Germany's new heating law introduces 'bio-staircase' mandating gradual renewable fuel blending

The Minister of Economic Affairs defends her draft, among other things, for more "bio" fuel. The Bundesrat is likely to demand many changes.

Publication date: 2026-06-11 15:58

Federal Minister of Economic Affairs Katherina Reiche (CDU) introduced the new heating law in the Bundestag this Thursday, stating: "With the Building Modernization Act, we are drawing a line under a policy of mistrust." The new law is intended to make it possible again to install fossil fuel heating systems.

"Technological openness, by the way, is not in opposition to CO2 reduction – on the contrary," explained Reiche, "which is why we are introducing the bio-staircase."

The law fulfills one of the Union's most important election promises following the breakup of the traffic light coalition: "liberating" the heating cellar. Under the previous Building Energy Act of the traffic light government, it was practically impossible to install fossil fuel heating systems in new buildings, as 65 percent of the energy used had to be emission-free.

What the "Bio-Staircase" Entails

The "bio-staircase" is a step-by-step path for new gas and oil heating systems:

• Anyone who installs a fossil fuel system will no longer be allowed to heat with fossil fuels indefinitely
• Starting in 2029, operators will be forced to gradually use more climate-friendly fuels such as biomethane, biogas, or later synthetic gases
• By 2035, fossil fuel heating systems must blend 30 percent climate-friendly fuels
• By 2040, that requirement rises to 60 percent

It remains unclear whether heating systems can handle these blended fuels, where the fuels will come from in necessary quantities, and what they will cost.

Criticism from Opposition Parties

Katharina Dröge, parliamentary group leader of the Greens, criticized the law in the debate: "In the midst of the biggest oil price shock, you are telling people: Buy fossil fuel heating systems again." She noted that both Trump and Putin use fossil energy as a weapon, adding: "This law seems so out of touch that it hurts." Dröge described the law's basis as "a spiral of anger that was instigated by men like Jens Spahn and Friedrich Merz three years ago."

Violetta Bock of the Left Party called the law an attack "on tenants, on future generations, and on the climate."

Bundesrat Demands Changes

The Bundesrat has a committee recommendation with 67 items, a spokesperson told taz. The joint list from the Economic and Environmental Committees is 59 pages long, describing the draft law as "technically flawed," "not practical," and causing "excessive bureaucracy and advisory effort."

Hamburg, for example, is pushing for a state clause, as the Hanseatic city wants to continue heating its buildings according to the traffic light law.

This Friday, the list will be debated in the state chamber, after which the proposed changes will go to the Bundestag. If the requests are not taken into account, the Bundesrat can call on the Mediation Committee.

Potential Legal Challenge

The Left Party is examining whether it can stop the new law with an expedited organizational lawsuit before the Federal Constitutional Court. Violetta Bock noted that climate protection has constitutional status: "Article 20a of the Basic Law implies a 'prohibition of deterioration' for existing climate protection measures."

This technology is also to be allowed again in new buildings in the future: Oil heating. Photo: imago

By Nick Reimer