Archive for the ‘climate change’ Category
Have you heard of the “Bathtub Model” for expaining CO2 accumulation? I hadn’t until last week, when I attended the sustainability symposium at Baldwin-Wallace College. Dr. Susan Solomon, who was the lead author of th 2007 IPCC report on global climate change, was the one who introduced the concept. Here’s a much more succinct description from, appropriately enough, a plumber.
Picture a bathtub with a running faucet and open drain. When we use energy, carbon dioxide (CO2) pours into the atmosphere just like water pours into a bathtub. If water pours into the tub faster than it can drain out, the tub fills with water. The bathtub stays full until more water is draining out than is pouring in. The same concept applies to CO2. At our current rate of energy consumption, CO2 emissions produced by burning fossil fuels are pouring into the atmospheric bathtub twice as fast as they are draining out.
Everyone can do something about CO2 emissions, and some of those changes are relatively easy to make – as the good folk at Raymond Plumbing go on to explain. For instance, using high-efficiency heating and cooling and Energy Star certified appliances. Even simple steps, like turning down the thermostat on the hot water heater will help – and save money, too.
A test of carbon capture technology in Wisconsin shows that – in the perfect world – technology might lessen the impact of coal-burning power plants on climate change. From Journal-Sentinel writer Thomas Content (via the good people at Energy News Network):
We Energies says carbon-capture project works
An $8 million pilot project in Wisconsin successfully showed that carbon dioxide can be captured and kept from being released from the smokestacks of coal-fired power plants, We Energies and two partners said Thursday.
The project was the first real-life demonstration of technology that uses chilled ammonia to act as a magnet to capture the greenhouse gas and purify it for possible shipment into underground geological formations instead of into the air.
The Wisconsin project, at the Pleasant Prairie Power Plant, was able to grab at least 90% of the greenhouse gas, officials said, and the French company Alstom that developed the technology is optimistic its next test will capture even more carbon dioxide.
(via Energy News Network)
Since this was just a test, the captured carbon dioxide was released rather than sequestered underground. A similar test at AEP’s Mountaineer power plant in West Virginia will be the first full-scale implementation of the technology. Alstom plans to begin selling the technology in 2015.
A few potential problems are already apparent:
- Ammonia is synthesized from natural gas. This process of ammonia synthesis generates CO2, so using synthesized ammonia to capture CO2 may not result in a net decrease. At the very least, the ammonia synthesis stage needs to calculated into the final reduction of this process for a true measure of the CO2 reduction accomplished through this process.
- Ammonia happens to be one of the major inputs for commercial agriculture. It is used in creating fertilizer. Reducing the ammonia available for farming will have much the same impact that diverting corn into ethanol production did: reduced availability resulting in higher prices for ammonia and ultimately higher food prices.
- The process of ammonia capture consumes between 20-25 percent of the energy produced from the coal-burning plant. This, too, has the effect of making electricity more expensive. As David Biello wrote in the Scientific American blog when the company announced the preliminary results of the test earlier this year:
In other words, capturing that CO2 will cost between $50 and $90 per metric ton, though (Robert) Hilton [Vice President of Power Technologies and Government Affairs at Alstom] believes that scaling up the process and refining it will reduce that cost…
The problem with the “efficiency of scale” argument made by Mr. Hilton is that he assumes a large-scale deployment of the technology. This is a circular argument, since widespread deployment of carbon-capture technology is dependent on making the technology affordable.
- It is also important to note that there has to be someplace to but the carbon dioxide after it is removed from the plant exhaust. In this “small” test, over 58,000 tons of CO2 was captured from a small fraction of the total emissions of one power plant. Nowhere in Wisconsin is there anyplace to sequester the captured CO2 from this and other coal-burning power plants in the state. Wisconsin lacks the proper geological formations to use the same underground deep-well injection technique planned for the Mountaineer plant. Sending the gas by pipeline to a neighboring state has been proposed, but there are no plans and no funding to construct such a pipeline.
Even if all those obstacles can be overcome, it still leaves a power generation system in place that is dependent on cheap coal.
For the billions (or trillions) of dollars it will take to test, develop, and implement carbon capture, isn’t it worth at least considering something truly groundbreaking and sustainable, like improved firming capability for wind and solar energy instead?
This press release from the Tennessee Valley Authority skims over quite a few interesting topics:
JOHNSON CITY, Tenn. – The TVA Board today authorized the purchase of as much as 2,000 megawatts of renewable and clean energy by 2011 as part of TVA’s plan to have 50 percent of its power supply from clean and renewable energy sources by 2020.
This is encouraging for several reasons. The 50 percent renewable energy goal is well above the target for any US power company. 2,000 megawatts is a respectable wind farm – just over the threshold to be considered “commercial” scale. Hopefully, this commitment will demonstrate that wind, solar, geothermal, and other renewables are a viable option for other US power companies to consider and deploy.
Farther along in the report, the TVA notes that the ongoing drought in the south has had some impacts on its primary function, managing the Tennessee River:
For the first three months of this year, rainfall in the eastern part of the Tennessee Valley is below normal and slightly less than rainfall during January-March of 2008. Runoff – the water that reaches streams and reservoirs – is slightly higher so far this year than it was during first three months of 2008, but is still below normal. The tributary reservoirs still need 4 to 8 inches of rain to reach normal summer levels.
I wonder if this presages a return of the water rights battles fought in recent years between Georgia (which needs the water primarily for human consumption in the Atlanta area) and Florida (which relies on that same water to support agriculture, tourism, and commercial fishing in the Okeechobee basin). I guess we’ll have to wait and see.