SINTEF Energy Research Emerging technologies for decarbonization of natural gas Dr. ing. Ola Maurstad

SINTEF Energy Research Outline of the presentation Emerging technologies Natural gas based power cycles with CO 2 capture Hydrogen production from natural gas Two energy chain calculations Gas to electricity Gas to hydrogen/transport

SINTEF Energy Research Decarbonization of natural gas: CO 2 capture and storage (CCS) CO 2 is a natural product of combustion of fossil fuels CCS is a strategy for reduction of greenhouse gas emissions CO 2 is captured at its source (power or hydrogen plant) Several storage options are being investigated depleted oil and gas reservoars geological structures etc Enhanced oil recovery (EOR) where CO 2 is used as pressure support This could give the CO 2 a sales value => would help market introduction of CCS technologies

SINTEF Energy Research The Sleipner project in the North sea (Norway) is the worlds first commercial-scale CO 2 capture and storage project (started 1996) 1 million tonnes are stored yearly in the Utsira formation 800 m below the sea bed Statoil: Storage capacity for all CO 2 emissions from European power stations for 600 years The project triggered by the Norwegian offshore CO 2 tax

SINTEF Energy Research Natural gas fired power plants with CO 2 capture Several concepts have been proposed Two concepts based on commercially available technology Post-combustion exhaust gas cleaning (amine absorption) Pre-combustion removal of CO 2 No plants have been built Could be built in 3-6 years from time of decision Cost of electricity increases with ~ 100 %

SINTEF Energy Research 1: Post-combustion principle 2: Pre-combustion principle 3: Oxy-fuel principle Principles of power plants with CO 2 capture

SINTEF Energy Research 65 SOFC+CO 2 capture Efficiency potential incl. CO 2 compression (2%-points) Year Time until commercial plant in operation given massive efforts from t= Combined Cycle Post-combustion amin-absorption Pre-combustion, NG reforming Chemical Looping Combustion AZEP Oxy-fuel Combined Cycle

SINTEF Energy Research Example: Oxyfuel power cycle Fuel Pressurized oxygen To storage Water Water separator HRSG Compressor Turbine Heat Recycle Steam cycle Combustor 83% CO 2 15% H 2 O 1.8 % O 2 96% CO 2 2% H 2 O 2.1 % O 2

SINTEF Energy Research Natural gas reforming (NGR) Cheapest production method for large scale hydrogen production NGR is a commercially available technology Gas separation systems are also commercially available However, no NGR with CO 2 capture and storage exist Cost estimate for hydrogen production: Without CO 2 capture: 5.6 USD/GJ With CO 2 capture: 7 USD/GJ

SINTEF Energy Research Simplified process description, steam methane reforming (SMR) Reforming reaction (endothermic) : C m H n + mH 2 O = (m+½ n)H 2 + mCO Water gas shift reaction (slightly exothermic): CO + H 2 O = H 2 + CO 2

SINTEF Energy Research Hydrogen liquefaction Why liquefy hydrogen? LH 2 is suitable for transport to filling stations because of the high energy density: 2.36 kWh (LHV) per liter Petrol: 9.1 kWh (LHV) per liter Mature technology but improvements expected Theoretical minimum work required to liquefy 1 kg of hydrogen: 14.2 MJ Best large plants in the US require 36 MJ/kg H 2 Linde cycle

SINTEF Energy Research Ortho-Para conversion The two forms of dihydrogen: diatomic molecule Equilibrium composition depending on temperature Room temperature: normal hydrogen (25 % para, 75 % ortho) Liquid hydrogen temperature: nearly 100 % para Necessity to convert from ortho to para in the cycle Heat released by conversion at 20,4 K: Q conv = 525 J/g Latent heat: Q vap = 450 J/g Without conversion from ortho to para => In 24 h 18 % of the liquid will evoparate even in a perfect insulated tank (spontaneous, exothermic reaction from ortho to para)

SINTEF Energy Research Modified 2002 Toyota Prius: Hydrogen combustion engine + electric motor

SINTEF Energy Research The energy chains – Two examples 1.Gas fired power plant with CO 2 capture Energy product: 1 kWh electricity delivered to the grid 2.Large scale hydrogen production from natural gas with CO 2 capture – liquefaction of H 2 for transport to filling stations Energy product: 1 kWh liquid hydrogen (LHV) Energy product: 1 km of car transport

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Assumptions used for the energy chain analyses Power plant with CO 2 capture: 50 % (LHV) efficiency, 85 % capture of formed CO 2 Power plant without CO 2 capture: 58 % (LHV) efficiency Hydrogen production with CO 2 capture: 73 % (LHV) efficiency, 85 % capture of formed CO 2 Hydrogen production without CO 2 capture: 76 % (LHV) efficiency Hydrogen liquefaction 36 MJ electricity required per kg of liquid H 2

SINTEF Energy Research Hydrogen filling station Insignificant electricity consumption compared with the liquefaction process Hydrogen car Storage tank with H2 in liquid form Hydrogen consumption of 14.2* gram/ km (corresponds to a petrol consumption of 0.52 litres per 10 km) * Energy Conversion Devices claims their modified Toyota Prius can drive 44 miles per kg hydrogen (

SINTEF Energy Research Results: Power generation

SINTEF Energy Research Results: Hydrogen production (natural gas to liquid hydrogen)

SINTEF Energy Research Results: Hydrogen production (natural gas to transport product)

SINTEF Energy Research Conclusions CO 2 Capture and storage (CCS) technologies can reduce the emissions of CO 2 by % per unit electricity or H 2 In general, the capture and storage processes impose an energy penalty on efficiency of around 2-10 %-points Estimate of the added costs today (technologies closest to commercialization): - Cost of electricity: ~ 100 % increase - Cost of hydrogen: ~ 30 % increase The costs will always be higher with CO 2 capture => Markets for CCS technologies will not be developed without government policies (economic incentives)

SINTEF Energy Research Thank you for your attention!