Overview of Wood Pellet Co- firing

Transcription

1 Overview of Wood Pellet Co- firing Presented by William Strauss, PhD President, FutureMetrics May 4, 2016

2 FutureMetrics Consultants to the World s Leading Companies in the Wood Pellet Sector Intelligent Analysis and Thought Leadership for the Pellet Sector 8 Airport Road Bethel, ME 04217, USA

3 Senior Leadership William Strauss 40 years of making thermal power from MSW and wood. Recipient of the 2012 InternaEonal Excellence in Bioenergy Award. John Swaan The grandfather of wood pellets. Recipient of the 2014 InternaEonal Founders Award for pioneering in the wood pellet sector. FutureMetrics - Globally Respected Consultants in the Wood Pellet Sector Les ONen The leader in the development of the US bulk heaeng pellet markets. Founder of Maine Energy Systems: North Americas largest pellet boiler and bulk fuel supply company.

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7 Why Wood Pellets are an Easy SubsOtute for Coal in Pulverized Coal Power Plants Wood pellets are upgraded solid fuel made from biomass. They are grindable. They are dry (~6% moisture content). They handle easily. They have an energy density of ~18 Gigajoules/tonne. At low co- firing raoos (less than ~6% white wood pellets) no modificaoons are required. In some applicaoons, advanced wood pellets can be used at 100% with almost no modificaoons. More on this later

8 White wood pellets are the default subsotuoon for coal in PC power plants. Steam exploded pellets, which are waterproof, are breaking into the market. The cost per unit of energy or $/GJ is the key metric. White Pellets Brown (steam exploded) Pellets Black (torrefied) Pellets

9 What about Ag Residues? FutureMetrics specializes in wood pellets because we think they are the best alternaove renewable low carbon solid fuel for pulverized coal power plants. Issues with corn stover and wheat straw: High in chlorine corrosion issues High in minerals and dirt erosion issues Low ash fusion temperature slagging and fouling Low bulk density costly to transport in terms of $/GJ large volume needed for fuel storage

10 Source: Ash- related Problems during Biomass CombusOon and PossibiliOes for a Sustainable Ash UOlizaOon, Friedrich Biedermann and Ingwald Obernberger, Austrian Bioenergy Centre GmbH, Sept., 2006

11 What are the key changes that are required to modify a pulverized coal power plant to be able to co- fire industrial wood pellets? At low blend raoos (less than 6% pellets to coal), no modificaoons are required. At higher blend raoos some modificaoons are required: Dedicated dry storage for the pellet fuel (silos or domes) Fuel processing and transport to the burners Burners Ash handling

12 There are many large power staoons that have been modified to co- fire (blending pellets and coal) or full fire (100% pellet fuel). There are several world class firms that have extensive experience in the design, engineering, and implementaoon of power plant modificaoons. Ramboll - EPC for modificaoons and conversions with a long list of successful co- firing and full firing projects Doosan Babcock Fuel processing, handling, and burners for co- firing and full firing Drax Power Power plant operaoons at equal or bener reliability than coal and no deraong with co- firing and full firing us/our- businesses/drax- power

13 Examples of Power Plants that Use Wood Pellets Avedore power staoon in Denmark - unit one 215 MW DONG Energy (was co- firing and expected to be 100% firing in 2017) 13

14 OPG s AOkokan 100% White Pellet Fueled Power StaOon

15 OPG s Thunder Bay staoon A super peaking plant that runs on 100% steam exploded advanced wood pellets Waterproof Arbaflame pellets have sat in the coal yard over winter with no degradaoon.

16 Thermal power Ramboll experts have designed and constructed more than 90 major power plants, including some of the most energy- efficient plants in the world, and been instrumental in the ongoing conversion from fossil fuels to biomass.

17 AVEDØRE POWER STATION DENMARK Avedøre, Unit 2 EPCM Plant MulO fuelled (gas, oil, coal, wood pellets, straw) Ultra Super CriEcal boiler pressure Conversion to wood pellets: Project analysis, planning, construcoon and commissioning Upgrading of boiler capacity

18 RAMBOLL - OWNERS ENGINEER LYNEMOUTH UK BIOCONVERSION Multi package Coal- wood pellet conversion 3 x 140MW power Bio conversion to wood pellets: Design development, design review, construcoon, safety and commisioning supervision

19 STUDSTRUP POWER STATION DENMARK EPCM Project Coal- fired/15% straw 350 MW e / 455 MJ/s Co-combustion of straw Now conversion to wood pellets: Project analysis and purchase, preliminary design, CAPEX, risk assessment, tendering and contracting

20 Drax, the largest decarbonisadon project in Europe Much more from Brian Moran from Drax at today s Keynote 20 speech

21 TransformaDon of Drax Power StaDon Three 645 MW lines running on 100% wood pellet fuel Boiler and generator - 3 unit conversion Transfer tower Transfer tower - Negligible impact on efficiency and no loss of output Screening building - Flexible output from 200MW to 645MW per unit Screening building Storage domes Screening building Rail unloading Rail unloading Storage domes

22 Drax Power StaDon 4,000MW facility that has undergone a substantial transformation in the last 5 years Before conversion to industrial wood pellets 6 coal-fired units 10Mt of coal consumed per year Post-conversion 3 coal-fired units and 3 wood pellet fired units Expect to be predominantly pellet-fuelled generator as coal is further phased out of the UK energy mix 4Mt of coal consumed per year 7-7.5Mt of wood pellets consumed per year Largest global industrial pellet portfolio Drax demand represents about 50% of 2016 forecasted industrial pellet demand of 13.6M 1 1 Hawkins Wright The Outlook for Wood Pellets Q4 2015

23 Very paroal list of conversions/modificaoons Project Name Country Lynemouth UK Yeong Dong Korea Lynemouth UK Gardanne France Drax UK Drax UK Ironbridge UK Atikokan Canada Drax UK Rybnik Poland Drax UK Hasselby C HP Sweden Scope 100% wood pellet conversion contract award Units x MWe 3 x 140 Contract Award Conversion of coal mills and burners to 100% wood pellet firing Hasselby Power % wood pellet conversion of downshot boiler 1 x KOSEP 100% biomass conversion FE E D study 3 x RWE Biomass conversion and turbine upgrade 1 x E.On Conversion of E- mills and associated burners to wood pellets 2 x Drax Power Ltd Conversion of E- mills and associated burners to wood pellets 1 x Drax Power Ltd Convert units 1 and 2 to 100% wood pellets 2 x E.ON UK 100% wood pellet firing 1 x Ontario Power Generation Conversion of two E- mills biomass 1 x Drax Power Ltd B iomas s unloading, s torage and milling E D F Twelve direct injection biomass co- firing systems 6 x Drax Power Ltd EPH Customer Doosan Babcock Biomass References

24 SelecOon of planned Co- firing and Full Firing Power Plants Country Company Project MW Fuel Completion Year Netherlands RWE Essent Amer Coal and Wood Pellets 2017 Netherlands Engie, formerly GDF Suez Rotterdam Coal and Wood Pellets 2017 Netherlands Eon Maasvlakte Coal and Wood Pellets 2017 Netherlands RWE Essent Eemshaven A 777 Coal and Wood Pellets 2017 Netherlands RWE Essent Eemshaven B 777 Coal and Wood Pellets 2017 Netherlands Vattenfall Hemweg Coal and Wood Pellets 2017 UK EPH Lynemouth 320 Wood pellet 2018 Belgium Antwerp Biopower Antwerp 300 Wood pellets 2018 Denmark Dong Energy Studstrup (Unit 3) 350 Wood pellets 2016 Denmark Dong Energy Avedore (Unit 1) 215 Wood pellets 2016 Finland Helen Salmisaari 100 Wood pellets

25 The Global Industrial Wood Pellet Market is Already Large and Growing GROWTH? By 2018, UK to about 9 million tonnes/year and the Netherlands potenoally to 3.5 million tonnes/year Japan likely to 3 million tonnes per year with 9 million possible by US under the Clean Power Plan starong in 2022?? 25

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28 The high level expected cost of modificaoons. The total cost per MWh is shown in the Co- firing Dashboard that we will take a look at arer this slide. Total cost for a 100% conversion from coal to pellets is about $700 per kw of installed capacity. About 50% of that is for the dry storage systems (domes or silos) and about 50% is for in- plant modificaoons. For co- firing, the dry storage poroon will be less since a smaller fuel storage system is needed. For example, a 200 MW plant for 100% conversion would be in the ballpark of 200 x 1000 x $700 = $140 million For co- firing at a max of 20% pellets / 80% coal: 200 x 1000 x 50% x $700 x (50% x 20%) x $700 = $84 million or about $420/kw of capacity.

29 Dashboard is free to use at the FutureMetrics website.

30 Technical ConsideraOons when using pellets in PC plants Courtesy of Doosan Babcock

31 PF Boiler Conversion: Project ObjecDves Project objecoves drive the design and therefore cost and schedule q Remaining life of plant and life of subsidy; how good is it worth making it? q Wood pellets are an expensive fuel and efficiency is important q Conversion can be used to help meet new emissions legislaoon q If maximum output is important then technical changes are more extensive q Need to decide just minimum change to safely fire biomass or to maximise output and efficiency and minimise emissions Courtesy of Doosan Babcock

32 Pulverized Coal Boiler Conversion potendal areas that may need awendon Mill Air Temp Reduction for safety Fuel Handling Bunker/feeder mods for safety & density Fans Milling Plant PA, ID, seal air uprate Replace or modify & add dynamic classifiers and fire & explosion suppression Pulverized Fuel Piping Replace or modify for correct velocity Dust Collection Combustion System Upgrade & refurbish Replace or modify & add over-fire air for primary NOx control Furnace Cleaning Usually needs to be extended Ash systems Fire & safety Courtesy of Doosan Babcock

33 Case Study: Short & Sweet Limited life Urgent Moderate emissions Minimum spend Maximum safety q New fuel feeding system q Replacement of tube mills with hammer mills for safety q Modified exisong burners for stability; switch to pellets alone gave required reducoon in NOx q Replacement PF piping q Furnace cleaning extension q Heat balance correcoon by PA cooler q No pressure part work q ESP upgrade q Very limited life extension work q 12 month programme q Derated to 75% q LCPD emissions met

34 Case Study: Drax Progressive Conversion Extended life Progressive conversion Progressive emissions reducoons Progressive increase in output q Extensive investment in fuel storage and handling q Progressive movement from co- firing to full conversion q IniOally modified burners, then trial low NOx burners, now new low NOx burners q Heat balance correcoon by PA cooler q Limited pressure part work q ESP upgrade q Progressive life extension work q Decade biomass programme and soll developing q ConOnuing development to keep pace with emissions limits q Maximise efficiency q No derate q LCPD emissions met Doosan Babcock

35 Case Study: Yeong Dong High Specification World s first downshot boiler pellet conversion Capacity on coal or biomass Boiler Firing System Mills 125 MWe (no derate) Furnace shape change from downshot to wall- fired configuraoon New circular dual fuel burner for pellets or bituminous coal ExisOng tube mill unsuitable New verocal spindle mill for pellets or coal AddiOonal hammer mill for 5% woodchip Fuel Feeding Auxiliary System Reuse exisong bunkers and feeders New PF piping PA cooler with bypass and flue gas recycle HeaEng Surface Furnace Cleaning Element modificaoons to suit wall- fired configuraoon Extended sootblower system Doosan Babcock Emissions (ppm) NOx 50 SOx 100 PM 20

36 Pellet Fuel ConsideraDons Low in: q N, moves NOx emissions down significantly q S, so no need for FGD, even for BREF limits q Ash, so ash capacity much reduced q Moisture But: q Low ash fusion temperature so potenoal to slag q High Ca in ash can lead to furnace whitening q Low CV and low density bulk density means larger volumes of fuel for same output q Low ignioon temperature having safety implicaoons q Dusty giving explosion and fire risk

37 Milling Plant Upgrade q Doosan Babcock has experience in both upgrade of existing milling plant and replacement with new hammer mills & vertical spindle mills q Typically vertical spindle mills are robust and can be converted to wood pellets with little capacity reduction q Ball and tube mills can not be successfully converted and would be replaced q Low pellet CV (relative to most coal) and density can impact capacity q Particle size for pellet PF is ~1mm, 10 times larger than for coal q Mill velocities have to increase q Control of particle size and PF distribution is critical leading to the use of dynamic classifiers q Mill air inlet temperature has to be reduced to prevent ignition q Explosion suppression has to be added with other safety measures q There can be tramp in the fuel which has to be removed q Larger particles need higher conveying velocities to prevent saltation

38 Mill or Primary Air (PA) Temperature q Mill air inlet temperature must be reduced to <170 C to eliminate mill fires q Can be achieved by adding cold air Ø But reduces the boiler efficiency as main air heater balance is upset q Much bener by cooling with LP boiler feedwater in PA cooler Ø Less impact on ID fan and ESP Ø Maintains cycle efficiency Doosan Babcock

39 Pulverized Pellet Burners q Doosan Babcock uses PF burner heritage to be able to modify or provide replacement low NOx burners q Milled pellets have a large particle size with a top-size in the range 1-3 mm and so particles take longer to heat up and ignite so flame stands off burner q For low NOx operation a rooted flame is required through lower injection velocities to allow particles time to ignite q Low NOx burners with over-fire air can achieve IED/ BREF NOx levels (Industrial Emissions Directive / Best Available Technology Reference Documents) q Boosted over-fire air offers higher efficiencies q Even lower levels can be achieved with additional SNCR, now proven on biomass at large scale

40 Boiler HeaDng Surface at high co- firing rados ( >75% pellets) Furnace White- Out q Thin white CaO deposit formed; reflecove and water wall heat pick- up is reduced and higher furnace exit temperatures result q Coupled with low ash fusion temperature may lead to superheater slagging q ConvenOonal furnace sootblowers are ineffecove, but water lances work Heat Transfer q Reduced ash content and different flue gas composioon gives lower heat transfer and again higher exit temperatures result, potenoal slagging q Balance of heat to furnace vs. convecove pass changes; need to verify that exisong steam temperatures remain acceptable q Thermal performance analysis is an integral part of idenofying the issues that arise from converong a boiler to pellet firing, and arriving at pracocal soluoons q May consider coal ash injeceon to increase heat transfer and dilute CaO 40

41 Fans & Ash Fans q Higher pressure drop and velocity in mill and PF system => PA and seal air fans need to be uprated q Amount of combusoon air for same output is very similar => FD fan generally OK q Higher flue gas temperature and flue gas volume => generally requires anenoon to ID fans ESP q 20mg/Nm 3 required is generally available by ESP electrical upgrade; 10mg/Nm 3 => bag filters Ash q Ash flow about 1/20 th that of coal q Even efficient combusoon gives ash residues high in carbon, because so linle ash material to dilute it q PotenOal to catch fire; needs fire suppression system q High CaO is causoc on skin or in water; best to keep dry and sealed q Fly ash by sealed mechanical conveyors; not pneumaoc

42 Case Study - Fuel Processing for a 100% conversion from PC coal to pellets at OPG. Stay tuned for Brent Boyko at 11:10 this morning 42

43 The co- firing scenario has a number of benefits versus other pathways to compliance. The co- firing strategy is low- cost and easy to implement. The strategy leverages the generaong capacity of exisong pulverized coal power staoons. The co- firing rates can begin at very low raoos and gradually be increased over 10 or more years. Capital costs, parocularly at low co- firing rates, are very low. The gradual increase over a decade or more allows the generators to cononuously assess not only the outcomes of their operaoons but also to incorporate technological advances into the incremental increases in the raoo of pellets to coal. Jobs and income for the local, state, and federal treasuries BUT The Cost of Generation will be Higher from Co- 8iring. How can the Generators be Incentivized to Co- 8ire? Typical Cost for a 400 MW plant

44 Straight pass through Ratepayer pays The generator could simply pass through the cost. The rate increase for the end user would be a weighted average of the rates at co- firing plants and the cost for all the other power delivered in the state. Assume that Alberta consumes 80 million MWh s per year and about half is from coal*. Assume co- firing produces 10% of the total demand. The net impact on rates in 2030 at a 32% reducoon in CO 2 would be expected to be about $1.17/ MWh or about $0.0012/kWh (one tenth of a penny). *From Alberta UOliOes Commission, 2014 data. Coal was 55% of total in 2014,

45 Contract for difference Taxpayer pays If the retail power rates were expected to remain constant, an incenove could be a based on the provincial government providing a contract to pay the generator the difference between an agreed upon base rate and the higher cost. The uolity would receive support sufficient to compensate for the higher cost of generaoon. In this example, the cost to the government increases from about $3.2 million in the first year to about $81 million in That cost would come out of the government s treasury and potenoally be paid for by the taxpayers. Year CO 2 Reduction 1.0% 4.0% 8.0% 12.0% 22.0% 32.0% Co- firing rate 1.5% 5.7% 11.2% 16.4% 28.3% 39.0% Incremental Co- firing Cost $ 3,160,000 $ 11,212,000 $ 23,096,000 $ 34,976,000 $ 57,701,000 $ 80,801,000 Net Cost/MWh over 100% Coal $ 1.22 $ 4.32 $ 8.91 $ $ $ Assumed Baseline/MWh for Coal $ $ $ $ $ $ Total Cost/MWh $ $ $ $ $ $ Suppose that Alberta s budget is $40,000,000,000*. The 2030 cost is about two tenths of one percent of the current budget. *was $38 billion in 2011.

46 A carbon emissions fee (tax!) ratepayers pay but taxpayers may bene>it If the government wants lower CO 2 from power generaoon, they could impose a carbon emissions fee. This model is based only on the power generaoon sector so actual carbon tax revenues would be higher. Suppose the province produces 80 trillion MWhs annually from all generaoon sources. That level of producoon under Alberta s generaoon coal and natural gas plants will produce about 59 million tons per year of CO 2. A $25.00 per ton carbon fee that does not escalate would generate about $1.25 billion per year (assuming no growth or decline in power generaoon and no change in the fuel mix). Over 8 years that totals $10 trillion!! Alberta GWh lb CO2/kwh Metric Tonnes per Year of CO2 Coal 44, ,436,841 NG 28, ,602,691 TOTAL => 59,039,532

47 A carbon emissions tax ratepayers pay but taxpayers may bene>it The 400 MW power staoon that is co- firing would pay a carbon tax on the poroon of the power generated with coal. Under a well- crared policy the staoon would also receive a 100% rebate on both the carbon tax and the co- firing cost if the co- firing rate year- on- year increases at the predetermined growth rate toward the CO 2 reducoon goal. The table below shows how the total cost over 8 years of the sum of the carbon fee rebate and co- firing cost rebates is WAY less than the total collected by the carbon emissions fee ($1.7 billion cost compared to $10 trillion collected). Year Co- firing rate 1.5% 5.7% 11.2% 16.4% 28.3% 39.0% Avoided CO 2 (Tons) 64, , , ,124 1,035,181 1,344,663 Coal Co 2 (Tons) 6,339,476 5,743,953 5,206,307 4,708,906 3,670,187 2,857,408 TOTALS Carbon Fee $ 158,486,904 $ 143,598,832 $ 130,157,676 $ 117,722,647 $ 91,754,676 $ 71,435,208 $ 1,362,538,741 Co- firing Cost Rebate $ 3,160,000 $ 11,212,000 $ 23,096,000 $ 34,976,000 $ 57,701,000 $ 80,801,000 $ 332,666,000 Sum of C- fee and Rebate $ 161,646,904 $ 154,810,832 $ 153,253,676 $ 152,698,647 $ 149,455,676 $ 152,236,208 $ 1,695,204,741 Most carbon tax models have the tax increase gradually over Ome. The carbon emissions policy should be to have the per ton tax increase modestly over the years to make sure the income was sufficient to cover the costs.

48 Conclusion The strategy makes sense economically, environmentally, and poliecally. It preserves power plants, jobs, and grid reliability. Problem is, many key decision makers do not know that this proven strategy exists. The Eme to get to work on this is now!

49 Thank you William Strauss FutureMetrics Intelligent Analysis and Thought Leadership for the Pellet Sector

50 Carbon Neutral in CombusOon? The fundamental criteria for carbon neutrality in combusoon is that the stock of carbon in the atmosphere cannot be increased by the combusoon of the fuel. Here is how that works for industrial wood pellets: The source of material for producing the pellets has to be a forest that is cerofied to be managed sustainably. Sustainable management means that the forest cannot be allowed to shrink in size. A forest that does not shrink in size also means that the stock of carbon held in the forest does not shrink. For example, the raw materials for the pellet producoon plant are procured from tree plantaoons that produce new growth at a rate of 1,000,000 tons per year. The daily harvest is about 1 million divided by 365 or about 2,740 tons per day. Those tons are converted to roughly 1,400 tons per day of industrial pellets (about 500,000 tons per year). Those pellets are co- fired in a pulverized coal power plant as low carbon fuel. The supply chain carbon soll counts for pellets just as it does for coal; but the net is that pellets produce about 88% less carbon emissions than coal for the same MWh s more on this later. The carbon released by the combusoon of 1,400 tons of pellets is absorbed contemporaneously by the 2,740 tons of new growth that same day. There is no net new carbon added to the atmosphere. 50