Posts tagged 2012
Fee makes big dent in disposable bag use
Mar 10th
After six months in effect, estimates show that the disposable bag fee has reduced use of paper and plastic checkout bags at grocery stores in Boulder by 68 percent. This reduction means the community has kept nearly 5 million disposable bags out of the waste stream since the fee went into effect on July 1, 2013.
“This is very positive news,” said Jamie Harkins, City of Boulder business sustainability specialist. “The bag fee arose from community concerns about the negative environmental and economic impacts of disposable bags in Boulder, and this progress report shows that we are addressing those concerns and doing so effectively.”
The disposable bag fee is one of several city initiatives aimed at bringing Boulder closer to its goal of becoming a zero waste community and diverting 85 percent of the waste stream away from the landfill and into recycling, composting and reuse facilities.
Of the approximately 22 million disposable checkout bags Boulder uses each year, 60 to 70 percent come from grocery stores. A study conducted by consultant TischlerBise in 2012 projected a 50 percent reduction in disposable bag use by the end of the first year of the fee, with approximately 3.6 million disposable bags subject to the fee (i.e. purchased) in the first six months. In actuality, Boulder shoppers have reduced disposable bag use by 68 percent and have purchased significantly fewer bags, approximately 2.3 million in total.
Of the 10 cents collected for each bag, 4 cents goes directly to retailers to defray fee implementation costs. The remaining 6 cents is remitted to the city to support education and outreach efforts about the bag fee as well as to cover expenses associated with providing bags to portions of the population that might be disproportionately impacted by the fee. No revenue collected as part of the fee program can be used to support General Fund services or programs.
The disposable bag fee does not apply to bags used inside stores for items such as produce, bulk food, or meat and fish, and does not apply to pharmacy prescriptions or newspapers.
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CU: Gas-fired plants help clean the air
Jan 10th
Power plants that use natural gas and a new technology to squeeze more energy from the fuel release far less of the greenhouse gas carbon dioxide than coal-fired power plants do, according to a new analysis accepted for publication Jan. 8 in Earth’s Future, a journal of the American Geophysical Union. The so-called “combined cycle” natural gas power plants also release significantly less nitrogen oxides and sulfur dioxide, which can worsen air quality.
“Since more and more of our electricity is coming from these cleaner power plants, emissions from the power sector are lower by 20, 30 even 40 percent for some gases since 1997,” said lead author Joost de Gouw, an atmospheric scientist with NOAA’s Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder. NOAA is the National Oceanic and Atmospheric Administration.
De Gouw, who works at NOAA’s Earth System Research Laboratory (ESRL), and his NOAA and CIRES colleagues analyzed data from systems that continuously monitor emissions at power plant stacks around the country. Previous aircraft-based studies have shown these stack measurements are accurate for carbon dioxide (CO2) and for nitrogen oxides and sulfur dioxide. Nitrogen oxides and sulfur dioxide can react in the atmosphere to form tiny particles and ozone, which can cause respiratory disease.
To compare pollutant emissions from different types of power plants, the scientists calculated emissions per unit of energy produced, for all data available between 1997 and 2012. During that period of time, on average:
- Coal-based power plants emitted 915 grams (32 ounces) of CO2 per kilowatt hour of energy produced;
- Natural gas power plants emitted 549 grams (19 ounces) CO2 per kilowatt hour; and
- Combined cycle natural gas plants emitted 436 grams (15 ounces) CO2 per kilowatt hour.
In combined cycle natural gas plants, operators use two heat engines in tandem to convert a higher fraction of heat into electrical energy. For context, U.S. households consumed 11,280 kilowatt hours of energy, on average, in 2011, according to the U.S. Energy Information Agency. This amounts to 11.4 metric tons per year of CO2 per household, if all of that electricity were generated by a coal power plant, or 5.4 metric tons if it all came from a natural gas power plant with combined cycle technology.
The researchers reported that between 1997 and 2012, the fraction of electric energy in the United States produced from coal gradually decreased from 83 percent to 59, and the fraction of energy from combined cycle natural gas plants rose from none to 34 percent.
That shift in the energy industry meant that power plants, overall, sent 23 percent less CO2 into the atmosphere last year than they would have, had coal been providing about the same fraction of electric power as in 1997, de Gouw said. The switch led to even greater reductions in the power sector’s emissions of nitrogen oxides and sulfur dioxide, which dropped by 40 percent and 44 percent, respectively.
The new findings are consistent with recent reports from the Energy Information Agency that substituting natural gas for coal in power generation helped lower power-related carbon dioxide emissions in 2012.
The authors noted that the new analysis is limited to pollutants emitted during energy production and measured at stacks. The paper did not address levels of greenhouse gases and other pollutants that leak into the atmosphere during fuel extraction, for example. To investigate the total atmospheric consequences of shifting energy use, scientists need to continue collecting data from all aspects of energy exploration, production and use, the authors concluded.
Authors of the new paper, “Reduced Emissions of CO2, NOx and SO2 from U.S. Power Plants Due to the Switch from Coal to Natural Gas with Combined Cycle Technology,” are de Gouw (CIRES), David Parrish (NOAA ESRL), Greg Frost (CIRES) and Michael Trainer (NOAA).
CIRES is a joint institute of NOAA and CU-Boulder.
-CU-
Solar eruption could be like an attack on the Earth
Dec 9th
points up need for society to prepare
A massive ejection of material from the sun initially traveling at over 7 million miles per hour that narrowly missed Earth last year is an event solar scientists hope will open the eyes of policymakers regarding the impacts and mitigation of severe space weather, says a University of Colorado Boulder professor.
The coronal mass ejection, or CME, event was likely more powerful than the famous Carrington storm of 1859, when the sun blasted Earth’s atmosphere hard enough twice to light up the sky from the North Pole to Central America and allowed New Englanders to read their newspapers at night by aurora light, said CU-Boulder Professor Daniel Baker. Had it hit Earth, the July 2012 event likely would have created a technological disaster by short-circuiting satellites, power grids, ground communication equipment and even threatening the health of astronauts and aircraft crews, he said.
CMEs are part of solar storms and can send billions of tons of solar particles in the form of gas bubbles and magnetic fields off the sun’s surface and into space. The storm events essentially peel Earth’s magnetic field like an onion, allowing energetic solar wind particles to stream down the field lines to hit the atmosphere over the poles.
Fortunately, the 2012 solar explosion occurred on the far side of the rotating sun just a week after that area was pointed toward Earth, said Baker, a solar scientist and the director of CU-Boulder’s Laboratory for Atmospheric and Space Physics. But NASA’s STEREO-A, satellite that was flying ahead of the Earth as the planet orbited the sun, captured the event, including the intensity of the solar wind, the interplanetary magnetic field and a rain of solar energetic particles into space.
“My space weather colleagues believe that until we have an event that slams Earth and causes complete mayhem, policymakers are not going to pay attention,” he said. “The message we are trying to convey is that we made direct measurements of the 2012 event and saw the full consequences without going through a direct hit on our planet.”
Baker will give a presentation on the subject at the 46th Annual Fall Meeting of the American Geophysical Union held in San Francisco Dec. 9 to Dec. 13.
While typical coronal mass ejections from the sun take two or three days to reach Earth, the 2012 event traveled from the sun’s surface to Earth in just 18 hours. “The speed of this event was as fast or faster than anything that has been seen in the modern space age,” said Baker. The event not only had the most powerful CME ever recorded, but it would have triggered one of the strongest geomagnetic storms and the highest density of particle fluctuation ever seen in a typical solar cycle, which last roughly 11 years.
“We have proposed that the 2012 event be adopted as the best estimate of the worst case space weather scenario,” said Baker, who chaired a 2008 National Research Council committee that produced a report titled Severe Space Weather Events – Understanding Societal and Economic Impacts. “We argue that this extreme event should be immediately employed by the space weather community to model severe space weather effects on technological systems such as the electrical power grid.
“I liken it to war games — since we have the information about the event, let’s play it through our various models and see what happens,” Baker said. “If we do this, we would be a significant step closer to providing policymakers with real-world, concrete kinds of information that can be used to explore what would happen to various technologies on Earth and in orbit rather than waiting to be clobbered by a direct hit.”
Even though it occurred about 150 years ago, the Carrington storm was memorable from a natural beauty standpoint as well as its technological impacts, he said. The event disrupted telegraph communications — the Internet of the Victorian Age — around the world, sparking fires at telegraph offices that caused several deaths, he said.
A 1989 geomagnetic storm caused by a CME from a solar storm in March 1989 resulted in the collapse of Hydro-Quebec’s electricity transmission system, causing 6 million people to lose power for at least nine hours, said Baker. The auroras from the event could be seen as far south as Texas and Florida.
“The Carrington storm and the 2012 event show that extreme space weather events can happen even during a modest solar cycle like the one presently underway,” said Baker. “Rather than wait and pick up the pieces, we ought to take lessons from these events to prepare ourselves for inevitable future solar storms.”
CU media release.