Published on February 19th, 2015 | by Glenn Meyers


New Perspective On Bioenergy Economic Model

February 19th, 2015 by  

Bioenergy, while environmentally cleaner and more sustainable than fossil fuels, has historically been too energy intensive to produce — a big negative from an economic perspective.


Modern biogas plant in Holland, using sugar beet pulp

However, recent bioenergy research from the University of Minnesota on combining solar thermal energy with biomass gasification for producing a natural gas substitute indicates a cost-competitive economic model may now work.

According to ScienceDaily, a new University of Minnesota study examining the financial viability of solar-heated biomass gasification technologies that produce a natural gas substitute product concludes that combining these renewable resources can make economic sense, even in the face of historically low natural gas pricing.

Here are the specifics on production economics: In traditional biomass gasification, 20% to 30% of the biomass feedstock is burned to produce heat for the process. But if the required thermal energy is supplied from a concentrated solar source, all of the biomass can be converted into useful synthesis gas.

University of Minnesota logo images (1)The Initiative for Renewable Energy and the Environment at the University of Minnesota Institute on the Environment funded the study, which was published in Biomass and Bioenergy.

A financial feasibility metric was developed to determine the break-even price of natural gas at which the produced syngas could be sold at a profit. Study results suggest that solar-heated biomass gasification systems could break even at natural gas prices of $4.04-$10.90 per gigajoule (metric standard for energy content is joules), depending on configuration.

About Gasification

Biomass Energy Centre logoAccording to the Biomass Energy Centre (BEC), gasification gases are known as ‘producer gas’ or product gas. Source material used to produce these gases include virgin wood, energy crops (currently corn, ie, ethanol), agricultural residue, and industrial waste and co-products.

In 2011, the widespread planting of corn to produce ethanol was blamed for creating severe food shortages worldwide — with 44 million people falling below the poverty lines due to an increase in food prices, according to 2010 World Bank estimates. As a result, World Bank president Robert Zoellick called for the world to “put food first” — first, that is, over biofuels, which, for example, make up 40% of US corn usage, an example of the issues facing the biofuel industry.

Depending on the feedstock, the precise characteristics of the gas will depend on the gasification parameters, including temperature and also what oxidizers are used.  If the oxidizer is air, in which the producer gas will also contain nitrogen (N2), or steam or oxygen, reports the BEC, reporting gasification dates back to the 19th century.

Gasification is not a new technology, it was originally developed in the 1800s and is the processes used to make town gas for lighting and cooking.  Small-scale gasifiers were also used to power internal combustion engine vehicles during fuel shortages during the Second World War.

Uses for gasification technology:

  • Heating water in central heating, district heating or process heating applications
  • Steam for electricity generation or motive force
  • As part of systems producing electricity or motive force
  • Transport using an internal combustion engine

“While the cost of adding solar energy generation to a biomass gasification facility can approach one-third of a plant’s total capital costs, other equipment required in traditional plants can be avoided and the amount of syngas produced per ton of biomass — a major variable cost of production — increases significantly,” said senior author and former University of Minnesota College of Food, Agricultural and Natural Resource Sciences student Tom Nickerson.

“With average US natural gas prices at $4.80 per gigajoule in 2014, two of the four configurations modeled were economically competitive,” said co-author Timothy Smith, director of the NorthStar Initiative for Sustainable Enterprise, IonE resident fellow and CFANS faculty member.

Though government incentives could significantly reduce the risks associated with volatile energy markets, demonstrating that the gap isn’t insurmountable is an important step toward environmentally preferred energy solutions. “Utilizing solar technologies to get more energy out of each acre of biomass reduces the impacts to the landscapes producing it,” Smith added.

No commercial plants currently exist, but the technologies modelled in this study are being developed at the Solar Energy Laboratory at the University of Minnesota under the direction of Jane Davidson and lead research scientist Brandon Hathaway of the College of Science and Engineering.

“Our novel approach to gasification has demonstrated its benefits at the bench scale, and testing with our 3 kW prototype is ongoing in the University of Minnesota’s High Flux Solar Simulator,” said Hathaway.

“We hope to find industry partners to join us in the next steps as we scale up the process and move towards testing on-sun,” Davidson added.

Photo credit: Modern biogas plant in Holland via Shutterstock

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About the Author

is a writer, producer, and director. Meyers was editor and site director of Green Building Elements, a contributing writer for CleanTechnica, and is founder of Green Streets MediaTrain, a communications connection and eLearning hub. As an independent producer, he's been involved in the development, production and distribution of television and distance learning programs for both the education industry and corporate sector. He also is an avid gardener and loves sustainable innovation.

  • JamesWimberley

    ” … all of the biomass can be converted into useful synthesis gas.”

    How? Cellulose has the formula C6 H10 O5. Methane is C H4. So the best you can theoretically get by conventional gasification is:
    2(C6 H10 O5) -> 5 (CH4) + 5(CO) + 2C

    but you probably get some harmful CO2 instead of combustible CO, or more solid carbon residue. In any case you can’t convert all the carbon to gas. A German team has proposed supplying extra hydrogen from electrolysis (link) to get more methane. I don’t know if they have put the idea into practice.

  • YeahRight

    Total BS. The efficiency gap in biomass production is at the source: the efficiency of photosynthesis sucks. Plants only use it because they simply don’t need a more efficient source of energy. A typical plant has a thermodynamic efficiency of between 0.1-1%, at least 15 times less than solar panels. Another factor of 3-10 is lost along the way of conversion into biomass and conversion of biomass into useful mechanical or electric energy. Why anybody would invest in such a boondoggle is beyond a rational mind’s imagination. Oh… wait… there is government subsidies!

  • Jim Seko

    To power one ev with solar energy requires roughly 25 square meters of solar panels. To power one E85 vehicle takes roughly 2 acres of corn. Biofuels are a SUPER inefficient way of collecting solar energy and no amount of research is going close the efficiency gap. Period.

    • No way

      One of them can power the car when you need it and regardless of season. The other can power it when it’s available only. Efficiency has little relevance when it’s cold and dark.

      • Bob_Wallace

        Do you realize that if you want your gas powered car to run in very low temperature parts of the country you need to plug your car into the grid and use a block heater?

        That same outlet can charge up your batteries and have your EV all nice and toasty when you climb in.

        • No way

          I do, that is how I do with my EV and how I did with my ICE before that. It was about the underestimation of biofuels that have done and are doing a lot more than EV’s and solar PV, and does it around the clock through all seasons because of the storable liquid form.
          EV’s will become the most important factor in the future though and I expect 90% EV’s 10% biofuels for cars a few decades from now compared to the 0,1% EV’s and 5% biofuels today or so.

    • Martin

      The only way bio fuel should be produced is from waste that does not have any other uses.
      NO bio fuel from food crops!

      • Menomuna

        Actually this is a false definition. Proper way to think is more low-level: whether crop grown could be eaten or not is entirely irrelevant.

        What matters is only indirectly about food safety. Directly it has to be with efficiency of bio-fuel production, considering both land usage (amount and type of land) and energy usage (in form of fertilizers and process of conversion).

        So criteria for deciding on optimality has more to do with questions like:

        1. Could the land be used for food crops or not: better to use sub-standard growth areas for bio-fuels, as this is more economical and will not compete with food production
        2. How resource-hungry is the crop being used: corn is typically high-maintenance and this is the reason it’s not good, NOT that it can be eaten. Instead, crops optimized to be used as an efficient source for fuel production should be used. These are then unlikely to be useful as food staple, but that’s not the goal, just side product.

        Put another way: turns out that corn (for example) is not optimal by any means — and much of that is because it has been optimized to other ends than as source for ethanol. But this is not because it is edible plant.

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