Stories tagged biomass

Apr
12
2013

How much of terrestrial plant and animal life can humanity safely consume without seriously damaging the live-support systems of our planet? It has been challenging to answer that question because of the difficulty of measuring how much biomass is produced annually on land and how much of this yearly production humans co-opt.

Huge regional variability exists in terrestrial productivity from year to year because of heat, cold, floods and droughts but what is striking from recent reviews of more than 30 years of satellite imagery is how little global variability there is annually. Each year, terrestrial plants fix about 53.6 petagrams of biomass – a gigantic quantity but what matters is not so much the size of annual biomass production but rather that it seems to vary by only about two percent per year.

Recent estimates from satellite imagery indicate that humans now appropriate 38 percent of all terrestrial biomass generated annually. That would seem to leave 62 percent on the table for expanded human consumption but the vast majority of this biomass appears to be not harvestable because it includes root growth below ground and biomass production on lands in parks or wilderness areas that are either protected or inaccessible.

It appears likely that the upper limit for how much of terrestrial biomass that humans can co-opt annually is only about ten percent more for a total of 48 percent. Current land use patterns and projections that the global human population may reach nine billion by 2050 suggest that this 48 percent of all available terrestrial biomass may be reached within the next few decades.
Earth's primary photosnythetic productivity: The darkest green  shading in the Amazon and Southeast Asia are regions of the world where photosynthetic activity is by far the most active on an annual basis
Earth's primary photosnythetic productivity: The darkest green shading in the Amazon and Southeast Asia are regions of the world where photosynthetic activity is by far the most active on an annual basisCourtesy NASA

Jul
15
2010

“…Welcome back, class. Please hand in your essays on the scientific fundamentals of phosphorus-driven eutrophication in the Gulf of Mexico, and note that our exam covering chapter eight, the Biogeochemistry of Acid Mine Drainage, will take place next Tuesday. Today we will be covering fluid bed catalytic oxidation, hazardous waste landfill leachates, and NIMBY. But, first, let’s take attendance: Bueller?... Bueller?... Bueller??”

Say what? “Nimby?” Girl, puh-lease! He just made that up… didn’t he??

It wasn’t long into my undergraduate stint as an Environmental Science major that I came across the word, “nimby.” Actually, it’s not a word at all. It’s an acronym, N.I.M.B.Y., standing for “Not In My BackYard,” that captures an important public attitude that affects environmental policymaking.

NIMBY explains many people’s attitude towards environmental policies, capturing sentiments like,

“That’s such a cool and important idea! As long as it’s not actually happening in my community, that is.”

“Whatever. I don’t care so long as I don’t have to see it everyday.”

NIMBY: Yuck.  Who wants to look out their bedroom window and see a mountain of trash?  Not these guys.
NIMBY: Yuck. Who wants to look out their bedroom window and see a mountain of trash? Not these guys.Courtesy The Voice of Eye

Think About It

Do you like having your trash removed from your home? Most everyone does. But, would you like having a landfill in your backyard? Almost nobody does. This is the classic example of NIMBY. Nearly everyone likes having their trash collected from their property and transported out of sight and smell, yet someone, somewhere has to live beside a mountain of trash. As long as we’re not the ones living across the street from the landfill, most of us are satisfied with this method of garbage disposal. The same idea goes for wastewater treatment facilities as well.

Another classic example is nuclear power. Some people support nuclear power as an inexpensive and “clean” alternative to fossil fuels like oil and natural gas. However, the construction, maintenance, and decommissioning of a nuclear power plant poses risks and creates radioactive waste. Whether or not you think the risks and waste production are acceptable consequences depends largely on your proximity to the plant and/or ultimate disposal site for the nuclear waste.

A recent example of NIMBY is occurring in California this summer as covered in Green, a New York Times blog. In a valley near Santa Clara, Martifer Renewables canceled their plan to build a hybrid solar power plant. Set on 640 acres of agricultural land, the plant was supposed to produce electricity by solar power during the day and biomass burning by night. How sweet is that?? A 24-hour source of renewable energy! The California utility PG&E thought it was a great idea too and signed a 20-year power purchase agreement for 106.8 megawatts, which became part of their energy portfolio. PG&E must obtain 20% of its electricity from renewable resources by December of this year and another 13% (for 33% total) by 2020, as mandated by California state energy goals. Now that the project is canceled, PG&E will have to look elsewhere for sources of renewable electricity or risk missing their mandated targets.

Regarding the canceled project, Martifer executive, Miguel Lobo, wrote in a June 17th letter that,

“We were not able at this time to resolve some of our issues regarding project economics and biomass supply amongst other things.”

What Lobo was likely referring to are the complaints of local residents and regulators who contested several aspects of the project. Chief amongst the complaints was the around-the-clock operation made possible by burning biomass. What exactly were they so excited about? Noise, waste, and air pollution – all realities of energy production, yet things we’d rather not experience ourselves. In short, NIMBY.

Alright, so what?

Now that I’ve opened your eyes to the existence of NIMBY, you might be wondering how it influences environmental policymaking. The easiest answer is that environmental policymakers seek to find a balance between the conflicting desires for new technology like this power plant and local opposition and the NIMBY attitude. Often both sides make compromises and projects move forward on a slightly different path than previously proposed. However, as in the California case of Martifer Renewables, occasionally a project is completely scrapped. Other times, the project proceeds as originally planned. Which of the outcomes occurs depends largely on the organization and influence of the local opposition. In turn, this often raises issues of environmental or eco-justice.

Clearly our modern society cannot exist without landfills or wastewater treatment facilities as smelly and unsightly as they may be. Whether or not nuclear or other renewable energy power plants are equally necessary today is debatable, but it’s not hard to imagine a future in which they will be. If no one agreed to have these facilities in their community, life as we know it would be very different. This begs the question: how do you think policymakers should balance the needs of society at large against the NIMBY attitude of locals?

Jan
08
2008

Large scale study shows 540% net energy gain when ethanol is produced from switchgrass

Panicum Vergatum: Switchgrass
Panicum Vergatum: SwitchgrassCourtesy U S Govt

Kenneth Vogel, a geneticist with the U.S. Department of Agriculture in Lincoln, Nebraska, and his colleagues, found that ethanol produced from switchgrass yields 540% of the energy used to grow, harvest, and process it into ethanol.

Their results, published online in Proceedings of the National Academy of Sciences, shows that switchgrass, farmed using conventional agricultural practices on less-than-prime cropland yields only slightly less ethanol per hectare on average than corn.

Farmers planted switchgrass on 10 farms, each of which was between 3 and 9 hectares. They then tracked the inputs they used--diesel for farm equipment and transporting the harvested grasses, for example--as well as the amount of grass they raised over a 5-year period. ScienceNOW Daily News

Switchgrass monoculture or mixed prairie grasses?

Anyone remember our Buzz post "Chalk one up for diversity"? David Tilman in that post is quoted saying, "diverse prairie grasslands are 240 percent more productive than grasslands with a single prairie species"
Now I read:

... Vogel says, is that yields on farms using fertilizer and other inputs, such as herbicides and diesel fuel for farm machinery, were as much as six times higher than yields on farms that used little or no fertilizer, herbicides, or other inputs to grow a mixture of native prairie grasses. ScienceNOW Daily News

Who is right? Can anyone explain why two reputable researchers are getting such different results?