Biomass CHP - benefits at local/regional level
Krzysztof Gierulski, EC BREC, Poland

Presentation at: managEnergy Workshop on Renewable Energy Good practice at local and regional level 1 July 2002, Brussels, Belgium

Presentation (343 Kb) | Case Study (70 Kb) | Proceedings and Recordings

Summary

The project focused on the preparation phase for a pilot investment in Koczala, Northern Poland, relating to an agricultural biogas CHP plant integrated with a converted wood-chip fired municipal district heating system. As a result of the project an integrated feasibility study has been prepared an a private-public partnership (PPP) has been established to accomplish the investment. Due to the model character of the project in Poland as regards production and utilisation of agricultural biogas the project focused on BAT obtainable from various European countries. The project was implemented in 2000-2002. Financial closure for the biogas investment which may require 34% or more grant is currently in progress.

Keywords: agricultural biogas, CHP, wood-chip district heating, fuel switch, public-private partnership

Results

The recommended technical solution for the biogas production plant included pumping of over 30,000 tonnes of pig manure from the two Poldanor farms situated less that 4.5 km from the Plant. Additionally 1500 tonnes of husk and energy crops will be delivered from the Poldanor owned feed mill in Koczala and the local set aside land.

Biogas at 65% methane content will be produced at two digesters 780 m3 each (retention time 13 days in average, thermophilic conditions around 52 ^oC) and a sequence of after-digestion chambers with lower methanisation temperatures. Process heat for the primary digesters will be provide by an automatic 300 kW wood-chip boiler.

Biogas CHP plant will be receiving 346 m3 of biogas per hour that will be combusted in a Jenbacher CHP unit 836 kWel and 1,010 kW heat (from cooling exhaust gases and the engine)

All electricity will be sold to the grid and the heat will be supplied to the municipal district heating system.

The old 5,5 MW coal-fired system will be replaced with an automatic 800 kW wood chip boiler with a daily storage system integrated with the building of the existing boilerhouse. Reserve/peak load boiler: with 3,15 MW capacity for biogas/light fuel oil and a 100 m3 heat accumulator tank will secure the overall district heating system in the town.

A project for the reconstruction of the municipal district heating distribution network had been prepared by a local Polish company Gaszystem and was after minor amendment was integrated with the other components of the new energy system planned for Koczala.

The new energy system in the town of Koczala is designed to generate:

• 4,850 MWh/year of electricity (to be sold to the grid)
• 4,830 MWh/year of heat production (from the CHP unit and the wood-chip boiler at DHP plant)
• 130 MWh/year of heat production (gas boiler)

When eventually turned into operation, the new integrated biogas CHP/wood-chip DHP system in Koczala will allow direct reduction of emissions as compared to the previous DHP system based on coal. The CO₂ emission will be reduced with 99½% (6800 t/a), the emission of SO₂ will be reduced with 96% (53000 kg/a) and the NOx emission will be reduced with around 51% (9900 kg/a).

Additionally, by treating manure in the biogas plant, production of methane will take place in a closed system and be utilised in the CHP unit. Hereby the emission of CH4 to the atmosphere will be reduced. As the methane production is optimised in the biogas plant, it is estimated that the emission will be reduced by 30% of the total production in the biogas plant (the methane outlet in the present situation), which is almost 4800 tonnes of CO₂ equivalent annually.

Direct net creation of job will be minor (2 people) as the biogas production plant, biogas CHP, the wood-chip boilerhouse will be almost fully automatic and the existing staff of the old coal-fired DHP plant will be trained to work at the biogas production plant. However, from a general social point of view the project is expected to stimulate local economy where currently, apart from the pig farms and a local saw mill there no other businesses.

From economic point of view, it can be concluded that implementing the overall integrated biogas/biomass project in Koczala is feasible and with a grant of around 34% and complementary soft loans. Implementing the project will be a showcase for the animal-producing sector in Poland, and the project will be in accordance with the national policy of development of renewable energy in Poland.