Towards carbon-negative bioenergy: U.S. Senator introduces biochar legislation

This week Biopact will zoom in on the latest developments in carbon-negative biofuels and bioenergy. Over the coming days we will be looking at the science behind the concept, at results of field experiments, at information resources and documentaries, and at new educational initiatives. By way of introduction, we present new legislation recently introduced to promote biochar research in the United States.

Biofuels and bioenergy are often presented as 'carbon-neutral' because the carbon dioxide emitted by their use is taken up again as new energy crops grow. Like wind or solar power, they do not add CO2 to the atmosphere. But the bioenergy community has long gone beyond this concept and has begun looking at the production of carbon-negative fuels and energy instead. These do not merely avoid new emissions from entering the atmosphere, they effectively take CO2 from the past out of the atmosphere.

Carbon-negative bioenergy can be obtained via two ways: a high-tech and a low-tech process. The high-tech pathway involves transforming biomass into energy and fuels, while capturing the CO2 and sequestering it in its gaseous form into geological sites such as depleted oil and gas fields, unminable coal seams or saline aquifers. They draw on 'carbon capture and storage' (CCS) techniques currently being developed by the coal industry.

The low-tech route consists of transforming biomass into useable fuels while keeping part of the carbon locked into an inert form, called biochar ('agrichar'). This biochar is then simply added to agricultural soils, in which the carbon can be sequestered safely for hundreds, possibly thousands of years. The discovery of ancient 'terra preta' soils demonstrates that carbon effectively remains locked up for a very long period of time.

More and more research shows that soils amended with the char have very beneficial effects on crop growth. The enhanced nutrient retention capacity of biochar-amended soil not only reduces the total fertilizer requirements but also the climate and environmental impact of croplands. Char-amended soils have shown 50 - 80 percent reductions in nitrous oxide emissions and reduced runoff of phosphorus into surface waters and leaching of nitrogen into groundwater. As a soil amendment, biochar significantly increases the efficiency of and reduces the need for traditional chemical fertilizers, while greatly enhancing crop yields. Experiments have shown yields for some crops can be doubled and even tripled (previous post).

Biochar thus offers the promise of carbon-negative biofuel production sustained by a cycle in which crop production is boosted, emissions lowered, and reliance on synthetic fertilizers reduced. Moreover, unlike CCS it is a cost-effective carbon sequestration method: under a basic scenario sequestering biochar from biofuels produced by pyrolysis would be competitive when carbon prices reach US$37 (carbon currently fetches €21.55 on the European market, that is $30.5, and prices are expected to increase strongly in the near future).

The great advantage of biochar is the fact that the technique can be applied world-wide on agricultual soils, and even by rural communities in the developing world because it is relatively low tech. It is hoped that at the upcoming UNFCCC summit in Bali, experts will include biochar as a strategy to fight climate change that would be eligible for carbon credits under the Clean Development Mechanism.

The biochar concept has meanwhile received formal political support. In order to speed up biochar research the U.S., Colorado's Senator Ken Salazar (D) recently introduced 'The Salazar Harvesting Energy Act of 2007' [*.pdf], focused on carbon-negative bioenergy production. The bill (S.1884) is awaiting discussion in the Senate Agriculture, Nutrition and Forestry Committee. The following is a summary of the legislation as it relates to biochar:
energy :: sustainability :: climate change :: carbon cycle :: biomass :: bioenergy :: biofuels :: biochar :: terra preta :: carbon negative ::

Carbon-Negative Biomass Energy and Soil Quality Initiative for the 2007 Farm Bill

Biochar and Bioenergy Co-Production: Protecting the Soil Resource and Combatting Global Climate Change
Bioenergy production from agricultural and forestry biomass can boost U.S. energy independence, create additional income streams for agriculture and rural communities, and help combat global climate change by displacing fossil fuel use. Policies to promote bio-energy production from agricultural products must preserve the soil resources necessary to support adequate U.S. food and fiber production, which provide the basis for a continued strong U.S. economy.

The biochar provisions in S.1884 promote commercial development of technologies that will simultaneously create clean, renewable energy from agricultural and forestry biomass products, while protecting and restoring soil resources and helping to address global climate change. Unlike most carbon-neutral biomass energy systems, biochar technology is carbon-negative: it removes net carbon dioxide from the atmosphere and stores it in the form of stable soil carbon 'sinks', improving soil fertility, water retention, productivity and crop yields.

The Biochar Process
Energy and biochar can be co-produced from biomass using thermal processes. Biochar production processes can potentially utilize virtually any agricultural or forestry waste biomass, including wood chips, corn stover, rice or peanut hulls, tree bark, papermill sludge, and animal manure, for instance.

Under proper production conditions, the biochar can retain up to 50% of the feedstock carbon in a porous charcoal structure. The biochar product is a fine-grained, porous charcoal substance that, when used as a soil amendment, effectively removes net carbon dioxide from the atmosphere. In the soil, biochar provides a habitat for soil organisms, but is not itself consumed by them. Thus, biochar does not disturb the carbon-nitrogen balance, but holds and slowly releases water, minerals and nitrogen to plants. When used as a soil amendment along with manure or fertilizer, the char significantly improves soil tilth, productivity, and nutrient retention and plant availability.

The energy produced from the remainder of the biomass is used to heat the pyrolysis unit and/or provide energy for on-farm use, such as heat and electricity for lighting, fans, refrigerators, milking machines, etc. The co-production of biochar from a portion of the biomass feedstock will reduce the total amount of energy that can be produced, but basic soil science research indicates that even at today�s energy and fertilizer prices the net gain in soil productivity is worth more than the value of the energy that would otherwise have been derived from that charcoal. Once the cost of carbon emissions starts to rise and the value of CO2 extraction from the atmosphere is also considered, the balance will become overwhelmingly attractive.

The two predominant biochar production processes under development are externally heated pyrolysis and downdraft gasification. At small scales, downdraft gasification with air can produce a gas that is immediately burned in an engine to make heat and electricity. This will be practical on farms and at agricultural processing plants at scales from 5kW to 5MW of electricity. At the local or regional agricultural co-op scale, processing 800 to 1000 tons of biomass per day, externally heated pyrolysis or oxygen gasification can be used to make synthesis gas. Syngas can be catalytically converted into liquid fuels including methanol, mixed alcohols that perform like ethanol as a vehicle fuel, ammonia, dimethyl ether, or even Fischer-Tropsch diesel at a larger refinery scale.

An Example of an Agricultural Biochar Production System
An example of a fully-developed system that would be supported by S.1884 is the development of an intermediate scale pyrolysis or thermochemical conversion system which produces energy for on-farm use. The pyrolysis or gasification system can produce bio-oils for transport to a central location for conversion to liquid or gaseous fuels; and/or gases that can be used to produce heat and electricity for on-farm uses. The biochar produced will have specific surface chemistries that, when applied to soils, will sequester carbon while improving agricultural productivity and replacing some chemical fertilizer inputs. The permanently sequestered carbon can be traded and sold in greenhouse gas markets. The system will effectively manage and use on-farm byproducts such as lignocellulosic residue and animal wastes. The system can also be integrated with chemical conversion and biological conversion in an intermediate scale biorefinery.


S.1884: Specific Biochar Provisions in The Harvesting Energy Act of 2007

Title I - Energy
o Renewable Energy Systems and Energy Efficiency Improvements: (pg. 3 of S.1884) Provides a total of $150 million for pyrolysis and thermochemical conversion systems to be acquired by agricultural producers, in Section 9006 of the Farm Bill. Annual funding of $30 million is authorized for each of FY 2008-2012.
o Bioenergy Program/Feedstock Residue Management Program: (pg. 7 of S.1884) Provides assistance to cellulosic biorefineries in the form of transition payments in preparation for bioenergy operations; requires that land conversions for such operations ensure the protection and enhancement of soil quality and the prevention of soil erosion and nutrient leaching, and other impacts. Provides a total of $1.458 billion over the 5-year period FY 2008-2012
o Research and Demonstration Grants for Biochar Production Systems: (pg. 11 of S.1884) Creates a competitive grants program for research and development to develop and commercialize biochar production systems on multiple scales, including on a single farm, local community, and cooperative scale. Provides a total of $50 million, with annual funding of $10 million for each of FY 2008-2012.

Title II - Direct Payments for value-added and Renewable Energy Enterprises
o Direct Payments for Qualified Value-added Enterprises: (pg. 15 of S.1884) Provides direct payments of up to $10,000 per producer to match equity investments in value-added enterprises, to include the production and use of biochar as a soil amendment. Authorizes such funds as are necessary to carry out this section for each of FY 2008-2012.

Title III - Conservation
o Biochar Demonstration Projects: (pg. 18 of S.1884) Provides that demonstration projects on a farm and cooperative scale be carried out to demonstrate the advantages of using biochar production systems to improve renewable energy production and protect and enhance soil quality; and for demonstration projects that demonstrate the manner in which biochar may be used to generate agricultural credits for carbon trading within greenhouse gas emissions reduction programs. Promotes high-priority biochar research and demonstration projects in three areas: biochar production and commercialization; biochar�s behavior in the environment; and economic and life-cycle analyses of biochar systems. Provides upwards of $100 million for the section, by authorizing �not less than� $20 million for each of FY2008-2012.
o Environmental Quality Incentives Program (EQIP): (pg. 22 of S.1884) Provides funds for bioenergy production, including the installation of biochar production units

Title V - Research, Development, and Education
o High-priority Research and Extension Initiatives: (pg. 24 of S.1884) Provides upwards of $100 million in research grants to promote biochar technology for adding biochar to soil to improve soil fertility, nutrient retention, and carbon sequestration; and the movement of the technology from a pre-commercial to a fully-commercial state. Authorizes not less than $20 million per year for each of FY 2008-2012.
o Renewable Energy Research, Education and Educational Program: (pg. 28 of S.1884) Requires the Secretary of Agriculture to establish standardized protocols for market-based trading of greenhouse gas emissions reductions from soil carbon sequestration; to provide information on economic opportunities available to producers from such markets; and to provide grants to land-grant colleges and universities to develop curricula and training related to renewable energy fields. Such sums as are necessary are authorized for this section.

Renewable Electricity and Renewable Fuels Research and Development: (pg. 30 of S.1884)
Creates a joint USDA/DOE research program that includes a quantification and verification of the carbon sequestration benefits of various bioenergy and agricultural crops and practices, including the development of models to estimate the carbon sequestration benefits for different crops on different soils; and an additional research and development program to study, among other things, methods to sustainable increase agricultural and forestry crop energy yields while enhancing environmental benefits, in particular improving soil quality and air quality; methods of developing small-scale and distributed renewable energy technologies; and biochar�and other potential non-fossil-fuel-based renewable fertilizers to integrate energy production or agricultural management practices with enhance soil quality and long-term carbon sequestration. Provides up to $300 million per year for each of FY 2008-2012.

References:
S.1884 - The Salazar Harvesting Energy Act of 2007 [*.pdf], introduced July 26, 2007.

An excellent introduction to biochar can be found in Johannes Lehmann: "A Handful of Carbon" [*.pdf], Nature, Vol 447, pp. 143-144, 10 May 2007.