How clean is grass biomethane for the environment and for human health?

Transcription

1 How clean is grass biomethane for the environment and for human health? UK-China Workshop on Shaping low carbon energy future Session 9: Affordable and clean energies, and their applications in rural areas Old Staff Common Room, Lanyon Building, Queen s University Belfast 30 th August 2016 Dr Beatrice Smyth School of Mechanical & Aerospace Engineering, Queen s University Belfast

2 Why grass biomethane? Climate change Renewable energy targets Security of supply EU 2020 targets 20% cut in greenhouse gas emissions 20% of EU energy from renew ables 10% renew ables in the transport sector Transport sector is dependent on imported oil - 99% in N Ireland % in Republic of ireland % pasture per county area Smyth et al (2011) (based on EPA corine land cover data)

3 What is grass biomethane? harvest silage weigh bridge silage storage vehicle fuel biomethane biogas anaerobic digester macerator

4 Is grass biomethane a good biofuel? Life cycle analysis shows favourable energy balance Gross vs net energy GJ ha -1 yr Soybean biodiesel Rapeseed biodiesel Wheat ethanol Corn ethanol Wheat ethanol, WDGS biomethane Sugar beet ethanol Palm oil biodiesel Grass biomethane Sugar beet biomethane Sugarcane ethanol Gross Net Adapted from Smyth et al (2009)

5 Comparing biofuels land use efficiency 400 Land req'd (ha/100 cars) Land req'd under contract (ha/100 cars) Grass biomethane Sugarbeet biomethane Wheat ethanol Sugarbeet ethanol Rapeseed biodiesel Based on data from Smyth et al (2009); Korres et al (2010)

6 Biofuel sustainability criteria To be a biofuel EU Directive 2009/28/EC requires: Minimum GHG savings (compared to fossil fuel replaced): 35% now...rising to 50% by % from 2018 (for biofuels from new installations) Biofuels must not to be made from land with recognised high biodiversity value or high carbon stock. Biofuels from wastes, residues, non-food cellulosic material, and ligno-cellulosic material get double credit.

7 Greenhouse gas balance (gco 2 /MJ energy replaced) Parameters Direct Indirect Total % total Agriculture Crop production Herbicide volatilization Lime dissolution N 2 O emissions Total agricultural emissions Transportation Biomethane production process AD plant Upgrading Total processing emissions Biogas losses Total Source: Smyth et al (2009); Korres et al (2010)

8 % savings & main sources of GHGs GHG savings of 21.5% in base case scenario Electricity 28.5% Heating digesters 26% Vehicle inefficiency 18% Biogas losses 15.5% Indirect agricultural emissions (dominated by production of N) 9%

9 Improving the GHG balance Base case 21.5 Wind energy for electricity 42 Wood chips for heat demand Digester configuration Vehicle efficiency t/ha/a C sequestration % CO 2 savings over diesel Percentage CO 2 savings over fossil diesel under various biomethane production scenarios (results are cumulative from top to bottom) Smyth et al (2009); Korres et al (2010)

10 GHG savings of grass biomethane and comparison with other biofuels % savings % 40 35% 20 0 Sugarcane E Sugar beet E Wheat E Corn E Palm oil BD Soybean BD Rapeseed BD Waste oil BD Grass BM Source: Smyth et al (2009); Korres et al (2010)

11 Will grass biomethane still meet the requirement if indirect effects are taken into account? Growth of grass biomethane industry in Ireland Intensification of agriculture beef herd dairy herd sheep flock live exports beef exports indigenous beef supply exports to UK other exports UK beef consumption unaffected UK beef consumption Scenario 1: Increase in UK beef production Scenario 2: Increase in beef imports from other countries Scenario 3: Increase in UK poultry meat consumption 1a: From beef herd 1b: From dairy herd 2a: From EU From non-eu Increase in EU imports 2b: From New Zealand 2c: From Brazil From The Netherlands

12 Indirect effects and GHG emissions Scenario Description Direct Indirect Total biofuel GHG savings Grass biomethane excluding indirect effects Indirect effects (kgco 2 e ha -1 yr -1 ) Grass biomethane (kgco 2 e ha -1 yr -1 ) Irish beef Replacement (kgco 2 e ha -1 yr -1 ) (gco 2 e MJ -1 fuel replaced) (%) a UK beef (suckler herd) b UK beef (dairy herd) a EU beef (suckler herd) b EU beef (dairy herd) New Zealand beef (optimistic) New Zealand beef (conservative) c Brazilian beef (with LUC) ,209 79, Brazilian beef (without LUC) Target = 60% Dutch poultry

13 How clean is grass biomethane from a health perspective? Improved air quality GHGs and climate change impacts local emissions Biomethane displaces fossil fuel Increase in codigestion of slurry with grass Increased demand for co-substrates for AD Digestate as fertilizer, decreased use of raw slurry contamination of water supplies Growth of grass biomethane industry in Ireland beef herd quantity of slurry produced exports to UK beef exports UK beef consumption unaffected UK beef consumption Scenario 1: Increase in UK beef production Scenario 2: Increase in beef imports from other countries Scenario 3: Increase in UK poultry meat consumption Intensification of agriculture, changes in net GHG emissions, climate change impacts, increased water pollution, land use change, food price changes, diet changes

14 Direct and indirect effects on water quality Ireland and UK have the highest rates of crypto in EU a In 2014 in Ireland b ~188,000 on public supplies at risk from Cryptosporidium ~30% of private wells are contaminated by E. coli Manure spreading followed by storm events is main source of crypto in water supplies c AD reduces pathogen content, by up to 100% if high temps used d Growth of grass biomethane industry in Ireland size of beef herd quantity of slurry produced Increase in demand for co-substrates for AD Increase in co-digestion of slurry with grass quantity of raw slurry applied to land Increase in demand for alternative fertilisers Grass and slurry digestate used as fertiliser contamination of water supplies related illnesses a HPSC; b EPA, 2015; c Tang et al, 2011; d Yiridoe et al, 2009

15 Conclusions Is biomethane clean? Environmental impacts Land use (direct) and energy balance GHG emissions, direct and indirect? Further research for health impacts? Scoping study to identify causal links between biomethane and health? Consequential life cycle analysis to quantify impacts

16 Thank you for listening! Contact details Beatrice Smyth School of Mechanical & Aerospace Engineering Queen s University Belfast beatrice.smyth@qub.ac.uk

17 References Environmental Protection Agency (EPA). Drinking Water Report Health Protection Surveillance Centre (HPSC). Epidemiology of Cryptosporidiosis in Ireland Annual Reports. Z/Gastroenteric/Cryptosporidiosis/Publications/EpidemiologyofCryptosporidiosisinIrelandAnnualReports/ Korres, N. E., Singh, A., Nizami, A.-S. and Murphy, J. D. (2010), Is grass biomethane a sustainable transport biofuel?. Biofuels, Bioprod. Bioref., 4: doi: /bbb.228 Stephen Mairs, Determining the regional potential for a grass biomethane industry in Northern Ireland, MEng Mechanical Engineering Final Year Project, supervised by Beatrice Smyth, School of Mechanical & Aerospace Engineering, QUB, 2015 Joan B. Rose, Debra E. Huffman, Angela Gennaccaro, Risk and control of waterborne cryptosporidiosis, FEMS Microbiology Reviews, Volume 26, Issue 2, June 2002, Pages , ISSN , Beatrice M. Smyth, Henry Smyth, Jerry D. Murphy, Determining the regional potential for a grass biomethane industry, Applied Energy, Volume 88, Issue 6, June 2011, Pages , ISSN , Beatrice M. Smyth, Jerry D. Murphy, Catherine M. O Brien, What is the energy balance of grass biomethane in Ireland and other temperate northern European climates?, Renewable and Sustainable Energy Reviews, Volume 13, Issue 9, December 2009, Pages , ISSN , Sustainable Energy Authority of Ireland (SEAI) (2014). Energy in Transport report.pdf Jialiang Tang, Stephen McDonald, Xinhua Peng, Sukha R. Samadder, Thomas M. Murphy, Nicholas M. Holden, Modelling Cryptosporidium oocysts transport in small ungauged agricultural catchments, Water Research, Volume 45, Issue 12, June 2011, Pages , ISSN , Emmanuel K. Yiridoe, Robert Gordon, Bettina B. Brown, Nonmarket cobenefits and economic feasibility of on-farm biogas energy production, Energy Policy, Volume 37, Issue 3, March 2009, Pages , ISSN ,