USE OF WOOD ASH FROM CENTRALISED HEAT RECOVERY

Abstract

The European Union (EU) is hurrying towards a climate-neutral economy, which includes increasing the use of renewable resources, including wood for heating. This direction means that the use of wood is increasing every year in the EU and beyond. The by-product of this activity, biofuel ash, is correspondingly increasing, so its further use should be considered a long-term issue. Energy producers face the challenge of making the best use of ash and often landfill it, thus moving countries further away from the EU Directive target. EU Directive 1999/31/EC and the National Waste Management Plan 2021-2028 require the amount of municipal waste landfilled (% of municipal waste generated) in 2035 will not exceed 10%. Otherwise, EU countries may face significant penalties. The energy produced from renewable energy sources (RES) In 2019, the total consumption of renewable energy sources (RES) in Latvia was 75.5 petajoules (PJ), according to the Central Statistical Office (CSO). In the five years 2015-2019, RES consumption increased by 16.7%. The decrease in RES consumption in 2019 was driven by a decrease in hydropower (HPP) generation, due to lower rainfall than in 2018. The main types of RES in Latvia are fuel wood (firewood, wood residues, fuel wood chips, wood briquettes, and wood pellets) and hydropower. Since 2010, the use of wood fuels for heat supply in Latvia has been increasing rapidly. Increasing the consumption of domestic energy sources reduces energy dependence on imported energy sources from 63.9% in 2005 to 44.3% in 2018. Fuel wood accounts for 82% of RES energy consumption. The share of fuel wood in total RES consumption was 82% in 2019 (80.7% in 2018). Biogas (landfill gas, sewage sludge gas, other biogas) consumption in 2019 was 3.4 PJ, 7.3% less than in 2018 (3.6 PJ), with a decrease of 8.1% or 0.3 PJ over the five years. The study aims to help solve the problems of district heating companies by preventing waste generation and reducing the costs for companies in its disposal. In addition, it can reduce, albeit slightly, the tariffs of heating users for the heat supplied.