Biogas. from farm waste, by-products and crops local solutions for local issues. BANZ conference Rotorua, New Zealand 16. May 2013.

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1 BANZ conference Rotorua, New Zealand 16. May 2013 Biogas from farm waste, by-products and crops local solutions for local issues Stephan Heubeck Dipl.-Ing. agrar (FH) M.Eng. Environmental Dr. Rupert Craggs Group leader Aquatic Pollution Dr. Rocky Renquist Crop physiologist & Director National Institute of Water & Atmospheric Research Ltd. Bioenergy Cropping Solutions Ltd.

2 The baseline In NZ we are vey dependent on non-renewable energy resources Source: NZMED Energy Data File 2011

3 The baseline Agriculture is using a divers mix of energy resources, but hardly any renewables: 2011 net energy use for agriculture, forestry and fishing sector in PJ/y Coal Oil N. Gas Electr icity Hydro Geoth ermal Solar Wind Liquid Biofuel Biogas Wood Ag use Source: NZMED Energy Data File 2012 Can the rural sector expect other sectors to take up bio-energy if there is no own use?

4 Biogas The most versatile renewable energy resource Source: From a feed-stock perspective o Manures and Effluents o Solid waste and processing by-products o Agricultural residuals and energy crops From a digester technology perspective o Thermophilic, mesphilic and cryophillic digestion o Tank and pond type digesters o Mixed, static and enhanced surface digesters From a scale perspective o From individual farm set-ups to industrial scale

5 Biogas The most versatile renewable energy resource Regarding utilisation pathways o Heating o Electricity generation o Transport fuel o Chemical feedstock, synthetic materials In addition biogas can be o Stored short and medium term o Relatively easy integrated with existing fossil fuel infrastructure Biogas could be the corner stone of a renewable energy future. However, biogas is a very case specific technology

6 Biogas Biogas is a mixture of gases Composition may slightly vary: o Feed stock o Contaminants o Technology Properties o Similar to natural gas o Corrosive gas components o Lighter than air o Calorific value: ~20MJ/m 3

7 Biogas use options Will be determined by goals we want to achieve o Generally biogas use can be classified for heating, electricity generation and for transport applications o Financial attractiveness, GHG reductions, Complexity of the set-up 1m 3 biogas methane can substitute: Substitute GHG mitigation Gross value Complexity ~ 1m 3 Natural gas boiler fuel kg Coal (Lig SB) Boiler fuel kwh electricity L Transport fuel (Diesel/petrol) ~ 2 kg kg CO 2eq $ Scale / location kg CO 2eq $ Location! NZ: kg CO 2eq $ exp +no AU: kg CO REC 2eq $ own use kg CO 2eq $ NZ & AU (no tax) Simple, cheap and easy Quite simple and cheap technology Modestly complex Modestly expensive Complex to organize Relatively expensive technology

8 Biogas heating Biogas use options o Despite its advantages quite uncommon around the globe other than for domestic applications in developing countries o Good examples: o Fonterra Tirau Natural gas substitution since 1984 o Nelson hospital o Highly efficient biogas use: % efficiency o International focus is on biogas generator waste heat utilisation o Scale: 5kW 10 MW

9 Biogas use options Biogas electricity generation o Base load generation considered to be mastered. o Reciprocating engines becoming more reliable, performance of gas-turbines and other heat engines so far disappointing. o New focus on on-demand and heat governed generation modes. o Scale: 30 kw 30 MW

10 Biogas use options Biogas transport fuel o Purified and compressed biogas (bio-methane) can be used in any CNG vehicle, however heavy vehicles have economic and logistic advantages o Highest financial and ecological value for biogas use o Chicken and egg problem building up production facility and user fleet in parallel o Minimum size: ~500L/day?

11 Case studies individual farm Substrates: Drivers: Cow shed effluent, feed pad wash, piggery effluent, other liquid wastes Odour reduction, Solids separation with effluent storage, On-site energy, GHG reduction Technology: Covered Anaerobic Pond Biogas use: Motor-generator, boiler, flare

12 Case studies individual farm Lepper piggery Taranaki :

13 Case studies individual farm Benefits: o 40-50% instant electricity savings o Replacement of heat lamps with reticulated hot water system will see energy self-sufficiency increases to 70 85% o Replacement of heat lamps a long term process o Gas storage + heat storage = total flexibility o Ability to keep piggery operational for several days without grid supply o Payback period < 3 years

14 Case studies individual farm Electricity generation record

15 Case studies individual farm Dairy farm: Better effluent handling and energy independence o o Requirement for diary farm effluent storage and / or low rate application technology demands effluent solids reduction Covered Anaerobic Pond as an alternative to mechanical solids separators and weeping walls

16 Case studies individual farm Dairy farm: Better effluent handling and energy independence o o o Security of supply concerns Biogas as regular back-up Options for the energy independent dairy farm and biogas as enabler for other renewable generation technologies Modelling results positive

17 Case studies individual farm Dairy farm: Better effluent handling and energy independence o Field scale project under construction in Canterbury at the moment. Photo taken: 10. May 2013

18 Case studies farmer group Example Margarethen am Moos Austria o From the farms for the farms o 12 Farmer co-operative o Biogas plant for manure and energy crops from 220 ha o 625 kw electricity generation base load o Waste heat for half the village o Vehicle fuel station for cars, vans and 2x 200 HP tractor o Truly on the way to energy independence

19 Case studies farmer group Differences to individual farm set-up: o Economies of scale to realize high value uses for biogas, i.e. vehicle fuel and heat network o Cooperation to bundle wastes not enough o Energy crops to gain scale Good alternatives for land use More engineered digester technology required o Logistics become the most important success factor o Co-operation can solve many chicken/egg problems

20 Case studies farmer group Where is scope for such concepts in NZ: o As a further alternative in locations where traditional land use is challenged, i.e. invasive weeds, nutrient sensitive areas (Taupo), draught areas o Where complex waste management is part of the mix, i.e. seasonal fruit and vegetable wastes o Where energy autonomy based on renewables has additional value, i.e. tourism areas, Maori communities o In a crisis situation, or wherever the fast start, moderate scale of the concept provides particular advantages

21 The New Zealand Institute for Plant & Food Research Limited Bioenergy Cropping, Nutrient Cycling Rocky Renquist, Bioenergy Cropping Solutions Ltd Huub Kerckhoffs, Massey University Stephan Heubeck, NIWA

22 Why biogas transport fuel? Km travel per hectare Land efficiency Source: The New Zealand Institute for Plant & Food Research Limited

23 Biomass Cropping Aims Produce biofuels that can be made with local scale technology and have a high fuel yield per ha: biogas. Demonstrate a cropping system in which bioenergy crops are fertilised with recycled crop nutrients: the Closed-Loop N system (CLN). Selected best biomass species Identify the best species, those with sustainable high biomass yield, adapted to sites that are often summer dry and that fit into the resilient CLN cropping system The New Zealand Institute for Plant & Food Research Limited

24 Rural benefits Substitution of fossil fuels used on the farm and by rural trucking with local, reliable biofuels. Little need for purchased fertilisers: Use N- efficient crops plus legumes and recycle nutrients. New land use opportunity: to supply crops to biofuel producers. Use marginal sites where crops are susceptible to moderate drought stress. The New Zealand Institute for Plant & Food Research Limited

25 Forage sorghum ( Jumbo ) Jumbo Sorghum Kerikeri m tall at leaf top 30 tdm/ha The New Zealand Institute for Plant & Food Research Limited

26 Forage sorghum ( Jumbo ) Jumbo Sorghum Hastings m tall leaftop 27 tdm/ha The New Zealand Institute for Plant & Food Research Limited

27 Jerusalem artichoke, tubers The New Zealand Institute for Plant & Food Research Limited

28 Jerusalem artichoke (JA) JA as an annual crop (first year plantings) in Hastings Shoot biomass 200 days after planting: tdm/ha 2013 (no rain) 16 tdm/ha The New Zealand Institute for Plant & Food Research Limited

29 Jerusalem artichoke (JA) JA as a perennial crop; (second year) Shoot biomass 190 days after emergence in Hastings: tdm/ha 2013 (no rain) 17 tdm/ha The New Zealand Institute for Plant & Food Research Limited

30 Giant Miscanthus Parallel project: other biofuel options Mxg is a perennial, highest DM of all biomass crops tested in NZ 2013 (dry year!) Hastings: 36 tdm/ha at late March peak (DM% = 47) The New Zealand Institute for Plant & Food Research Limited

31 Cropping Conclusions The most promising combinations of new biomass species and legumes to maximise biomass production for biogas on summer-dry marginal land: (1) forage sorghum in combination with tickbean or crimson clover (H. Bay north) (2) Jerusalem artichoke and/or lucerne (H. Bay south) Our biomass crop yields in good sites: forage sorghum 20-25tDM/ha + 10tDM/ha for legume Jerusalem artichoke 16-25tDM/ha Lucerne tdm/ha (3-4 cuttings) (all are well adapted to the CLN system) The New Zealand Institute for Plant & Food Research Limited

32 Rural NZ Biofuel potential Biofuel yield from only 5% of summer dry land: 3.9 million tdm 900 million m 3 methane (630 million m 3 net) (= energy equivalent to 595 million litres of diesel) The New Zealand Institute for Plant & Food Research Limited