Archive for Technology

Heating a building with heat from a road

The December 6 Technology Quarterly from The
Economist
magazine profiles
a Dutch office building which is both heated and cooled using heat (or cold) from the asphalt of the road outside the building
, as opposed to the more conventional use of solar thermal panels on the building’s roof.  The article optimistically ends,

The result is cheap heating in winter and cheap cooling in summer. And there is a bonus. Summer heating softens asphalt, making it easier for heavy traffic to damage the road surface. Dr de Bondt’s system not only saves electricity, but also saves the road. Expect to see more examples of it, in other countries, soon.

While this is a very elegant solution, the author fails to grasp that,
because the road is essentially an unglazed thermalOoms collector, and only gets
warm in the summer or cool in the winter, requiring that seasonal heat be stored.   Summer heat from the asphalt is used to heat the building in winter, while the chill of the inter road cools the building in summer. 

In this particular case, seasonal storage is accomplished with heat exchangers placed in not one, but two separate natural aquifers near the building.  The fortunate proximity of two such aquifers is extremely rare.  While this is a very elegant way to heat and cool a building, the lack natural aquifers in which to store seasonal heat will likely prevent widespread adoption of this
technology, no matter what the author believes.

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Transport Fuels and Solar Technologies: Bird’s Eye View

For my last couple AltEnergyStocks Columns, I’ve been taking a step back and looking at how we can get an understanding of the broad trends of energy technologies. Last week, I added to the Visual comparison of Electricity Generation Technologies I did last spring with a new Visual Comparison of Transport Fuels.

Following up, today I published a look at the varius solar technologies through the lens of their applications.

Before we go back to looking at trees, I hope you enjoy this look at the forest.

(and don’t miss the National Tour of Solar Homes next Saturday)

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Visual Comparison of Electricity Generation Technologies

I just put together a couple graphs for a talk I’m giving on Monday to give people a visual feel of the various technologies for generating electricity.  These come with a gigantic caveat: the numbers are far from precise.

With changing technologies, it’s impossible to represent any of this with a single number anyway.  I’m trying to show how the technologies compare to each other, and I used four parameters:

  • Cost ($/MWh),
  • Availability (better the closer the profile of the technology matches a normal demand curve (wind is bad, baseload is okay, dispatchable is best, solar),
  • Emissions (and I count waste storage when it comes to nuclear),
  • Bubble sizes represent the size and durability of the resource (I’ve tried to combine in one number how much power we can get from the resource, but also how long supplies of fuel will last.) 

In both charts, the “best” technologies are in the upper left (low cost, low emissions, and available when we need them.)

I know that I’m going to upset a lot of people because I was too harsh with their favorite technology, so feel free and comment on the numbers I’m using, but also please provide references for where you get your numbers.  Most of these are off the top of my head, so their accuracy is admittedly questionable.   Here are the numbers I used to make the graphs.

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Holistic Approaches to Energy Problems

H. L. Mencken said, “For every human problem, there is a neat, simple solution; and it is always wrong.”  When it comes to solving the problems of peak oil and global warming, I also think that the loudest barking is up the wrong tree.  We look for the quick fix, trying to find a substitute energy source that allows us to change the way we do things little as possible, when the real problem is actually what we’re doing, not how we’re doing it.   We need holistic solutions, not quick fixes.

Too abstract?  Here are some concrete examples:

 Problem: Peak Oil

Quick fixes: Ethanol and slight increases in vehicle efficiency standards.

Holistic solutions: Change our driving culture and infrastructure, by changing the way car use is priced from fixed charges to a per mile basis (“Pay as you drive”).   Removing subsidies to use cars when other forms of transport are available, and redesigning our cities to make them easier to get around on foot, bike, and public transport.  Like other holistic solution, all these steps increase safety and reduce congestion, reduce obesity and associated health problems, as well as reducing the use of gasoline.

Problem: Wind and Solar are intermittent resources, but coal produces too much CO2 and natural gas prices are rising rapidly.

Quick Fixes: Nuclear power and “Clean” Coal.

Holistic Solutions: Shift our demand for electricity to times when it is available, by using time of use pricing, energy storage and demand alignment, and distributed energy storage such as plug in hybrid vehicles.

Investing opportunities:On thing that’s striking about these examples is it’s much easier to find investment opportunities in the quick fixes than in the holitistic solutions.  To invest in ethanol, you can just buy ADM or one of the multitude of ethanol stocks that have been going public recently, but I have yet to come up with a satisfactory way to invest in better urban planning (except buy a house in a walkable community, which is something I’m planning on doing this summer.   Stapleton is the community.  I currently live there, but I’ve been renting and waiting for the end of the housing bubble.  I actually don’t think that housing is going to go up again any time soon, but I’m tired of waiting.) 

The investment landscape is a little better when it comes to energy management.  Itron and Siemens both have divisions that help utilities manage their grids better, and there are many battery and other energy storage companies to choose from.  Still, it’s a lot harder to pick through battery companies than to just buy a nuclear powered utility or uranium miner.

Holistic solutions, by their nature, have weak boundaries… the benefits tend to be diffuse, and spread over society as a whole, so it is difficult to charge fairly for them.  This, I think, is why there are so few companies pursuing them when they can pursue a quick fix that they can charge for up front.  

Companies have an obligation to their shareholders to make money.  It’s our job, as human beings, to work towards regulations that make it easier for companies to make money with holistic solutions that actually solve the problem than it is to make money with quick fixes that just cover the problem up.

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Vision of a sustainable energy future

I’ve been meaning to write an article outlining a vision of a sustainable energy future, where biomass is converted into fuel and electricity through pyrolysis and the waste product, carbon is used as a fertilizer a-la terra preta to produce more biomass.  The good news is I don’t have to.  The Engineer Poet did, and it’s just part of a much broader vision you’ll find here.   He also goes into a great discussion of transportation technologies and efficiency which would never have made it into the article I’d write.  I like it when other people crunch numbers, so I don’t have to.

Give yourself a half hour to read the whole article.  It’s worth it.

( Terra Preta: I got a comment from Erich J Knight on terra preta here that went into a lot of depth, but I deleted it by mistake.  Forturnately, he says pretty much the same thing in his blog.  I first heard about terra preta from Ron Larson, chair of the American Solar Energy Society, who is very active in the local (Denver) renewable energy scene.  If you haven’t heard about terra preta, and are concerned about globabl warming or soil fertility without fertilizers from fossil fuels, it’s worth looking into.)

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Large Scale Electricity Storage.

One of the biggest barriers to the adoption of wind and solar electricity generation is the lack of storage technology with the capacity to handle the hundreds or megawatt hours necessary.    

Large scale electricity storage technology also allows utilities to flatten their demand, and defer construction of expensive new generation. 

Here’s a quick rundown of some of the technologies vying to meet this need.  Most of this is information is drawn from the Electricity Storage Association website.

Technology

Description

Comments

$/kWh; efficiency

Investment opportunities?

Pumped Hydro: Reservoir to Reservoir

Energy is stored by pumping water from a low reservoir to a higher one, and recovered by running the water back out through a turbine.  This system can be easily retrofitted into existing reservoirs, but has limitations due to water regulations.  First used in 1890.

The cheapest and most developed technology, pumped hydro is nevertheless limited by the availability of suitable sites.

$3-$50 per kWh;

70% to 85%

The major supplier in the business is private.  Could look for opportunities in utilities that have good potential projects.

Compressed Air Storage (CAES)

Energy stored by compressing air into large underground caverns.  Air combined with natural gas on exit and burned in turbine.  The gas compensates for the cooling as air decompresses. 

Gas used is about 40% of the amount used in comparable peaking turbine.  First built in 1978.

70% to 80% efficient; $30-$100 per kWh

 

Underground Pumped Hydro

As above, but water is pumped between an aquifer and an above ground reservoir.

More sites available, developing application.  Might have some water quality issues.

Costs Low

75% to 85% expected efficiency.

Small turbine/pump makers.

Polysulfide Bromide battery

A regenerative fuel cell based battery technology (aka “Flow Battery.)  Seems have run into difficulties due to the toxicity of the chemicals involved.  

15 MW demonstration project in 2003; more recent projects canceled.

75%, unknown cost;

Regenysis, the owner of this technology, was a subsidiary of
Germany’s RWE.  No recent activity; the program may have been wound down.

Molten Sodium-Sulfur (NaS) Battery

Molten battery technology.  “Safety concerns addressed in

30 sites in
Japan, mostly for peak shaving.  Largest is 6 MW for
Tokyo electric

Cost “High” compares to BrS and hydro/ CAES.

NGK, Japanese power equipment supplier focused.  Can be bought by US investors on the Pink Sheets NGKIF.PK

Regenerative Fuel Cell (Hydrogen)

Fuel cells can be run in reverse for electrolysis, with the hydrogen stored in large tanks.

First pilot project 2004

“much less” than 80%

Fuel cell manufactures: Ballard, FCEL, and others.

All these technologies except hydrogen are dealt with very well on the Electricity Storage Association site.  They have some great technology comparison graphs which deal with a lot more variables than I have here in their technology comparison section.

Cost Comparisions

Click to enlargeClick to enlarge

Efficiency/Quality Comparisons:

Click to enlargeClick to enlarge

Of these technologies, Pumped Hydro and CAES are the only ones ready for near term, large scale deployment (with NaS and Flow Batteries applicable in some markets highly constrained markets.)

The major downside for pumped hydro is siting, part of which problem can be solved with the smaller scale reservoir to aquifer option.   For CAES, the downside is the need to use gas to run the turbine, albeit a very efficient one.  One option might be to substitute for the natural gas used in CAES with hydrogen from electrolysis, allowing the system to work at locations remote from natural gas supply, and, for wind energy storage systems, be 100% renewable.

 10/20/06- Article about a flow battery from VRB power systems for an Irish wind farm.

8/5/07: Here’s an article I just wrote about two potential investments in utility scale electricity storage.

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That “Free” set-top box isn’t free

Here’s an article from Reuters about the hidden costs of set top boxes… up to $76 a year in electricity bills for a cable set-top box.

This is one of those opportunities for energy conservation that I really like to push: you not only can save energy, but money as well, and it does not require sacrificing quality of life.  CFLs and Passive Solar architecture also come to mind… there are so many energy saving opportunities that pay for themselves, it breaks my heart.

Most consumers don’t see the money or electricity they’re wasting here, and so they don’t know that they need to be more discriminating.  These hidden cost provide a great opportunity for useful government regulation.  Requiring that A/V equipment have a sleep mode that uses 1 watt instead of 30 watts would only add marginally to the cost of most equipment (See this great Economist in-depth article on the subject from this spring)  Oops- it’s only available to subscribers.   Some highlights:

 STRANGE though it seems, a typical microwave oven consumes more electricity powering its digital clock than it does heating food. For while heatictq237.gifng food requires more than 100 times as much power as running the clock, most microwave ovens stand idle—in “standby” mode—more than 99% of the time. And they are not alone: many other devices, such as televisions, DVD players, stereos and computers also spend much of their lives in standby mode, collectively consuming a huge amount of energy. Moves are being made around the world to reduce this unnecessary power consumption, called “standby power”.

In 1998 … standby power accounted for approximately 5% of total residential electricity consumption in America, “adding up to more than $3 billion in annual energy costs”…. results, published in 2000, revealed that standby power accounted for as much as 10% of household power-consumption in some cases.

…In 1999 the International Energy Agency, based in Paris, adopted Dr Meier’s proposed “one-watt” standard as a target for standby consumption. In 2000 Australia became the only country to adopt this standard nationally, in the form of a voluntary scheme that began in 2002. The aim is for most new products to meet the one-watt standard by 2012.

In addition to these various voluntary schemes, there have been some mandatory measures. Perhaps surprisingly, one of them was introduced by President George Bush, as a result of the California energy crisis of 2001. That year, Mr Bush issued Executive Order 13221, which states that every government agency, “when it purchases commercially available, off-the-shelf products that use external standby power devices, or that contain an internal standby power function, shall purchase products that use no more than one watt in their standby power consuming mode.” Given that Mr Bush is not renowned for his environmental credentials, this came as quite a surprise to those in the industry.

That law does not apply to consumers, and there are a ton of energy hog products out there.

What can you do?  Buy Energy Star  rated products.   I also have a tester called a Kill-a-Watt from P3, to see which of the gadgets I already have are energy hogs.  Some nonprofits have these available for loan, and if you live in Denver, I’ll loan you mine.  The Center for Resource Conservation in Boulder has a nice little calculator you can use with it, too.

If you find you already have products that use a lot of power on standby (and you probably will,) consider plugging them into a power strip, and turning them off that way.  That’s not always an option, though.  I found that my VCR/DVD combo uses 30 watts all the time, and it would lose it’s programming if I turned it off with a power strip.   I’m thinking about replacement.

I also think this is a great argument for laptops over desktop computers… laptops are designed to conserve power, because they have to make the battery last… most desktops are not.  If you want a big screen and a keyboard, you can always use a docking station. 

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National (and Colorado) Tour of Solar Homes, October 6

Note: This post was originally for the 2006 Tour. The 2007 Tour of Solar Homes will be on October 6, 2007. See the original post after the break.

———————Info about 2007 Tour of Solar homes————————

Colorado Solar Tour link
Colorado Tour of Solar Home Flyer
For Southwest Colorado, there’s some info on the SWCRES website.
For Fort Collins area tour, see NCRES Website
For other states, go to the National Solar Tour link

———————Info about 2006 Tour————————
Read the rest of this entry »

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Water and energy

Last month, several nuclear power stations in Europe had to shut down during a heat wave (and consequent period of extreme electricity demand) to avoid releasing overheated water back into the environment.  As many other astute observers have pointed out, this pokes another big hole in the arguments that nuclear is our best choice of carbon-neutral generating technology.  A power plant that goes down precisely when you need the most power is almost useless for the current grid.

It also brings up the broader point of the role of water in electricity generation.  Nuclear is not the only technology that uses water for cooling.  Coal plants, including “next generation” IGCC plants mostly use water for cooling (air cooling can be used, but it makes them less efficient, and hence more expensive to run, and is seldom used in practice.)

This is a problem because water, in most countries is under-priced.  Resources that are under-priced tend to be overused, since the user does not have to bear the full cost of supply.  This is the cause of a large number of ills, such as the drying up of the Aral sea due to irrigation for cotton farming.  It is not only poor countries who don’t have enough water.  In the US, mispricing means that almost every aquifer is being pumped at much faster than sustainable levels.  In this context, it seems certain that power plants are also paying too little for the water they use for cooling.

 With a looming need to increase farming to supply biofuels, it is more important than ever that water be priced appropriately, especially in planning scenarios for power plants.  When water is under-priced, generation technologies which use more water are likely to be inappropriately favored in comparison to technologies which use little or no water for generation.

 Like nuclear, thermal electric systems are usually water cooled.  Fossil-fueled power plants account for approximately 39 percent of the water used in the United States, second only to agriculture. For coal plants, this typically amounts to 3 gallons of water (Texas study) or 0.5 gallons (NREL study) for every kWh produced (25 gallons are used for cooling, but only 3 evaporate in the process).  Nuclear, Biomass, and Oil fired plants also require large amounts of water lost as steam in the cooling process.   Some Solar thermal technologies also require significant water for cooling.

Water use by large hydropower projects is more complex, since water in reservoirs is more useful for some purposes (recreation) but often less useful for wildlife.  However, there is no question that reservoirs increase evaporative losses.  An NREL study quantifies these losses in the US.  Overall, in the US evaporative losses average over 18.2 gallons per kWh of hydroelectric power generated.  These numbers vary widely depending on the reservoir, from 2-3 gallons per kWh in cool northern states, up to over 100 gallons per kWh in KY, OK, SD, and WY.  Keep in mind that a lot of these reservoirs have other uses besides power generation, such as storing water for dry seasons, but the numbers can be mind-boggling.

Technologies which use little water include gas turbines (both natural gas and gas from renewable sources such as landfill gas), and geothermal (the water is typically re-injected into the ground).

Wind, photovoltaic, and wave power require no water to generate electricity. 

Energy efficiency, by its nature, uses no water.  Readers will recognize that as an ongoing theme: Given the choice, it is better to avoid using a kWh than it is to generate a kWh (regardless of source… even renewables have environmental impact.)

Renewable energy advocates should also be advocating for more rational water pricing, especially in planning scenarios.  Water use in generation will eventually come to be recognized as a significant cost (and source of uncertainty, as France found out last month).  The sooner this happens, the better for everyone.  Pricing water properly will not only save water, it will help move us to renewable energy technologies.

Investors may do well by concentrating their investments on low water use technologies, especially in parts of the world where water is (or will soon be) scarce.

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John Turner’s Renewable Energy Future; renewable technologies compared.

When you want an informed, but unbiased opinion, it’s usually best to ask someone John A Turnerwhose livelihood does not depend on coming back with the “right” answer.  When it comes to comparing different renewable energy technologies, one of the best experts I’ve heard from is John Turner.   Dr. Turner is a principal scientist for the Center for Electric & Hydrogen Technologies & Systems at the National Renewable Energy Laboratory (NREL), in Golden, Colorado.

The Hydrogen economy is that long hoped for world in which one day our cars will fill up at the corner hydrogen station, and combine that fuel with oxygen in the air, a process which will create electricity for the car’s motor, and with the only emissions being water.  It all sounds wonderful, but to reach that nirvana of zero emissions, the hydrogen itself needs to be produced with non-emitting technology.  That is because, contrary to oversimplified hype from politicians, hydrogen is not an energy source, but rather an energy carrier.  Like a battery, it has to be produced (charged) before it can be used.

Dr. Turner’s goal is to guide us to the hydrogen economy with as few missteps as possible, with missteps in his mind being the used of unsustainable technologies to get there.  Since he wrote his visionary 1999 article in Science, outlining a path to a “Renewable Energy Future” in which hydrogen serves as portable energy storage for an economy fueled solely by renewable sources of power.  The weak link in this chain is fuel cell technology.  Fuel cells are used to efficiently convert hydrogen and oxygen to electricity and water.  They have been around for well over a century, but are still too expensive for use in cars, although they are practical in some military and larger scale civilian operations.  A similar problem exists for hydrogen storage.

In contrast, hydrogen as a storage medium for electricity from intermittent power sources such as wind is a technology whose time has come. Norsk Hydro is currently doing a trial run of a wind/hydrogen combination system on a small Norwegian island, powering 10 homes.

What is most interesting to me about his presentation, is his unbiased comparison of different renewable technologies, along with nuclear, and Internal Gasification Coal Combustion (IGCC) with carbon sequestration.

He compares these technologies for robustness: the ability to meet our future energy needs; for expense, and for Energy Payback.  Energy payback and the related measure EREOI (Energy Return on Energy Invested) give us an idea of how much of our energy will have to be devoted to making more energy.

Here’s the run-down (with some additions of my own):

Technology

Energy Payback/ EROEI Robust? Price per kWh (approximate 2003 prices) Long term?
Wind

3-4 months; 20-30x

Yes

5-8 cents

Yes

Solar PV

3-4 years; 8x

Very

21-24 cents

Yes

Concentrating Solar

5 months; 40x

Very

8 cents

Yes

Biomass

varies

No

7 cents

Yes

Geothermal

varies by source

No

4-7 cents

Yes

Nuclear

1 year, not counting waste disposal. <20x

Yes

13-18 cents

?

Coal (w/ carbon sequestration)

16% of energy required for sequestration.

For now

5-6 cents

70 yrs, at current growth rates.

Energy efficiency

months; 50x +

Can never get all energy from efficiency

1-2 cents

Yes

(Items with links are from linked sources)

We’ll need all these energy sources, but Wind and concentrating Solar (CSP) stand out as near-term, robust, economical solutions, while Energy Efficiency and Geothermal will give us the most bang for our buck as we try to get started down the road.

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Why I Bought a Jeep

            First published on the Colorado Renewable Energy Society Website in April 2006.

            I started by looking at hybrids.  After all, I love my Prius to a degree most people reserve for friends, family, and pets.  While another Prius would not be big enough to haul the occasional sheet of plywood for my woodworking hobby, and lacked 4WD for


Denver snow, there are now four distinct hybrid SUVs on the market that would do quite nicely.

            So my wife and I looked at the Ford Escape and the Toyota Highlander. 

I did extensive web research.

We took test drives.

We got sticker shock.

Value for money is very important to me.  In fact, it is a central passion in my life.  As an investment advisor, I know that finding great companies is not particularly difficult.  Great companies are all around us.  Finding a great company that’s also a great value is another thing altogether, but that is where the real money in investment is made.

The problem with all the hybrid SUVs out there is that they are targeted at Blue Sun Libertythe luxury market.  Rather than using hybrid technology to primarily boost efficiency, the makers instead decided to focus on power.  The end results are fun to drive, but the relatively small boost to economy does not justify the increase extra $8,000 to $9,000 you can expect to pay when you leave the dealer’s lot.

At current gas prices, buying a hybrid SUV saves only about $0.02/mile, so the vehicle would have to last for about 450,000 miles to make back the extra cost of the vehicle, and that does not count the cost of replacing the battery pack once or twice in that time.  I believe that gas prices will continue to rise, but not enough to make the miniscule savings from a hybrid SUV justify the sticker price.

But what about the environmental benefits?  Were my wife and I doomed to squander our planet’s resources just because we wanted a roomy vehicle with four wheel drive?

Then I thought of diesel.  Diesel engines are more efficient than gasoline engines to begin with, and the newer “common rail” diesel (CRD) engines start quicker and create less particulates than the old diesel engines we remember from the last gas crisis.  Using B20, or 20% biodiesel, further reduces emissions, and since it comes from soy and canola, it is renewable, and the amount of energy necessary to make it is lower than the rather controversial ethanol.

While it is possible to cook up biodiesel from used cooking oil, I have neither the time nor confidence in my rusty chemistry skills to try that for myself.  Fortunately, we have a local company, Blue Sun, (www.gobluesun.com) that pays farmers to grow soy and canola for use in biodiesel, and sells it through about 15 gas stations throughout
Colorado, including in Denver, Boulder, Golden, Fort Collins, Colorado Springs, and Pueblo.  My only complaint about Blue Sun is that it’s private, so I can’t invest in it.

I would have to plan my fill ups (although I could use regular diesel in a pinch), but it would be quite possible to fill up with B20 most of the time, with a little planning.  As an added benefit, I would know I was aiding the distribution of a renewable energy technology.  My B20 purchases would encourage the expansion of the biodiesel-at-the-pump network, to the point where it wouldn’t just be compulsive renewable energy advocates like myself who fill up with B20.

I had a vision of a day when every gas station had a biodiesel pump, and diesel engines running on B20 were as popular as…, well, as popular as hybrids are today, with people paying way too much for them.

There was only one thing to do, and I looked up diesel SUVs on my favorite car research site, Edmonds.com, looked under diesel SUVs…And found the Hummer H1.

My heart sank… until I scrolled down the screen.

Below the Hummer, looking very out of place, was the Jeep Liberty.  Apparently Daimler decided to equip a few models from its recent Chrysler acquisition with their diesel engines.  It was a match made in renewable energy heaven, as far as I am concerned.

I ended up paying about $25K for my Jeep Liberty CRD, or about $8,000 less than I would have paid for a comparably equipped Ford Escape Hybrid (the
Toyota costs more.)  I’ll be spending about 50% more for fuel for the Jeep than I would be spending had I bought the Escape, but it will be 100,000 to 200,000 miles (depending on how quickly fuel prices rise) before the extra fuel costs add up to $8K. 

In addition, diesel engines last longer and need less maintenance than gasoline engines, and using biodiesel only adds to their longevity.  Hybrids, on the other hand, need an expensive battery pack replacement around 100,000 miles.

How does the diesel Jeep Liberty compare to the base model?  Fuel for the diesel engine costs about the same as gas for the standard V8, because B20 currently costs more than regular gas, although the diesel gets about 20% better mileage.   There are some savings in maintenance for a diesel engine over a gas engine, and the vehicle will probably last longer, but unless diesel prices fall, it probably won’t make up for the extra cost (about $2000… the diesel option costs more than that, but the current high cost of diesel fuel meant that the salesman was happy to get it off his lot, and I had more bargaining power.)

I paid about $2000 over the base model Jeep so I could feel good.  People buying Hybrid SUVs are also paying extra so they can feel good, too.  I think that’s wonderful, but even when you’re paying extra to feel good about your purchase, it’s important to keep in mind how much extra you are paying.

Is my Jeep better for the environment than the Escape I didn’t buy?  Probably not, but it’s not much worse, and I can leave that $8,000 I saved invested in one of my favorite renewable energy companies.  The earnings may even pay for that extra $.04 a mile I’m spending on B20… it would only require a 5% return if I drive 10,000 miles a year.

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Ethanol vs. Biodiesel

A new study from the university of Minnesota comparing the lifecycle energy costs and emissions of corn ethanol to soy biodiesel is all over the press this morning. 

The results are no surprise to any of us who follow the industry: corn ethanol yields 25% more energy than it takes to produce it; while soy biodiesel yields 93% more.

The numbers for ethanol ar not new: people have been arguing about the EROEI (Energy Return on Energy Invested) for ethanol for years, and the numbers have slowly risen with improving technology from about -10% to today’s 25%.  What are new, are the EREOI numbers for soy biodiesel.  I had only heard one number for the EREOI of “biodiesel” before – and no mention of the feedstock was made, nor was I able to trace it back to a reputable source… I suspect it was a back of the envelope calculation by a biodiesel advocate.  That number was a 220% return, quoted to me twice, once by management at Blue Sun Biodiesel, and once by the person manning the booth for the International Center for Appropriate and Sustainable Technology, both of whom do good work, but who have an incentive to believe this highest number they hear.  Disclaimer: I too have an incentive to believe the highest number I hear because I have a Jeep that I use biodiesel in to minimize my carbon emissions.   Using the new numbers, my Jeep Liberty has about the same carbon footprint as my 2002 Prius, when running on B100.  On B20, which I use in the winter, the Prius still looks much better.   I’m pining for a plug-in hybrid diesel.

But I’m very happy to see reality injected into the whole biofuels debate.  Neither ethanol not biodiesel (nor both together) is going to save the US from having to import petroleum: if our entire corn and soybean output were shifted to these biofuels, that would only replace about 12% of gasoline demand, and 6% of diesel demand… are we ready to start talking about massively investing in increasing the efficiency of our vehicles yet?

One other new note in the article, which I like given my affection for biodiesel, is that soy is a much less fertiliser intensive crop than corn, and so growing it has fewer local environmental impacts. I hope these authors continue their work, and expand the study to include other feedstocks for both ethanol (sugarcane, cellulostic) and biodiesel (canola, algae, recycled oil).

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