Although anaerobic digestion of small amount of organic and food waste was considered unprofitable a few years ago, it is growing today with a new model of biogas production: small-scale digestion plants (or micro-scale digestion). By the end of 2016, 130 micro-scale digestion facilities were in operation in Europe. Smaller, less expensive, easily self-sufficient, these production units attract farmers, but also investors in eco-neighborhoods, wishing to develop new sources of clean energy.
There are over 20,000 full-scale AD systems in the world and over 1,000 new projects per year. However, the valorisation process for organic waste can still be optimized. One way to do so is to use small-scale digestion. Today’s trends: modular approaches (e.g. in containers), mobile units and “plug and play”.
Micro-scale digestion involves the production of biogas, but on a small scale within farms or small communities. The small-scale digestion production units are below 80 kW. Most agricultural units have a power capacity between 100 and 300 kW, while some industrial units exceed 1,000 kW. A small-scale digestion project is carried out starting from 100 dairy cows or 200 cows or between 200 to 5000 tons of organic waste per year. ”The interest for small-scale digestion is not to have to invest in large facilities,” explains François Xavier Dumur, Nov & atech Project Manager. ”Micro-scale digestion allows the autonomy of the system by supplying the digester with the farm products.”
The development of micro-scale digestion on-farm plants emerged after 2010. Agriculture is truly well fit to be juxtaposed with anaerobic digestion for many reasons. It helps farmers:
In France, this energy alternative is becoming very successful, particularly in Brittany, where a dozen projects are planned. For farmers, small-scale digestion is a good way to diversify their activity at a reasonable cost.
Until recently, the costs of a biogas plant were hampering farmers in opting for micro-scale digestion. However, since December 13, 2016, in France, a decree fixes the new rules for the electricity feed-in tariffs generated from biogas, which has helped reassure potential investors.
Farmers now benefit from a resale tariff of 0.175 € / kWh. They are also entitled to a premium of 0.05 € / kWh if they transform more than 60% of the residues of their activity. Starting at € 220,000, a farmer can now install a 22 kW power station on his farm. The Government also decided in February 2016 to extend the duration of electricity purchase contracts produced by methanation from 15 to 20 years. This action will help them achieve the objectives of the Energy Transition Law.
Similarly, the Energy Transition Law requires the generalization of waste sorting at the source to all stakeholders by 2025. This obligation will also promote waste recovery solutions such as small-scale digestion.
Until now, the laws and regulations adopted mainly favor installation with a power of several Kw supplied by multiple sources of inputs, according to Énergies & Environnement. Positive fact: according to this website, some of the big players in the Small-Scale digesters sector have a return on investment time of less than 10 years!
Nevertheless, other obstacles remain: regulations that are not adapted to small-scale digestion, the complexity of the authorization request, the evaluation of the environmental performance still to be carried out, etc.
In France, one of the challenges in the years to come will be to develop small-scale digestion in cities. Several companies have created small-scale digesters and stations for the treatment of organic and food waste adapted to urban spaces.
HomeBiogas, located and manufactured in Israel, has developed an anaerobic digester specifically designed for domestic use, in which food waste is converted into biogas and fertilizer. Six liters of food waste per day is needed to feed it. The biogas produced can thus be used for cooking, heating and even lighting.
HomeBiogas systems have already been installed in several eco-districts in Great Britain and close to 1,000 family sized Biogas systems have been deployed to over 90 countries since 2015. The new model, HomeBiogas 2.0, offers a larger micro-scale of Biogas production- it can digest up to 36 Liters of animal manure and/or up to 12 Liters of kitchen waste.
The small scale anaerobic digester by MyGug is another example of a micro-technology that helps people and business manage their food waste better. This system is fully automated and insulated. They are available in varying sizes suited to domestic or commercial uses and have a capacity starting at about 0.5 tonnes of food waste per year. Another feature that makes them unique? The systems are shaped like an egg.
However, a legal framework should be applied in order to develop micro-small digestion in cities. The legal framework must allow small-scale digestion plants in urban space, although the development of renewable energies is still defended by the French government.
Funded by the European Union under the Intelligent Energy Europe Program, the project BioEnergy Farm 2 aims to open the market for micro-scale digestion. The project was carried out by a quite large consortium, representing 7 European countries.
The project objective is to assist 700 farmers in checking the feasibility of their project by doing business plans. The project has played an important role in producing and sharing knowledge about all aspects regarding small scale digestion. Bioenergy Farm also presents a report on the whole market for the various small-scale digestion technologies and assesses the development potential of 13 European countries.
HoSt launched a few years ago the Microferm. It was designed for agriculturalists who want to process manure on a small scale, and to convert it to sustainable energy. Depending on the size of the company, the farm can produce between 60 and 150 kWe green energy. Apart from the production of electricity and heat, the formed biogas can also be upgraded to natural gas quality and be supplied to the natural gas grid. Furthermore, in 2019, HoSt was building his first MicroFerm+ agricultural biogas-to-biomethane plant in France, at a cattle farm.
Methania is a Tunisian company that specializes in developing solutions for biogas, cogeneration and energy. She combines her knowledge of the most advanced technologies with her expertise in engineering and project management to provide reliable and high-quality solutions for your project. Its Jallagaz process helps farmers to valorize cows, goats and sheeps manure, crop waste and others type of waste that have a dry matte higher than 25%, through their small-scale dry digestion system.
Greenmac offers turn key delivery and servicing of biogas upgrading systems for vehicle fuel and injection in the gas grid applications. Their broad international experience could be an asset for your project. Their Bio-up small-scale system uses an innovative LP Cooab Technology that allows you to get a viable solution even if you have a farm of about 200 cows, for example. They commissioned a first unit of 20Nm3/h in 2014, then another unit of 60 Nm3/h biogas for conversion into 40Nm3/h green gas.
PlanET Biogas Solutions is a German company that is specialized in designing, constructing and servicing of advanced biogas plants. Their systems are known for their focus on their customers, reliability and innovation. Their small-scale system VALENTIN is perfectly suited for farms that have not been able to implement larger units! It is high-quality, profitable, has a modular design and a capacity between 75 to 150 kW. It uses the same components than in their +1,000 built digesters, so you can trust the quality of this system.
Bekon is an innovative company specialized in turn key solutions of dry fermentation and composting for municipalities and waste management companies. They offer the BEKON MINI dry fermentation system. It is suited for a minimal space and low input quantities and require low capital and operational expenditures. It is a particularly efficient system to generate dencentral electricity and heat.
Published by Bioenergy Farm, the handbook « Implementation Guide for Small-Scale Biogas Plants » accompanies you in your microscale digestion units project. Different topics are discussed:
– What steps should I follow to achieve my project?
– What technology should be chosen and what size adapted to my operation?
– What legislation applies to my project and what assistance can I get?
– What financial assistance can I get for my project?
– How can I ensure that the project is profitable?
BiogasWorld will be pleased to help you to achieve your small-scale anaerobic digestion project. We have a large network in the industry. We can help you find the right suppliers at the right time to facilitate the development of your project.