I haven't posted here for a while again. I've been busy with a lot of work for my research project. I know all about coal gasification, ethanol land use, problems with ethanol, new solar projects, and other good stuff. I should have a paper done mid March.
I've also been going to the gym a lot this semester. I have been there about twice a week riding a stationary bike in a cycling class. I can really tell the difference in my performance. Just this week I noticed I can ride at a very high output for long periods of time. I wish they had power meters on the bikes so I could see my watt output, and how I've improved. This week I also started doing some weight lifting after the hour bike rides. I should be in very good shape by the time spring arrives (will it this year?).
Last fall I purchased a big 4 meter traction kite, which is basically a big powerful kite designed for a large amount of pull on the lines. I bought it for fun and exercise, and it meets my goal of entertainment requiring little or no fossil fuel. It looks like a parachute and is designed similarly. I measured its air speed with a video camera and the kite reaches speeds in excess of 100 mph during 18 mph wind gusts! The kite has the power to lift me off the ground in higher winds, and it easily drags me through grass even with slow 12-15 mph wind conditions. One day I was practicing "kitejumping" and I was lifted about 4 feet off the ground and thrown about 40 feet forward! It is a huge adrenaline rush to be thrown through the air!
I finally decided to take advantage of the constant winter precipitation known as snow and bought a snowboard about two weeks ago. I bought it (or pretty much stole it based on the price) used from a guy here at the University. Most people would go to a ski hill to test it out, but I had different plans.
My new winter sport is kiteboarding. It consists of using my kite to drag me on a snowboard. I start by setting up the traction kite in an open area and then do a test flight to evaluate the wind conditions. Then I land the kite and attach the brake lines to a rope attached to a post or fence. I normally use a 12" steel spike stabbed into the ground, but that doesn't work good this time of year. I then strap into the snowboard and attach the kite killers to my wrists (they provide somewhat of a safety by pulling the brake lines on the kite if I lose control). I unhook the rope from the brake lines, tilt the handles back, and the kite launches into the sky.
This is where it gets interesting. The kite requires a lot of practice to fly. There are four lines and two handles. Each handle has two lines attached. The main lines provide the pull, and the other two are the brake lines. You can do simple maneuvers by changing the relative line length between the left and right side of the kite, but you really need to know how to apply the brakes to partially depower the kite in high winds and to provide power assisted cornering using just one brake line to make the kite turn very sharp. Besides all the control, which requires constant arm movement for steering along with wrist movement to control brakes, you have to be aware of the power window. The kite has to fly downwind of you, and it provides the most power about 10 meters off the ground directly downwind. There are parabolic shapes of wind power, depending on how far to the side you are away from directly downwind and the height above the ground. In simple terms, it will rip your arms out when downwind, and it flies like a little plastic kite with hardly any pull when directly overhead or far to the side.
I've used the kite quite a bit, so I have most of the understanding of the wind and control figured out. Now add a snowboard. I have done some downhill skiing, so I am familiar with sliding on snow. Snowboards are different, and my past experiences have all involved a small kid-sized plastic board I used last year. The kid design was rated for about 50 lbs, and I have only gone down tiny sledding hills with it. Basically, I have no snowboarding experience. I figured being dragged by a kite will be a perfect time to learn.
It's not.
The wind has thrown most of the snow off of the field I fly at. I am left with an inch or two of powder with ice underneath. Snowboards don't grip wind swept ice at all, and I need the snowboard to grip so I can change direction and get going fast. I don't want to travel with the wind, or else I will end up a few hundred feet away from where I started and I won't be able to get back. Speed is also limited going downwind due to a decrease in relative wind speed as I go faster. The best way travel is across the wind, that way you can accelerate to speeds several times the wind speed.
Trying to control a snowboard without falling over while turning and maneuvering with no prior snowboarding experience is a big challenge. Now add in the fact that I am attached to a kite, with both of my hands busy. I am trying to pay attention to where I am going on the snowboard while controlling the kite to be at the right spot in the wind window to give me the amount of power I want pulling me in the correct direction. Throw a gust of wind at me and I accelerate really fast, and suddenly pay attention to the snowboard and lose track of the kite, and then the kite swings back to the center of the power window and tries to drag in a direction I don't want to go and knocks me over in the process. I can't use my hands for balance, and I have to use the snowboard to resist my movements. When the wind is strong or a gust hits the kite, it tries to pull me over forward and knock me down, so I have to lean back. While I'm leaning back, the wind will die and I will fall over backwards.
As you have probably figured out by now, there are a ton of things to pay attention to at a single time. I need more practice, but it is definitely fun. I have gone out three times now. The first time I only went a few hundred feet due to poor wind conditions (either barely blowing or gusts approaching 25 mph lifting me off the ground). The other time the wind was marginal but the snow was good, and I was able to travel at least 1000 meters across the snow. The last time the wind was somewhat gusty, and all the snow had blown off the field. I traveled probably 500 meters before the kite knocked me over knee first onto a patch of ice and I quit for the day.
What may be surprising to those of you reading this from the warmth of indoors is that kiteboarding in 30 below wind chill is not cold at all. I use about every muscle in my body when kiteboarding and I end up overheating and unzipping my coat after a short amount of time. Controlling the kite and snowboard works some weird muscles and I feel it the next day.
Maybe this weekend we will have a good combination of wind and snow and I will try again.
Thursday, February 21, 2008
Monday, January 28, 2008
Free GIMP
If you have wanted to try your hand (or pointer, electronic pen, etc) at more advanced image editing than just cropping and basic color enhancement, you should really try out The GIMP. It is available at http://www.gimp.org/. The software is freeware with no fees for use. It is just like the high end Photoshop software, but the cost is much more reasonable.
The software does have quite the learning curve, but it is similar to other advanced image manipulation programs. Once you learn the basics of working with layers and start experimenting with the different image effects, you will get the hang of it. There are tutorials online you can use that will teach you how to do specific things, but at the same time teach you shortcuts, methods, and easy navigation through the program. There are also books you can purchase to speed the process.
The software does have quite the learning curve, but it is similar to other advanced image manipulation programs. Once you learn the basics of working with layers and start experimenting with the different image effects, you will get the hang of it. There are tutorials online you can use that will teach you how to do specific things, but at the same time teach you shortcuts, methods, and easy navigation through the program. There are also books you can purchase to speed the process.
Thursday, January 24, 2008
Graphics
Now that I'm back to the blog, I hope to make it look a little sharper. I was playing around tonight learning some graphics tools and created the "Jeff's Blog" image shown here.
This is my first creation like that, and I'm surprised at the amount of work it takes. There are five layers of different colors, textures, and text to create what you see, including a shifted layer to make a shadow. I think it looks good. I will hopefully make another more detailed version soon to place at the top. Then I will update the photo on the side, or just include it in the main header.
This is my first creation like that, and I'm surprised at the amount of work it takes. There are five layers of different colors, textures, and text to create what you see, including a shifted layer to make a shadow. I think it looks good. I will hopefully make another more detailed version soon to place at the top. Then I will update the photo on the side, or just include it in the main header.
Wednesday, January 23, 2008
A number check on ethanol
I haven't posted on here for a while. I've been very busy over the past six weeks.
The grad school work has kept me busy. Recently I have been looking at biomass, which led me to do some interesting calculations.
Here is the question (when you get into engineering, all questions have multiple parts): If you have an acre of corn grown and converted to ethanol, how much energy do you get? How does it compare to the solar energy striking the ground? How does it compare to a single wind turbine?
From various sources, the amount of ethanol per acre comes out to about 450 gallons. The energy content is equivalent to about 40 GJ (gigajoules, it didn't take long for me to run away form the inferior US units). To put 40 GJ in perspective, that is equivalent to about 11,000 kilowatt hours. That is a deceiving number, because the energy is not available except as heat in that quantity. If the ethanol is used to drive an engine to power a car or produce electricity, the actual amount of energy available will be about 3,500 kWh.
Solar energy strikes the land at a year round average in Iowa of about 160 Watts per square meter. Working out the numbers, 5,650,000 kWh of solar energy strikes an acre annually. Once again, not all can be harvested. Lets figure a photovoltaic panel is used with 10% conversion efficiency, and they are placed to collect about half of the energy available. Even with these low numbers for efficiency, 282,500 kWh of electrical energy is produced. This is about 80 times the amount of energy gained from ethanol.
Wind energy varies, but typical wind turbines output between 4,500,000 and 6,000,000 kWh a year. Each one takes up 1/4 acre of land. They must be spaced apart or else the turbines will interfere with each other and disrupt the wind. Working out the numbers, it takes about 37 acres for a wind turbine. From a one acre plot of land, a wind turbine will output about 120,000 kWh of energy, or about 34 times the output of growing corn for ethanol.
To put the numbers in perspective, if fields were not cultivated at all and turned into a natural prairie with wind turbines covering the landscape, about the same amount of energy would be produced. If we covered 600 square feet of a house roof in solar panels, we would output the equivalent energy of an acre of corn (43,560 square feet).
None of this analysis takes into account the energy input for ethanol. A wind turbine must be constructed, and it typically pays back the amount of energy for construction in a few years. Photovoltaics are the same way, with payback of a few years. Very little fuel consumption goes into the annual upkeep of the wind and solar technologies, compared to the huge amount of fuel that goes into an acre of corn for ethanol.
The problem with any biocrop is the efficiency of photosynthesis. The efficiency is less than 0.5% at best. Corn is only growing for a few months out of the year, and the rest of the year the field is bare and not collecting energy, further reducing the amount of solar energy collected.
Does it require more fuel to make ethanol than we get from the fuel? I am not totally sure. A lot of the pro-ethanol studies are done by pro-ethanol groups. I did a calculation the other day showing that it takes about 1,000 kWh of energy to make the ammonia to feed an acre of corn. Considering we only get 3,500 kWh out of the crop, and I didn't account for transportation of ammonia, corn, ethanol, or the huge amount of natural gas used at the ethanol plant, the net energy gain is going to be very very small.
Keep in mind that the energy food energy consumption of a human is about 2.5 kWh per day. We can feed thousands of meals off of that acre of land if used for food. We can fuel an SUV for less than half a year on the corn energy from an acre of land. Which one should be our priority? Which method of land use (solar, wind, corn ethanol) is the most efficient and best use of our resources?
The grad school work has kept me busy. Recently I have been looking at biomass, which led me to do some interesting calculations.
Here is the question (when you get into engineering, all questions have multiple parts): If you have an acre of corn grown and converted to ethanol, how much energy do you get? How does it compare to the solar energy striking the ground? How does it compare to a single wind turbine?
From various sources, the amount of ethanol per acre comes out to about 450 gallons. The energy content is equivalent to about 40 GJ (gigajoules, it didn't take long for me to run away form the inferior US units). To put 40 GJ in perspective, that is equivalent to about 11,000 kilowatt hours. That is a deceiving number, because the energy is not available except as heat in that quantity. If the ethanol is used to drive an engine to power a car or produce electricity, the actual amount of energy available will be about 3,500 kWh.
Solar energy strikes the land at a year round average in Iowa of about 160 Watts per square meter. Working out the numbers, 5,650,000 kWh of solar energy strikes an acre annually. Once again, not all can be harvested. Lets figure a photovoltaic panel is used with 10% conversion efficiency, and they are placed to collect about half of the energy available. Even with these low numbers for efficiency, 282,500 kWh of electrical energy is produced. This is about 80 times the amount of energy gained from ethanol.
Wind energy varies, but typical wind turbines output between 4,500,000 and 6,000,000 kWh a year. Each one takes up 1/4 acre of land. They must be spaced apart or else the turbines will interfere with each other and disrupt the wind. Working out the numbers, it takes about 37 acres for a wind turbine. From a one acre plot of land, a wind turbine will output about 120,000 kWh of energy, or about 34 times the output of growing corn for ethanol.
To put the numbers in perspective, if fields were not cultivated at all and turned into a natural prairie with wind turbines covering the landscape, about the same amount of energy would be produced. If we covered 600 square feet of a house roof in solar panels, we would output the equivalent energy of an acre of corn (43,560 square feet).
None of this analysis takes into account the energy input for ethanol. A wind turbine must be constructed, and it typically pays back the amount of energy for construction in a few years. Photovoltaics are the same way, with payback of a few years. Very little fuel consumption goes into the annual upkeep of the wind and solar technologies, compared to the huge amount of fuel that goes into an acre of corn for ethanol.
The problem with any biocrop is the efficiency of photosynthesis. The efficiency is less than 0.5% at best. Corn is only growing for a few months out of the year, and the rest of the year the field is bare and not collecting energy, further reducing the amount of solar energy collected.
Does it require more fuel to make ethanol than we get from the fuel? I am not totally sure. A lot of the pro-ethanol studies are done by pro-ethanol groups. I did a calculation the other day showing that it takes about 1,000 kWh of energy to make the ammonia to feed an acre of corn. Considering we only get 3,500 kWh out of the crop, and I didn't account for transportation of ammonia, corn, ethanol, or the huge amount of natural gas used at the ethanol plant, the net energy gain is going to be very very small.
Keep in mind that the energy food energy consumption of a human is about 2.5 kWh per day. We can feed thousands of meals off of that acre of land if used for food. We can fuel an SUV for less than half a year on the corn energy from an acre of land. Which one should be our priority? Which method of land use (solar, wind, corn ethanol) is the most efficient and best use of our resources?
Subscribe to:
Posts (Atom)
