North America and China will have to clean up their act by using technology that turns coal into gas
When it comes to global power-plant emissions, coal is the major culprit. Coal-fired stations are one of the biggest contributors to climate change, yet their use continues unabated, especially in North America and developing countries.
The good news is, there is state-of-the-art technology to make coal cleaner and more climate-friendly.
It’s an issue that has come to the fore given U.S. President Barack Obama’s recent decision to order a 30-per-cent cut from 2005 levels in carbon emissions from the nation’s power plants by 2030. That doesn’t mean the end of coal, but it does mean that the CO2 cannot continue to pour out from coal-powered plants.
Each person on the planet consumes an average of 2.9 kg of coal per day for power, heating, cooling and work. Per-capita coal use is much higher in North America. Although some places, such as Ontario, have phased out coal for power plants, there are still 17 coal plants in Canada, and coal generates more than 40 per cent of the electricity in the United States. So it’s important that new cleaner coal technology now reaching the marketplace is more energy efficient than ever. It’s becoming cost-effective, too.
Turning coal into gas, known as gasification, is one solution. It’s not new: The first technology to tap into energy from coal by turning it into gas was used in the 1780s. Those quaint gas-lit streets in the mid-19th century were illuminated by coal gas, before the electric light came into use.
“Gasification is a proven, reliable technology,” says DeLome Fair, General Manager, Gasification Engineering for GE Power and Water. “In developing countries with strong demands for energy and abundant coals reserves, like China and India, coal gasification, in particular, is expected to have a continued and sustainable future.”
The newest generation of gasification technology is still based on turning coal into a synthetic gas, or syngas, extracting the hydrogen and carbon monoxide from the lumps. But that’s like saying a microchip is based on simple arithmetic — true, but there are a lot of advanced steps.
Gasification is more important now because the process allows most of the CO2 to be removed; it can then be stored underground. Specialized syngas turbines made by GE collectively have more than 2 million hours experience burning this synthetic fuel, which has a low BTU and ordinarily would burn with a high flame and unstable combustion.
Syngas turbines are specially designed to capture the CO2 early in the process and divert it for storage, and then to burn the fuel using a system that diffuses the flame so it burns more evenly. (GE calls this diffuser system Multi Nozzle Quiet Combustor.) When used in a configuration called an integrated gasification combined cycle, or IGCC, this technology can deliver anywhere between 70 and 880 megawatts of power, depending on the fuel and site.
IGCC is the part of the process that turns coal into the cleaner and efficient fuel. Potential emissions such as sulphur dioxide, mercury and particulates — old, 1970s-style pollution — are removed at this stage. Up to 90 per cent of the CO2 can be captured for underground storage. One 618-megawatt GE-built plant in the United States “may be the world’s cleanest power plant,” Fair says.
Combined with the unconventional gas revolution that has made available huge new quantities of natural gas, GE and other companies are betting heavily that demand for turbines by power providers will grow. GE already has a fleet of nearly 7,000 installed gas turbines around the world; just one of its 350-tonne 9H models provides enough lower-CO2 energy to power 450,000. In June 2014 the company cleared the last hurdle for its $17-billion (U.S.) purchase of France’s Alstom SA’s energy assets, paving the way for joint ventures between the two manufacturers.
While these and other companies produce natural-gas-burning turbines, what’s crucial for the future is to scale up the ability to use coal in cleaner ways than before.
Regulation, such as the new Obama rules, is just a tool. The real catalyst for developing cleaner coal technology is necessity. Even with rising evidence and concern about climate change, world coal use went up by 54 per cent between 2000 and 2011. Something needs to be done with the CO2 from all that coal, and to capture and store it.
“There is still some time ahead of us before non-fossil energy, such as wind or solar, can truly substitute the traditional energy,” says Fair. China used some 3.7 billion tonnes of coal in 2013, nearly half the world’s consumption, and still growing. “It is just a rational decision for China to continue utilizing coal, but with more efficient and cleaner solutions,” she says.
The CO2 captured from a 1,000-megawatt power plant is equivalent to 2.8 million people trading in gas-guzzling pickup trucks for fuel-efficient hybrid cars. IGCC can capture the carbon and generators can burn the fuel more efficiently − setting the conditions to build the infrastructure to take CO2 out of emissions and put it where it belongs, underground.
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This content was produced by The Globe and Mail's advertising department, in consultation with GE. The Globe's editorial department was not involved in its creation.