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Is the Science Barge Sustainable?

June 18, 2009

The Science Barge is supposed to demonstrate sustainable urban farming using technology that could grow vegetables on New York City rooftops. It was designed by engineering firm New York Sun Works, whose website describes the project with an audacious claim:

The Science Barge is a prototype, sustainable urban farm and environmental education center. It is the only fully functioning demonstration of renewable energy supporting sustainable food production in New York City. The Science Barge grows tomatoes, cucumbers, and lettuce with zero net carbon emissions, zero chemical pesticides, and zero runoff.

The Science Barge is an attempt to demonstrate sustainable urban agriculture. In 2007 it was docked in Manhattan.

The Science Barge is a well-intentioned, but unsuccessful, attempt to demonstrate sustainable urban agriculture. Docked in Manhattan in 2007 and Yonkers since 2008, it has attracted thousands of school children and considerable media attention but promotes a form of agriculture that could dramatically increase energy consumption and greenhouse gas emissions.

There are much better examples of renewable energy supporting food production in urban environments. Compared to them — or even to conventional means of feeding New Yorkers — the Science Barge is an energy hog with a gigantic ecological footprint.

The Science Barge technical specs (pdf) show that this is not a sustainable operation. Powering the 1,300 sq. ft. growing space requires about 25 kWh per day, or about 25 megajoules per square foot per year (do the math). In comparison, US farmland uses about 0.018 megajoules per square foot per year (1.8 exajoules over 2.26 billion acres, do the math). Each square foot of growing space on the Science Barge consumes as much energy as 1,400 square feet of typical US farmland.

Admittedly, small-scale vegetable production can be more energy intensive than the land-extensive field-crop and pasture production systems that occupy the bulk of US farmland. Last year we used 0.07 megajoules per square foot to grow vegetables and grain in a tractor-based production system, but only 0.01 megajoules per square foot to grow the same crops using hand tools (preliminary results of ongoing study). The Science Barge used about 350 times more energy per square foot of growing space than our tractor-based system, and 2,500 times more energy per square foot than our human-powered system.

A well-managed hydroponic greenhouse — like the Science Barge — can produce 10-20 times more food per square foot than a typical field vegetable operation. Even so, the greenhouse is orders of magnitude less energy efficient than the field.

Less than 30% of the Science Barge surface can actually grow food. The remainder is dedicated to the 12 solar panels and five wind turbines capable of generating 4.5 kW of electricity when the sun is shining and the wind is strong. Their capacity pales in comparison to the 400-pound furnace that can burn through 29 gallons of oil each day to warm the growing space in the cool season. Every week the furnace operates at capacity it burns enough to coat the entire growing space in a quarter-inch of oil. Then there’s the generator — which also burns oil — needed to supply the electricity demand that the solar panels and wind turbines can’t.

Such obscene energy consumption to grow food is sustainable, say Science Barge promoters, because the fuel oil is a waste product. The Science Barge burns vegetable oil from New York’s deep fryers.

But the oil that fuels the Science Barge wouldn’t necessarily go to waste otherwise. New York City deep fryer oil can be recycled into biodiesel for use in any diesel engine. The energy needed to keep the Science Barge’s furnace operating at capacity for a single day is enough to bring 1.3 tons of vegetables from California to New York by truck, or 4.2 tons by train (source, truck math, train math). New Yorkers could save energy by eating field-grown vegetables from anywhere in the country, instead of greenhouse-grown vegetables from the Science Barge in Yonkers.

The claim of “zero net carbon emissions” is suspect, too. The fuel sources may be renewable, but carbon was emitted to manufacture the aluminum greenhouse frame; the glass and polycarbonate cladding; the furnaces, fans, and computers; the solar cells and windmills; the PVC hydroponic troughs; the fertilizer in the hydroponic solution; the pumps and water purifiers; and all of the other components of this complex system. The only way to arrive at the “zero net carbon” figure is to omit these factors.

Even if the Science Barge were carbon neutral, aiming for zero net emissions is setting the bar low for a model sustainable agriculture system. A good soil-based vegetable farmer aims to sequester carbon by building soil organic matter levels. Farmers should strive to be carbon negative, not carbon neutral.

Below are a few links to stories and websites about New Yorkers who know how to grow food using soil, sun, rain, and urban waste, without relying on furnaces, generators, hydroponic systems, and other high-tech, resource-intensive gadgets. Each of these is a “fully functioning demonstration of renewable energy supporting sustainable food production in New York City.” The Science Barge is not.

14 Comments leave one →
  1. November 28, 2009 10:52 pm

    I think this is a great post. I just found out about the Science Barge and thought it was a great idea. Now I’m more of the opinion that it is the beginning of a great idea. I have to agree with Ted Caplow; this is just a prototype. It is the beginning of an idea that we could really benefit from. I am happy to see that someone has brought another perspective to the story though. Just one other comment. I slightly disagree with how you stated your “carbon negative, not carbon neutral” paragraph, in regards to farmers. While I think you’re right, farmers do need to strive for a carbon negative balance, I also question why the onus is on farmers alone? In this day and age, everyone should strive for a carbon negative balance, not just farmers (I’m the son of a farmer, and a student in an agricultural program). Other than that, I think this was very informative!

  2. Tami Wells permalink
    November 9, 2009 11:17 pm

    I briefly read through all of your comments. I would like to reply to the comment about the “dead zone” in coastal waters. We have to reduce nutrient and pesticide runoff. The dead zones are increasing and protein, as a food source from fisheries, is decreasing proportionally. Next, I believe that the photoperiods above the 35 parallel are increasing your need for energy resources. The same project implemented in the southern states may limit the energy requirements. Field crops may reduce the energy required per square foot of biomass yet I am not sure that is the case if the farm is rural and requires transport to consumers. The science barge technology may provide an alternative for growing fresh produce on a local scale that will reduce the overall transportation cost and carbon footprint. There will always be room for improvement. I really like the concept of the science barge. I am interested to know if any of your educators have determined the educational impacts on K-12 students (i.e. surveys, pre and post test, and others). Remember, educational is a long-term benefit of the science barge. One must also consider the health (physical and mental) benefits from fresh produce gardens/greenhouses in relation to energy consumption. I am very interested in implementing this technology in the south.

    • Ted Caplow permalink
      November 15, 2009 12:19 am

      Tami, thanks for your interest in the Science Barge and New York Sun Works. You are correct that heating is a critical area of energy management for greenhouses and that a southern climate reduces the heat load very signiicantly. However, and without going into a lot of details here, the energy footprint of greenhouses can be managed in a more sustainable way, to the point that parity is reached or exceeded with field crops from other parts of the country. Large commercial greenhouses in the industry are not energy conscious as a rule; but the systems we design (the Science Barge and the many designs we have underaken since) take a different approach. There are many techniques to reduce the carbon footprint, and each project is an opportunity to pursue a tailored set of these techniques, which range from the low carbon fuel on the science barge to waste heat capture from buildings, advanced heat pumps, heat curtains, lower setback temperatures, etc.

      Overall, sustainable food production — not just veggies but meat, fish, and cereals — is a goal shared by many. There are various camps and vested interests who each espouse a different path toward a solution set. Our belief is that technically sophisticated methods of high yield, low impact, climatically independent farming can (and will) make a big difference. We do not pursue genetic modifications; we do not pursue organic for its own sake; we do not pursue offshoring. Our philosophy is one of integrated, local self-sufficiency, where feasible.

      Leaving the subject of current impacts and comparative advantages over field ag to one side, however, I agree with your emphasis on the educational benefits of the barge system. The volume of creative ideas, newfound interest, derivative projects, and productive discussions in the wake of the Science Barge has been tremendous, so much so that I used to be quite surprised by all the attention the barge has attracted (including blogs like this one!). But I have come to believe that, so long as we are clear about the goals and values of the project(s), all this attention to sustainable food production can only improve the state of knowledge and practice in the field. Our students become more interested in earth science and engineering, and more informed about the food system.

      To your question about measurable results: we did a few teacher surveys and we have a lot of anecdotal positive reports, but we do not have a systematic, scientifically meaningful study of results. Bear in mind that the science barge, for its first three years anyway, has been a one-afternoon experience for students. I believe a more lengthy engagement would be more effective (at the expense of serving fewer students). The system we are now building on a NYC public school will address this need for a regularly available sustainability lab (and at the same time showcase rooftop greenhouse methods with the potential to deeply reduce the net environmental impact of selected crops in the NYC marketplace).

      Thanks again,

      Ted Caplow

  3. August 21, 2009 6:10 pm

    Pretty bold post. As an utterly partial reader (I designed the Science Barge system), I will just point out that (a) the barge is just a prototype with a lot of room for improvement and these improvements will be happening on larger projects; (b) the energy metric that matters is MJ/kg of vegetable delivered to the consumer, so talking about on-farm energy without talking about yield and transport is way off target; (c) transportation is the main energy consumer in the US fresh vegetable supply chain; (d) neither energy nor carbon are the whole ballgame with regard to agricultural sustainability – water and land use are of equal or greater importance.

    • August 24, 2009 10:04 am

      I agree wholeheartedly with points (a) and (b), but my post ignores neither yield nor transport. Heated greenhouses have higher yields, but still use far more energy per unit delivered to customers than field-grown produce transported by truck or train. Dr. Yoshi Wada made this point back in 1993, and subsequent studies have shown consistently similar results. See, for example, Tables 8 and 17 in Dr. Carlsson-Kanyama’s “Energy Use in the Food Sector: A Data Survey.”

      Point (c) is simply wrong. Transport is a relatively minor energy consumer in the US fresh vegetable supply chain. See my posts from April 16 and May 4 for sources.

      Point (d) is correct in stating that energy use and carbon emissions are not the be all and end all of food system sustainability, but they’re important parts of the picture, and they can’t be swept under the rug by saying “we’re very sustainable in other ways.”

      So the question is: Can we grow in urban environments without increasing our energy consumption? I believe we can (and do). I actually really like the Science Barge concept because you’re trying something that’s real, instead of just talking about a vision. My critique is an earnest attempt to point out the shortcomings so that future attempts can be made to overcome them. You claim in point (a) to have the same goal.

      I’m working on a post called “Building a Better Science Barge” to share some of my ideas.

      But why? Why would some guy in Kentucky start criticizing an urban agriculture project in New York City?

      My interest in the Science Barge comes, in part, from a proposal that Kentucky State University construct a Science Barge-type demonstration on the Kentucky River, in Frankfort, the state capitol. That combines with my broader interest in food energy issues, and my history of working as a consultant in large greenhouses in British Columbia.

  4. July 30, 2009 1:22 pm

    I’d very much like to read Michael Bomford’s response to some of the points made by Curt Collier regarding rooftop hydroponic greenhouses. So far, Bomford has addressed issues of energy consumption. He hasn’t yet addressed the other concerns which are hugely important in how we choose to organize food production. These include runoff from impervious urban surfaces; runoff of fertilizers and pesticides from soil-based agriculture (causing huge dead zones in our waters); winter heat escaping from urban buildings; the summer urban heat island effect of our current rooftops (and the inability of many existing buildings to support soil-based green roofs). Another advantage Collier describes for rooftop hydroponic greenhouses is their lengthening of the growing season as they capture heat rising through urban buildings that would ordinarily escape into the atmosphere. I’d also like to hear Bomford’s rebuttal to Collier’s point that most of the energy used by the Science Barge is sun and wind.

    “One third of America’s energy use goes towards food production – energy most commonly generated by coal and fossil fuels. By only using sustainable energy, urban farms not only help to eliminate food transport miles, irrigation, fossil-fuel generated pesticides and fertilizers, but the carbon emissions from these activities. It may be true that that hydroponic systems require more solar energy than a sunny plot in Florida, but what does that matter if it’s the same sun’s energy?”

    Collier also raised issues of changing our relationship with food. We need to debate this as well, but for the time being would be very interested in hearing Bomford’s evaluation of the immediate environmental issues listed above.

    As you can see from our website, our local environmental group ( is extremely interested in hydroponic agriculture, most immediately for already-existing buildings that can’t support soil-based green roofs. However, we make every effort to be open-minded and to consider potential problems. We welcome evidence against elements of hydroponic rooftop agriculture. But in arguing for its non-sustainabilty, we need to take into account all the environmental problems our cities face, not energy use alone – especially when most of that energy derives from limitless resources such as sun and wind.

    Econeighbors has come to rooftop hydroponics in part out of concern for how urban buildings are increasingly and massively replacing living environments of plants and animals with impervious surfaces. These roofs and streets are broiling in summer and cause rain to run off into sewers and waterways, carrying pollutants they pick up (e. g. auto chemicals) along the way. Meanwhile, as world population increases, our agriculture is destroying ever more naturally-diversified land to replace it with monocultures that don’t support the range of plants and animals that were present before. It seems like a sensible approach in the future to require that all buildings move to their rooftops some of the natural environment they’ve destroyed below. In the case of already-existing buildings which cannot support soil-based roofs, hydroponics appear the only way to go.

  5. July 23, 2009 5:46 pm

    While scanning the internet we came across this article written by Michael Bomford of Kentucky State University’s Organic Agriculture Working Group. While I appreciate the technical aspects of Bomford’s article, he makes several false comparisons. Perhaps it would have been better had Michael spoken with us prior to printing this e-article as it is precisely this type of misinformation that limits needed agricultural progress in this country.

    First off Bomford correctly notes that the Science Barge was built as a “prototype, sustainable urban farm” for demonstrating how food can be grown on New York City rooftops. However, he then goes on to compare the Science Barge’s energy-to-yield ratio with “traditional” organic farms using soils. This is a false argument, as no one disputes that soil based farming, in season, takes far less energy to produce vegetables (in most regions) than hydroponically grown vegetables on skyscrapers. But that’s not the point. Anytime you grow an organic vegetable within its hardiness zone outside using the free energy of the sun you will out compete an urban greenhouse on energy usage – as long as you have the land and soils to do so. But that was never our argument. As I recall, and looking out my window, most of the New York City area is heavily urbanized with little arable land for growing vegetables in season. Vegetables grown outside the area would need to be trucked into this city. By living within a few meters from where our food is produced we eliminate massive amounts of energy needed to transport that food. However, this energy is the free energy of the sun and wind. The Science Barge does use waste vegetable oil ….and the emphasis here is waste ….during winter to grow food, but this is during the same season when traditional fields across vast stretches of the US (including in Kentucky) remain fallow. For example, we began harvesting tomatoes in June, two months after planting, and months before most farms in New York even get a blossom. If we use only free solar and wind energy, and waste oil, what does it matter how much energy is used? Free clean energy, regardless of its amount, is still free clean energy. Of course he is right that we could grow vegetables in warmer climates, such as in my native South Texas, in Arizona, or California during winter months, but you still have to truck the food the several thousand miles to New York. I don’t understand how truck farms producing vegetables in areas thousands of miles away can be more energy efficient than food grown on rooftops using free and clean energy. One third of America’s energy use goes towards food production – energy most commonly generated by coal and fossil fuels. By only using sustainable energy, urban farms not only help to eliminate food transport miles, irrigation, fossil-fuel generated pesticides and fertilizers, but the carbon emissions from these activities. It may be true that that hydroponic systems require more solar energy than a sunny plot in Florida, but what does that matter if it’s the same sun’s energy?

    In regards to the waste vegetable “furnace” aboard the Science Barge, it must be understood that the Science Barge was built as a prototype to demonstrate the technologies that could be employed upon rooftops within New York. Sitting as it does on the Hudson River, the Science Barge does need to use heating during the winter– all greenhouses do. Yet that would hardly be the case if these technologies were implemented in the locations for which they were intended; that is on rooftops. As anyone who has ever lived in an upper-story apartment in NY City can attest, the amount of waste heat rising through our buildings is enormous. Mr. Bomford’s calculations fail to take into consideration the substantial amount of heat rising up from these buildings which would be “bottled” within the greenhouse and utilized. Ambient air temperatures matter less to many growing vegetables than root temperatures. This heat can easily be incorporated into the roof-top farms growing areas thus stretching the growing season considerably. Mr. Bomford’s calculations also need to incorporate the energy savings that “green” roofs bring to apartments. Essentially utilizing the sun’s energy during the summer months, the urban vegetable farms also would offer the advantage of significant energy savings by preventing radiant heat from falling upon apartments. Come to New York, Los Angeles, Boston, or Chicago during a brownout on a hot summer day and you’ll appreciate the amount of energy savings that greenhouse roofs could provide.

    Mr. Bomford also fails to consider the other positive environmental impacts of urban farming. For example, large areas of exposed concrete have created significant problems with stormwater runoff in most American cities. Water that normally would have been absorbed into the ground in most areas is guttered away into storm drains.. As most of our cities have combined stormwater and sewer systems, heavy rainfalls often result in massive amounts of untreated waste being flushed by rain into our urban rivers and streams. Urban farms would effectively use most of the water that fell on its roofs, as does the Science Barge. As no water is wasted on the barge (as evaporation and non-plant absorption waste is limited) urban farms would not only help to preserve our rivers and streams but more effectively use our dwindling precious water resources. We emphasize on the Science Barge that we are not campaigning against conventional farming, but with a rapidly increasing population and the relative urbanization that comes along with it, our need for food is increasing while our resources are decreasing. Approximately 1/32 of the groundcover on earth is arable land and urbanization is fast encroaching upon what remains. An even smaller portion of water is available.

    Finally, Mr. Bomford fails to take into consideration the most important aspect of the urban farm; the changing relationship between humans and their food. Mr. Bomford points out that our “farm” is visited by thousands of school children, media, scientists, and agriculture experts from around the world each year. This is true. For many urban youth, this is their first time visiting a place where food is grown, and for some here in Yonkers, the first time they have seen a tomato that wasn’t processed in some way. Americans must change their relationship to food as our current production and transportation systems are destroying our planet. Food related illnesses like cancer and heart disease, as well as obesity and nature deficit disorder riddle our urban communities, while we burn our jungles to grow feed for cattle. Urban farms would help millions of Americans to rethink food. By moving food production into our cities we re-envision an America where there are more, not less farmers. Instead of the current .5 percent of Americans involved in agriculture, imagine significant numbers of urban farmers; green jobs that would revitalize an American economy and thwart the corporatization of our food production. Without rooftop farms, that dream could never become a reality as the majority of Americans don’t live in rural areas. What Mr. Bomford’s dismissal of urban agriculture fails to take into consideration is the positive impact that growing food has on residents. Imagine schools where youth grow their own lunches, apartment dwellers who stop upstairs before going home to pick fresh lettuce, poor inner-city community centers with their own farmers’ markets, and the myriad of other psycho, social, economic, and spiritual impacts of growing food. People come to the Science Barge and to urban farms because they want to reconnect to something essential and intimate, even if they don’t know yet what it is. I am not sure how he would take all these advantages into his energy calculations ….but Mr. Bomford should.

  6. July 20, 2009 11:32 pm

    I agree with Frank in that we should support interesting projects like this one that will keep school children interested in science and that there are many things that can be learned from this project. I agree with Michael as well, somebody has to point out the holes in any project with constructive criticism. Just because a project gets positive press doesn’t mean it is perfect.

  7. June 22, 2009 12:58 pm

    Harnessing the power of google’s unit conversions for sane agricultural policy!

    Next task is to use a similar approach to assess an hypothetical vertical farm.

    In comparison, I’d imagine the science barge would look pretty good. To the best of my knowledge, after generating media attention that a field-based farming system could only dream of (from Wikipedia:
    Mass media attention began with an article by Lisa Chamberlin, that featured Arcitectural designs and infographic illustrations by Chris Jacobs, in New York magazine.[5] Since 2007, articles have appeared in The New York Times[6], U.S. News & World Report[7], Popular Science[8] and Maxim (magazine), among others, as well as radio and television features.)

    …the vertical farm has never been assessed using a simple but consistent quantitative analysis such as the one Mike makes in this post.

    Take the science barge, add all of the energy-intensive structural requirements needed to achieve skyscraper heights, add artificial lighting, and you’d have something like a vertical farm. It would make for a fun piece of math.

    One student analysis of a proposed vertical farm made the thermodynamics-busting claim that vertical farms would be net energy positive (found the essay here. This would be achieved through in-house anaerobic digestion of livestock and crop wastes. Their analysis neglected to consider livestock feed or plant nutrients as energy inputs in the system. Oh well.

    A relevant analysis ( of a chicken barn — the animals responsible for producing much of the vertical farm’s proposed electricity in the student paper — found that, “…feed provision accounts for 80% of supply chain energy use, 82% of greenhouse gas emissions, 98% of ozone depleting emissions, 96% of acidifying emissions and 97% of eutrophying emissions associated with the cradle-to-farm gate production…”

    The author uses a nice term in the abstract that I haven’t seen thrown around much but I hope gains some traction:

    “The Fallacy of Landless Farming”

    Nice work!

  8. June 20, 2009 5:01 pm

    One of my day jobs is case studies of green building projects, primarily LEED. The LEED standard certainly isn’t perfect, but one thing it does well is require third-party objective evaluation of the costs and benefits of green build projects as a precursor to achieving LEED certification. If your building gets LEED certified it’s because a third-party team took an impartial and objective look at your project and deemed it so.

    Years ago I worked as an ag agent for the UC Cooperative Extension service here in California. At that time there was no such thing as the USDA’s National Organic Program (NOP). NOP isn’t perfect either, far from it in fact. Like LEED though, NOP farm applicants must meet objective standards and be evaluated by third-party Organic Certifying Agents to get and keep a USDA Organic certification.

    With both LEED and NOP the details of the standards are public and well documented. The third-part certifiers must follow methods and practices in their certification work that are also public and well documented. LEED and NOP certifiers must themselves go through a rigorous program of training and accreditation before being allowed to perform certification evaluations of buildings or farms.

    The bottom line is that building owner/operators and organic farmers don’t get to claim their building or farm meets the LEED green building or USDA NOP standards unless an accredited third-party objectively evaluates it and certifies it is so.

    There is no objective third-party standard for evaluating and certifying innovative sustainable ag projects (such as the Science Barge) that are trying to contribute solutions to reengineering the food system sustainably.

    MIke Bomford is one of the most qualified and experienced sustainable ag researchers and farm advisor professionals in the USA. His critique of the Science Barge is well-reasoned and objective. The logic of his critique is transparent and backed up well with references and web links to info and tools. His critique provides a framework and set of tools we can use to evaluate other innovative sustainable ag endeavors. Much obliged, Mike.

    I’d love to see the Science Barge founders and current operators build on Mike’s critique and expand it into a thorough case study that covers best practices and lessons learned as well as addresses the fundamental sustainability points that Mike made. The Science Barge example has much to offer in the way of do’s and don’ts, especially for urban sustainable ag projects.

    And perhaps someday we’ll have a Sustainable Food System (SFS anyone?) rating system (akin to USGBC LEED and USDA NOP) and accredited certifiers that can help us design and certify projects that meet the sustainability challenges we are all facing on this wonderful fragile planet of ours.

  9. June 19, 2009 3:28 pm

    I am not so critical of this project or many others like it. There are many facets to the project to look at and learn from that can be improved or used in future (rooftop?) systems. This is a ‘school’ to get kids interested in science and, perhaps, trying something in a fish tank or their back yard. Each failure is something learned and a project to work on improving. I doubt this small project was intended for someone to make a working pay (perhaps hoping it would?) but something to peak an interest. And that being a goal it is successful. I suggest we encourage these type small interesting projects and not put them down.

    Frank Shields
    B-ISA member

    • June 19, 2009 4:22 pm

      I agree that the project can be considered a success if we can learn from it and work on ways to improve it. To do that demands an honest and critical assessment of its strengths and weaknesses. The Science Barge project has generated plenty of positive press, but I have yet to see a critique of its shortcomings. By holding this up as a model of sustainable agriculture I fear we will make the ecological footprint of our plates bigger, not smaller.

  10. June 18, 2009 2:46 pm

    Hysterical! The problem with many well intentioned BS projects is they do not stand up to rigorous analysis. Frequently, that is OK with the innumerate, feel good, media puff pieces.

    Keep it coming.


  1. Sustainable Urbanized Agriculture « Agriculture 2.0

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