 4 metric tons of CO2₂ per year. So, it would cost somewhere between $30 and $120 a year to eliminate the emissions from one car. Perhaps that is a price we need to pay until we ditch gasoline cars.

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How Growing Rocks Can Help Reduce Carbon Emissions

Photo, posted October 17, 2011, courtesy of Glen Bledsoe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Changing Face of Electricity

March 15, 2019 By EarthWise Leave a Comment

The New York Times recently published an article on how electricity is made in the United States on a state-by-state basis and how it has been changing over the past two decades. Two conclusions to draw are that the mix of energy sources is wildly different from one state to another and that the mix has been changing rather dramatically in many places.

Overall, the past two decades have seen the dramatic rise in the use of natural gas and a dramatic drop in the use of coal. Coal plants used to account for over half of the electricity produced in the U.S. at the turn of the 21st century. Now natural gas has passed coal as the largest energy source at roughly 1/3 of the total generated.

Switching from coal to natural gas is a good thing since modern gas power plants emit only about half the carbon dioxide as modern coal plants. But industry spin about “clean gas” is just spin. Gas is not really clean; it is just cleaner than coal. So, having the electric grid powered by gas is not really going to solve our emissions problems.

That being said, there are still states that make nearly all their electricity with coal. Indiana, Kentucky, Missouri, Utah, Wyoming, and West Virginia are on that list. Meanwhile, Delaware, Massachusetts, Mississippi, Nevada, and Rhode Island are powered mostly by gas. Idaho, Oregon, Washington, and Vermont rely heavily on hydropower.

Newer renewables like solar and wind are starting to make major contributions in many states. Wind contributes only 6% nationwide but is much bigger in places like Iowa, Kansas, Minnesota, the Dakotas, Oklahoma and Texas.

The face of electricity continues to change.

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