refineries

Scrubbers to clean up shipping

May 1, 2025 By EarthWise Leave a Comment

Cargo ships are significant sources of global air pollution because of their fuel oil. Most ships burn heavy fuel oil that is loaded with sulfur, so when it is burned it produces noxious gases and fine particles that can harm human health and the environment. The International Maritime Organization enacted a mandatory cap of 0.5% for the sulfur content of marine fuels in 2020. Heavy fuel oil has a sulfur content of 2 to 3 percent.

Shipping companies can comply by burning low-sulfur fossil fuels or biofuels, but these are much more expensive. The most feasible and cost-effective option is to install exhaust gas cleaning systems, known as scrubbers.

A scrubber is a huge metal tank installed in a ship’s exhaust stack. Seawater is sprayed from nozzles to wash the hot exhaust. The seawater reacts with sulfur dioxide and converts it to sulfates, which are environmentally benign natural components in seawater.

A study by the National Technical University of Athens in Greece has performed a lifecycle assessment of the use of scrubbers and has found that burning heavy fuel oil with the use of scrubbers can match or even surpass the benefits of using low-sulfur fuels.

Producing low-sulfur fuel causes additional greenhouse gas and particulate matter emissions in refineries. On the other hand, scrubbers reduce sulfur dioxide emissions by 97% and dramatically reduce other pollutants as well.

The study shows the importance of incorporating lifecycle assessments into evaluation of environmental impact reduction policies.

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Study: Burning heavy fuel oil with scrubbers is the best available option for bulk maritime shipping

Photo, posted August 3, 2015, courtesy of Lotsemann via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Biofuel refineries and toxic pollution

July 5, 2024 By EarthWise Leave a Comment

There have been decades of government support for renewable, crop-based fuels – primarily corn ethanol. In fact, it is a required component of gasoline sold in this country. The biofuels industry has long claimed ethanol to be a clean, greener alternative to petroleum.

There have been arguments all along that the environmental benefits of corn ethanol are dubious at best because of the energy required to produce the stuff. There are also issues related to burning a food crop instead of feeding it to people and that the conversion of grasslands and forests to produce it releases massive amounts of carbon.

Recently, another serious concern has emerged. A new review of industry data has found that the country’s biofuel refineries, mostly located in the Midwest, produce large amounts of toxic air pollutants, in some cases ever more than from their petroleum counterparts.

Emissions data from the country’s 275 ethanol, biodiesel, and renewable diesel plants revealed that they release carcinogenic formaldehyde as well as other potentially dangerous substances including acetaldehyde, hexane, and acrolein. In 2022, biofuel refineries released 12.9 million pounds of hazardous air pollutants, compared to 14.9 million pounds emitted by oil refineries, and the biofuel plants actually emitted more of the four chemicals just mentioned than petroleum refineries did.

The broad use of crop ethanol is the result of intensive industry lobbying. Ethanol plants are even exempt from some air pollution permitting requirements. Perhaps the time has come to revisit its pervasive and mandated use.

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Biofuel Refineries Are Releasing Toxic Air Pollutants in Farm Communities Across the US

Photo, posted February 27, 2021, courtesy of Sue Thompson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

California renewable energy

June 12, 2024 By EarthWise Leave a Comment

California has aggressively pursued the use of renewable energy, particularly solar and wind power. Last year, renewables supplied 54% of the state’s electricity needs. This year, California has been achieving some remarkable milestones with its renewable energy.

As of May 26th, California had produced more than 100% of its electricity demand with wind, solar, and hydropower for parts of 51 straight days and 75 out of 81 days. On May 25th, California’s grid ran entirely on renewable energy for 10.1 straight hours and renewables provided 83% of the state’s electricity for the entire 24-hour period. California uses more electricity than any other state apart than Texas, which uses more than half its energy for operating refineries and petrochemical plants.

Excess power in California is either exported to other states or is used to charge up the state’s growing arrays of energy storage batteries. California has the largest grid-connected battery storage facility in the world, located in Kern County. The facility can store nearly 3,300 megawatt-hours of energy.

The ability to produce more power than the state needs occurs during the day when the sun is shining, and when many people are not at home. At night, demand goes up and solar power is not available. But as the quantity of energy storage available continues to grow along with additional solar installations, California will ultimately be able to wean off of the gas-fueled power plants it predominantly uses at night.

According to some experts, California may operate entirely on renewables and battery storage as soon as 2035.

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California exceeds 100% of energy demand with renewables over a record 30 days

Photo, posted January 11, 2016, courtesy of Jared Eberhardt via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Plants Paying For Biofuels | Earth Wise

May 7, 2020 By EarthWise Leave a Comment

Biofuels are an important element in broader strategies to replace petroleum in transportation fuels like gasoline, diesel, and jet fuel. The idea is that biofuels recycle carbon by getting it from growing plants rather than from fossil sources. The biggest problem with biofuels is that they cost more than conventional petroleum fuels, so there is economic incentive to keep burning the fossil fuels.

One strategy to make biofuels cost competitive is to have the plants provide additional economic benefits beyond being a feedstock for fuel. This in principle can be done by engineering plants to produce valuable chemical compounds, or bioproducts, as they grow. Bioproducts include such things as flavoring agents and fragrances as well as biodegradable plastic. These bioproducts can be extracted from the plants and then the remaining plant material can be converted to fuel.

Researchers at Lawrence Berkeley National Laboratory recently published a study to determine what quantities of bioproducts plants need to produce to result in cost-effective biofuel production.

The study looked at a compound called limonene, which is used for flavoring and fragrance. They calculated that if this compound was accumulated at 0.6% of the biomass dry weight, it would offer net economic benefits to biorefineries. This corresponds to recovering 130 pounds of limonene from 10 tons of sorghum on an acre of land.

Such quantities are completely practical but, on the other hand, none of these substances are needed in huge quantities. Just six refineries could supply the world with limonene. So, fuel crops would need to be engineered to produce a broad range of bioproducts to enable a viable cost-effective biofuel industry.

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Making Biofuels Cheaper by Putting Plants to Work

Photo, posted September 28, 2019, courtesy of Michele Dorsey Walfred via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Cleaner Air For China

December 5, 2018 By EarthWise Leave a Comment

For more than 15 years, the Chinese government has been grappling with some of the deadliest air pollution in the world. Extreme pollution events are a regular wintertime occurrence and health experts estimate that more than a million people die each year in China from particulate air pollution.

Too Much Of A Good Thing

June 10, 2016 By WAMC WEB

Germany has continued to be the most aggressive adopter of renewable energy among large industrial nations. The country has the goal of shifting to 100% renewables by 2050. Its continuing embracing of solar and wind generation resources over the past decade has resulted in renewables supplying a third of the country’s power on average.