1 / 13

IEA Bioenergy Task 38 Case Study on the Greenhouse Gas Budgets of Peat Use for Energy in Ireland Kenneth Byrne and Sari

IEA Bioenergy Task 38 Case Study on the Greenhouse Gas Budgets of Peat Use for Energy in Ireland Kenneth Byrne and Sari Lappi Forest Ecosystem Research Group Department of Environmental Resource Management, University College Dublin. Objectives

sorena
Download Presentation

IEA Bioenergy Task 38 Case Study on the Greenhouse Gas Budgets of Peat Use for Energy in Ireland Kenneth Byrne and Sari

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. IEA Bioenergy Task 38 Case Study on the Greenhouse Gas Budgets of Peat Use for Energy in Ireland Kenneth Byrne and Sari Lappi Forest Ecosystem Research Group Department of Environmental Resource Management, University College Dublin

  2. Objectives • To improve our understanding of GHG emissions from undisturbed peatland, from peatland used for energy and from the different restoration approaches (e.g. forestry, restored wetland) when the peat extraction has ceased. • To examine the potential of co-firing with biomass to reduce the GHG emissions from peat use for energy.

  3. Energy use of peat in Ireland • 4 million tonnes of milled peat is produced annually from over 20 000 hectares of peatland. • Milled peat is used by four power plants for electricity production. Sod peat and briquettes are used as home heating fuel. • Peat contributes : •  6% of the total primary energy requirement •  7.6% of the electricity used in Ireland • Fossil fuel - renewable fuel???

  4. Lifecycle of peat use for energy Atmosphere ??? ??? Dryland Wetland Forestry regeneration development Undisturbed Extraction Cutaway peatland Combustion peatland of peat CH CO 4 2

  5. Lifecycle approach • Lifecycle analysis for peat use for energy needed to be able to examine the total climate impact of peat energy and compare with other energy lifecycles. • Peat energy lifecycle includes GHG-fluxes from: •  Initial stage - undisturbed peatland •  Harvesting of peat •  Combustion •  After-use of cutaway peatland. • More information needed on GHG fluxes from production fields and different after-use management practices.

  6. Role of peat in national GHG budget • Energy use of peat generates 4000 Gg of CO2 yr-1. • This represents 5.7% of the total GHG emissions in Ireland. • Emissions from peat combustion are the most significant in the whole lifecycle of peat use for energy. • Emissions from peat production fields are highly uncertain. • Based on the available emissions factors, this would contribute 1 - 10 % of the total emissions from peat use for energy.

  7. Potential to improve the GHG balance • Replacement of old peat burning plants with new more efficient ones  38% reduction in the amount of CO2 produced per electricity unit • Carbon sequestration with after-use practices • Combustion of biomass in addition to peat •  Drying part of the peat prior combustion - lower moisture content of peat will lead to reduced emissions per electricity unit •  Cofiring peat with biomass

  8. Cofiring biomass in Edenderry power plant • First of the three new peat burning plants - bubbling fluidised bed boiler with 38% efficiency • Electricity production capacity 118 MW • 1 million tonnes of peat burned annually - fuel supply agreement with Bord na Móna • Annual CO2 emissions around 900 000 tonnes CO2 - emission reduction likely required by the emission trading scheme • No major technical obstacles to replace part of the peat with biomass.

  9. Potential for energy production by biomass (TJ)

  10. Lifecycle of combustion of peat

  11. Lifecycle of cofiring peat with recovered wood Atmosphere Undisturbed peatland Forest By-products, Harvesting , tree tops, branches Preparation of Processing to Wood processing peatland Þ residues wood products Extraction of peat Building Þ Landfill Demolition After use of peatland forestry Þ wetland Þ Processing to fuel dryland Þ Conversion to electricity Carbon flux to the atmosphere Carbon flux from the atmosphere or within the system Avoided process

  12. Comparison of CO2 emissions between peat combustion and cofiring with recovered wood 1000000 20% CO2 (t) moisture 500000 10 % moisture 0 Sole Cofiring 50000 Cofiring Cofiring combustion of tonnes 100000 tonnes 180000 tonnes peat recovered recovered recovered wood wood wood

  13. Emission reduction potential with cofiring peat and biomass • 8-40 % reduction of CO2 emissions with cofiring 50 000-180 000 tonnes of recovered wood • In short-term, maximum 15% emission reduction with cofiring recovered wood is possible • Price of the biomass still high compared to fossil fuels -in future, the price may decrease due to increased price of carbon

More Related