While biomethane, or renewable natural gas, foresees a bright future in North America and Europe, especially in California and the United Kingdom, it is incumbent without delay to work on determining the official value of digestate to optimize the profitability and the commercial equilibrium of anaerobic digestion, and thus foster its attractiveness. This is precisely the objective of the ABC Digestate Standard Testing and Certification Program (ABC DSTCP). Moreover, as stated in our Biogas Plant Development Handbook: “[A] project must have a long term inexpensive outlet for digestate otherwise the project will not succeed.“
When it comes to the breakdown of organic matter, we often talk about the differences between anaerobic digestion and composting. Composting, which takes place in the presence of oxygen, results in compost thanks to the aerobic bacteria that make possible the process. The chemical result is, however, different when it comes to anaerobic digestion.
As a matter of fact, during the anaerobic digestion, the breakdown of organic matter occurs without oxygen. Anaerobic bacteria will thus generate partly biogas, up to an extent of about 10% of the initial volume of organic inputs, while the rest will result in liquid and/or solid digestate.
Regarding anaerobic digestion, digestate has only belatedly been truly considered in terms of valuation. Indeed, five years ago, interest in anaerobic digestion was mainly economic considering the biogas it generates, which is a carbon-neutral and methane-rich biofuel that can be used to generate electricity or refined into biomethane and replace natural gas, a fossil fuel. Nevertheless, in recent years, the energy market being relatively disadvantageous for this renewable energy source has resulted in significantly reducing its profitability potential, which greatly affected its attractiveness to project developers such as farmers, industrial, and municipalities.
This is why it is increasingly a matter of the official value of digestate in order to add an additional avenue to those of biogas and energy to generate revenue through anaerobic digestion. On the other hand, since digestate is still mostly unregulated and its definition has not officially been enacted, it remains laborious for producers to achieve the sale of their digestate on the market.
In this spirit, the American Biogas Council, with the support of the biogas industry, has set in motion the ABC DSTCP to “fill gaps in the marketability of digestate and digestate-derived products” as reported by Katie Fletcher from Biomass Magazine.
The ABC DSTCP aims to ensure that digestate is officially recognized as a commodity, such as compost, so that is can be easier to sell and market by producers. In fact, the ABC DSTCP is inspired from the model that has already been implemented by the US Composting Council. The program will establish standards and strict tests in order to define and characterize the digestate, with the aim to make it eventually as common as compost in the eyes of the market and the population.