Carbon dioxide release: What can we do to reduce it?
Your choice of fuel sources change how carbon dioxide release is counted.
July 11, 2012 - Author: Mark Seamon , and Ray Miller, Michigan State University Extension and MSU AgBioResearch
Carbon dioxide (CO2) levels in the atmosphere have been increasing steadily for several decades. The National Oceanic and Atmospheric Administration reports the measured atmospheric CO2 levels increased from 318 ppm in 1961 to 392 ppm in 2011. This increase of 23 percent in 50 years has caused concern because of its potential negative effects as well as future effects if this increase continues at its current rate. Around the world, scientists and policymakers are working to lower the rates of CO2 release to the atmosphere.
So, where is this carbon dioxide coming from and what can we do about it?
According to the U.S. Environmental Protection Agency, the main human activity that emits CO2 is the combustion of fossil fuels (coal, natural gas and oil) for energy and transportation. The combustion of fossil fuels to generate electricity is the largest single source of CO2 emissions in the nation, accounting for about 40 percent of total U.S. CO2 emissions and 33 percent of total U.S. greenhouse gas emissions in 2009.
Fossil fuels contain massive amounts of carbon and as long as they are buried deep within the earth, they don’t become part of the atmospheric carbon pool. It is only when these fuels are extracted from the earth and burned that the carbon is released into the air. Efforts to replace fossil carbon with other forms of energy are under way in attempt to reduce fossil CO2 emissions. One such form of energy is plant biomass. Carbon contained in recently living plants is referred to as biomass. CO2 is taken up by plants through photosynthesis during plant growth. Carbon is stored in the plant while oxygen is released into the air.
Crops grown for biomass can be harvested and converted to biofuels and bioelectricity. Burning these fuels returns the carbon back to the atmosphere – where it originated, thus closing the loop. The amount of carbon absorbed by plants and used throughout the production system can be measured and tracked in order to determine a net balance. If the amount of CO2 absorbed by plants equals or exceeds that emitted by producing the plants and by biomass combustion, the system is considered CO2 neutral or CO2 negative. With the goal to reduce fossil CO2 emissions as much as possible, researchers at Michigan State University are working to determine which crops or plants and which conversion processes conserve the largest amount of CO2.
As the United States struggles to develop policies governing energy and CO2 release, definitions of what constitutes a renewable and CO2 neutral fuel are being developed. These may vary, but in general the intention is to provide for the sustainable production, harvest and use of biomass. The biomass sources may include waste woody biomass, crop residue or crops grown specifically for use as biofuels. Careful attention is being paid to prevent deforestation and the depletion of long-term soil productivity. Sustainability is a key objective to the management of resources that will allow for the reduction of fossil fuel use.
Michigan is in a strong position to supply this growing alternative energy industry with biomass. Our soils, climate, infrastructure and proximity to population centers are all positive factors that allow us a competitive advantage over other geographic regions.
Populations around the world will continue to need increasing amounts of energy. Careful and strategic efforts will allow for this advancement while we identify alternatives to our current system. Reducing CO2 emissions through the use of biomass to produce electricity is one promising method to achieve it.