SDE++: Renewable heat

Biomass digestion

You can apply for a subsidy for renewable heat in these 3 categories:

Combined applications

You can combine applications for production installations that are part of a renewable gas hub. A renewable gas hub is a group of installations that produce renewable gas together. The hub uses one or more connections to feed the gas into the gas grid.

Combining applications can be useful if you and other applicants want to build production installations together, but only if all applications in the group receive a subsidy.

If we receive more subsidy applications on the same day than the available budget allows, we rank the applications based on the subsidy intensity. This is the amount of subsidy in euros per tonne of CO₂ reduction. For a combined application, we use the highest subsidy intensity of all applications in the group.

If it is necessary to draw lots, we treat the bundle as one single application.

Sewage treatment plant, improved sludge digestion

In sewage sludge digestion, micro-organisms break down sludge without oxygen. This process produces biogas. Biogas is a renewable source of energy.

There is no required technology to qualify for a subsidy. This gives you more freedom to use new technologies. Wastewater treatment plants also differ greatly in size and type of installation.

If you want to apply for a subsidy for additional biogas from sewage sludge, you must show that your installation will produce at least 25% more biogas than it does now. The parts of the installation that make this extra production possible must be new.

You can apply for a subsidy for:

• heat production;
• combined production of heat and electricity.

Biomass combustion

For biomass combustion, you can only receive a subsidy for the renewable heat you produce.

New in 2026 is the subcategory 'Continuation of a large B-wood boiler'.

You can apply in one of the following 8 categories:

• A liquid biomass boiler with a capacity of at least 0.5 MWth and up to 100 MWe for district heating.
• A liquid biomass boiler with a capacity of at least 0.5 MWth and up to 100 MWe for other uses.
• A large solid or liquid biomass boiler with a thermal capacity of at least 5 MWth, where the heat is used in industry.
• Continuation of a large B-wood boiler with a thermal capacity of at least 5 MWth, where the heat is used in industry and the current subsidy period ends within 3 years.
• Continuation of a solid or liquid biomass boiler with a thermal capacity of at least 5 MWth, where the heat is used in industry and the current subsidy period ends within 3 years.
• A steam boiler using sustainable wood pellets with a thermal capacity of at least 5 MWth and less than 50 MWth, where the heat is used in industry.
• A steam boiler using sustainable wood pellets with a thermal capacity of at least 50 MWth, where the heat is used in industry.
• A burner using sustainable wood pellets for industrial use, with a thermal capacity of at least 5 MWth. Existing equipment may be reused in this category. The maximum capacity is 100 MWe.

Liquid biomass boilers up to 0.5 MWth

With installations using liquid biomass, you can use bio-oil in an existing boiler, furnace, or stove. The subsidy is for the bio-oil that is used.

Examples include a peak-load boiler in a district heating network, a boiler that produces steam for industrial use, or a bio-oil burner that heats an industrial process, such as drying products in a furnace or oven.

This category has different advantages under the Emissions Trading System (ETS) [link to that section]. For this reason, we divide it into 2 subcategories: district heating and other uses.

Every year, you must submit a report showing that the liquid biomass you use meets the sustainability requirements.

Continuation (formerly ‘lifetime extension’)

The continuation category is for SDE projects with a subsidy period that is nearing its end.

These projects often still have operating costs. Because of these costs, part of the project may still not be profitable. This is why a continuation category is available. It is for installations with a thermal capacity of 5 MWth or more.

You may only use woody biomass to produce high-temperature heat above 100°C for industrial use. It is not allowed for greenhouse horticulture. The minimum temperature of 100°C applies to the end user of the heat.

You can apply for one of the following 2 continuation categories:

• a solid or liquid biomass boiler
• a B-wood boiler

We also distinguish between 3 types of installations that use wood pellets:

• a burner
• a steam boiler with a capacity of less than 50 MWth
• a steam boiler with a capacity of 50 MWth or more

Subsidy only for woody biomass used for high-temperature heat

You can apply for a subsidy if you burn woody biomass to produce high-temperature heat above 100°C for industrial use. It is not allowed to use this heat in greenhouse horticulture. The heat must be above 100°C when it reaches the first user.

Since 2021 there has been no subsidy for burning woody biomass, such as prunings and wood chips, to produce heat between 20°C and 100°C (low-temperature heat).

You only receive a subsidy for the heat you produce

For all biomass combustion categories, you only receive a subsidy for the heat you produce. You are not allowed to use this heat to generate electricity.

Fuel requirements

For most biomass combustion categories, you are not allowed to use B-wood. B-wood is treated or processed wood, such as painted or glued wood, or particleboard. The basic subsidy amount for these installations takes into account the higher cost of clean wood.

If you apply for a subsidy in a category that uses sustainable wood pellets as fuel, you may produce:

• up to 15% of the energy from A-wood pellets; and
• up to 25% of the energy from biorefinery residues made from A-wood pellets.

In the SDE++, biorefining means a process in which the main product replaces a fossil-based raw material. In other words, biomass is processed into products that are normally made from fossil raw materials.

For this reason, lignin from the paper industry is not allowed. However, lignin from the production of sugars from wood is allowed. If these sugars are then used to make bioplastics, the remaining lignin is considered a biorefinery residue.

For all installations, at least 97% of the energy content of the fuel must come from biogenic (biological) sources. This ensures that the installation is not burning waste or using natural gas as part of the fuel.

You may also use liquid biomass in all biomass combustion installations.

Biomass sustainability requirements

If you use solid, liquid, or gaseous biomass, you must meet the European sustainability requirements of the Renewable Energy Directive (RED). The requirements depend on the capacity of your installation. Read more about the requirements and limits on RED sustainability criteria for biomass for the SDE++ scheme.

You must show that your biomass meets these requirements. You do this by using certificates that are approved by the European Commission. In most cases, your company must also be certified.

Solar thermal energy

In the Solar Thermal Energy category, you can apply for a subsidy for installations with covered or concentrating solar collectors. The total thermal capacity must be at least 140 kW.

If your system is smaller, you may be able to apply for a subsidy through the Sustainable Energy Investment Subsidy (ISDE).

When you apply, you must enter the surface area of the collectors or of the mirrors or lenses that collect the sunlight.

There are 2 capacity categories for solar thermal energy:

• 140 kW up to 1 MW
• 1 MW or more

Larger systems produce more energy at a lower cost. For this reason, they have a lower basic subsidy amount. The basic energy price and the correction amount are also different for small and large installations.

To calculate the capacity of your installation, multiply the total surface area (in m²) of the collectors or mirrors by 0.7.

Light-transmitting layer

To qualify for a subsidy, the light-absorbing surface must be integrated with the transparent cover so that they work together as one system. The transparent cover provides insulation and can be made of glass or a glass tube.

Only installations in which the light-absorbing surface and the transparent cover (such as glass or plastic) form one integrated unit are eligible for a subsidy.

The glass of a greenhouse is a transparent cover, and PVT systems also have a transparent cover. However, in both cases the transparent cover is not integrated with the light-absorbing surface. For this reason, these systems are not eligible for a subsidy under the Solar Thermal Energy category.

Geothermal energy

In this category, we make a distinction between geothermal energy for:

• the production of renewable heat; 
• the production of low-CO₂ heat.

Shallow and deep geothermal systems that use a heat pump with a halogen-free refrigerant, and where the heat pump is part of the installation, fall under the low-CO₂ heat category.

Within both renewable heat and low-CO₂ heat, there are several different subsidy categories:

Download a table with tariffs for your installation

Would you like to know the amounts that apply to the category you are interested in? Download the table Tariffs Renewable heat SDE++.

Download a table with documents you need

Would you like to know which attachments you need to include with your application? Download the table Attachments SDE Renewable heat and CHP.

Emission Trading System (ETS)

ETS stands for the Emissions Trading System. It is the European system for trading CO₂ emission allowances for industry.

In this system, an industrial company must surrender one emission allowance for every tonne (1,000 kilograms) of CO₂ it emits. Companies can buy and trade these allowances. This means that industry pays for its CO₂ emissions. The ETS helps the European industry gradually reduce its CO₂ emissions to net zero by 2057.

If your installation benefits from the ETS, we adjust this benefit in the SDE++ correction amount. We may update this adjustment during the subsidy period.

For renewable heat production, your installation may benefit from the ETS if it is part of an ETS installation. We set an ETS adjustment for each installation category. When we assess your subsidy application, we check whether your production installation is part of an ETS installation. If it is not, or is no longer part of one, we do not include the ETS adjustment in the correction amount.

If you receive a subsidy for biomass digestion that produces both renewable electricity and renewable heat, we only apply the ETS adjustment if the production installation is part of an ETS installation.