• Jun 5th 2009 at 9:26AM
  • 19
We recently heard that, according to one group of researchers at Environmental Science & Technology magazine, corn ethanol has a water cost of 50 gallons per mile. Now, a team working from the University of Twente in the Netherlands has calculated the water cost of ethanol and other biofuels and to make bioelectricity. The results are not pretty. The researchers looked at 13 crops and tried to calculate the most efficient way to turn them into energy depending on where the crops were grown, and which process was used to turn the biomass into either biofuel or electricity. The worst offenders included making biodiesel from rapeseed or soya (14,000 liters of water to make just one liter of biodiesel) and jathropha (20,000 liters of water), according to the abbreviated description we found at Alpha Galileo. The researchers found that the most efficient crop-to-energy ratio came from turning whole sugar beet plants into electricity. If you're just interested in making biofuels, then sugar beets are still your best bet. A liter of ethanol made from sugar beets uses "just" 1,400 litres of water, the Twente researchers found. Second and third generation biofuels made form algae or advanced cellulosic processes were not included. Coskata, for example, says their process uses less than a gallon of water to make a gallon of ethanol.

[Source: Twente (in Dutch), Alpha Galileo via Greenbang]
Photo by D Sharon Pruitt. Licensed under Creative Commons license 2.0.




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  • 19 Comments
      • 6 Years Ago
      These researchers did Not take into account that soybeans also produce a valuable high protein livestock feed byproduct, after the oil is extracted. Any water used should be apportioned between the food and the fuel, not just allocated to the production of fuel alone. Likewise, corn ethanol produces corn oil and high protein distillers grains livestock feed, in addition to ethanol fuel. So, again, the amount of water used to produce ethanol must be divided proportionately - between the food and the fuel produced from the total amount of water. These researchers have an agenda – to bash the water economics of biofuels. One of the tricks they use is omitting credits for the food byproducts.

      They also over estimate the amount of water consumed by using water data for irrigated crops, and the truth is, most soybean and most corn is Not irrigated.

      Another red flag is, they are trying to compare apples with oranges, the biofuel efficiency of stationary electric power with portable liquid fuels. This is Not a valid comparison. Liquid fuels are totally more practical, because 95 percent of the vehicles on the road today run on liquid fuel, not electricity. That is until EVs and Plug in hybrids become mainstream 15 to 20 years from now. Biofuels are still the transition fuels that are here now and get you off of imported oil today.

      Their water consumption data is way, way off. Someone who knows how much water is used are people in the field actually producing biofuels. Jeff Broin head of Poet Ethanol, the largest producer in the world, recently reported that most of their ethanol waste water is being recycled, and less than 4 gallons of water is used to produce 1 gallon of finished fuel. Again, most of the corn being used for ethanol is not irrigated.

      Sugar beets are only suitable for certain climates, like where this study was conjured-up. In Brazil it’s sugarcane. In Asia, it’s cassava. In the Corn Belt, it’s corn. In Texas, it’s sorghum. Sugar beets are not your best feedstock. They have to be processed within a few days, or they rot. Corn can be dried, stored, and used all year – much more practical. If efficiency was the bottom line instead of practicality, we would all be riding bikes instead of driving vehicles consuming energy intensive liquid fuels.

      Very interesting that they left out algae and cellulosic biofuels. That ought to tell you something. Petroalgae reported today that they’re producing 65 tons of algae biomass per acre per year from open ponds. And there are four other companies reporting algae biomass yields of over 100 tons per acre per year. So if you’re swayed by the above report, don’t be. Biofuels are coming, and in a big way. The water use will be solved by recycling and new technology.
      • 6 Years Ago
      When talking about the water/energy nexus, I think we have to keep a few things in mind:

      1. There's a huge difference between water draw and water consumption. A nuclear plant that sucks a lot of water from a river, uses it for cooling, and then returns the water to the river has a high draw but a much smaller consumption. The consumption is basically the portion that evaporates.

      2. When assessing any technology's water requirements, it's worth thinking of both sides of the relationship. In other words, you build a huge facility of some sort in a location, and it uses a lot of water from a local lake or river. The new facility impacts other uses of that same water (there's less to go around, it heats or pollutes the water, etc.). This is the side most people think of, naturally enough. The flip side is that you're now creating a new, ongoing dependency on that water supply. If the river level gets too low, or the water gets too hot in the summer (always a threat when it's used to cool a thermoelectric plant, for example), you potentially have a big problem.

      When we build some kind of energy facility that depends on water--coal plant, biofuels farm, whatever--we're making an assumption about the nature of the water supply at that location for anywhere from a few growing seasons to multiple decades. As climate chaos continues to shift rainfall patterns, wipe out glaciers (which supply summer water in many places around the world), and generally make dry areas drier, wind and solar power will look even better than they do now.
      huisj203
      • 6 Years Ago
      In other news, did you know that plants take water to grow? Oh my goodness, we should all stop eating vegetables. They use so much water.
        • 6 Years Ago
        @huisj203
        There is quite the rabid antibiofuel noise box about (most likely funded by fossil).
        • 6 Years Ago
        @huisj203
        I just found out there's this thing called the water cycle... it's not like a bike or anything, but it's good news for biofuel makers, I think...

        http://www.usgcrp.gov/usgcrp/images/ocp2003/ocpfy2003-fig5-1.htm

        Also, I remember my kindergarten teacher telling me about conservation of mass and particle physics... apparently we can't kill water. Weird, I know.

        I'd hate to see how many gallons it takes to grow a person. I'll bet there are lots of zeros in front of that decimal.
      • 6 Years Ago
      Wow another so what, next they will get into how much tolet water they use per employee, can you get credits for puting in back as in doing #1? how about the squirrls that get killed on the way to work by employees of all the companys from the oil riggers to the gas station attendents to the people that buy it! Come on. People can make news out of anything. Clean water is a problem. People are working on that as we speak. With so many of us here on the big E, resources wil be getting tighter but we will adjust. Need water and only have dirty water, go to your local outdoors mart and buy a water filter, use a straw and drink out of a ditch if you need water! PLEEEEse!
      E
      • 6 Years Ago
      If they were using seawater to produce biofuel no one would be concerned, but the big concern is using irrigation water from aquifers.

      Temperatures are rising, and water tables are falling everywhere. Wasting water on biofuel boondoggles until aquifer depletion becomes yet another crisis is the height of idiocy.

      http://www.eoearth.org/article/Aquifer_depletion
      "Scores of countries are overpumping aquifers as they struggle to satisfy their growing water needs, including each of the big three grain producers—China, India, and the United States. These three, along with a number of other countries where water tables are falling, are home to more than half the world’s people.
        • 6 Years Ago
        While I do agree with you, aquifer depletion is not a new problem. At least in the US, the biggest one, the Ogallala Aquifer, has been on the decline since the 50's. The problem is getting worse, but what's stupid is that the farmers using it know that they are pumping their own demise. They also know that if they don't take the water then someone else will, so they don't stop. They should be limited and forced to use more efficient means of watering their crops. It is possible and the tech is already available. It is more expensive, but that's why we (governments, actually) have the power to make policy changes; so farmers and other people in free markets don't just do what's "best" for them at any given moment. For a quick and dirty on the subject I'm posting a generic wiki article, but everyone should be aware of this. It is a real problem, and you should talk to your representative about it.

        http://en.wikipedia.org/wiki/Ogallala_Aquifer
        • 6 Years Ago
        Well Matt, if you know this, why the snarky condescending post (#2 above).

        Obviously the problem isn't water being destroyed, it is source depletion that is the problem. A very real problem before the biofuel boondoggles started and they are obviously going to make it worse.

        And this is only one of a myriad of issues with the biofuel boondoggle.
      Atul
      • 6 Years Ago
      What I always find funny is how people and companies keep leaving the Great Lakes states and head to the south and southwest because of better weather or the cool factor or whatever. The cities don't keep an eye on population and industry growth versus water supply? How dumb. Atlanta ran low on water a few years back to the point that it was critical.

      I predict that in 10 years, people and companies will start moving back to the Great Lakes where we have fresh water in abundance. And if they want us to pipe it out of here, I'm sure our states will put up a fight.
      • 6 Years Ago
      zeph is right on here, I agree.
      • 6 Years Ago
      Couldn't find the study (although I haven't looked too much yet). But their news release raises a red flag:

      "In their article, the researchers show the water footprint of thirteen crops: the volume of water – rainwater and irrigation – required per gigajoule of energy production."

      Rainwater, huh? What the h#ll does that have to do with anything? That will seriously skew their numbers.

      ... and it would therefor be a pretty poor comparison with Coskata, since they surely aren't including whatever rainfall feeds their biomass sources. Couldn't if they're claiming less than a gallon of water used.
      • 6 Years Ago
      "Obviously the problem isn't water being destroyed, it is source depletion that is the problem. A very real problem before the biofuel boondoggles started and they are obviously going to make it worse.

      And this is only one of a myriad of issues with the biofuel boondoggle. "

      I would think the aquifers would fill back up pretty quickly if there was a fuel shortage and no market for all those crops.

      • 6 Years Ago
      Agreed. Until fresh water scarcity becomes an issue at the location WHERE the biofuel is being produced, I don't think this is so urgent. No one is stealing all the water in Darfur to make biofuel. Of course we should conserve, but if you look at the water consumption of all industry, this is typical.

      If you consider that it takes more like 20000 liters to make just one kg of beef, then perhaps no one should eat meat either.

      Good thing my biodiesel comes from RECYCLED oil.
        Atul
        • 6 Years Ago
        You're right. Beef does take a lot of water AND energy to produce. If you want to be green, you should stop, (or at least cut back on), eating meat. Hundreds of millions of healthy people don't eat any.

        I think the best solution is to create biodiesel from algae. Doesn't algae grow in unclean water? Hopefully that pans out as a solution.
        • 6 Years Ago
        Just becauses it's not scarce(yet) where you live, it is around most of the world. While it's not scarce yet why be wasteful?
      • 6 Years Ago
      The article forgot to mention how much water goes into pumping oil out of the ground or the ocean. Or at any other part of the oil to gasoline stream.
      • 6 Years Ago
      Can someone please point me in the direction of a peer reviewed article that explains the excessive water use of Jatropha? I'm looking at a peer reviewed journal that says it only uses 0.8 L of water from irrigation in Guatemala. And yes, it would be terrific if we used seawater for irrigation and took advantage of halophytes for biofuels but that would be a major development project, very high risk.
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