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Home SolutionsBiogas & Biomethane Co-substrates for biogas production

Co-substrates for biogas production

We design biogas plants for agricultural and processing enterprises with predictable economics and a controlled fermentation process.

Without a biogas plant:

  • Searching for ways to utilise field residues or production by-products.
  • Loss of profit in an unstable market.
  • Accumulation of organic waste and rising disposal costs.
  • Dependence on raw material markets, price instability.
  • Increase in energy costs.

With it, you get:

  • Energy independence.
  • Diversification of income.
  • Own digestate to replace chemical fertilisers.
  • Stable income from biogas production.
  • An impeccable reputation as a conscientious and sustainable company.

When should you contact us?

01

You have by-products of production: straw, pomace, grain residues, plant residues.

02

The operation of the biogas plant needs to be stabilised.

03

You are looking for an alternative to using only one substrate.

04

You are planning to produce biomethane or electricity from waste.

About raw materials

Stable co-substrates are additional types of raw materials that do not replace the base substrate but enhance and stabilise biogas production. Such co-substrates include straw, pomace, distiller’s grains, plant residues, fatty waste, and other organic by-products of the agricultural and food industries.

Straw has a high structural carbon content and is used to correct the C:N ratio in the reactor. Pomace and distiller’s grains, on the other hand, are readily available organic substrates that are quickly incorporated into the fermentation process. It is the combination of different types of raw materials that makes it possible to obtain stable biogas, reduce the risks of inhibition, and increase the overall energy yield.

Steam explosion, a technology borrowed from the pulp and paper industry, is used to prepare lignocellulosic co-substrates (in particular straw). It increases the availability of organic matter for bacteria and makes the use of straw feasible as a supplement rather than the basis of the process.

Co-substrates are added to the main raw materials (manure, litter, grain residues, pomace) to balance dry matter and stabilise fermentation.

The most common co-substrates for biogas plants:

  • Sugar beet pulp: easily fermentable, biogas yield — 110–130 m³/t of raw mass.
  • Grain residues: liquid, high organic content, biogas yield — 55–65 m³/t.
  • Corn silage: can be used as a co-substrate for electricity production in biogas plants, is a stable co-substrate in terms of biogas yield, typical yield — 180–200 m³/t.
  • Straw (after preparation): used to increase the organic content in liquid substrates and balance C:N, approximate yield — 250–350 m³/t of dry matter.
Co-substrates for biogas production - photo — pro-energy.com.ua

Find out whether your farm-based BGU requiresthe use of co-substrates

Book a free consultation, and our managers will provide comprehensive information regarding your questions.

Cooperation options:

  1. Development and implementation of a turnkey project.
  2. Support in attracting funding and grants.
  3. Co-investment models and private investor participation.
  4. Preparation of a project for biomethane export certification.

Ways to recoup costs:

  • Realisation of excess heat.
  • Export of biomethane.
  • Own consumption.
  • Fertilisers from digestate.

Biogas technologies for agricultural and processing enterprises

For biogas production using stable co-substrates, such as pomace, grain residues, straw, silage, and mixtures of agricultural raw materials, we recommend classic CSTR agricultural reactors with flexible covers and membrane gas holder roofs. This configuration is optimal for raw materials with a high dry matter content, heterogeneous composition, and seasonal variability, ensuring uniform mixing and stable gas flow.

Before feeding into the reactor, the raw materials undergo preliminary preparation: grinding and homogenisation. After storage in compressed form, pulp and silage are broken up and homogenised in solid loading systems; straw undergoes additional soaking or mechanical processing. This preparation prevents stratification, local acidification, and losses in biogas yield.

Biogas is purified from H₂S, moisture, and siloxanes using adsorption technologies and drying, provided that the substrate is thoroughly mixed, which protects the gas infrastructure and energy equipment. The gas is then directed either to electricity generation (CHP) or to upgrading to biomethane, depending on the economic model chosen. A phased transition from CHP to biomethane is possible without stopping production.

We integrate all technological nodes into SCADA and commercial accounting systems with control of loads, fermentation parameters, gas quality, energy balances, and material flows — for a predictable economy and a controlled process.

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Your single partner for effective solutions

A systematic approach
from Pro-Energy

We provide a range of engineering and consulting services for project implementation. From concept to efficient operation of the plant using your raw materials and location.

More about the systematic approach

Our services:

Concept development and feasibility study
Project development and permits
Development of project documentation
Supply of technological equipment
Construction and installation
Start-up and commissioning works
Service maintenance

Biogas projects implemented

Generation of feed-in energy at an agricultural enterprise

Chernihiv region
The plant was put into operation: February 2022
More details
Co-substrates for biogas production - photo 1 — pro-energy.com.ua
Project completed

Biomethane plant with a capacity of 750 Nm3/h of raw biogas

Khmelnytskyi region
Year of implementation: December 2023
More details
Co-substrates for biogas production - photo 2 — pro-energy.com.ua
Project completed

Biomethane plant with a capacity of 600 Nm3/h of raw biogas

Ukraine, Chernihiv region
Commissioned: 2023
More details
Co-substrates for biogas production - photo 3 — pro-energy.com.ua
Project completed

Why choose Pro-Energy?

We are committed to long-term partnerships!

More About us
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Many years of experience

We have been successfully operating in the bioenergy sector since 2014. We have the knowledge, experience and understanding of the specifics of working in the Ukrainian market.

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Unique partnerships

We have reliable partners. Therefore, we can offer solutions that will allow each project to reach its full potential.

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Reliable technologies

We use technologies with 90% availability for stable operation of installations, which guarantees efficiency and return on investment.

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Stable work

We do not leave our customers alone after commissioning the facility. We provide 24/7 technical support and remain available under any circumstances.

More About us

Ready to discuss the implementation of your project?

Leave a request for a free consultation.





    Frequently asked questions

    Can straw be used as the sole raw material for biogas?

    Technically, yes, but from the point of view of reliability and economics, straw is most effective as a co-substrate. It works well in combination with pomace, distiller’s grains or manure, stabilising biogas production.

    What role does straw play in a biogas plant?

    Straw adjusts the C:N ratio, reduces the risk of inhibition, and makes the process more predictable. That is why biogas from straw is most often considered as part of a comprehensive raw material strategy.

    Are silos required for co-substrates?

    Not for straw. Standard storage facilities can be used for pomace or distiller’s grains. The absence of the need to ensile straw reduces the capital costs of a biogas plant.

    Which reactors are best suited for working with co-substrates?

    Depending on the composition — HLR, CSTR, or UASB. The key is to select the right technology for the combination of raw materials, not for a single component.

    Can straw, pomace, and grain residues be combined in one project?

    Yes, and this combination is considered one of the most stable for biogas plants in Ukraine.

    How do co-substrates affect the economics of the project?

    They reduce the risk of downtime, increase the average biogas yield, and make the payback period more predictable — usually within 5–7 years.

    Are such projects suitable for biomethane production?

    Yes. A stable raw material base is a key condition for purifying biogas into biomethane and subsequent certification according to EU standards.

    How are co-substrates better than relying on a single type of raw material?

    One substrate = high risks. Co-substrates allow you to adapt to seasonality, the market, and changes in production without stopping the biogas plant.