March 11, 2017 by Species Ecology
Bio fuel over green house gas (GHG) emission- An ecopolitical perspective
For the last 200 years, the burning of fossil fuels, such as coal, oil coupled with deforestation have caused the concentrations of heat-trapping “greenhouse gases (GHG)” to increase significantly in our atmosphere. These gases prevent heat from escaping to space, somewhat like the glass panels of a greenhouse. GHG are necessary to life as we know it, because they keep the planet’s surface warmer than it otherwise would be. But, as the concentrations of these gases continue to increase in the atmosphere, the earth’s temperature is climbing above past levels. According to NOAA and NASA, the earth’s average surface temperature has increased by about 1.2 to 1.4ºF in the last 100 years. The eight warmest years on record since 1850 have all occurred since 1998, with the warmest year being 2005. Most of the warming in recent decades is very likely the result of human activities. Other aspects of the climate are also changing such as rainfall patterns, snow and ice cover, and sea level. Leading to what is known as the Climate Change. Climate change affects people, plants, and animals. Observed effects include sea level rise, shrinking glaciers, changes in the range and distribution of plants and animals, early blooming of plants and trees, lengthening of growing seasons, ice on rivers and lakes freezing late and breaking up early, and thawing of permafrost.
Biomass is derived from living, or recently living organisms, such as wood, waste, and alcohol fuels. Biomass is commonly plant matter grown to generate electricity or produce heat. For example, forest residues (such as dead trees, branches and tree stumps), yard clippings, wood chips and garbage may be used as biomass. However, biomass also includes plant or animal matter used for production of fibers or chemicals. Biomass may also include biodegradable wastes that can be burnt as fuel. It excludes organic materials such as fossil fuels which have been transformed by geological processes into substances such as coal or petroleum.
Why Bio fuel?
Bio fuel energy facilities provide a range of environmental benefits from cleaner air to better forestry management. The air emissions from carbon monoxide (CO), sulfur dioxide (SO2) and nitrogenous oxide (NOx) from biomass plants are significantly lower compared to traditional fossil fuel plants, such as coal plants which are displaced by biomass plants. SO2 and NOx emissions are the major contributors to smog and acid rain. The U.S. Department of Energy estimates that electricity generated from coal produces about 50 times more SO2 emissions than biomass fuels and significantly more NOx emissions. Biomass plants also produce far less particulate matter (PM) than would result from the alternative method of open burning the wood wastes.
Bio fuel and climate change
As opposed to energy derived from fossil fuels such as coal, oil and natural gas, biomass energy does not contribute to climate change. The carbon which is stored in biomass material as it grows is already part of the atmosphere. Biomass energy does not add new carbon to the active carbon cycle unlike fossil fuels which remove carbon from geologic storage. The carbon emissions emitted from biomass facilities would have been released back into the atmosphere through some other fate or mechanism such as natural decay or an alternative disposal method such as open-burning. The advanced emissions controls on a biomass energy facility significantly reduce the amount of CO2 emitted into the atmosphere along with other emissions such as particulate matter.
According to a new study prepared by S&T Consultants Inc., commissioned by the Global Renewable Fuels Alliance, world bio fuel production in 2009 has reduced GHG emissions by 123.5 million tons, representing an average reduction of 57% compared with the emissions that would have occurred from the production and use of equal quantities of petroleum fuels. The study utilized a life cycle assessment (LCA) approach to estimate global GHG emissions reduction achieved through the production and use of bio fuel from “cradle-to-grave,” including the acquisition of raw materials, manufacture, transport, use, maintenance and final disposal, a release from the Global Renewable Fuels Alliance stated.
Among the study, other findings were:
“World bio fuel production surpassed 100 billion liters [L] of annual production in 2009. After accounting for energy contents, this is displacing 1.15 million barrels of crude oil per day, which creates approximately 215 million tons of GHG emissions annually.
“In 2009, world ethanol production of 73.7 billion L is estimated to reduce GHG emissions by 87.6 million tons — approximately the same as the total GHG emissions reported for Austria in 2007.
“With respect to bio diesel, forecast global production of 16.4 billion L will reduce GHG emissions by 35.9 million tons — greater than the GHG emissions reported for Croatia in 2007.
“The combined GHG emissions reduction from global ethanol and biodiesel production of 123.5 million tons represents an average reduction of 57% compared to the emissions that would have occurred from the production and use of equal quantities of petroleum fuels. This is equal to the national GHG emissions of Belgium or Greece, as well as the combined emissions of Monaco, Liechtenstein, Iceland, Latvia, Luxembourg, Slovenia, Estonia, Lithuania and Croatia.”
Bio fuel worse for climate change than fossil fuels. In many cases biofuels cause more global warming than fossil fuels. This is the conclusion reached by scientists modeling the carbon dioxide impact from both types of energy sources. Until recently most scientists have compared fossil fuels and bio fuels by totting up their direct GHG emissions. Direct emissions include things like the diesel used to drive the tractor to cultivate the maize, but not the carbon in the bio fuel itself. Comparing like for like, fossil fuels were considered to produce more carbon dioxide than bio fuels, which has led to the assumption that fossil fuels cause more greenhouse warming than bio fuels. However, when ‘indirect’ emissions and timing of emissions are taken into consideration, bio fuels begin to lose their green credentials.
Michael O’Hare of the University of California, in Berkeley, US, and his colleagues developed a model to assess the greenhouse-gas impact from both fossil fuels and bio fuel over their entire life cycle. In each case they studied how carbon dioxide emissions change over time, and how long-lived the carbon dioxide is. In a case study they used their bio fuel Time Integrated Model of Emissions (BTIME) to compare the production of maize ethanol with that of ordinary gasoline, over a 100-year period. For the maize ethanol there is a large release of carbon dioxide initially, when forests and pastures are converted to grow replacement food (food that would have been grown where the new bio fuel crop is growing). There is then a steady release of carbon dioxide (60g MJ of energy) during the years of production. When production ceases, perhaps after 25 years, the cleared land begins to revert to its original state and a small amount of carbon dioxide is sequestered. Gasoline, by contrast, does not produce an initial pulse, but instead a steady stream of carbon dioxide (94g per MJ of energy) over the same 25-year period. “Fossil fuel emit the carbon as you use them, whereas crop-based bio fuel emit an initial pulse of carbon dioxide that is large,” O’Hare told environmental research web.
In a parallel project, they estimated the “indirect” discharges from worldwide land clearing, caused as economic signals move through world food markets when land is used for fuel instead of food. Putting the findings together from both models they were able to calculate the direct and indirect emissions associated with bio fuel and consider how the emissions change over time. Once carbon dioxide gets into the atmosphere it takes a long time to leave. “It follows an exponential decay pattern, losing a constant percentage every year,” explained O’Hare. The sudden and early nature of the emissions associated with bio fuel makes them more damaging than fossil fuel. In the case of maize ethanol it leads to a higher abundance of carbon dioxide in the atmosphere for the first 15 years of its production, compared to gasoline. Even when the gasoline emissions catch up with maize ethanol, the global-warming damage from the maize ethanol emissions is greater, because they have been in the atmosphere for longer. The results are published in the journal Environmental Research Letters. Such calculations are crucial when it comes to climate policy. Many countries are now starting to consider carbon taxes and it is essential that the taxes reflect the damage that a product causes over similar timescales. O’Hare stressed that it is only bio fuel that are grown in locations where food might otherwise have been grown that compare unfavorably with fossil fuels. “Bio fuels that don’t compete with food for land are fine on this measure, such as ethanol that is produced from trash, or from ocean algae,” he said. And it is possible that some bio fuel could become less damaging. “Increasing yields, by making ethanol out of the whole plant for example, could reduce their overall impact,” said O’Hare
Any new discovery and innovation is an intruder until it proves its benefit or harmfulness. Therefore, biomass usage is still facing refusal by some scientists and acceptance by others. But as our fossil fuel resources will come to an end, we have to think logically. Biomass can be a practical solution as an alternative, we have to look for substitutes for energy resources and to think and work to be prepared for the time that all fossil fuels will be replenished from this earth. The fear of the concept planting food for fuel, especially in our hungry world can be managed by increasing the dependence upon generating energy from waste biomass. More studies and researches need to be conducted by scientists to figure a way of mitigating the impact of biomass. International cooperation toward the goal of finding alternatives for the next generations is crucial. Looking for other alternative than biomass can also eliminate the pressure on this resource; we still have to concentrate on adapting the solar, tidal and wind energies to our daily life.