The last Council of Ministers approved a royal decree limiting the emissions of nitrogen oxides (NOx), sulfur dioxide (SO2) and particles in suspension (PM) from medium combustion facilities (between one and fifty megawatts) of all types , biomass and biogas included. This transposes the corresponding EU directive with deadlines that must be fulfilled by new facilities as of December of 2018, whether they are power generation plants, community boilers or heat networks.
Some exceptions for biomass
However, it also states that "in consideration of the recent investments in biomass plants aimed at increasing the use of renewable energy sources and that have already led to a reduction in emissions, and in order to take into account the investment cycles Member States should be able to allow more time for these installations to adapt to the emission limit values set out in this Directive ".
More info: https://www.energias-renovables.com/biomasa/las-instalaciones-de-biomasa-de-mas-de-20171226