Combined heat and biochar: A revolution for greenhouse bioenergy


Looking at the benefits of biochar and its potential as a greenhouse bioenergy resource, with implications for seedling propagation for the silviculture industry.

In the October 2011 issue of Silviculture Magazine, John Kitchen makes a sensible argument for turning to woody energy crops as a source of clean energy. Many people from around the world share the excitement for biomass' potential to supplement our energy needs. For greenhouse growers and seedling producers, energy costs and productivity are top of mind. Combined heat and biochar (CHAB) reactors are a sustainable heating and soil amendment solution that together, can reduce costs, increase crop productivity, seedling survival and carbon sequestration while demonstrating a corporate commitment to sustainability.


Touted as ‘carbon neutral’, conventional woody biomass heating systems for greenhouse boilers burn chips or pellets to generate heat, producing waste in the form of air emissions and ash. In contrast, carbon-negative CHAB systems thermally decompose biomass in limited oxygen environments at high temperatures. Processes of pyrolysis or gasification result in a high-carbon product known as biochar and capture emissions as bio-products (oils and gases). While woody biomass is a common feedstock, sustainable CHAB systems may also reduce input costs by utilizing excess crop residues, municipal stream wastes and recyclables, construction materials and manures. Further converting bio-products and heat to electricity makes for exciting possibilities.


“Bio-energy through pyrolysis in combination with biochar sequestration holds promise for obtaining energy and improving the environment...for every unit of energy produced or possibly even consumed, greenhouse gases would be removed from the atmosphere. This could be the beginning of a biochar revolution...” Johannes Lehmann et al. 2006


The body of science surrounding biochar production and application are now expanding rapidly. The International Biochar Initiative ( is an organization leading efforts worldwide. Canadians like Lloyd Hefferty have been instrumental in raising awareness and developing national and regional biochar networks like the Canadian Biochar Initiative (


Biochar is not new. In fact, use of biochar by ancient civilizations has been found where infertile soils were transformed into productive agricultural land. Rich dark earth containing biochar have been documented dating back tens of thousands of years. Asian farmers have been using biochar for centuries. Biochar improves soil fertility by increasing water retention, availability of air, nutrients and soil amendments used by plants and crops.


More recent research trials of biochar in greenhouse pots and poly blocks have demonstrated significant gains in plant growth, root development and crop production. Research is underway to evaluate the inoculation of biochar with soil biota and beneficial mycorrhizae. Reduced fertilizer use and substitutions for non-renewable soil and soil-less mixtures make biochar on its own an attractive addition to greenhouse operations. The feather-light weight of biochar makes it cost effective and easily transported.


 As awareness of biochar and CHAB furnaces builds among greenhouse growers, there are several challenges to overcome. First, there are barriers to investment. With strongly developed distribution networks for fossil fuels and a relatively low investment requirement for traditional greenhouse furnaces and boilers, the incentive to adopt CHAB systems may be invariably low for operators who cannot make an investment. That said, a variety of funding programs do exist to help supplement investment. Upfront costs must come down. For many existing greenhouse operators a return on investment beyond three years is unacceptable. Also, we do not have systems in place in many parts of the country to support the diversion of biomass from landfills or traditional waste streams that would allow for the efficient collection, drying, processing and delivery of biomass to where it is needed. It is critical for proponents to secure a biomass feedstock supply pairing availability with the CHAB system. Transportation and service logistics must be thoroughly evaluated before committing to the technology purchase.


Secondly, many CHAB reactors are presently in research and development phases with new products coming on line in 2012 and beyond. As the demand for CHAB systems increases, advances in technology, availability of feedstock and systems to support these ventures will be advanced. This is especially true for small operators whose current CHAB offerings are limited. Most successful projects are characterized by joint ventures, partnerships and collaboration. It is with great hope and excitement that the biochar community can together help address some of the world's most serious environmental challenges, while providing a greener way of growing.


Scott Scholefield, RPF is Director, Business Development at Out of Ashes BioEnergy Inc. whose company vision is to become a leading supplier of biomass heating solutions for greenhouses with a range of organic biochar available for purchase under our boutique brand, Turtleback Biochar®. For more information please visit