Washington: Reducing carbon dioxide emissions alone may not be enough to curb global warming. There is a need to develop technologies that remove large amounts of the gas at the source, say researchers.
Approximately 60 percent of global CO2 emissions come from power plants and other industries fuelled by coal, natural gas and oil. Capturing and sequestering those emissions could play a major role in curbing global warming.
"We need to start thinking about how to implement a negative-emissions energy strategy on a global scale," said Chris Field, professor of biology and environmental earth system science at Stanford University.
Field, who co-authored a report for the Global Climate and Energy Project (GCEP).
Field and Jennifer Milne described a suite of emerging carbon-negative solutions to global warming - from bioenergy technologies to ocean sequestration.
Many of the examples cited were initially presented at a negative carbon emissions workshop hosted by GCEP in 2011, according to a Stanford University statement.
"Net negative emissions can be achieved when more greenhouse gases are sequestered than are released into the atmosphere," explained Milne, energy assessment analyst at GCEP.
"One of the most promising net-negative technologies is BECCS or bioenergy with carbon capture and storage."
Estimates show that by 2050, BECCS technologies could sequester 10 billion metric tonnes of industrial CO2 emissions annually worldwide.
But according to the GCEP report, major technical and economic hurdles must be overcome such as the relative inefficiency of biomass fuels and the high cost of carbon capture and storage (CCS).
A typical BECCS system converts woody biomass, grass and other vegetation into electricity, chemical products or fuels, such as ethanol. CO2 emissions released during the process are captured and stored.
The technology can be used in power plants, paper mills, ethanol processors and other manufacturing facilities.
The GCEP report identified 16 BECCS projects at various stages of development around the world.
The first project was launched in 2009 by the Department of Energy at a corn ethanol production facility in Illinois.
Each day, about 1,000 tonnes of CO2 emitted during ethanol fermentation are captured and stored in a sandstone formation some 7,000 feet underground.
The goal of the project is to sequester one million metric tonnes of CO2 a year - the equivalent of removing 200,000 automobiles from the road