Potential for biomethane technologies to treat waste, substitute for fossil fuel, and reduce GHG emissions. UCC Climate Change Workshop Boole 5, University College Cork, May 29 th 2013 Dr Jerry Murphy, BioEnergy and Biofuels Research, Environmental Research Institute, University College Cork, Ireland

Bioenergy and Biofuels Research Group (B2RG) Funding of €3 M since inception in 2007 from:  EPA, SFI, DAFF, IRCSET, BGE, BGN, HEA PRTLI, Marie Curie ITN Published  59 peer review journal papers  29 peer review conference papers Papers have received1500 citations H factor of 23 (23 papers cited at least 23 times) Three PhD students in place, funding for a further 5 Graduated 12 research postgraduates Supervised 4 post-doctorate students, funding for a further 2

EC, Proposal for a DIRECTIVE OF THE EUROPEAN PARLIMENT Brussels In : The share of biofuels from cereal and other starch rich crops, sugar and oil crops limited to consumption in 2011 (ca. 5%) Biofuels (from algae, municipal solid waste, manures and residues) and gaseous fuels from non biological origin shall be considered at 4 times energy content Directive 2009/28/EC (Renewable Energy Directive) Share of renewable energy sources in transport by 2020 at least 10% Biofuels must achieve a 60% reduction in GHG as opposed to fossil fuel displaced. Biofuels from lignocellulosic material shall be considered as twice energy content.

Ireland 4.4 Mha agricultural (65%) 4 Mha grass land (91%) Export 85% of beef 400,000 ha arable (9%) Net importer of grain Agriculture Energy Biofuel feed-stocks Cross Compliance and EU Biofuels Directive do not encourage conversion of grass land to arable land for biofuels. Forestry less than 10%; Not a lot of straw.

Irish Gas Grid Serves: 153 towns 19 counties (26 counties in Ireland) 619,000 houses (ca. 45% of houses) 24,000 industrial and commercial

Number of vehicles running on CNG worldwide

Grass to transport fuel in Austria harvest silage storage macerator Source: energiewerkstatt, IEA and personal photos anaerobic digester weigh bridge Biogas service station Scrubbing & storage

versus CSTR SLBR-UASB

Bioresource of Biomethane from Grass

Food Waste from UCC canteen Composition of UCC Food Waste (percentage mass) Table 1. Characteristics of Food Waste from UCC canteen ParametersUnitValue pH4.05 Total Solids (dry solids) % total mass 29.4 ± 1.1 Total Volatile Solids % DS95.3 ± 0.4 Proteins% DS18.1 ± 1.5 Carbohydrates% DS59.0 ± 3.0 Lipids (fats)% DS19.0 ± 0.8 % C% DS49.6 ± 1.2 % H% DS7.3 ± 0.2 % N% DS3.5 ± 0.4 % Ash% DS4.7 ± 0.4 C 16.5 H 31.2 O 9.5 N

Theoretical maximum methane production (1) Energy Balance to estimate methane production Energy content of food waste ~ MJ/kg Volatile Solid (VS) Energy content of CH 4 ~ 37.8 MJ/m 3 1 kg VS destroyed = 20.74MJ= 549 L CH 4 / kgVS (2) Buswell Equation to estimate methane production Stoichiometry description of food waste: C 16.5 H 31.2 O 9.5 N Buswell’s Eqn. 587 L CH 4 / kgVS (3) Relationship between kg VS destroyed and COD produced 1.6 kg COD to oxidise 1 kg VS; 1 kg COD = 350 L CH 4 ; 560 L CH 4 / kgVS

Biomethane Potential Tests

Bioresource of Biomethane from OFMSW

Sea Lettuce (Ulva Lactuca)

Macro-algae: 3 rd generation biofuel Green tides in eutrophic estuaries 10,000 tonnes of sea lettuce arise in Timoleauge annually. 20m3 CH4 /t wet vs 100 m3 CH4/t dry

Ultimate Analysis of Ulva

Sample type and year BMP yield L CH 4 / kg VS Pro-rata calculated yield L CH 4 / kg VS % increase Slurry136-- Fresh Ulva205-- Dried Ulva226-- Dried Ulva 75%: Slurry 25% Dried Ulva 50%: Slurry 50% Dried Ulva 25%: Slurry 75% Fresh Ulva 75%: Slurry 25% Fresh Ulva 50%; Slurry 50% Fresh Ulva 25%: Slurry 75% Co-digestion improves the specific methane yield by ca. 17% for all fresh samples Results of BMP assays

Thermal production of Biomethane CO + 3H 2 = CH 4 + H 2 O CO H 2 = CH 4 + 2H 2 O 2CO + 2H 2 = CH 4 + CO 2 Typically ca. 65% energy efficiency Gas upgrading Removal of CO2

Plant Size MWth50 Land area (ha)6800 Annual Energy Input (GJ)1,440,000 Plant Efficiency65% Annual Energy Output (GJ)936,000 Annual Energy Output (PJ)0.94 Number of plants required11 Energy Produced10.34 PJ As a % Energy in Transport5.5% As a % of agricultural land1.7%

Electricity to Methane via Hydrogen coupled with Carbon Sequestration H 2 : energy Density 12.1 MJ/m n 3 : CH 4 : Energy density 37.6 MJ/m n 3 Sabatier Equation: 4H 2 + CO 2 = CH 4 + 2H 2 O  H 298 =-165 kJ/mol Typically ca. 60% energy efficiency (75% conversion of electricity to H2; 80% conversion of H2 to CH4)

Methane resource from electricity to methane as described by the Sabatier Equation Source of CO2 from biogas: Mix biogas (50% CH4 and 50% CO2) with H2; generate double the CH4 (1 mol CO2 generates 1 mol CH4). Resource can be equal to biomethane (8.4%)

ResourceEnergy in transportWeighingRES-T Grass (100,000 ha)15.8 PJ8.4%*216.8% Food waste (530,000 t/a)2.65 PJ1.4%*22.8% Gasification 75,000 ha Willow10.34 PJ5.5%*211% Electricity8 PJ4.2 %* 417% Total36.8 PJ19.5%47.6% Resource equates to 1000 Mm 3 /year biomethane, VW Passat consumes 4.5 kg / 100 km (6.3m 3 /100km). Average car in Ireland travels 16,708 km/year Resource equals 950,000 cars or 48% of private fleet

Thanks for the funding: Science Foundation Ireland (SFI) Environmental Protection Agency (EPA) Department of Agriculture, Fisheries and Food (DAFF) Bord Gais Eireann (BGE) Irish Research Council for Science, Engineering & Technology (IRCSET) Teagasc (Padraig O Kiely) Marie Curie ITN