Lee Devlin's Weblog

A few weeks ago I visited the National Renewable Energy Lab open house in Golden, CO with a few other members of the Northern Colorado Clean Energy Network. I'd wanted to see this facility for some time, and figured that an open house on a Saturday would allow some of our members who normally are unable to attend our energy tours during the week to join us. As it turned out, we only had 4 members of our group show up. Despite the low turnout, we had a good time carpooling there and back because we got to chat for a few hours about renewable energy topics.

The NREL has a visitor's center and there was a presentation in progress when we arrived about how to do an energy audit on one's home. Several of us had just been to an NCRES presentation on this topic recently so we did not sit down to listen to the presentation. The presentation took up much of the visitor's center display area, making it impossible to talk without disrupting the presentation so our ability to wander around inside was a bit limited.

The exhibits were very nicely constructed and a docent explained the various renewable energy programs underway and the purpose of the various buildings on the campus. There are numerous projects going on all over the facility, but unfortunately they are off-limits for visitors. Only the visitor's center is accessible. I had expected this to be the case, and so I tried to gather some information about what would be necessary to get a tour of the actual laboratories in the hope that some future visit would allow us to get better access to what's going on in the labs. I can see that it will be a challenge as they are not set up to handle tours of the actual labs.

The docent who was our guide had spent most of his career in the power field, and I had a long discussion with him about transmission of power over high voltage DC lines. Transmitting power over DC lines is counter-intuitive for most engineers who were taught that you can only transmit utility scale power on AC lines. But thanks to advances in high power semiconductor components to handle utility scale power, DC power transmission lines are becoming more common to deliver electrical power long distances and to help isolate grids through interties. This method of transmitting power will become more important in the future as some of the best potential sources of renewable power generation such as wind and solar tend to be far removed from population centers. HVDC power transmission has the advantage of being able to isolate the grids so that the need to control the phase of the AC power over long distances is not required. The largest DC line in the U.S. is the Pacific DC Intertie which takes hydroelectric power from the Columbia River in Washington State and delivers it to customers in the Los Angeles area.

My favorite Visitor's Center exhibit was the section of the GE 37-meter wind turbine blade. I've seen these blades up close during our Ponnequin Wind Farm tour, but was curious about the materials of construction. With the section exposed, I saw that the materials looked identical to those used in my LongEZ and Cozy. They consisted of wood, foam, fiberglass, and epoxy albeit on a much larger scale that what is used in my planes.

Labels: energy, technology, wind

A few months ago I did some research and wrote some blog postings about hydroelectricity in Colorado. I had been asked by my friend, Bevan, whether we were failing to take advantage of the hydroelectric power that was available from the rivers in Colorado simply because of the political issues associated with damming our beautiful river canyons. In doing this research, I found that we do, in fact, harvest some of the hydro power and, due to the fact that the flow rates of these rivers are not large or consistent, we would not really gain much power generating capacity even if we extracted all of their theoretical hydroelectric energy.

One of the most fascinating public projects I read about during my hydroelectric research is the Colorado Big Thompson water diversion project. Using a series of tunnels, pipes, canals, reservoirs and pumping stations, this project collects and diverts water from west of the continental divide and brings it to the eastern slope. About 70% of the population of Colorado lives along the Front Range, yet 70% of the precipitation falls on the western side of the continental divide. The C-BT project provides about 213,000 acre feet of water to the eastern slope each year. Nearly all of this water has its energy extracted through a series of electric generating stations with a combined capacity of 162 MW. That's enough electricity for about 80,000 homes. It also provides enough water for about 425,000 homes. To put it in perspective, the C-BT project delivers more water to the Front Range than both the Big Thompson and Cache la Poudre rivers combined.

An acre-foot of water is about 326,000 gallons. Each household in Colorado uses about .5 acre feet per year which about 13,600 gallons per month. This is about 30% more than the national average, which is due to the need to irrigate our lawns. Colorado has a very dry climate and in order to have a lawn and shrubbery, they must be irrigated. It made me wonder how much water we use for things that are essential compared with uses those that are not essential, such as growing lawns.

A general rule of thumb is that each person in the U.S. uses about 50 gallons of water per day. You can estimate your daily consumption by visiting a USGS site and using their calculator. The calculator uses the following values for personal water consumption:

• Bath: 50 gallons
• Shower: 2 gallons per minute
• Teeth brushing: 1 gallon
• Hands/face washing: 1 gallon
• Face/leg shaving: 1 gallon
• Dishwasher: 20 gallons/load
• Dishwashing by hand: 5 gallons/load
• Clothes washing (machine): 10 gallons/load
• Toilet flush: 3 gallons
• Glasses of water: 8 oz. per glass (1/16th of a gallon)

Another way measure your household's water consumption is to look at one of your water bills from a winter month. I found that our water consumption comes out very close to the estimate of 50 gallons/person per day. The real shocker for me was looking at a summer water bill and comparing it to a winter water bill. Our summer water consumption goes up by a factor of 10! For about 4 months out of the year we need to run the sprinkler system and its water consumption dwarfs the amount of water for personal use during those months. Overall, watering our lawn for those 4 month accounts for more than 65% of our annual water consumption!

I began to wonder what this is costing us so I began to study our water bills. Interpreting utility bills is not always easy. There are sometimes so many charges that it's hard to tell what drives the overall cost. I had to call our city's water department to figure out how the charges are computed. In the case of our water bill, there are three charges. The first is for the storm sewer, which is based on the size of the property. The second is for the regular sewer bill, which is determined by water consumption during a winter month to eliminate the effect of irrigation water, which doesn't return to the sewer. The last is the cost of the water used based on a meter reading to measure actual water consumption. Included in the water charge is a flat connection charge, which is around $8/month. When you combine the two sewer charges of $18 with this $8 charge my water bill is already at $26/month before I've purchased my first gallon.

The cost per 1000 gallons of water in Greeley is $2.41, which is about the average in U.S.. That's up about 40% from what we were paying 6 years ago, so it's been increasing faster than inflation. For those of you in other countries who measure water in cu. meters, there are about 264 gallons per cu. meter.

I visited the manufacturer's web site for my sprinkler system and found out that each 360-degree sprinkler nozzle uses about 3 gallons per minute. The quarter and half nozzles use proportionally less water per minute. I have 9 sprinkling zones each with a total of about 5 "360-degree equivalent" heads, so when I'm watering my lawn, I'm using about 15 GPM. My watering cycle takes 3 hours so that comes out to 2700 gallons. At the $2.41/1000 gallon cost, it costs about $6.50 each time the sprinkler cycles. We're restricted to 3 days a week that we can water the lawn, so that adds about $80/month for watering the lawn in the summer time. Now that I know how much each watering costs, I'm being more vigilant about using the timer's 'rain' button to suspend watering when we've just gotten some rain. I've even been looking at the weather forecast to see if it makes sense to skip a cycle if rain is predicted.

Sometimes people have asked if we can do something more intelligent when it comes to watering lawns, such as using 'gray water', i.e., the water that would normally be sent to the sewer and directing it to water the lawn instead. That might work for water that is lightly contaminated such as water from a shower or dishwasher, but there is no easy way to separate that from the other contaminated water that you (and your neighbors) wouldn't want on your lawn. We also need to consider that waste water from inside the house is eventually treated and put back in rivers where it can be used downstream. Also, now that I know that it takes 10 times as much water to keep the lawn green as the amount we need for personal use, I can see that recycling gray water would hardly put a dent in one's overall water consumption.

How about collecting rain water from the roof and other surfaces and storing it? In my case, only about a third of our 1/2 acre lot has grass on it. The rest is covered with impervious surfaces like the house, concrete patios, the driveway, and landscaping rock. If it were possible to capture the rain water, would this work to offset or even eliminate a watering bill? I did the calculations and there does appear to be enough precipitation that falls on this lot (about .5 acre-foot per year) to supply all of our watering needs. However, to store and treat this water would not be practical. A single lawn watering takes 2700 gallons which comes out to 8000 gallons per week. Since it can sometimes go for weeks without any significant rain during the summer, we'd likely need a 20,000 gallon storage tank to store $50 worth of water. Then you have to consider that it would take chemicals to keep it from turning into a bacteria pond and it's easy to see why cisterns have never proved to be very popular when tap water is available. There are even laws about capturing one's own rain water in Colorado since water rights and property are separate and so it is against the law to capture and hold your own property's rain water. Here's an article about water harvesting in Colorado that contains more information about it.

The other option is xeriscaping which means having a lawn with plants that can survive with no supplemental irrigation water. However, this is not always possible and the attractiveness of this approach will no doubt vary with the eye of the beholder. My friend Peter lives in a subdivision where the covenants require the residents to have a certain percentage of green grass in their lawns. Some people say that they love the look of natural desert, but to be honest, it's only beautiful at a distance. The natural ground cover on Colorado's Front Range is mostly noxious weeds full of pointy things that will pierce your skin. There is not much attractive about what grows on Colorado's Front Range naturally. Most people think of Colorado as beautiful mountains filled with Aspen and pine trees. That all starts about 30 miles to the west. Most of us live on the plains.

The availability of water is starting to limit growth in this area and if we get a serious drought, it will likely cause a further restrictions on new growth. The new water tap connection fees are already in excess of $14,000 per home in Greeley.

People like living in dry climates because it's almost always sunny and there's very little humidity. But we all need water to survive and to create an attractive environment. We all like having green grass and shade trees nearby. We have plenty of land in Colorado for future growth, but not enough water to support unrestricted growth. Every gallon of water I conserve will likely get used up by some new construction project that is enabled by the water's newfound availability. It's quite a dilemma about what to do when it comes to water conservation. Everyone wants to do their part, but if the reward for it is more growth and more people, then that takes some of the incentive out of it. We could grow the population of Colorado until we're all walking around in stillsuits, but what good would that be?

Having said that, I do realize that certain industries like construction depend on new growth to survive. I hate to be like the people who, once they have found a promised land, put up a no trespassing sign and tell everyone else to stay out. That's not an uncommon sentiment to hear people express in this area. The city of Boulder has had an anti-growth policy for many years. Everyone wants to be the last one in.

Colorado is somewhat unique among the dry western states because we have areas in the state that get in excess of 50 inches of precipitation per year and areas that get less than 10 inches per year. Most of the areas where people live get between 10 to 15 inches per year, which is not enough to grow much more than cactus, thistles, and tumble weeds. To put it in perspective, states east of the Mississippi get between 40 to 50 inches of precipitation per year and it's quite consistent throughout the region. When you get over about 40 inches per year, it's usually not necessary to irrigate one's lawn. In Colorado, most of the high precipitation areas are the mountain peaks, which tend to hold the precipitation throughout the winter in the form of snow and release it gradually during the spring runoff. This runoff is captured in a number of reservoirs and used during the dry summer months for residential, commercial, and agricultural use. It's a very delicate balance that requires carefully matching the supply with the demand.

The problem with precipitation is that it is local and seasonal. In other words, it's difficult to match the amount of precipitation you get with where you need it, when you need it. And that problem is compounded in states like Colorado where the population and seasonal effects of precipitation are not matched very well. We need to be very resourceful about how we collect, distribute, and use the water resources we have. And one must not underestimate the beneficial environmental impact of paving corn fields and constructing strip malls in their place, an activity that has continued unabated in Colorado over the past decade.

That leads me to my last observation. Is agriculture on a high desert plain an intelligent use of land and water? I'm sure that for people who are involved in farming that they'd consider it to be the most beneficial use of the land. They'll no doubt maintain that attitude until someone offers them several hundred years' of annual farming profits for the property to construct a residential neighborhood or a strip mall on the land. In the case of high density living where one builds apartments, this would definitely qualify as a net water savings. Irrigated crops in this region take about 1.3 acre-feet of irrigation water per acre on the average, whereas if you put about 12 people on that acre, it would take less than half of the amount of water, especially if you pack them in so that you don't have much lawn to water. If you pave the parking lot and streets around the neighborhood, all the better, because the water that falls on it can be collected and used elsewhere. Similarly, virtually all the water that crops use evaporates, but most of the water people use gets treated and put back in the river just a few miles away, so it can be used downstream. I do realize that water that evaporates will eventually get recycled, but unlike a river, it's a lot harder to maintain claim to it once it goes into the sky.

So it would appear that for every acre of agriculture we give up, we can jam another 12 residents into Colorado. Then all we need to do is find some jobs for them.

Labels: energy, hydro, technology

On Thursday, May 15th several members of the Northern Colorado Clean Energy Network toured the Denver Arapahoe Disposal Site to see a new landfill gas-to-energy project currently under construction and nearing completion. The site is constructed on a concrete pad that had previously been used for remediation of materials removed from the Lowry landfill, a superfund site, which is adjacent to the DADS landfill. For a period of around 13 years, beginning in 1967, the Lowry landfill received more than 100 million gallons of liquid chemical waste. I had incorrectly assumed that this Lowry superfund site was in some way associated military activity because it shares its name with the former Lowry Air Force base, but it was actually created by legal dumping at the city-owned landfill. The landfill's name is likely a result of its proximity to the Lowry AFB Titan 1 Missile Complex 1A which is just to the west of it.

In addition to touring the facility, our tour guide also drove us up on to the top of the landfill where large earth movers were organizing the waste into 'cells' that were compacted and covered up with dirt. The dirt helps to keep the trash from blowing away and reduces its odor. The mountain that they are now constructing in this section of the landfill will eventually reach a height of 300 feet. If you want to see an aerial view of the site, here's a link to Google Maps. You can see the Lowry landfill in the lower southwest section, a completed portion of the landfill that is 150' tall in the northwest section, the new part under construction in the north east section, and a decommissioned Titan 1 nuclear missile site in the southeast section. If you zoom into active part of the site with the Google Maps view, please note the number of earth movers you can see on the site. That helps to give you a perspective on how big this site is.

The methane gas that will power the 4 16-cylinder 1100 HP Caterpillar engines is piped from various sections of the landfill. This gas is currently being flared (burned) and relased to the atmosphere in compliance with government regulations. Once the plant has been commissioned, the gas will be re-routed to the engines where it will be used to generate electricity. The current flow is 1200 cfm and that can produce 3.2MW of electricity which is enough to power about 3200 homes.

Landfills leak methane gas as the organic materials buried in them decompose and so if it's not collected, it's possible for it to accumulate and if it does that, it can become an explosion hazard. Even if the methane were not to accumulate, it would eventually find its way into the atmosphere and methane is about 25 times more potent as a greenhouse gas than CO2 so it's better for the environment to collect and burn it and turn it into CO2.

The gas that comes out of a landfill is actually about half methane and half CO2 with small amounts of water along with minute amounts of other gases. The water needs to be removed from the gas to prevent it from corroding the engines and there is an apparatus that uses alternating heating and cooling of the gas to condense out the water. The water removed from the gas is sent to a water treatment facility. The diesel engines have been specially modified to run on a mixture of methane and CO2.




One part of the facility that I found particularly interesting were the controls that took the electricity and converted it for use on the grid. They used Woodward controllers and large cabinets with impressively large bus bars and capacitors. It was one of the parts of the facility where no pictures were allowed.

The 4 engines are currently 16 cylinder models but the facility is sized so it can be re-fitted with 20 cylinder engines that would produce twice as much power should the gas flow continue to increase. Because of Denver's arid climate, the gas flow from these sizable landfills is just a fraction of what it would be in a moist climate. This is a disadvantage in some ways, but a benefit in other ways. It takes a much larger landfill in an arid climate to make economic sense for electricity generation, but it should also produce methane for a longer period of time, because it will take longer for the organic material inside the landfill to decompose. At the current rate of gas production, the existing wells should produce for another 20 years. There is enough land available for many decades before this landfill would be considered 'full' and the newer mountains will be much larger than the existing ones and so this landfill may be producing electricity for many decades.






This landfill is owned by the city of Denver and receives about 1200 truckloads of solid waste per day. It operates 6 days a week, 24 hours a day. In addition to burying trash, there is a concrete recycling operation on site where old concrete is ground up and used over again, saving cost on materials and energy over making concrete from scratch. There are several other recycling operations on the site.

I came away from this trip impressed with the engineering that has gone into designing and maintaining a modern landfill. We have come a very long way from just a few short decades ago when we though it was environmentally responsible to handle liquid chemical waste by simply dumping it in an out-of-the-way place, not realizing that a city would eventually grow out to meet it. To be fair, at that time the links between the long term health effects of exposure to toxic substances were not well known and so many waste handling policies of that era were formed out of ignorance. This site is continually monitored to make sure that nothing hazardous makes its way into the water table or atmosphere.

We'd like to thank Brad Gagne and Steve Derus for making this trip possible and for answering the numerous questions we had about the facility. Everyone felt like they got a lot of out seeing an operation like this up close.

Labels: energy

I've written before about Vestas, a Danish wind turbine manufacturer that built a blade facility in Windsor, CO about 10 miles from where I live. I was out flying around the other day and took an aerial photo of the plant and found that they had more than 70 blades on their property. I was impressed because they hadn't even broken ground at this time last year and they are already up and producing blades. They had started out with a planned capacity of 1200 blades per year, but announced a 50% expansion while the plant was still under construction. They feel as if the U.S. will continue forward with wind development, despite our government's reluctance to commit to a long-term strategy when it comes to renewable energy.

The amount of energy that this blade plant produces annually will generate enough electricity to power about 400,000 homes. I computed this by de-rating the 600 sets of blades to 1/3 of their 2 MW nameplate capacity. This is similar to the amount of power generated annually from a conventional coal-fired power plant.

I subscribe to a Google Alert for news on Vestas, and on Friday morning I found out that Vestas will be building a new facility in Colorado to manufacture steel towers for their turbines. The facility will employ 400 people and be capable of producing 900 towers per year. They didn't specify a location, but according to the Northern Colorado Business Report, it appears that several communities in Northern Colorado are under consideration.

Labels: energy, wind

There's probably no topic more important to those of us who fly General Aviation aircraft than the continued availability of aviation fuel. For those of you who may not be familiar with aviation, the fuel used in aircraft is made the old fashioned way because it uses tetraethyl lead to increase the octane rating. High octane fuel is necessary because about 30% of the aviation fleet use high compression engines, and those aircraft use 70% of the aviation fuel. The engine I'll be putting in my Cozy MKIV will require this fuel. Leaded fuel has been outlawed by the EPA for all other uses, but aviation fuel got an exemption for a period of 30 years. That period ends in 2010, which is coming up soon.

I agonized over the decision over whether to use a high or low compression engine in the Cozy but I figured that with all the aircraft fleet that need 100LL, there would be some fuel developed that would come to the rescue, possibly an ethanol based biofuel. Of course, with an experimental aircraft, I could always put lower compression pistons in the engine and use autogas, if I had to, but that's not ideal. So I was very excited to hear about this new fuel that is being developed that has so many advantages that it's hard to believe it's true.

I emailed the owner of the company and he responded. That's always a good sign. Not only that, he graciously referred me to his associates on the project if I had any more questions about it. I'm really hoping that these guys are successful. Here's the report I got from Avweb:

New GA Fuel Promises Better Range, Lower Cost

"Not only can our fuel seamlessly replace the aviation industry's standard petroleum fuel [100LL], it can outperform it," says John Rusek, a professor at Purdue University and co-founder of Swift Enterprises. The company recently unveiled a new general aviation fuel that it says will be less expensive, more fuel-efficient and environmentally friendlier than any on the market. Unlike other alternative fuels, Rusek said, SwiftFuel is made of synthetic hydrocarbons that are derived from biomass, and it can provide an effective range greater than 100LL, while costing about half as much to produce. "Our fuel should not be confused with first-generation biofuels like E-85 [85 percent ethanol], which don't compete well right now with petroleum," Rusek said. Patented technology can produce the 1.8 million gallons per day of fuel used by GA in the U.S. by using just 5 percent of the existing biofuel plant infrastructure, the company said.

The synthetic fuel is 15 to 20 percent more fuel-efficient, has no sulfur emissions, requires no stabilizers, has a 30-degree lower freezing point than 100LL, introduces no new carbon emissions, and is lead-free, Rusek said. In addition, he said, the components of the fuel can be formulated into a replacement for jet/turbine fuels. The company now is working with the FAA to evaluate the fuel.

Labels: aviation, energy, ethanol

I'm helping to organize another Energy Reality Series tour this month. The Northern Colorado Clean Energy Network and NCRES are planning a tour of the Denver Arapahoe Disposal Site to see the new Landfill Gas-to-Energy Project.

Today’s modern, engineered landfill is an environmentally sound system for waste disposal that minimizes the impact on the environment. Landfills also offer a clean, renewable energy resource that is generated continuously through the decomposition of waste in landfills. This resource is known as landfill gas or methane.

Most landfills collect landfill gas, a greenhouse gas, and burn it in a flare system to destroy it. Instead of simply flaring the gas, the Denver Arapahoe Disposal Site will use this gas to generate electricity. Our tour director from Waste Management will explain how this is done and answer any questions you may have about it.

Date/Time: Meet on Thursday, May 15th, 2008 at 8:15 a.m. We will depart at 8:25 a.m.
Meeting place: Northwest corner of Harmony Road/I-25 Park-and-Ride in Fort Collins, CO

The park-and-ride is located just north of the first traffic light when you head west on Harmony Road from I-25.

We will leave at 8:25 a.m. and carpool to the Denver Arapahoe Disposal Site which is located in Aurora south of Denver International Airport . Directions from Harmony/I-25 intersection:

• Go south on I-25 and take the exit for E-270.
• Meet up with I-70E and continue until you come to the 225S exit. Take 225S until you reach the Parker Road Exit.
• Take Exit 4 and merge on to CO-83S - Parker Road.
• Turn left on E. Hampton Ave and follow it for approximately 6 miles to the entrance of the Denver Arapahoe Disposal Site.

The address for the site is 3500 S. Gun Club Road, Aurora, CO for those who want to program a GPS.

It may be faster to take E-470, but it is a toll road. The tour is scheduled to begin at 10:00 a.m.

The tour should takes about 1.5 - 2 hours and the drive time each way from Fort Collins will be about 1.5 hours.

If you want to go on the trip, please contact Lee Devlin via email at lee810@yahoo.com or by phone at 970-978-6188 and let me know the names of the people you're bringing, and whether you will be carpooling. That phone number is my cell phone that I'll have with me at the time of the tour in case you need to contact me.

The most current information about this tour can be found here:
http://www.k0lee.com/dads-tour.html

I'd like to thank Peter Olins and Patrick Gill for their help in setting up this tour.

Labels: energy

Link

For the first time in history, Boeing demonstrated a manned, hydrogen fuel cell powered aircraft. I had written about a Sonex electric aircraft I saw at Oshkosh last year, albeit as a static display model that used 250 lbs of batteries. It would only operate for about 18 minutes at full power, or just a small fraction of the time you'd expect from a gasoline powered aircraft.

In this case, the flight was at a speed of 55 kts, at an altitude of 3300 feet for 20 minutes in a converted motor glider, so the range/capacity is likely to be on par with the Sonex. Boeing does not anticipate that hydrogen fuel cells will be able to provide primary power for a commercial aircraft.

I think that the outcome of these recent demonstrations show that the future of air travel will continue to depend on liquid hydrocarbon fuels. Short of a miraculous discovery, when fossil fuels are exhausted hydrocarbon fuels will need to come from biomass feedstocks. After a rash of articles inspired by a recent Science article critical of biofuels, even Time Magazine has jumped on the dogpile, parroting the statements that biofuels are a scam and an environmentally damaging approach to generating energy.

In the future, the sun and wind will likely provide enough energy to heat our homes and provide us with electricity. Those energy sources may even power a commuters vehicle a few dozen miles a day. But to move something like a ship, a truck, a train, or a plane, it appears we'll be dependent on liquid hydrocarbon fuels for some time. This might not be the case if the energy density of battery technology would approach that of hydrocarbon fuels per kg., but thus far it's still several orders of magnitude away. Even with the thermal to mechanical energy inefficiency of the internal combustion engine which averages around 30%, energy density is still the primary advantage of conventional fuels over batteries.

Perhaps the best chance to please everyone would be to use wind and solar power to pull carbon dioxide out of the atmosphere, combine it with hydrogen, and synthesize clean burning hydrocarbon fuels. I suspect that no sooner than a method became practical, there'd be another dogpile forming, no doubt protecting existing interests by decrying the evils of robbing CO2 from the atmosphere.

Renewable energy certainly has a lot of controversy and drama associated with it. You wouldn't expect that from a field that should be primarily technical and scientific, but when anything has the potential to affect economics, politics, and the environment, technical arguments seem to hold little sway.

Labels: aviation, biomass, energy

My friend Peter asked if I would write about the amount of water it takes to produce a gallon of ethanol. I have often heard this figure to be quoted at 1000 gallons of water per gallon of ethanol. I wasn't sure how accurate this was, so I started doing some investigation. I found that I live in a county in Colorado that has the most irrigated acres of any of Colorado's 63 counties, accounting for 11% of the state's total. I found that corn requires a moderate amount of irrigation as far as crops go, about 16.5 inches per year in my county. Alfalfa has the highest watering requirements or about 23 inches and melons only require about 8 inches annually. When you compare irrigation requirements with Colorado's average rainfall of 15.5 inches per year, it is obvious that more than half of the corn's water requirements must come from irrigation and this is even more apparent when you consider that corn only grows for 3 months out of the year and during those months, the rainfall total is only about 5 or 6 inches.

Some of the irrigation is provided through surface canals fed by mountain runoff and some is from center pivot irrigation which brings water up from deep wells. I will calculate the energy cost per acre of using a center pivot irrigator assuming a 200-foot deep well and a 50 psi pressure at the pivot's center.

Since an acre is 43,560 sq ft. and we need to apply 16.5" of water to it during the corn growing season, this comes out to 59,895 cu. ft. or 497,128 gallons of water per acre. Last year's average Colorado irrigated corn yield was 189 bushels/acre and the average conversion rate is 2.7 gallons of ethanol per bushel of corn. So the ethanol yield per acre is 456 gallons. Dividing that into 497,128 shows that the number of gallons of water to produce a gallon of ethanol in Colorado is around 1100. This seems quite substantial. Colorado has a very dry climate where virtually no crops can grow without irrigation. In most of the corn belt states like Iowa and Illinois, the average rainfall is closer to 40 inches per year, and so irrigation shouldn't be necessary and thus even though it may take just as much water to grow corn as it would in Colorado, the rain will fall whether you're growing grass, or forest, or corn, so I don't think that the amount of water consumption is as much of a concern as it is in states like Colorado where water is considered a scarce resource.

I mentioned I'd also do the energy calculation for lifting the water from a 200 foot well. 497,128 gallons of water weigh about 4.1 million lbs. and lifting that much water 200 feet and maintaining 50 psi at the center pivot would require 1300 M ft-lbs of energy. This is equivalent to 490 kWh. Derating for a pumping efficiency of 65% we can estimate it would require about 760 kWh in electricity consumption per acre at a cost of $76/acre using $.10/kWh for the electricity rate. With corn selling for around $4.60/bushel, this accounts for about 9% of the value of the corn. So spending $76/acre seems like a reasonable trade-off considering that without irrigation, the corn yield in Colorado would be close to nothing.

Water is the most renewable of all natural resources but sometimes it's treated like it's a scarce or even endangered resource. The stuff does literally fall from the sky. So I guess it all depends on one's situation as to whether water is scarce or plentiful. If you are in the middle of a flood, water is anything but scarce, yet if you're dying of thirst, it can be more precious than gold.

Is it worth 1000 gallons of water to produce 1 gallon of ethanol? Again it depends on one's perspective. If you need to drive a car for 20 miles, 1000 gallons of water will be of no help, but a gallon of ethanol certainly would be. And in the majority of corn-growing states, not planting corn on the land will not prevent rain from falling on it so there'd be no real water savings.

Labels: energy, ethanol

Back in 1987, on a cold January day, I found a Harley-Davidson ElectraGlide Classic advertised in the local newspaper. I had known from a relatively young age that the one thing separating me from true and everlasting happiness was owning a Harley-Davidson motorcycle. And so, with that in mind, I embarked on the pursuit of making that bike mine. It had been repossessed and was owned by the local bank, and they only wanted to get the bad loan off their books, so they did little to properly advertise the bike. It was in a shop in an out-of-the way place and so I went over to take a look at it. It was in very good condition, only 3 years old and had the highly desirable 80 cu. inch Evolution V-twin engine which was new for the 1984 model year. It also had an accessory that was not on my ‘must have’ list, namely, a sidecar. I always felt a sidecar looked somewhat odd on a motorcycle, but I reasoned that if I could get the bike for a price that made the sidecar look virtually ‘free’, it would be a good deal because I could always sell the sidecar separately. New sidecars added about $3500 to the cost of a Harley at the time. So I put in a bid slightly below the motorcycle’s book value and in a relatively short time, the bike was in my garage.

The first thing I noticed about riding a bike with a sidecar was that it felt very strange going around corners. Previously, cornering was an exhilarating experience on a motorcycle, but with the sidecar, it became a chore because I felt like I was being thrown off the bike. When turning right, going a little too fast could actually bring the sidecar’s wheel off the ground. I decided that the sidecar, as novel as it looked, took much of the joy out of riding and I promptly removed it. For the next 8 years, the sidecar sat idle while I rode the bike without it. Finally, I sold the sidecar to someone who wanted it, content that I’d never use it again.

I eventually sold the Harley too, after 16 years of owning it, for approximately what I paid for it, around $7500. For those of you who think I’m a shrewd investor, if I used the $7500 and purchased Harley stock instead of that bike, the stock’s value over the same period would have been worth nearly $400,000, so the bike wasn’t really a great investment compared with owning a part of the Harley Davidson company. But “50-bagger” stocks are few and far between and Harley stock has now been flat for about the past 7 years. However, the same amount of money invested in the S&P index would have yielded about $40,000 over the same 16-year period, so again, the Harley would hardly qualify as an 'investment'.

Here are the lessons I learned from it:

1. There is no one material thing that separates you from true happiness.

2. When you think there is, take the money and buy a stock market index fund instead.

3. Continue searching for the one and only thing that separates you from true happiness.

The reason I mention this experience is because I’ve been contemplating alternative modes of transportation and trying to imagine what a fuel-efficient futuristic vehicle might look like. I spend about 7 months of the year riding my BMW1150RT motorcycle, which was my mid-life crisis replacement for the Harley. I do really enjoy riding it. But for the other 5 months, I need something that can deal with cold weather and snow typical of Colorado winters. Many, if not most, of my cold weather trips are made solo, which means I could use a two-place vehicle like a motorcycle since I don’t need all the room afforded by an SUV. Ideally, it would have very little frontal area and would need to be fully enclosed. Most critically, it would need to be able to lean into turns. Oh, and I must look cool while riding/driving it. I almost forgot to mention that, but it’s probably more important than any other consideration for most people.

I thought I saw the future of transportation at Epcot nearly 20 years ago when I saw the ‘Lean Machine’ , a fully-enclosed 3-wheel vehicle that looked very much like what I just described and capable of leaning into corners. But the machine was designed by GM and they apparently opted not to pursue it, probably because the public was more interested in buying SUVs, trucks, and Hummers than single-seat quirky vehicles with excellent fuel economy.

Now that gas is heading toward $4/gallon with no end in sight, fuel economy is starting to appear on everyone’s radar screen again as a desirable attribute in a vehicle.

An electric motor scooter was profiled in the 'First Ride' section of the latest issue of Motorcyclist magazine and it got me to thinking about whether it may be just the right time for an electric motorcycle or possibly a futuristic 3-wheel leaning vehicle to come to the market. The electric motor scooter profiled is called the Vectrix Maxi-Scooter and it has an electric 20 KW (26.8 HP) motor, along with a 200lb., 3.7 kWh battery. Simple math will tell you that this battery would hold about 11 minutes of juice if you were able to run the vehicle at full power, although that probably wouldn’t be possible to do unless you were climbing up a hill at full speed. The company states that the scooter will get between 20 to 60 miles per charge depending on how it’s driven. A charge takes 2 hours to get to 80% battery capacity. The author in the Motorcyclist article got 40 miles from a charge. So it would stand to reason that average riding consumes about 95 Wh per mile. To put that in perspective, it’s the same as using 1 oz. of gasoline per mile assuming a 30% thermal conversion efficiency in an internal combustion engine. You don’t need a calculator to realize this is the equivalent of 128 mpg. The entire battery holds about the same amount of energy as 1/3 of a gallon of gasoline, again assuming a 30% thermal conversion efficiency. Since 1/3 of a gallon of gasoline weighs about 2 lbs., the energy density ratio of the NiMH battery to gasoline is 1:100. Herein lies the biggest problem with electric vehicle energy storage and that is energy density or lack thereof. The 200 lb battery accounts for 43% of the scooter’s 462 lb weight. That's a nearly identical battery-to-vehicle weight ratio of the GM EV1 that I wrote about previously. With an MSRP of nearly $12K, this scooter costs about twice what an equivalent gas powered scooter would cost.

I have a confession to make. I like riding scooters. I didn’t think I would, but Terri and I rented one our honeymoon and we explored most of Grand Cayman on it. I know that I don’t look cool on a motor scooter -- no guy does -- but I had already landed the girl, and she didn’t seem to mind, so I figured, “What the heck? I might as well enjoy it.” We rented a scooter in Tuscany and loved it too, especially on the back country roads between Florence and Sienna. We did find ourselves forced to use the autostrada while on a jaunt over to Pisa and the 125cc engine strained to keep up with the flow of traffic. So when no one is watching, I’ll ride a scooter, preferably with a full-faced helmet and dark face shield, so no one will recognize me.

But I’ve tasted what it’s like to ride Ducati and when you pull up at a stop light on a bike like that, everyone just stares, mouths agape, and it’s then that you know you’ve truly arrived. Women want you, men want to be you. You can’t underestimate the psychic value of looking cool on your ride.

So how can we solve the fuel economy/cool factor/all-weather transportation needs of the future? Well, the primary issue is the coolness factor. It has to look cool, not geeky, and be quick too, because the coolness factor will wear off quickly if you’re getting passed by bicycles. Secondly, It must lean into corners, because if it doesn’t, it will either need to be wide or unstable. Third, it must be enclosed for cold weather. That means it needs either three wheels or outrigger wheels that deploy when stopping to keep you from tipping over. I’ve seen a few examples of the latter, but for some odd reason they all cost upward of $100K. It could be an all-electric vehicle, but not if it requires gobs of weight in batteries. So I think that means that it may need to be a hybrid.

I’ve seen a few promising examples of what I’ve described and I’ll show some pictures and links here:

Venture is an American licensee of the leaning technology developed by the Dutch company Carver. Make sure to visit their website and watch the videos, most of which are of the Carver.

Carver seems like it’s ahead of the game here, with vehicles available for sale, although at a hair-raising price of €50,000 (about U.S. $75,000)

The vehicle of my dreams may be available today, but it’s priced beyond what I’m willing to pay. For now I guess I’ll have to be content to ride a 45-mpg BMW sport touring bike in warm weather and suffer sticker shock each time I fill up at the pump with my 14-mpg Dodge Durango in the winter months. I do love the Durango because it will comfortably haul 7 people around in the nastiest weather Colorado can dish out and it can even swallow whole sheets of 4’x 8’ plywood. It’s hard to put a price on that. But the weather’s warming up now and I’m itching to lean into some curvy canyon roads so it feels like it's time to pull out the BMW.

And, if at some point if you see some dude cruising by on a geeky electric scooter with a full-faced helmet and dark face shield, it just may be me. :-)

Labels: energy, motorcycles, technology

I am trying to recruit one of my favorite gurus to attend the EntConnect conference this year. If you're into electronics, you've no doubt heard of Don Lancaster. Don is a prolific writer and has written numerous columns in most of the electronics hobbiest magazines over the years. He's also authored numerous electronics books such as the TTL Cookbook and the CMOS Cookbook. Nowadays, his columns can be found on his website.

Don was responsible for my finding out about Midnight Engineering magazine and so he's indirectly responsible for my involvement with the EntConnect conference. Similarly, many other conference attendees give him credit for their discovery of it as well.

My favorite articles that Don writes about are related to energy, especially his energy fundamentals article. He recently followed it up with another one entitled more energy fundamentals. I also appreciate his take on patents.

I've asked him to run a banner ad on his site for the conference. I've combined two elements that are distinctly Don, the aqua blue color of his website and the word 'tinaja'. We'll see if he chooses to run it as is or if I'll be doing some editing of it. You can see the example below. And...if you're interested in coming to EntConnect, please note the discount code available in the banner ad when you register.

Labels: energy, entconnect

On March 4^th, 2008, a group made up of members from the Northern Colorado Clean Energy Network and the Northern Colorado Renewable Energy Society toured the Rawhide Energy Station. It was the third of our ‘Energy Reality Tour’ series. Previous tours have included the Ponnequin Wind Farm and Front Range Energy ethanol plant.

You may wonder why organizations focused on clean and renewable energy would want to visit a fossil-fuel burning plant, but I can assure you that visiting an operating power plant gives one plenty to contemplate in terms of energy generation on a utility scale. Whenever someone proposes a solution to global warming with a renewable energy technology, it helps to get a dose of reality by seeing firsthand what it is that we would need to replace.

The Rawhide Energy Station is located 26 miles north of Fort Collins, CO. It was built over a 4.5 year period during the early 1980s and started generating power on March 31, 1984. It has a 274-megawatt coal-fired steam turbine for the base load and 4 gas turbines capable of generating 260 megawatts for backup of the steam turbine and for supporting peak loads during the summer time when electricity demand is high. It uses approximately 4000 tons of low sulfur coal per day. Rawhide is one of the cleanest coal-fired power plants in the nation and generally ranks in the top 5 of the cleanest plants in the U.S. in terms of sulfur dioxide emissions.

The Rawhide Energy Station is owned and operated by the Platte River Power Authority, a community-owned utility that provides electric service to the cities of Fort Collins, Loveland, Longmont, and Estes Park. In addition to full ownership of the Rawhide plant, the PRPA owns an interest in a coal-fired plant in Craig, CO. It also owns 10 wind turbines near Medicine Bow, WY and purchases hydroelectric power from federally owned facilities in Colorado, Wyoming, and New Mexico. Hydroelectric power accounts for approximately 20% of the power distributed by the PRPA.

The plant is situated on a 4000 acre site that includes a 500-acre, 5 billion gallon reservoir that is used for cooling and recondensing the steam. This reservoir maintains a temperature of approximately 70F year round and is home to numerous waterfowl. Another unique feature of the site is that it has its own bison herd. The plant employs approximately 100 full time employees and is staffed around the clock, 365 days a year.

The coal is delivered to the plant by rail from the Antelope mine in the Powder River Basin region in Wyoming, which is about 200 miles to the north. PRB coal has a very low sulfur content and an energy content of 8850 BTU/lb. The ‘heat rate’ or thermal conversion efficiency on the coal in this plant is 10,200 BTU/kWh which translates to about 33% thermal efficiency. When the steam turbine is producing its nominal output of 297 MW, about 23 MW is used to run the plant and the rest (274 MW) is sent to the grid. The cost of coal per BTU is very low for PRB coal, about $.84/MBTU (using a price of $15/ton which is the historical average for PRB coal). I should also include the coal’s transportation cost, which, on average, doubles the effective price for a PRB coal customer. However, that assumes a much longer journey than the relatively short 200 mile distance to Colorado. Since the coal transportation cost by rail is just under $.02/ton-mile, transportation fees would increase the cost by about $4/ton or about 25%. To put that in perspective, the current cost of natural gas at the plant is $9.33/MBTU. The gas turbines have lower thermal efficiency, also called the ‘heat rate’, than the coal-fired steam turbine, requiring about 13,400 BTU/kWh. This means that the fuel cost for a natural gas turbine is 11 times as much per kWh as coal at this plant. That is, it requires $.011 of coal per kWh vs. $.126 of natural gas per kWh. I had to calculate this number several times to make sure it was correct, but I’m quite sure I had written down the gas turbine ‘heat rate’ correctly. This means that the fuel cost for every kWh of gas-fired power generated is nearly twice as expensive as the Fort Collins average of around $.07/kWh electricity retail rate. They were not running the gas turbines when we visited, but had the coal-steam turbine operating at full capacity. When there is such a disparity in fuel costs, it’s no wonder that the gas turbines are only brought on-line when necessary. It also illustrates just how inexpensive coal is in comparison to other fuels.

I should mention a few more details about thermal efficiency. If a process had a 100% thermal efficiency, it would require 3412 BTUs of heat to produce 1 kWh of electricity. A gas turbine typically has a similar efficiency to a steam turbine, about 10,000 BTU/kWh which translates to about 34% thermal efficiency. If you can use a combined cycle to further recover the heat from the gas turbine’s exhaust and run a steam turbine with it, you can get between 50-60% thermal efficiency from the natural gas, making it better, but still much less economical than coal, costing about 5 or 6 times as much as coal per kWh for the fuel. Also, if you plan to run a combined cycle, then it’s not practical to take advantage of one of the primary benefits of a gas turbine which is that it’s easy to bring on line and shut down when not needed. A boiler system and steam turbine require much more time to be brought on line than a gas turbine (hours vs. minutes) so when running a combined cycle, it’s better to keep everything running continuously. For comparison’s sake, the $15/ton price for PRB coal is quite inexpensive, about 30% of the average for coal mines in the central and eastern U.S. coal regions on a cost/BTU basis. Its low price combined with low sulfur content helps explain why Wyoming coal is so popular with electric utilities, accounting for 38% of all coal mined in the U.S..

The coal is stored outside the plant surrounded by a series of earthen berms and is large enough to hold a 90-day supply of coal. It is sprayed with a surfactant to keep the dust from blowing off the piles of coal. Having grown up within 300 yards of an anthracite coal breaker in Pennsylvania, I can attest to how hard it is to deal with coal dust in an environment where coal is stored or moved, yet despite the wind blowing in excess of 25 mph during our visit, we saw no coal dust blowing around the facility.

Pictorial of the Rawhide Energy Station inner workings

From the storage area, the coal is delivered by conveyor to 4 mills which pulverize the coal into a powder with the consistency of talc. After milling, the coal is blown into the boiler where it is ignited and heats up the inside of the boiler to 2800F. The inside of the boiler is lined with steel pipes that are part of the closed-cycle steam system. The water inside this closed system must be purified so that it doesn’t ‘plate out’ on the inside of the pipes or otherwise damage the turbine. The water circulates through this system at the rate of 3800 gallons/min. When the steam in the boiler achieves a temperature of 1000F and a pressure of 1890 psi, it is sent to the high pressure stage of a 3-stage turbine. From the high pressure stage, it makes a trip back to the boiler to pick up some more heat before it is fed into the turbine’s intermediate pressure stage. From there it goes to the turbine’s low pressure stage. After that, the steam is re-condensed, using a heat exchanger and water from the reservoir. The reservoir water is not part of the closed system. It circulates into the heat exchanger at the rate of 196,000 gallons per minute. The water temperature of the cooling water is raised 15 degrees in the process of cooling down the steam. Although that rate of flow is impressive, it would take about 18 days for all the water in the reservoir to circulate through the heat exchanger.

All three steam turbine sections are connected to the same shaft that runs the generator. The Westinghouse generator has a rating of 24,000V and 8068A and feeds a transformer to step up its 3-phase output to 230KV for transmission to the grid.

The steam turbine and generator reside in a large room with an overhead crane and are contained in a very large structure called a ‘dog house’ to help keep down the noise. While in this room, it was hard to believe that we were standing just a few feet of a prime mover that was outputting nearly 400,000 horsepower. The room seemed much larger than it needed to be, almost like a large aircraft hangar, and our tour guide explained that this was because it was necessary to dismantle the turbine and generator every 3 years for preventative maintenance and all the floor space was needed to arrange the parts during this process. They generally try to schedule these maintenance operations for spring or fall when peak electrical demand is much lower than the summer or winter months. When the coal-fired turbine is down, the electricity can either be generated with natural gas or purchase from other providers to make up for the loss of the generating capacity.

The coal portion of this plant is enormous, requiring a 16-story building just to house the pulverizing mills and boiler along with portions of the process that are designed to clean the resulting exhaust. The exhaust from the boiler is first run through a scrubber, where the nitric and sulfur oxides are removed by combining them with calcium carbonate to form gypsum. From there the exhaust moves on the ‘bag room’. In the bag room are a series 6576 filter bags 12” in diameter and 34 feet in length that all exhaust must pass through which removes 99.7% of the particulates. These Teflon-coated fiberglass bags are continually cleaned to remove the fly ash which is collected buried on site. Some of the fly ash is also used in the cement block industry. About 5% of the coal by weight is turned into ash and there is a landfill on the site large enough to completely store all of the ash generated by the plant through its design life.

A mercury monitoring system was installed recently and the plan is to remove 80% of the mercury emissions by 2012 and 90% of it by 2018. This was done not to comply with regulations, but rather on a voluntary basis. Rawhide is only one of two plants in the state to voluntarily install mercury monitoring equipment.

Seeing power generated on a utility scale is a bit daunting. You quickly realize how much time, effort, and expertise has gone into building our nation’s electrical generating systems and how absolutely dependent we have become on them. As we begin to hear more and more about renewable energy, it’s important to recognize that the challenge is not just about matching the overall capacity, but also the reliability and availability of the fossil fuel generating systems they’d eventually replace.

I got many positive comments from the other tour attendees regarding the friendliness and professionalism of the PRPA staff. They really went out of their way to make us feel welcome and to answer the numerous questions from our group. I’d especially like to thank Jon Little, John Bleem, Brian Frisbie, and Pete Ungerman for their part in setting up and hosting our group for the tour. They all went above and beyond the call of duty to make the tour as enjoyable as it was informative.

Labels: energy

I've written several articles for BiomassAuthority.com this past month. The first article was about the pine beetle damage of the lodgepole pine trees in Colorado, and whether they can be converted into ethanol or some other useful product. Then I wrote one about climate change and the Gaia hypothesis, which may sound a little like sci-fi depending on your viewpoint.

The third article was a result of finding an advertisement for a corn-burning stove. I compare the relative costs of a number of fuels from corn, wood, oil, etc. and how it relates to heating a home.

Labels: biomass, energy

Link

As I mentioned in a previous posting, I'm helping to organize an entrepreneurial conference called EntConnect in Denver on March 27-30th. One of our regular conference attendees, Gary Skinner, will talk about a home he built recently that was profiled on EcoTech on the Discovery Science channel. You can catch a 2 minute clip of it here:



There are always glimpses of the future that I get from other attendees at EntConnect. Whether you're a freelancer, a business owner, or an employee, if you have an entrepreneurial spirit, you should consider joining us in 6 weeks.

The conference fee is 50% off if you sign up before March 1st.

Labels: energy, entconnect

I recently received a pointer to this blog article which references a NY Times piece about articles in Science that state that biofuels actually increase global warming by pulling land into the agricultural pool that was previously a carbon sink. The first of these Science papers is focused on the ethanol industry in the U.S.

During the past 14 years, 15 separate studies have shown that ethanol has a net positive energy balance. Only one study has contradicted it, but the researchers of that study (Pimental and Patzek) wrote the same paper 4 times so you may hear that the ratio is 15:4. It’s the one that always gets quoted (usually unknowingly) when someone tells you it takes more energy to produce a gallon of ethanol than you can get out of it. Now it appears ethanol opponents will have another study to quote, this time about biofuels creating additional greenhouse gases.

In looking in the supporting materials in Science Express, I found this curious assertion:

If corn-based ethanol could not receive a credit for removing carbon from the atmosphere – deleting the feedstock uptake credit from the GREET model-- it would increase greenhouse gas emissions by 48%. It follows that if the use of land to grow corn for ethanol has the net effect of reducing land-based carbon sequestration, the overall effect will be a bigger release of greenhouse gasses.

In other words, they are stating that when comparing greenhouse gases from corn to gasoline, corn should not get a credit for having removed carbon from the atmosphere. Instead they think it should be compared to growing a forest or prairie in the place of farmland which would allow the carbon to be sequestered year after year. Forests and prairies give back carbon to the atmosphere every year when their leaves and grasses die. In the case of forests, every few decades the trees die, or burn, or are used for some other purpose and thus also give back their carbon in a brief instant of geological time. Unless you’re burying the carbon deep under the earth’s surface or oceans, any carbon taken in by plants is given off in a few months or decades. Soils also have a limited capacity to hold carbon and eventually reach a homeostasis after only a few decades. So I consider the logic used in this study to be flawed.

But I will expect that every biofuel opponent will quote it with abandon, never realizing that the authors of the paper are not comparing biofuels with fossil fuels, but rather biofuels with some imaginary state of affairs where forests that capture but do not release carbon to the atmosphere have been replaced by farmland.

All land capable of sustaining plants, whether it be used for farming, prairie, or forest eventually reaches a homeostasis when it comes to CO2 sequestration. Farming allows us to take advantage of the CO2 to carbohydrate conversion that occurs on land whereas prairies and rainforest that go unharvested do not. But in the end, they all return CO2 back to the atmosphere in a relatively short span of geological time. The only counter-examples are swamps that can, over the course of millions of years, turn vegetation into coal by trapping a tiny percentage of carbon each year.

Labels: energy, ethanol

The Northern Colorado Clean Energy Network and NCRES are planning a tour of the Rawhide Energy Station.

Date/Time: Meet on Tuesday, March 4th, 2008 at 9:15 a.m.
Meeting place: Northwest corner of Harmony Road/I-25 park-and-ride in Fort Collins, CO

The park-and-ride is located just north of the first traffic light when you head west on Harmony Road from I-25.

We will leave at 9:20 a.m. and carpool to the Rawhide Energy Station. Here are the directions from Harmony/I-25 intersection:

Go north on I-25 for about 22 miles and take Exit 288. Drive east for approximately 3 miles and turn north at the plant entrance. The tour is scheduled to begin at 10:00 a.m. The tour takes about 1.5 hours.

The Rawhide Energy Station is located 26 miles north of Fort Collins. It was built in the early 1980s and started generating power on March 31, 1984. It has a 274-megawatt coal-fired steam turbine for the base load and 4 gas turbines capable of generating 260 megawatts for backup of the steam turbine and for supporting peak loads during the summer time when electricity demand is high. It uses approximately 4000 tons of low sulphur coal per day. Rawhide is one of the cleanest coal-fired power plants in the nation in terms of sulphur dioxide emissions.

If you want to go on the trip, please contact me via email at lee810@yahoo.com or by phone at 970-978-6188 and let me know the names of the people you're bringing, and whether you will be meeting at the Harmony park-and-ride for carpooling.

That phone number is my cell phone that I'll have with me at the time of the tour in case you need to contact me on the morning of the tour.

Detailed maps of the meeting area and directions to Rawhide Energy Station are located here.

Labels: energy

The website owners at SolarPowerAuthority.com had asked me to write an article related to solar energy, since they were familiar with my renewable energy articles on this site and liked the way I wrote them. Based on the quality of the other solar energy articles I found on the site, I was happy to do it. The article is entitled “How much does it cost to install solar on an average U.S. house?” My goal in writing the article was to explain to a lay person how much one should expect to spend on a photovoltaic (PV) solar system capable of supplying a household’s electrical needs.

In Colorado solar panels on the roofs were a common sight back in the 70's and 80's when the government was offering attractive subsidies for solar systems. Mostly they were hot water-based thermal collectors because PV cells were much too expensive for the amount of power they generated. Now with the increasing cost of natural gas and electricity, solar power is making a comeback and this time it's likely to stay because as utility costs have increased, the cost of PV solar systems has dropped dramatically. The equipment that lets you connect a PV system to a household electrical system has also grown more sophisticated, allowing you to sell power back to the electric company during peak solar generating times. This essentially causes your electric meter to spin backwards and can reduce your electricity bill down to nothing. The article has many more details and so I recommend you head over to SolarPowerAuthority.com to check it out as well as many other solar-related topics.

Labels: energy

One person's eyesore can be another person's art. Modern wind turbines fascinate me. I find them to be graceful and stately works art. I do realize that not everyone feels the same way, for example, a small yet powerful group of people living around Cape Cod.

I was visiting my home town near Wilkes-Barre, PA last September and was gratified to see 12 wind turbines up on the eastern ridge of the Wyoming Valley spinning slowly while generating clean and renewable energy. When operating at their full capacity, the turbines collectively provide enough electricity to power about 24,000 homes. I had to get up close to them for a better look. I wrote a blog article about it last October.

I received an email the other day from someone in Australia asking for permission to use one of the images from that article to promote an arts festival. It’s the image of me standing with 3 wind turbines in the forest behind me. They plan to print it on 30,000 brochures and 2000 posters. I think that’s an appropriate use for that image, to promote an arts festival. Something tells me the organizers must have good artistic taste. :-)

Labels: energy, wind

Last week I toured the Front Range Energy ethanol plant in Windsor along with 9 other members of the Northern Colorado Clean Energy Network many of whom are also members of the Northern Colorado Renewable Energy Society. I had requested the tour because I had a desire to see this facility up close to find out what is involved in an operation capable of producing 40 million gallons of ethanol per year. The company manager, Dan R. Sanders, and FRE employees very graciously set up a tour for our group and explained the details of ethanol production at the facility.

Ethanol has been an additive in auto fuels in the U.S. for many years. In addition to making the gasoline burn cleaner, ethanol increases the fuel’s octane rating and helps reduce our dependence on imported gasoline by more than 5 billion gallons per year. While this is still a small percentage of the U.S. consumption rate of 140 billion gallons of gasoline each year, its recent growth rate is impressive as is the rate of ethanol plant expansion and construction. I’ve written about E85 ethanol previously, including using it in vehicles that were not designed for it as well as in aircraft.

I am aware that ethanol is still controversial in some circles primarily due to some persistent myths such as it taking more energy to produce a gallon of ethanol than it returns, which is not true. Ethanol production in this country provides 40% more energy than it requires to produce it and that number continues to improve, but more importantly, ethanol's energy has 3 times the value to consumers than the type of energy it uses, which is usually natural gas. When it comes to energy, some types of energy are worth much more than others because of convenience or compatibility with existing infrastructure. It’s the reason you probably don’t heat your house with coal, even though it’s the cheapest fuel per BTU by a significant margin.

The Front Range Energy plant was built in 2005 and began producing ethanol in 2006. Our tour included a 35 minute presentation to describe the operation in detail by Amanda Huber, the process manager, who walked us through each step in the highly automated process of converting corn into ethanol. She also answered many questions from our members. We were then taken through the facility by the company manager to see and hear all the equipment up close. The words that come to mind to describe the plant’s equipment are large, loud, and highly automated. There are many large cylindrical tanks connected with numerous pipes and pumps. The smell of the plant reminded me of the smell of our kitchen when we make pizza dough.

The corn arrives to the plant by both truck and rail and is stored in two impressively large 500,000 bushel storage silos. The corn from local growers arrives by truck and the corn from outside the region, primarily Nebraska, arrives by train. From the storage silos, the corn moves by conveyor to the hammer mills where flailing hammers pound the dried kernels through screens containing holes that will only allow particles smaller than about 1/10 of an inch to pass. This helps to expose the starch inside the kernel, which accounts for about 65% of the corn by weight. From the hammer mills, the corn passes to the slurry blender which mixes it with water and enzymes and cooks for several hours. It is inside this slurry cooker that enzymes begin to break the corn starches down into fermentable sugars.

From the slurry cooker, the mixture passes through some liquefaction stages and then on to one of four 535,000-gallon fermentation tanks. Additional enzymes and yeast are added to the mash, as it’s called at this stage, and it is allowed to ferment for about 50 hours. This stage is critical to monitor because it’s where the sugars are converted to alcohol and if this process is not properly controlled, it could ruin the entire batch. They use a combination of analytical instrumentation to monitor the health of the yeast as well as the concentrations of sugar, alcohol, and acids in this tank. After the fermentation step is complete, the mixture will contain somewhere between 15-18% alcohol. Another output of the fermenters is carbon dioxide which could be vented to the atmosphere, but in this plant it is fed directly to another plant that condenses it and provides it to bottling plants for carbonating drinks and for making other CO2 products such as dry ice.

The mix is moved from the fermenters to a 735,000 gallon beer well which feeds the distillers. Using a combination of heat and vacuum, the alcohol is separated from the rest of the mix using a beer column to produce alcohol in a 70% concentration and then it is transferred to a rectifier column to get the concentration to 95%. Alcohol and water form an azeotrope at this concentration, meaning that distillation can no longer further separate the water and alcohol. So the next stage is to run the mixture through a molecular sieve to remove the remaining water and produce anhydrous ethanol. The ethanol is then denatured to make it unfit for human consumption by mixing it with about 5% gasoline. It is then pumped into one of two 500,000 gallon tanks where it awaits transportation by truck or rail car to its destination.

From the bottoms of the distillation towers, the solids and water are pumped to a centrifuge which separates the water from the solids. The solids then become wet distiller’s grain which is used as an animal feed. In some plants, this grain needs to be dried so that it will not spoil during transportation and storage, but in northern Colorado, because of its proximity to numerous cattle feedlots and dairies, it can be shipped in its moist state directly to the dairies and feedlots. Trucks remove approximately 1100 tons of this material a day from the plant. If the distiller’s grain had to be dried, it would more than double the amount of natural gas consumed by the plant, so there is definitely a benefit to having large meat packing and dairy industries nearby.

I have simplified my description of this process considerably. There are many auxiliary steps to achieve a high level of efficiency for the plant. For example, there are steps for adding nitrogen to the fermenters, recycling the water, regenerating the molecular sieve, extracting and remixing syrup with the grain, and recovering alcohol which I did not mention. This plant has a lot of very sophisticated and finely-controlled processes. If you’d like to see a little more detail, there is an explanation complete with a diagram at the ICM website, the company that designed and built the FRE plant.

As an engineer, one area I found particularly fascinating was the control room which had a series of computer screens that showed a pictorial view of the real-time status of every level, temperature, flow, and pressure of the entire process from beginning to end, all being monitored by one person. The plant is so automated that it can be run by as few as 3 people. The plant only requires 32 full time employees to run a 24-hour a day, 365-day per year schedule. The plant is able to process 55,000 bushels of corn into 145,000 gallons of ethanol every day of the week and have minimal plant downtime, typically less than 7 days over the course of a year. The plant achieves a yield of 2.7 gallons of ethanol per bushel of corn.

I was curious to know how close to the nameplate value this plant was producing. I had interpreted the nameplate value to be the maximum output if everything ran perfectly every hour of the year. I was very impressed that the plant regularly exceeds the 40M gallon per year nameplate value by more than 20%.