Glenn Meyers :
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.
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.
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.
