Flanders: how support for electricity from biogas works — certificates, OT and banding factor

Flanders supports electricity from biogas with green certificates rather than a fixed tariff. The generator receives certificates, which it sells on the market, and their number results from a calculation of how much a given technology lacks to be profitable. For projects commissioned from 1 January 2025, the calculated cost gap for biogas plants is 67.8–103 EUR/MWh, but the maximum banding factor of 0.56 means that support is lower. The overview below concerns Flanders; Wallonia and Brussels have their own certificate systems.

Two types of certificates

Flanders uses two instruments. Green certificates (groenestroomcertificaten, GSC) are due for electricity from renewable sources and are awarded for every 1,000 kWh, multiplied by the banding factor. Cogeneration certificates (warmte-krachtcertificaten, WKC) are due for primary energy saved thanks to qualifying cogeneration, also calculated with a banding factor. A biogas plant with a CHP engine can therefore benefit from both: in the VEKA report, separate categories describe "groene stroom uit biogas" and "kwalitatieve WKK op biogas".

How the banding factor is calculated

The basis is the onrendabele top (OT), i.e. the output-dependent part of revenue that an investment lacks in order to achieve the required return over its whole lifetime. The banding factor is the OT divided by a divisor: 97 for green energy and 35 for cogeneration. VEKA recalculates the OT at least once a year, taking into account investment costs, fuel prices and the energy price. The parameters used in the calculations include reference internal combustion engines running on 100% biogas with a capacity of 2,500 kWe (agricultural biogas plant), 1,300 kWe (bio-waste digestion at a composting facility) and 7,000 kWe (installations of 5–20 MWe), with an economic lifetime of 15 years.

Results for projects from 2025

In the report for projects with a start date from 1 January 2025, the OT was 67.8 EUR/MWh (Bf 0.699) for biogas up to 5 MWe from manure, agricultural streams and other OBA. For bio-waste digestion at an existing composting facility it was 71.5 EUR/MWh (Bf 0.737), and for installations of 5–20 MWe 103 EUR/MWh (Bf 1.06). However, Article 6.2/1.1 of the Energiebesluit caps the banding factor at 0.56 for green energy from biogas in projects with a start date in 2025, so all three categories receive 0.56 of a certificate per MWh. Multiplying by the divisor of 97 gives about 54 EUR/MWh in OT terms.

Exclusions and limits

The agricultural biogas category (5/1) does not include landfill gas, installations digesting wastewater and sewage sludge, or bio-waste digestion at an existing composting facility. For biogas and biomass projects with a start date from 1 January 2020, a maximum support volume is taken into account when awarding certificates, as the Flemish government portal notes. Biogas plants must also meet sustainability criteria for feedstock streams.

Support and the market

Certificates do not replace revenue from selling energy: the generator sells electricity at the market price, and certificates come as additional revenue. In VEKA's calculations the market margin is included as part of the investment's revenue, and from 2025 the expected annual growth of the marktwaarde of energy was set at 0%. The OT, rather than the electricity price itself, is therefore the main parameter determining the shape of support.

Calculation example

An installation in category 5/1 that produces 4,000 MWh of electricity in a year will receive, at Bf 0.56, 0.56 of a certificate for every 1,000 kWh, i.e. 2,240 certificates a year in total (4,000 × 0.56). If the banding factor were not capped and stood at 0.699, the number of certificates would be about one quarter higher: 2,796. This shows that the level of support is determined not only by the calculated cost gap but also by a political ceiling, and the monetary value of a certificate additionally depends on the market.

Division into projects with citizen participation

In each category the report distinguishes variants "a" (the project provides for citizen participation) and "b" (other projects). In the table for biogas both variants have the same OT and Bf values, so participation does not change the level of support for biogas plants commissioned from 2025.

How to read this

The banding factor cap means that for larger installations (category 10/1) support covers about half of the calculated cost gap. For smaller installations (category 5/1) the uncovered part of the gap is smaller, at about 13.5 EUR/MWh.