Getting the Carbon Out of Hydrocarbon Fuels
By Eric Larson
We Americans love our cars, and our cars love gasoline. Like most love triangles, this one is not without its problems. Namely, the transportation sector, which runs almost exclusively on oil, accounts for a full one-third of U.S. fossil fuel greenhouse gas (GHG) emissions. These greenhouse gases are likely responsible for a large portion of global warming that has occurred in the past several decades. And an even greater cause for concern in many people’s view is the nation’s dependence on imported oil — in 2009, the U.S. imported 2.2 barrels of oil for every barrel produced domestically — not exactly a ratio for self-sufficiency.
A paper published online in the journal Energy and Fuels on December 6th, reporting on research I did with colleagues at Princeton University, identifies technologies that just might help solve both problems simultaneously. The paper builds on one we published earlier this year.
We designed and analyzed systems that would use technologies that are mostly already available at commercial scale to co-produce low-carbon petroleum-like fuels and electricity. These systems would use coal, an abundant domestic energy source, as the major energy input.
How can hydrocarbon fuels be low carbon, you might ask, with coal as the starting material? After all, the fuels are hydrocarbons and coal is the most carbon-intensive of all fossil fuels.
There are two key features of these systems that would enable low carbon emissions — one involv...
Midwestern Wind Turbines Keep Fresh Breeze Over Nearby Crops
Climate In Context
Three things you need to know
-- The U.S. Department of Energy projects that it is possible for the U.S. to get 20 percent of its electricity from wind energy by 2030, if there is a major investment in building the needed infrastructure.
-- Some of the country’s best wind energy resources are found blowing over the rich agricultural lands of the Midwest.
-- Wind turbines set amidst agricultural land in the Midwest refresh the air around the plants, and now researchers are studying how changes in airflow will impact corn and soybean crops.
The Debrief
Wind turbines such as these have been erected across the Midwest recently. Credit: flickr/WindeBabe.
When wind turbine blades absorb energy from the wind to generate electricty, they also channel some airflow down towards the ground. Now, researchers are getting a sense of how air currents change at the ground level near large turbines, fueling speculation about how this might affect crops growing nearby.
Last week at the American Geophysical Union’s annual meeting in San Francisco, Eugene Takle, an agricultural meteorologist from Ames Laboratory at Iowa State University, shared new data (not yet published) showing that at ground level where crops are growing, areas below wind turbines experience more exchange of air than where there aren’t any turbines. Last summer, Takle and his collaborators sampled the air within cornfields that also contain large wind turbines. By measuring the temperature changes, moisture levels, carbon dioxide (CO2) concentrations and wind speeds of...
Global Warming’s Potential Impact on Wind Energy
Three things you need to know:
-- Increasing global average surface temperatures may reduce the amount of wind energy available for electricity production, a new study says.
-- Global air circulation is influenced by many aspects of the global climate, including differences in atmospheric temperatures between the equator and the North and South Poles.
-- Across North America, average wind speeds have decreased slightly over the past 40 years.
Turbines at Shanghai's Donghai Bridge Offshore Wind Farm capture wind energy in the late summer of 2010. A new study suggests that further global warming could reduce available wind energy by the end of this century. Credit: Alyson Kenward
The Debrief:
People tend to think wind energy is a classic example of a renewable energy resource. But while it is true that wind will still blow no matter how many wind turbines are built, some new research suggests that wind power may decrease in some regions of the world as global temperatures rise.
Atmospheric scientist Diandong Ren, from the University of Texas at Austin, recently compared a number of common climate projections to study how wind patterns might change if recent global warming trends continue. Narrowing in on China, Ren found that each of the climate models indicated the wind power available over China, at the average height of a wind turbine, is expected to decrease by about 14 percent within this century.
“We show that the efficiency of tapping wind energy is adversely affected by future global warming,” says Ren, in his recent paper.
This research is among the first to clearly predict a continual decrease in wind energy as average global temperatures go up, but the reasons why w...
Energy Outlook Portends High Oil Prices, Low Adoption of Hybrid Vehicles
By Eric Larson
The International Energy Agency (IEA) recently released its annual World Energy Outlook (WEO) for 2010, a report that is eagerly anticipated by governments and companies worldwide. The IEA was created 36 years ago in the wake of the first oil price shock and now has 28 member countries, including the U.S., most Western European nations, Japan, and several others.
The main writers of the WEO 2010 (all 26 of them), with input from many outside experts (203 are listed in the report), gazed into their crystal balls to try to discern what’s going to happen with energy during the next 25 years. When reading a document like this, I always try to keep in mind some sage words attributed to Yogi Berra, “It’s hard to make predictions, especially about the future.” It’s almost guaranteed that the quantitative predictions in a report like this won’t come to pass, but the deep analysis of trends presented in it offers a useful way to better understand where the world is today with regard to energy, and where we are headed. (And the analysis is really deep! The sheer volume of the document is intimidating, spanning 731 pages and including 120 tables and 267 graphs).
The WEO treats all manner of esoteric topics in depth — such as unconventional oil, energy poverty, energy in the Caspian region, and fossil-fuel subsidies. While many of these are primarily of interest to expert energy analysts (or those with too much free time on their hands), at least one topic — crude oil pri...
The Bike of the Future: Cumbersome but Swift
By Emily Elert
A few years ago my friend and I rode our bicycles a couple thousand miles across the country, and there was this weird thing that happened with the wind. On the headwind days (and there were a lot of those, traveling east to west), it was impossible to forget about the wind — it’s blasting into your face and screaming in your ears, and you can see every speck in the asphalt because, hard as you pedal, you’re barely moving.
But the tailwind days were different. Everything would go so beautifully and quietly and quickly that we would forget the wind existed, and instead we would begin to believe we had reached a new plane of physical fitness/existence in which riding an 80-pound bicycle across the country is easy.
Then the wind would shift again.
I forgot all about the tailwind/headwind thing until recently, when I spent a week test riding an electric bicycle around New York. Riding an electric bicycle — or, at least, riding the Optibike — is like having your own personal, perpetual tailwind.
Before the test ride, the whole concept of an electric-powered bicycle struck me as stupid. In the city, I ride a road bike with one gear, and everything from my bike-geek, quasi-physics-based philosophy about the joys of simple machines to the vain, ultra self-conscious basis of my outward identity directed me to love my single-speed 1974 Schwinn LeTour, and hate the electric bicycle.
Still, I wasn’t going to pass up the opportunity to ride one, s...
