WASTE-TO-ENERGY TECHNOLOGIES 20/01/2015 This activity received funding from the Department of Industry as part of the Energy Efficiency Information Grants Program. The views expressed herein are not necessarily the views of the Commonwealth of Australia, and the Commonwealth does not accept responsibility for any information or advice contained herein.
Waste to Energy Webinar 'Beyond compost and fertiliser - Using farm waste to generate energy' Fernando Johnstone & Phil Shorten | January 2015
What we will cover in this session…. Types of waste for energy Types of waste to energy technologies Case examples Financing options
Our assumptions You have considered the use of alternative fuels such as biomass/biogas at your site… Starting to look at our first opportunity Looked at many options, but none has progressed to implementation Implementing our first project now Have an existing alternative fuel
What are your Waste-to-Energy fuel options?
Types of waste Agricultural waste: straw, bagasse, nut shells, cotton gin waste, horticultural waste Animal farm waste: manure, slurries, chicken litter Wood waste: woodchips, sawdust, forestry residues Urban waste: municipal solid waste (MSW), commercial and industrial (C&I), sewage waste
Types of technologies 12 MWth woodchip Direct biomass combustion: biomass fuel is boiler – Bega, NSW burnt in excess air to produce heat. Anaerobic digestion: a biochemical process that uses microorganisms to produce a biogas rich in methane, which can be combusted for heat or used as fuel in reciprocating engines for Anaerobic digesters Barrybank Farm, VIC power generation Gasification: gasification of biomass takes place in a restricted supply of air or oxygen and produces a fuel gas that is rich in combustible carbon monoxide, hydrogen and methane (syngas) Pyrolysis: thermal degradation of biomass in the absence of oxygen to produce a combination of solid char, bio-oil and gaseous products Other – biofuels: fermentation, esterification New Energy Waste to Energy project (low temp gasification) – Port Hedland, WA
What can I do with it? PRODUCTS 2. Wastewater 1. Gas genset + food waste
...but Well proven Cost-effective Biogas from anaerobic digestion and direct combustion of biomass are more suitable for small to medium-size applications
Biogas (anaerobic digestion) Is produced by anaerobic digestion of organic waste in an oxygen-free environment (i.e. sealed container: covered ponds or digester tanks) Biogas produced has a methane content of 50 – 70%. Moisture and hydrogen sulphide too! (gas cleaning is important) Digestate is a byproduct with high nutrient value: fertilizer Covered anaerobic lagoons (CAL) are very common in some farms and abattoirs. Lower capital and O&M costs compared to digester tanks. N/A in Australia Digester tank Biogas can be also used in gas-fired boilers to generate steam or hot Pre-treatment such as water cutting, shredding or diluting may be required Food waste is an depending on waste excellent substrate. characteristics (as Proper screening of Covered pond received) MSW is key
Biogas (cont.) Digestion in tanks or plug reactors is considered rather expensive for small scale applications (capacity: 5 – 100m 3 ). Better outcomes for farm-scale applications (100 – 800m 3 ), e.g. piggeries Biogas yield (m 3 /ton) depends on type of material but also on process conditions (temperature, residence time, pH, mixing). Co-digestion with food or crop waste is typically used to improve methane yield. Biogas is typically used in gas-fired boilers (co-firing with natural gas). Use in gas engines is also typical but requires biogas cleaning due to hydrogen sulphide (H 2 S) content which can corrode internal parts. Biogas yields (Source: Ecofys bv)
What is suitable for my business?
Key drivers for considering W2E 1. Drivers: a) Increase in waste and regulation from conversion to intensive operations, e.g. paddock to feedlot b) Rising energy prices c) Increasing waste disposal cost – Landfill levies 2. Barriers: a) Typically large capital costs and limited access to capital: long term projects b) Lack of understanding around waste-to-energy c) Alternative use of waste: waste can be sold as fertiliser, applied on site, or composted and then sold/applied
Small and medium-scale applications $1,000s $10,000s Small - Medium farm $100,000s $ millions Large farm
Small and medium-scale applications Greater scale improves profitability…. Indicative cost* Piggery size Potential return for biogas project Source: Australian Pork Limited & Pork CRC
Biogas – how much can I generate? Waste generation and biogas yields: Source: World Bioenergy Association (WBA) fact sheet Example: How much biogas is needed for a motor-generator of 100 kWe output capacity? A biogas plant with an installed capacity of 100kWe, an electrical efficiency of 35% and an annual production of 800,000 kWh electricity requires 470,000 Nm³ biogas. This equals the biogas output from a manure slurry of 950 intensively housed milking cows, 6,000 pigs or 45 ha of maize. 6,000 pigs x 1.9 m3 manure/pig = 12,000 m3 manure/yr. 12,000 m3 manure x 42 m3 biogas/m3 manure = 470,000 m3 biogas/yr 470,000 m3 biogas x 50% methane = 235,000 m3/yr of methane 235,000 m3 methane x 37 MJ/m3 = 8,700 GJ/yr of energy 8,700 GJ/yr * 35% generator efficiency = 3,000 GJ/yr or 840 MWh/yr of electricity
Biogas example 1 • First piggery in Australia to install a commercial-scale Blantyre Piggery (22,000 pigs) system to generate power from methane from an anaerobic (covered pond) system • Produces biogas which is fed into a cogeneration unit to generate heat and power • 3 x 80kW Dongguan Camda gensets with heat recovery on engine cooling circuit and exhaust (hot water). Running 24/7 and gas is still being flared! • The farm's feed mill consumes only part of the electricity generated. Rest gets exported to the grid. • Capital cost: $1m. Total savings: $15,000 per month. (electricity & gas). Additional revenue of $5,000 per month for selling power back to the grid. Payback: <3yrs (incl. CFI credits + RECs) Covered pond captures methane produced from the anaerobic digestion of pig manure (Source: NSW Farmers) 80kW biogas gensets
Biogas example 2 Darling Downs Fresh Eggs • First digester project within the Australian egg production sector • Digester produces biogas which will be supplied to gas gensets to produce power and heat • Generators to meet 100% of the farm’s non -peak power requirements and reduce electricity usage by 60% • Expected savings: $250,000 p.a. (electricity & gas) • Capital cost: $2.86m. Co-financed by CEFC and NAB + $330K CTIP funding • Build-Own-Operate (BOO) contract: Quantum Power built, owns and operates the anaerobic digester using poultry waste from Darling Downs. Darling Downs purchases the energy from Quantum at a lower price that grid supplied electricity.
Key factors to develop a waste to energy solution
Key factors to consider Waste Availability: • What, where and how much is available? Distance to site? (transport cost). Can you combine waste fuels from different sources? • Consistent supply to ensure savings are achieved, i.e. long-term contracts (is 10yr+ possible?). Are there any seasonal variations? (eg. some crops available only 3-4 months per year) • Cost: does it include delivery or pre-treatment? Is the price subject to other alternative use & markets? (eg. straw used for fodder) Waste Quality • Variations in heating value, moisture/chemicals content or particle size can cause combustion problem, equipment damage, or represent an environmental risk • MSW and C&I waste: large variations due to mix of different materials. Hazardous materials can be present (eg. treated timber: arsenic)
Key factors to consider Existing Infrastructure: • Energy baseline: measure your thermal and electrical load • What are the key energy users? Thermal vs electrical equipment. Co-firing capabilities? • How is energy currently supplied? Energy sources, type of contract, cost. Is the supply of alternative fuel going to affect my existing contract? • How much waste do you generate? Do you treat your waste onsite? Technology Options: • How well does biomass or biogas technology integrate with your existing facility? Is co- firing feasible? Do you have layout constraints? Storage and handling equipment require space! • Is the technology commercially available? Is there a good number of suppliers Australia? • Is cogeneration an option? (eg. do you need heat as well as power?) • Variations in waste quality: robust technology can be more flexible but very expensive
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