Power-to-Gas Biomethanation: A Unique and Sustainable Approach to Renewable Natural Gas and other products Kevin Harrison & Nancy Dowe National Renewable Energy Laboratory AGA/EPA 2019 Renewable Natural Gas Workshop Peppermill Reno – Reno, NV September 24, 2019

NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. Me,an LCOE $/MWh

$3,60 359

330 Advanced e,ner,gy techn 1ologaes are :providi'ng

re,al-wo1 rld s,olutions by: 300 • Becoming increasingly cost-competitive 270 ., Boosting the US. energy ·ndustry

240 • Providing jobs ~or American workers

2 10

180

150 S135 1.20 23 $11 102 Coal (8%) 90 83 60 O , ...... _. o 1n d C cl { 27) 50 Utill Scale olar (86 ) 30 .______$ 5 Wind (67 o) 2009 2010 2011 2012 2013 2014 2015, 2'016 20 7

Rt I 6 Source: lmard's lOl 7 L v llzed Co r ofEn rgy Analysis, V r ion L 2 No m 20 7 https://www.lazard.com/perspective/levelized-cost-of-energy-2017/ New U.S. Electricity Generating Capacity Additions, 2010-2018 Recent U.S. Electricity 100% 90% ...... Wind .,:,:g ''New ,Capacity'' 80% -00 c:: 0 E ,:, 70% 'Cl <( >, 60% -~ 32% ro C. 50% NG uro ~ 40% ;a: 0 30% ~ .cro Far from {{alternative,,, (J) 20% ren,ewable en,ergy and 10% Solar 0% natural gas is the new 2010 2011 2012 2013 2014 2015 2016 2017 2016 normal in the United States ■ Solar ■ Natural Gas ■ Coal ■ Wind Othar Source. Wood Macken~e Power & Renewables FERC (All o her tec:hnolog1osl The Need for Long-Duration Energy Storage

Figure 4. Total Renewable Generation Serving California Load by Resource Type

100 000 Estlm te

BTM Solar 90,000 14% BTM Solar Solar 13, 18 80,000 Wind Geothermal ■ Solar 70,000 31% Small Hydro 30,262 60,000 Biomass J: ~ '!let.id t.:) 50,000 M

Wind 40,000 29% 27,838 30,000

20,000 1 Geothermal 3,249 10,000 4% Small Hyd o % 4,347 0 I Biomass I I 1983 I 8,04 2002 2006 20 1 2015 2018 Ff5l Ca lfCf ,a RPS e bliYled RPSmcreased to ZO%by 2010 RPS aeased RPS increased RPS1ooe.1~ (?OO(i by 20m CSI Initiated Global warm11g to 33%by 2020 lo 50% by 2030 to 60% b'{ 2030 Sokltlons Acl of n Source: Ca lifo rnia Energy Commission, staff analysis November 2018 H2@Scale Initiative Conventional Storage Hydrogen Benefits of ~Vehicle Renewable H2 ~ • Enables higher Upgrading penetration of Oil / renewable electricity Biomass • Electrolyzer can provide grid services Ammonia/ • H2 provides Fertilizer flexibility • O2 is a byproduct, too Growing Electric Grid • Infra structure • transportation sector Reduces• fossil fuel 2.5M miles End Use consumption Scale- able, non-toxic, low temperature process

10 MM tons H2 /year in U.S.

https://www.energy.gov/eere/fuelcells/h2scale Storing Renewable Electricity as Molecules

] ______------

l!i!lir 100 □ I ·------~- 1 Ma11th 100 ..., Over 130 billion cubic ~------1Day feet of natural gas ______,_ storage capacity exists in 1 .,- --- Southern California. E-101.:ir o.:m. To put this in O.ol perspective, this is enough to supply all of 0.001 --+- the gas-fired generation 1 kWll 10 klMI 100 kWh Ml.Wh 10 MWh 100 MWil 1

~ 175,000 .c 500,000 ~ e., 150,000 ... 461,054 ::, 400,000 _g 125,000 401,493

1ro 100,000 300,000 O'l 308,421 Q) Curtailed MWh ~ 75,000 200,000 187,722 100,000 :::: 111 1 I II .. 111 11 I I I I I I I I - Jan '17 Jul '17 Jan '18 I Jul '18 Jan '19 Jul '19 2015 2016 2017 2018 2019 http://www.caiso.com/informed/Pages/ManagingOversupply.aspx

Year MWh MT kg H2 MT CO2  Solar and wind curtailed by year 2015 187,722 3,754 19,992  Production only assume: 50 kWh/kg H 2 2016 308,421 6,168 32,846

 Thru August of 2019 alone, over 2017 401,493 8,030 42,757 76,000 Metric Tons of CO2 could have been recycled! 2018 461,054 9,221 49,100 2019 714,445 14,289 76,085 Waste-to-Energy: Biogas Sources of CO2

End Uses: Heat, fuel, chemical feedstock Re-electrification via fuel cells Solar Energy Meets SoCalGas’ or gas-fired power plants Rule 30 gas Wind Energy quality standard NG Storage Other Low-Carbon (...__]Network HHV R30: 970-1150 CO R30: 3% max e - Heat 2 H R30: 0.1% Biogas Sources O Renewable 2 2 Trigger* Wastewater Electrolysis CH 4 *SoCalGas doe not Fermentation have a shut-off Landfill H Water limit, but this level Energy Crops 2 BIOMETHANATION triggers additional Manure REACTOR study/testing.

Biogas Supply CO2 + 4H2 → CH4 + 2H2O CO2 (~40%) CH (~60%) 4 Nutrient Supply Renewable Hydrogen Production Step 1: Using renewable electricity to split water into hydrogen and oxygen in an electrolyzer ½” dia. H2 tube at 400 psig

Rules of Thumb

• MW-scale: 50 – 55 kWh make 1 kg of H2 1 MW electrolyzer, ~400 kg /day - • e 2H2O + e 2H2 + O2 + Heat • 1 kg H2 ~1 gallon of gasoline (gge) Electrolyzer – Electricity Grid Support _44 - PJM RegD Command ! 42 - Electrolyzer AC Power -~ 40 38 Q.~ u 36

Source: Harrison K., Mann M., Terlip D., and Peters M., NREL/FS-5600-54658 Biomethanation – RNG Production from CO2

Step 2: Using the renewable H2 (from Step 1) and CO2 in a downstream biomethanation process to produce renewable methane and water

Biocatalyst 4H2 + CO2 CH4 + 2H2O + Heat

Benefits of Biomethanation

• Recycles CO2 …. As well as the CH4 o Ethanol, dairies, wastewater, breweries, fossil • Meets (SoCalGas’) pipeline quality standards

o 998 BTU/CF, 0.89% CO2, 0.4% H2 • Scale-able, non-toxic, self-replicating biocatalyst, • Low temperature (65°C) systems Rule of Thumb: 10MWe of electrolysis feeding a bioreactor can produce ~500 scfm (12,000 Nm3 or 440 MMBTU per day/6 g/L-hr) of methane

and recycles ~20 tons of CO2 per day H2 & RNG Systems at NREL

Electrolyzer System H2 and RNG R&D Site  Today, 250 kW PEM stack #1) 350 and 700 bar pre-cooled H2 dispensing system  5 kg H2 / hr #2) Diaphragm and piston compressors  30 bar H2 Pressure #3) 700 L bioreactor – operates at 18 bar (260 psig)  Up to 70 bar max and 60 - 65oC with agitation, recirculation loop and  (4) Power Supplies cell recycle  Current-sharing mode #4) 200, 400 & 900 bar storage - 350 kg Total

 4000 Adc at 250 Vdc

#3 #1 #2 #4 Varying Input Gas Flows

7  Step-up and step-down response 6

5 shown J 4 i  Bioreactor can load follow like an Carbon Dioxide 3 electrolyzer 2 Gas Flow Rate (kg/hr)Gas Flow Rate

Hydrogen  1 Challenge: Low density gas, like H2,

0 is difficult to monitor 2:52:48 PM 3:07:12 PM 3:21:36 PM 3:36:00 PM 3:50:24 PM Time 7  Goal: Maintain > 98% methane 6 production under varying input 5 A1•--~ gas flows 4 Carbon Dioxide 3 ~ .__. fttJ.8'1 ••• , f 7 2  Trace CO2, H2 and H2S remaining 2 1 Cd f Hydrogen  Maintain H:C Ratio L ■ C a•n-

Gas Flow Rate (kg/hr) GasFlowRate 0 3:47:31 PM 3:54:43 PM 4:01:55 PM 4:09:07 PM 4:16:19 PM 4:23:31 PM 4:30:43 PM  Ideally 4:1 H2 to CO2 / Time \ SoCalGas – 700L Bioreactor Start-up After 24 hours of total 100 operation conversion reached 92% 90 Increased Agitation  During this start- 80 up phase the Started new biocatalyst grew 70 to 10x the initial Day at lower population agitation 60 Increased  Agitation reached Agitation 50% of maximum 50 RPM  Flow rates 20% of 40 rated Percentage (%) Percentage Low Agitation Methane 0.6 kg/hr H2  Reactor pressure 4 30 bar during this 3.0 kg/hr CO2 CO2 time 20  18 bar (260 psig) max. 10 Day 1 Day 2 Day 4 0 Day 3 0 5 10 15 20 25 Hours of Operation Increasing Pressure to Improve Conversion Conversion reached -0-% Conversion 100 -0-Methane 98% 90 CO2 Conversion = % CH4 80 % CH4 + %CO2

70 Increased Increased Pressure to 7 Bar Increased 60 Pressure to 6 Bar Agitation Operational State 50 ,_____,A~-...... 50% r ,  Start pressure 5 bar 40  Returned to low

Percentage (%) (%) Percentage 30 agitation rate 20  0.6 kg/hr H2 10  3.0 kg/hr CO2 0 28 30 32 34 36 38 40 Hours of Operation Biocatalyst – Methanogenic Archaea

Growth Requirements Long Term Stability

• Capable of daily startup • Seawater environment • “Load” following • Salts and minerals • Robust • 60 ‒ 65oC Electrochaea’s proprietary • Self-replicating • Anaerobic conditions biocatalyst is a selectively • Fast recovery during • Feedgas: CO and H evolved – not genetically 2 2 start/stop cycles modified – strain of methanogenic archaea, a Methanothermobacter thermautotrophicus single-celled microorganism that has populated Earth for 98.6% of carbon goes into methane Efficient billions of years

Productive VVD* of 800, H2 mass-transfer limited http://www.electrochaea.com/ Quick return to methane production within technology/ Responsive seconds/minutes Selective 100% methane, no intermediates Tolerant to oxygen, H S, CO, Sulfate, Ammonia, Robust 2 particulates Simple Moderate temperature range (60 ‒ 65°C) ectrochaea Challenge – Reducing the Cost of H2

4.5 r;:== 4.20 R&D Advances ■ Other Costs u4· _0•, .::.:: - ·...... - ,41'). ■ Feedistoc:k Costs ·~ 3,5, 1Q ■ F11xed O&M t; 3.0 t--,2.77 ■ Capita I Costs 't:I= 2.s 3.46 0.e t: 1.05 mtit) 2' ,,0 --' 1p I., "D> 1.S~ ::c 1.16 -----. 1.56 1.0 c.., 0.58 ,v, u1g o.s 0.0 Ca!P•acirty Factor '97% 40% 40% Cost ,of E 1ectriicity 1------+---:--~-~-:--~""."'."""1 ¢6. 6/kWh ¢2/kWh I ¢1/kWh ¢2/kWh I 1¢1/lkWh Capita1I Cost Steam $400/kW $400/kW $ 100/kW Effi de ncy ( LHV) ·66% 66% 60% !Methane Reforming Upcoming Projects

 DOE Bioenergy Technology Office, SoCalGas and Electrochaea  Biopower: Upgrade biogas to pipeline quality RNG  Design and build a scaled-down mobile bioreactor CURB SIDE VIEW  Analytical development

 SoCalGas, Bioenergy and Fuel Cell Technology Offices  H2@Scale: Systems integration and optimization  IP development  Gas mixing and mass transfer Biomethanation – Bulk Energy Storage and…

• Recycles CO2 in addition to the CH4 • Sector Coupling – Electrons-to-Molecules

• Biogas and pure CO2 are potential sources • Uses the existing NG network (2.5 Million miles) • Produces a “Drop-in” replacement for fossil NG • Heat and oxygen are (also) produced in this two-step process • Enables higher penetrations of solar- and wind- generated electricity Meets SoCalGas’ Rule 30 gas quality standard

Higher Heating Value: R30: 970-1150 • Shifts, in time and space, the BTU/CF Carbon Dioxide: 3% max. production of renewable electricity Hydrogen: R30 - 0.1% Trigger for more testing and study, SoCalGas does not have a shut off limit set. Partners

U.S . DEP.AIRTMENT OF

Southern Electroc a California ENERGY Gas Company Energy Eff ciency & ). Renewable Ener,gy A ~ Sempra Energy utility" Bioenergy

H2 & Fuel Cells Solar Energy Doris Hafenbradl, CTO Mich Hein, CEO Ron Kent Pictures taken on August 13, 2019 at NREL’s 3rd Partnership Forum during the SoCalGas bioreactor dedication ceremony Contact Information

Kevin Harrison Senior Engineer National Renewable Energy Laboratory (303) 815-3721 [email protected]

Nancy Dowe Senior Scientist - Microbiology National Renewable Energy Laboratory (720) 227-2009 [email protected] System Comparison B1i0Cat Project 'o I

P2G - BioCat P2G - SoCalGas Location Copenhagen, DK NREL - Golden, CO Volume 3,500 L 700 L Electrolyzer 1 MW – Alkaline 125 kW - PEM

Production 30.4 scfm CH4 4.1 scfm CH4

CO2 Source AvedØre WWTP Delivered Pressure 9 bar 18 bar

“The core of our power-to-gas system is a selectively evolved microorganism – a methanogenic archaea – that excels through unprecedented catalytic ability and industrial robustness.” Tronsform;ng EN RGY

MsoCalGas http://www.electrochaea.com/about/ A ~ Sempra nergy utilitl 1) Electrolyzer'. n 2) Pre-Processing 3) BioCat Reactor 4) Post-Processing Scrent1fic Approach •i Utilize excess el.ectricity production for the electrolys·si of water to Hi2 and 02

•i Opfmized strain of methanogenic archaea to performi 1 trt ty methanation under industrial conditionsi ----=---=--==-- ., 98% Carbon efficiency of CO2 to CH4 • Post-processing for pipel"ne quaUty natural gas Cubon Dk»dde IHI r s gnificanc a d I pact Bioca alysl •i Potential long term storage stra egy via conversi,oni

of e ect icitv & CO 2 to CH 4 •i High efficiency CO2 capture and conversion strategyi •i Demonstrated route to renewable methanei NRELTransformingE RGY ~- MsoCalGas Electrocha a B_oCatProject A�' mpra nt>rgy tJIIDty !J A IOLOOIC I. CAUi, 1 lN RE1l II 9