Tag Archives: biomass

A new study on biomass fuel says smoke is more damaging to lungs than we assumed

Biomass cooking fires can incur “considerable damage” to the lungs of people who use them, a new study reveals. This effect is caused by “dangerous concentrations” of pollutants and bacterial toxins released during the burning of plant matter.

A biomass-fueled kitchen of one of the participants.

Roughly 3 billion people the world over still use biomass fuel for cooking, such as dry brush. This is making a significant contribution to the number of deaths related to household air pollution — an estimated 4 million annually. Governments around the world have launched projects to support the transition towards cleaner cooking fuels, such as liquefied petroleum gas, but economic and social factors, alongside faulty education on the benefits of this transition, means that many fires still burn on wood or brush.

Smokey issues

“It is important to detect, understand and reverse the early alterations that develop in response to chronic exposures to biomass fuel emissions,” said study co-author Abhilash Kizhakke Puliyakote, Ph.D., a postdoctoral researcher from the University of California San Diego School of Medicine.

The team used computer tomography scanners to analyze the lungs of 23 people who cook with wood biomass fuels or liquefied gas from Thanjavur, India. They also took air samples from their homes (which they used to measure pollutant concentrations there) and studied the lung function of the participants through traditional testing methods (such as spirometry). The scans were used to make quantitative measurements, so the team would, for example, take a scan when a person inhaled and another one when they exhaled, so they could measure the difference.

All in all, those who cooked with wood biomass were routinely exposed to higher levels of pollution and bacterial endotoxins. They also showed a much higher quantity of air trapping in their lungs, which is associated with lung diseases. Among the group, some participants had very high levels of air trapping and also showed abnormal tissue mechanics in their lungs, even when compared to their peers. This subgroup (around 30% of all biomass-burners) had more than 50% of the air they inhaled ending up trapped in their lungs.

“Air trapping happens when a part of the lung is unable to efficiently exchange air with the environment, so the next time you breathe in, you’re not getting enough oxygen into that region and eliminating carbon dioxide,” Dr. Kizhakke Puliyakote said. “That part of the lung has impaired gas exchange.”

“This increased sensitivity in a subgroup is also seen in other studies on tobacco smokers, and there may be a genetic basis that predisposes some individuals to be more susceptible to their environment”.

Smoke tended to affect the small airways of the lungs of participants, the authors explain, although the exact process is not yet clear. The study focused on cooking and biomass-fueled fires, but the findings are applicable to smoke from any source. Furthermore, the authors say that conventional testing has underestimated just how damaging smoke is to the lungs.

“The extent of damage from biomass fuels is not really well captured by traditional tests,” Dr. Kizhakke Puliyakote said. “You need more advanced, sensitive techniques like CT imaging. The key advantage to using imaging is that it’s so sensitive that you can detect subtle, regional changes before they progress to full blown disease, and you can follow disease progression over short periods of time.”

It is “crucial” for anyone who is exposed to biomass smoke for any extended duration to have a complete assessment of lung function by healthcare professionals to ensure that any potential injury can be resolved with appropriate interventions,” he adds. With the blaze of wildfires we’ve seen this year, this probably means that many, many people need to get their lungs checked.

The findings have been presented at RSNA 2020 – Radiological Society of North America Annual Meeting in Chicago.

Redwood National Park

Curbing climate change: carbon storage is good, forests are oft-times better

Carbon capture can definitely help our efforts of curbing climate change — but in many areas, we may be better off by simply maintaining forests, a new paper suggests.

Redwood National Park

Redwood National Park, California.
Image via Pixabay.

By now, we’re pretty well committed to a future that includes one degree (pun intended) or another of climate change. Carbon dioxide (CO2) takes a while — hundreds of years — to break down in the atmosphere. Even if we were to stop all emissions right now, future generations will still feel the effects of these gases in shifting climate, changing ocean patterns, and their ecological implications.

With this in mind, one idea has been bounced around with increasing optimism: carbon capture. The term broadly refers to technologies that can suck up CO2 and then lock it out of the atmosphere. One particular form of this tech, biomass energy with carbon capture and storage (or ‘BECCS’), has garnered a lot of optimism. BECCS-type approaches propose the use of crops to capture CO2 out of the atmosphere; these crops are later used to fuel power plants, and the resulting CO2 is stored underground, in bedrock.

It’s like having your CO2 and storing it too. Which is ideal.

However, BECCS may not be the silver bullet many people hope it to be, a new paper reports. While it sounds nice on paper, in practice BECCS power stations could end up increasing the levels of CO2 in the atmosphere, the authors warn.

Between a rock and a hot place

The study shows that for BECCS to have a meaningful impact on CO2 levels in the atmosphere, we’d need to convert massive expanses of land into fields to grow crops. In wooded areas, this ends up as a net-carbon-positive affair — replacing forests with crops would actually leave more CO2 in the atmosphere than doing nothing.

Carbon flow diagram.

Diagram stylizing carbon flow for different types of energy generation. ‘Up’ symbolizes emissions to the atmosphere, ‘down’ symbolizes storage. A forest only stores carbon.
Image credits Elrapto / Wikimedia.

With this in mind, the team reports that protecting and regenerating forests is a better option than BECCS in many cases.

“The vast majority of current IPCC scenarios for how we can limit global warming to less than 2°C include BECCS,” said lead author Dr. Anna Harper, from the University of Exeter (UoE).

“But the land required to grow biomass in these scenarios would be twice the size of India”.

The team used a cutting-edge computer model known as IMAGE to gauge how levels of greenhouse gases will evolve in the atmosphere over time. The model takes into account factors such as global vegetation and soils, but also factors such as economics, energy policy, resource availability, population dynamics, or climate change projections.

They then ran scenarios of land use that would be required to stabilize climate at less than 1.5°C and 2°C over pre-industrial levels, respectively. In areas where these crops would replace forests, BECCS-style approaches would actually increase the levels of CO2 in the atmosphere, they report.

“In some places BECCS will be effective, but we’ve found that in many places protecting or regenerating forests is much more sensible,” says co-author Dr. Tom Powell, also at the UoE.

“Carbon removed from the atmosphere through BECCS could easily be offset by losses due to land-use change. If BECCS involves replacing high-carbon content ecosystems [e.g. forests] with crops, then afforestation/reforestation and avoided deforestation are often more efficient for atmospheric CO2 removal over this century than BECCS,” the paper explains.

No universal solution

The effectiveness (or ineffectiveness) of BECCS in climate-change-mitigation relies upon the relative change in CO2 carbon capacity compared to the previous ecosystem — i.e. how much or how much less CO2 is saved this way. This, in turn, is built on several factors: the choice of crop grown for fuel, the gain or loss of carbon due to the change in ecosystem — i.e. what we do with the plants that used to grow in an area –, how well the system can store the CO2 it produces, and the level of fossil-fuel emissions it replaces from the grid.

Bituminous coal.

This chunk of bituminous coal (5.5 cm / 2 in across) was formed from ancient plants. When we burn it, we release the carbon it stores as CO2. BECCS-type installations capture and burn CO2 that’s already in the atmosphere.
Image credits James St. John / Flickr.

In other words, while it may not be the right choice for many areas now, future improvements in BECCS technology can change this. The team didn’t set out to demonize the process. Rather, they wanted to show that we need to apply some discretion in regards to which areas we devote to BECCS-type systems. And, at the same time, that we cannot rely solely on carbon capture to solve our problem.

“Our paper illustrates that the manipulation of land can help offset carbon dioxide emissions, but only if applied for certain, quite specific locations,” says co-author Chris Huntingford, a Professor at the UK Centre for Ecology and Hydrology.

“To meet the climate change targets from the Paris agreement, we need to both drastically reduce emissions and employ a mix of technologies to remove carbon dioxide from the atmosphere,” adds Dr. Harper.

“There is no single get-out-of-jail-free card.”

Which is solid advice in all areas of life, not just climate change.

BECCS and forests?

Given that BECCS-type systems scrub CO2 out of the atmosphere, and that forests store a lot more carbon than regular crops, I asked the team whether we couldn’t merge the two for a super-duper carbon removal system. In my mind, we could grow forests in lieu of crops, and then use the wood for fuel. It sounds sweet in theory, right? I thought so too.

Just as I was waiting to be handed a diploma, Dr. Harper sadly informed me that my fail-proof plan is quite fallible. Forests simply take much more time to grow compared to regular crops.

However, pre-existing forests have already scrubbed a lot of carbon while growing, she told me, so maintaining their health and integrity would effectively keep that carbon out of the atmosphere. Furthermore, fully-fledged forests contain a lot of biomass, which means there are many (and large) roots to feed. They lap up much more CO2 out of the atmosphere than a simple fuel crop could. Proper management and conservation would only see this scrubbing potential increase — and, for many parts of the world, it would simply outshine any benefits BECCS-type processes can bring to the table.

“An important point is that the carbon benefit from forests often comes from existing forests, underlining the value of maintaining present-day forests and avoiding deforestation,” Dr. Harper explained for ZME Science in an email.

“Even with more optimistic yet realistic assumptions [about the yield of crops and the efficiency of the BECCS process] there are still about 35-40% of the locations where [maintaining forests is] a better option.”

BECCS-type ventures would make sense in areas that either lack forests today, or those whose forests aren’t lush enough to capture more CO2 than a simple fuel-crop would.

BECCS-forest comparison.

The difference in total carbon stocks (including accumulated storage via BECCS) by the year 2100 on grid cells where the two scenarios have conflicting land­use change. Blue areas indicate more carbon stored with BECCS and red areas indicate more carbon stored by forests under two land use scenarios.
Image credits Harper et al., 2018, N.Comms.

There is, however, one clear advantage of carbon capture over forests — security. One of the effects of climate change is an increased rate of wildfires, spurred on by higher average temperatures and shifting patterns of precipitation. A paper recently published by researchers from the University of California, Davis suggests that this increased occurrence of wildfires effectively turned the forests of California from carbon sinks into carbon sources. Dr. Harper agrees with the point raised by the authors but, instead of giving up on forests entirely, she says we should double-down on our efforts to keep them from burning down.

“I saw that paper recently, and it’s a good point — carbon stored in forests is not guaranteed to stay there. I would say this highlights the point that we need to manage forests if they are being grown for carbon dioxide removal so we can increase the likelihood that the carbon will stay out of the atmosphere.”

“The decision between growing crops, maintaining forests, or growing new forests will always be very location-specific and there’s not one answer that applies everywhere. That study was based on California where the climate lends itself to fires (as we are seeing now, unfortunately), and in those regions it probably doesn’t make sense to invest lots of money into growing a forest,” she concludes.

Asked whether vertical farms could help provide space for fuel crops while maintaining forest integrity, Dr. Harper replied that the current paper doesn’t take such installations into consideration — but that it would be “really interesting to evaluate” their potential in this role.

The paper “Land-use emissions play a critical role in land-based mitigation for Paris climate targets” has been published in the journal Nature Communications.


Flying insect biomass decreased by 75 percent over 27 years in nature reserves

Dutch researchers at Radboud University report that over the last 27 years, flying insect biomass has plummeted by 75 percent in Germany. The findings serve as a wakeup call given the current climate of accelerating decline in insect populations reported all over the world.


Credit: Pixabay.

Insects, be them land loving or wing buzzing, are essential to ecosystem functioning and health. They’re responsible for pollinating 80 percent of wild plants and provide food to a wide range of species, including 60 percent of all birds. Previously, scientists have identified a pattern of decline in insect diversity and populations. These studies, however, tend to focus on single species or taxonomic groups, which can fail to grasp the bigger picture.

Caspar Hallmann and colleagues at Radboud took a different route by assessing flying insect biomass, which indicates if the number of insects in a given area rose or fell, regardless of the species involved. The team measured flying insect biomass collected using Malaise traps from 63 natural reserves in Germany over 27 years. Malaise traps were deployed through the spring, summer, and early autumn, operating day and night. The catch was emptied at regular intervals, on average every 11.2 days.

The team found that flying insect biomass declined by 76 percent on average in just 27 years and by up to 82% in midsummer. The dramatic decline took place everywhere, regardless of the habitat type. Land use or changes in weather could not alone explain the steep drop in insect biomass. These depressing figures underscore how the entire flying insect community has been decimated over the last few decades, as reported previously by papers which found declines in vulnerable species such as butterflies, wild bees, and moths.

A malaise trap in a nature protection area in Germany. Credit: Hallmann et al (2017).

A malaise trap in a nature protection area in Germany. Credit: Hallmann et al (2017).

Since 2006, honeybee populations have drastically declined at the hand of a peculiar phenomenon called colony collapse disorder (CCD). Today, most bee species are in decline, with annual regional losses as high as 60 percent. Nobody is completely sure what causes CCD, but studies seem to point towards neonicotinoid pesticide use. Earlier this month, researchers reported that neonicotinoids were found in 75 percent of honey samples collected from all over the world.

Monarch butterfly populations have also been declining significantly, reaching the lowest count ever recorded during 2013-14 as a result of habitat loss, particularly the loss of milkweed (the species’ only food source), and mortality caused by the use of pesticides. West North America lost 95 percent of its Monarch butterflies over the last 35 years, according to a distressing recent report.

While the Dutch researchers focused on flying insect biomass in protected areas around Germany, a similar pattern of population decline is happening all over the world. Rodolfo Dirzo, an ecologist at Stanford University, developed a global index for invertebrate abundance that showed a 45 percent decline over the last four decades. 

“Although invertebrates are the least well-evaluated faunal groups within the IUCN database, the available information suggests a dire situation in many parts of the world,” says Dirzo.

Hallmann says that more work is required to investigate the full range of climatic and agricultural variables that might impact insect biomass. Whatever’s the case, evidence so far points towards humans interfering with insect habitats, foraging, and diet. We caused this mess and it’s up to us to clean it up.

“There is an urgent need to uncover the causes of this decline, its geographical extent, and to understand the ramifications of the decline for ecosystems and ecosystem services,” the authors concluded.

Scientific reference: Hallmann CA, Sorg M, Jongejans E, Siepel H, Hofland N, Schwan H, et al. (2017) More than 75 percent decline over 27 years in total flying insect biomass in protected areasPLoS ONE 12(10): e0185809. https://doi.org/10.1371/journal.pone.0185809

banana leaf

Reverse photosynthesis turns plants into biofuels

Photosynthesis is maybe the most important chemical process on Earth, turning sunlight and CO2 into the oxygen we breath and the food we eat. This process can be reversed, however. Danish researchers were the first to demonstrate how biomass can be broken down by sunlight in the presence of an enzyme and turned into useful chemicals like biofuels or renewable plastic.

banana leaf

Image: Pixabay

“This is a game changer, one that could transform the industrial production of fuels and chemicals, thus serving to reduce pollution significantly,” says University of Copenhagen Professor Claus Felby, who heads the research published in Nature Communications.

“It has always been right beneath our noses, and yet no one has ever taken note: photosynthesis by way of the sun doesn’t just allow things to grow, the same principles can be applied to break plant matter down, allowing the release of chemical substances. In other words, direct sunlight drives chemical processes. The immense energy in solar light can be used so that processes can take place without additional energy inputs,” says Professor Claus Felby.

Breaking down plant material is mainly done using industrial processes with high energy inputs, and can take a long time. The process developed in Denmark relies on lytic polysaccharide monooxygenases, a natural enzymes also used in industrial biofuel production, which aided by the sun’s energy can break down plant material in less than 10 minutes.

Tests were made on biomass — straw or wood — sprinkled with chlorophyll and the enzyme. The sun’s rays then break the sugar molecules inside the biomass into smaller constituents.

“We use the term “reverse photosynthesis” because the enzymes use atmospheric oxygen and the Sun’s rays to break down and transform carbon bonds, in plants among other things, instead of building plants and producing oxygen as is typically understood with photosynthesis”, says Postdoc Klaus Benedikt Møllers

Using this process biofuels could be made much faster. Methanol, an important fuel, could be sourced directly and at ambient conditions without additional energy inputs, for instance.

There’s reason to believe this reaction occurs naturally on the planet, though no one has reported it yet.


NREL energy

US electricity demand could be 80% supplied by renewable sources by 2050

NREL energyAccording to a recently publicized rapport by the  Department of Energy’s National Renewable Energy Laboratory (NREL), renewable energy sources could account for as much as 80% of the US’s electricity demand by 2050. The rapport signals the various difficulties that need to be overcome to reach this goal, and note that while 80% might be very challenging to reach, a 50% reach is highly possible.

The major players in the renewable energy game of 2050 will be  wind, photovoltaics, and biomass power plants. Surprisingly, hydropower, which is the current dominant renewable energy source in the US, will amount to a smaller proportion in the future.  Increased offshore wind and biomass power plants is where the Department of Energy is currently seeking to invest, and hopefully reach its ambitious 80% renewable energy covered demand.

The US has made significant efforts in increasing the renewable energy stake, and in 2010 renewable energy actually surpassed nuclear energy in provided electricity. Still, the nation is still lagging pretty far behind, compared to other countries’ efforts. Currently, Germany has 17 GW of solar PV installed, versus less than 4 GW in the US – even though the US covers a much larger surface. Scotland has over 31% of its current electricity demand covered by renewable energy, and, along with Denmark, plans to reach 100% by 2050.

The study notes that 439 gigawatts of wind capacity will be required in 2050 for the U.S. to be adequately supplied by renewables. Only 50 gigawatts are currently installed, meaning if the US is keen on reaching its goal, it needs to develop 10 gigawatts per year for almost 40 years, or install ~3,000 wind turbines per year.

“Annual renewable capacity additions that enable high renewable generation are consistent with current global production capacities but are significantly higher than recent U.S. annual capacity additions for the technologies considered,” said the study. “No insurmountable long-term constraints to renewable electricity technology manufacturing capacity, materials supply, or labor availability were identified.”

Whether the Department of Energy can back its claims and walk the talk, it remains to be seen. What’s pretty certain is that fossil fuel monopoly is shacking more nervously by the day.

source: IEEE