CHP operation case study: how a large farm turned manure into 315 kW of electricity and heat
- Aug 31
- 5 min read
A real reference site: PE «Sigma», Dnipropetrovsk region, since 2015 has been operating a Dieselmash DvGA-315 cogeneration unit on its own biogas. More than 10 years of operation, a closed loop: manure becomes electricity, heat, and fertiliser. We break down the economics, project layout, and what it takes to run something similar yourself.
CHP operation case study - reference site: PE «Sigma», Dnipropetrovsk region
Since 2015, PE «Sigma» (Dnipropetrovsk region) has been operating a Dieselmash DvGA-315 CHP on biogas. More than 10 years of operation make this unit one of the longest-running biogas projects in Ukraine's agricultural sector.
The project is notable because it shows biogas cogeneration not as «green marketing» but as a working industrial scheme with a 2–3 year payback and stable income for more than a decade.
Closed-loop technology
How biogas cogeneration works on a farm:
STEP 1. FEEDSTOCK COLLECTION
Manure from the livestock complex. For a base of 500+ cattle, that is 15–30 m³ of feedstock per day. Besides manure, silage, processing waste, and plant residues can be used — they increase biogas yield.
STEP 2. BIOREACTOR (DIGESTER)
Anaerobic fermentation: microorganisms process organic matter at 35–40 °C and produce biogas (methane 55–65 % plus CO₂). The reactor runs continuously; fermentation cycle is 20–30 days.
STEP 3. BIOGAS CLEANING AND SUPPLY TO THE CHP
Pre-treatment to remove hydrogen sulphide (H₂S) is required — this is critical, otherwise the engine wears out quickly.
STEP 4. ELECTRICITY AND HEAT GENERATION
The CHP produces electricity (250–300 kW) and heat (about 350–400 kW of recovered thermal power).
STEP 5. DIGESTATE AS FERTILISER
Digestate — the residue after fermentation — is spread on fields as organic fertiliser. It retains all nitrogen-phosphorus-potassium components of manure, but without odour and without the risk of overloading the soil with pathogens.
The closed loop is not an abstraction. Every kilogram of manure yields three economically valuable products: gas, heat, and fertiliser. Without the bioreactor you lose all three and incur costs for manure disposal plus purchases of electricity, heat, and fertilisers. |
Equipment: DvGA-315, 500, 630 CHP units on biogas
DvGA-315, DvGA-500, DvGA-630 — the biogas engine-generator range from Dieselmash.
Key parameters:
■ Electrical output: 315, 500, and 630 kW
■ Engine: 6 and 8GChN25/34 (6 and 8 cylinders, bore 250 mm, stroke 340 mm)
■ Rotation speed: 500 and 600 rpm
■ Specific biogas consumption (at calorific value 5,500 kcal/Nm³): 0.5 Nm³/kWh
■ Recovered thermal power: up to 450, 720, 900 kW
■ Time to major overhaul: no less than 80,000 operating hours
■ Total lifespan: 240,000 operating hours
Key differences of the biogas modification from the base gas version:
■ Enhanced fuel cleaning system (H₂S and condensate filters)
■ More conservative automation settings for the lower calorific value of biogas
■ Special spark plugs with extended service life
Project economics: CAPEX
Estimated turnkey cost of a biogas project for a base of 500 cattle:
■ Bioreactor (250–500 m³) — UAH 8–15 million depending on volume
■ Biogas cleaning system (H₂S, condensate) — UAH 0.5–1 million
■ Digestate storage tanks — UAH 1–1.5 million
■ DvGA-315 CHP turnkey — around UAH 15 million (set with automation, heat recovery, cabinet)
■ Civil works, piping, electrical connection — UAH 1.5–2 million
Total: UAH 25–35 million depending on scale and regional factors.
For comparison: an equivalent diesel generator with fuel tanks would cost UAH 6–8 million — that is 3–4 times cheaper on CAPEX. But the economics reverse entirely at the operation stage.
Project economics: annual savings and revenue
At an estimated operation of 315 kW × 0.8 utilisation factor × 8,000 hours = 2.0 million kWh of electricity per year.
Annual sources of revenue and savings:
■ Replacing purchased electricity (at UAH 12/kWh): 2.0 million kWh × 12 = UAH 24.0 million/year
■ Replacing purchased heat for cowsheds and technology: UAH 4–5 million/year
■ Selling surplus electricity to the grid at feed-in tariff: UAH 1–3 million/year
■ Savings on organic fertilisers (replacing purchased): UAH 1–2 million/year
Gross savings: UAH 30–35 million/year
Savings on digestate as fertiliser are often underestimated. A large farm spends several million UAH per year on nitrogen fertilisers. If this budget is replaced by in-house digestate, that is direct working capital preservation. |
OPEX of a biogas CHP
Annual operating costs:
■ Fuel: practically free (own biogas), but there are costs for cleaning and preparation — UAH 0.5–1 million
■ Bioreactor maintenance — tank cleaning, replacement of bacterial cultures, electricity for heating — UAH 2–3 million
■ Feedstock and digestate transportation — UAH 1.5–2 million (depending on farm logistics)
■ Payroll for CHP and bioreactor operators (2–4 people needed) — UAH 1.5–2.0 million
■ CHP service (oil, filters, spark plugs, scheduled maintenance) — UAH 0.5–1.0 million
■ Equipment depreciation — UAH 2.5–4 million
Total: UAH 10–13 million per year.
Annual net effect: UAH 16–20 million depending on farm scale and local conditions. Payback including bioreactor investment: 2.0–2.5 years.
For comparison: for a base natural gas CHP the payback per the feasibility study of 01.07.2026 was 1.7 years. A biogas CHP pays back more slowly because CAPEX is higher (a bioreactor is required), but it is economically attractive because the fuel is essentially «free» and the output is three products at once.
Digestate as fertiliser
Often an underestimated part of the project. After anaerobic fermentation of manure, digestate remains — a liquid rich in nitrogen (N), phosphorus (P), potassium (K), and micronutrients.
Advantages of digestate over fresh manure:
■ No odour — important for fields near populated areas
■ Lower risk of soil pathogen overload — bioreactor bacteria destroy harmful microorganisms
■ Faster uptake by plants — nitrogen in a form ready for assimilation
■ Precise chemical composition — application rates per hectare can be calculated
By replacement cost of mineral fertilisers: UAH 1–2 million/year for a mid-sized farm. Plus soil humus is preserved — long-term benefit for yields.
What you need to run something like this yourself
Realistically, biogas cogeneration pays off on a farm of 500+ cattle or equivalent. Fewer — not enough feedstock volume for stable reactor operation. More — economics are even better.
What you need as inputs:
■ A stable feedstock flow (manure, silage, processing waste) — 15–30 m³ per day
■ A plot for the bioreactor and digestate tanks — 0.3–0.5 ha
■ Electrical infrastructure — the ability to connect to the grid (to sell surplus)
■ Permit from environmental services for biogas production
■ Registration in the green tariff system (to sell surplus electricity to the grid) — takes 2–3 months
■ Permit to apply digestate to fields (in some cases — environmental review)
What really speeds up the project:
■ Cooperation with the regional grid operator during network connection design
■ Agreements with neighbouring farms for feedstock supply (to increase volume)
■ Planning the digestate application schedule with local agronomists
A biogas project is not «install a CHP and run it». It is integrated infrastructure: bioreactor, piping, tanks, fields for digestate. All components need to be planned together, not separately. |
Biogas cogeneration is one of the few solutions that simultaneously addresses several problems of a large livestock farm: manure disposal, autonomous energy supply, organic fertilisers, and additional revenue from selling electricity. CHP operation case study
2–3 year payback is a realistic scenario with a base of 500+ cattle.
Dieselmash manufactures biogas modifications of the CHP based on 6GChN25/34 and 8GChN25/34 engines adapted for biogas. Operating experience at PE «Sigma» — more than 10 years of work — confirms the viability of the technology.
Calculate a biogas project for your farm
Describe the situation: number of cattle, availability of free land, demand for electricity and heat. Dieselmash engineers will prepare a preliminary feasibility study within 5 working days with a payback calculation for your specific facility.
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