I recently listened to one of my favorite podcasts, On Point with Tom Ashbrook, and heard an interview with Bob Lutz, General Motors’ Vice Chairman. In this interview he expressed dismay that Toyota is thought to be the fuel efficiency leader in the industry. This week I will run some numbers to shed light on the subject.
This weeks question is from Nick Gruber: “My question has to do with linen napkins vs. paper napkins. Is it more efficient to use linen napkins (factoring in the energy for picking them up and washing them) or paper napkins (recycled paper napkins)?”
This week’s question comes from Olle Holm, the editor of The Baltic Eye. “A question about ‘arctic OTEC’: I saw somewhere the idea to utilize the temperature gradient between arctic under-ice seawater (+1¬∞C) and the air above the ice (-40¬∞C). Would that be at all feasible for an OTEC-plant?” This question came in response to a column on OTEC (Ocean Thermal Energy Conversion) that I wrote a few months ago (read it here).
In honor of memorial day I will be taking a carbon-neutral trip to the mountains. I will be back with answers to your sustainability questions next week. If you have a great question please send it to pablo.paster(at)gmail.com.
Energy supply problems and the realization that a carbon-based economy cannot be sustained indefinitely have prompted us to look for alternatives. One such alternative is hydrogen, a noble gas abundant in water (H2O). Combustion of hydrogen releases only pure water and hydrogen fuel cells have a theoretical efficiency of 83%. Why is there not a fuel cell in every car and every basement? As this emerging technology matures, prices will decrease and fuel cells will become increasingly prevalent. Is hydrogen fuel cell technology suitable for use in vehicles? Or will the internal combustion engine remain the vehicle propulsion of choice? Bill Ford, Chairman of the Ford Motor Company says, “I believe fuel cells will finally end the 100-year reign of the internal combustion engine.”
This week Julio asks: “Is it more environmentally friendly to shop online or shop in-store? Or, is there a guideline I should use, since I shop online a lot?” I will try to offer my best answer and hopefully we will all learn something. I would like to remind the rest of you to please send in your sustainability-related questions or just topics that interest you. Just send me an e-mail at: Pablo.Paster(at)gmail.com.
Perhaps spawned by the immense popularity of Michael Pollan’s book The Omnivore’s Dilemma or just the recent explosion of interest in both food safety and climate change, people are demanding locally grown. Such “locavores” are participating in the 100 Mile Diet and are making the local farmers’ market the place to be. In March 2005 the BBC published an article entitled “Local food ‘greener than organic’” in which they quoted a report in the journal Food Policy that states “Food miles are more significant than we previously thought, and much now needs to be done to encourage local production and consumption of food.” Foodmiles is a term coined by Tim Lang, professor of food policy at London’s City University, that refers to the distance that a given amount of food travels from farm to plate.
In Part I we learned about the energy required to overcome rolling resistance and aerodynamic drag. In Part II we learned about the energy consumed in acceleration. Now it’s time to bring it all together. We know how much energy it takes to get a vehicle up to a certain speed and to keep it there. We also know that the fuel we put into the tank contains more energy than we get back out. My car’s efficiency came out to be 19.9% (see Part I), but where does the other 80.1% go? And is there anything else to consider?
This week we are continuing last week’s discussion on vehicle efficiency, from well to wheel. In last week’s column I introduced calculations for determining the energy needed to overcome aerodynamic drag and rolling resistance at a constant freeway speed of 65 mph. Using these equations I was able to show that my car is about 18.8% efficient at converting fuel energy into constant forward motion.
With gasoline prices as high as they are many people are concerned about vehicle efficiency. Other people who are concerned about their impact on the future of our climate care about vehicle efficiency as well. Where does the energy that we put into our cars actually go? And what is the overall efficiency of a car? Since I have pretty extensive data on my own vehicle, a 2005 Toyota Matrix XR, I will use it as an example in this week’s AskPablo.
This week’s question comes to us from Pete, who writes
“Okay – I’ll admit it, I’m lazy. I work in a second floor basement, and we make a couple trips a day to the street level to bring in furniture and supplies. There is an elevator that we can use. There are also stairs. I used to be really good about taking the stairs every time. But now, about 9 months after I started here, I find I’m choosing to use the elevator every time. Both going up and coming back down. I know, I know… See, I know that’s the wrong choice. But I was wondering if there was some way to quantify exactly how wrong of a choice it is. So to convince me to get back to taking the stairs, I think I just need a numerical push, and you might be able to help.”
Well, since Pete already knows that he is making the wrong choice I won’t need to try and convince him of that. All I have to do is spit out some numbers that confirm his feelings, and that shouldn’t be too hard…
Is it better to let your car warm up for a bit or tear off down the road right after ignition? Having lived in Maine I know that automatic car starters are a hot commodity when it is -30F outside. It is understandable that people don’t want to get in their car if their hands are going to freeze to the steering wheel but some people take it a bit too far. Some have been know to use the running car to get rid of the ice on the windshield. This is what the ice scraper was invented for, suck it up! Here in sunny California people may run their car for other reasons; to get the AC going or because they think it is better for the car (or the environment).
Are you concerned about your contribution to the climate change crisis? Are you still unsure about carbon offset programs? Well, you are not alone. While I am a strong believer in the value and importance of offset providers such as DriveNeutral and Native Energy I also realize that there are some organizations out there, whose carbon offsets might not be as verifiable or that take too much profit for themselves. If I can’t convince you to offset your emissions with a legitimate offset provider I would certainly like to help you to neutralize your climate impact in another way.
This week we are honored to have climate change expert Hoff Stauffer answering reader submitted climate change questions. Thank you to all of you who submitted questions during the last week.
According to Supercomputing Online ” in 2005, total data center electricity consumption in the U.S., including servers, cooling and auxiliary equipment, was approximately 45 billion kWh, resulting in total utility bills amounting to $2.7 billion.” The average emissions per MWh in the US are 0.61 metric tons (mT), so US data center electricity use amounts to 27.45 million tons of CO2 emissions annually. With 200,000,000 internet users in the US (2005), that is 137 mT for each one of us. But this is a whole other topic…