芬兰森林的生物质能源_可持续_高效_现代的木材利用（英文版）_34页_4mb

Summary of "BIOENERGY FROM FINNISH FORESTS"

Core Content

This document explores the sustainable and efficient use of Finnish forest wood for energy and industrial production. It highlights the country's long-standing tradition of combined heat and power (CHP) production, the role of modern technologies like fluidised bed combustion (FBC), and three case studies that demonstrate innovative approaches to bioenergy integration.

Main Points

• Finnish Forest Resources:
  Finland has the highest forest coverage in Europe, with 26.2 million hectares (Mha) of forest land. Of this, 18.7 Mha (70%) is actively managed, while 4.5 Mha (17%) is in nature reserves and 3 Mha (13%) is protected. Sustainable forest management has ensured a growing biomass stock over the last 50 years, supporting both economic activities and carbon storage.

• Wood Utilisation:
  Half of the wood harvested in Finland is used for energy, and the other half for products. In 2013, 75.1 Mm³ of wood was used in the economy, of which 73.9 Mm³ was roundwood. Of this, 38.3 Mm³ went to the pulp and paper industry, 26.2 Mm³ to the mechanical wood industry, and 4.1 Mm³ to heat or CHP plants. Durable wood products (lumber, board, etc.) and unharvested forest growth store carbon for years, contributing to Finland’s carbon sink.

• Energy Use:
  Wood is primarily used in district heating (DH) and CHP plants. CHP plants account for 42% of Finland’s heat and 26% of its electricity. Biomass supplies 45% of the country’s renewable electricity and 42% of its heat. DH and process steam account for 74% of biomass use, with the rest used for heating households and buildings.

• Efficient Technologies:
  Fluidised bed combustion (FBC) is a key technology for burning biomass efficiently, especially in CHP plants. It allows for the use of low-calorific fuels like bark and wood residues and enables the displacement of coal. CFB (circulating fluidised bed) technology is particularly flexible, accepting high moisture and ash content fuels, and is cost-competitive across a wide range of system sizes.

• Sustainable Sourcing and Harvesting:
  The sustainable sourcing of forest wood is supported by long-standing policies and modern practices. The Forest Act of 1996 ensures ecological, social, and economic sustainability. The use of retention trees, controlled burning, and leaving decaying wood in forests enhances biodiversity and carbon storage.

• Case Studies:

  1. Metsä Fibre Bioproduct Mill at Äänekoski

  • Feedstock Supply: Uses 6.5 Mm³ of softwood and birch annually, with storage facilities for roundwood and pulp chips.
  • Bioproducts: Produces standard pulp mill products and high-value bioproducts like textile fibres, biocomposites, biofuels, and lignin upgrades.
  • Energy Use: Runs on 100% renewable energy, using gasification in a lime kiln. It supplies electricity to the Nordic power market and district heat to nearby towns and industries.
  • Impact: Supports the bioeconomy in Central Finland, which is expected to grow from 15,000 to 19,000 jobs by 2040.

  2. High-Efficiency Multifuel CHP Plant at Järvenpää

  • Efficiency: Achieved 96.5% efficiency in 2014 with 99.5% biomass fuel.
  • Fuel Flexibility: Can use up to 30% farmyard manure and other residues. It uses a flue gas condenser to capture energy from moist fuels.
  • Technology: Operates with bubbling fluidised bed (BFB) technology, which allows high combustion efficiency and low excess air demand.
  • Cost: Still in the lower half of the cost range for typical biomass CHP boilers.

  3. Bio-Oil Production Integrated into CHP Plant at Joensuu

  • Process: Uses fast pyrolysis to convert forest residues and sawdust into bio-oil.
  • Integration: The bio-oil is used in a CHP plant, with coke and uncondensed gases providing additional heat and electricity.
  • Advantages: Demonstrates how biofuel production can be integrated with CHP to improve cost-effectiveness and flexibility.

Key Information

• Wood Flow Distribution:

  • Total Drain: 79.2 Mm³ in 2013, of which 65.3 Mm³ was used in the economy.
  • Energy Use: 38.3 Mm³ for pulp and paper, 26.2 Mm³ for mechanical wood, and 4.1 Mm³ for heat/CHP.
  • Total Energy Use: 36.7 Mm³ of wood used for energy, with 23.3 Mm³ in large-scale CHP and DH systems.

• CHP and DH Systems:

  • Finland has 136 CHP systems with a combined generating capacity of 7,000 MW for electricity and 8,000 MW for heat.
  • CHP plants produce 26% of the country’s electricity and 42% of its heat.
  • Biomass is a major source of renewable energy, contributing 45% of electricity and 42% of heat.

• Environmental Impact:

  • The net carbon sink of Finnish forests averaged 38.2 MtCO₂eq per year from 2006-2015.
  • Over 39.9 Mm³ of annual forest growth continues to store carbon in subsequent years.
  • Sustainable practices such as retention trees and controlled burning have increased the volume of deadwood in commercial forests.

• Policy and Certification:

  • Over 90% of Finnish forests are certified under PEFC, while only 4% are under FSC.
  • The Forest Act of 1996 outlines ecological, social, and economic sustainability principles.
  • The Act on Financing of Sustainable Forestry encourages sustainable production and afforestation.

• Future Outlook:

  • Renewable energy is expected to supply 90% of Central Finland’s energy by 2040.
  • The bioproduct industry is a key growth sector, supporting job creation and innovation in bioenergy and bioproducts.

Conclusion

The document outlines Finland's successful integration of forest biomass into energy and industrial systems through sustainable sourcing, advanced technologies like FBC and CHP, and innovative case studies. These strategies not only support economic growth and energy security but also contribute to reducing greenhouse gas emissions and enhancing carbon storage. The flexibility of modern CHP and biofuel technologies allows for efficient use of diverse feedstocks, making Finland a model for other countries aiming to develop forest-based bioenergy systems.