Presentation on theme: "Small-Scale Wind for Hydrogen Production for Rural Power Supplies: HyLink System at Totara Valley MUCER Energy Postgraduate Conference Wellington 3-5 June."— Presentation transcript:
Small-Scale Wind for Hydrogen Production for Rural Power Supplies: HyLink System at Totara Valley MUCER Energy Postgraduate Conference Wellington 3-5 June 2008 presented by Peter Sudol (Massey University)
Totara Valley Demonstration site for Massey University and Industrial Research Limited on distributed generation Aims: - design a renewable hybrid micro-power system at the end of 11 kV distribution line - provide network support
HyLink System Demonstration on hydrogen as a means of balancing and transporting the fluctuating wind power System implementation by IRL System analysis by Massey University Massey University’s 2.2 kW wind turbine incl. control system will be used in conjunction with a larger electrolyser currently being developed at IRL.
CharacteristicHyLink SystemPower Line Initial cost incl. labour NZ$55,000 - current configuration - incl. pipeline mole ploughing NZ$60,000 - NZ$100,000 - underground wiring requires a trench - overhead wiring complicated due to difficult terrain Cost of conversion devices NZ$17,000 - electrolysis setup NZ$16,000 - fuel cell system 2 x NZ$2,500 - step up and step down transformers Energy loss at conversion devices η e/conv = 60% - converter/electrolyser subsystem η pemfc/inv = 35% (electr.) - fuel cell/inverter subsystem 2 x 200 W power loss - power consumption at both transformers Lifetime50 years - MDPE gas pipeline 4,000 operational hrs - ReliOn PEM fuel cell 10,000 operational hrs - PEM electrolyser 60 years Energy StorageHydrogen pipeline/tank - easy to scale up Batteries - expensive for large-scale storage
Hylink in the IRL Laboratory Electrolysis setup Hydrogen was stored in 150m MDPE pipeline located in a container filled with sand, outside of the lab.
Alkaline Fuel Cell DCI 1200 Setup Source: IRL The electricity produced was used to charge batteries or was inverted to the grid.
Electrolyser Stack Connection hydrogen outlet water inlet positive electrical potential water and oxygen outlet negative electrical potential hydrogen pressure meter Distilled water is pumped just through the anode compartment (oxygen side) of the electrochemical cells which is not pressurised.
Lynntech Electrolyser Stack catalysed membrane metal flow field The right stainless steel endplate (+ electronics) was used for a previous application and was replaced by a titanium endplate. Source: Lynntech Industries active area of 33 cm 2
Electrolyser Stack - VI Curves At higher stack temperature there is a higher electr. current flow ( higher hydrogen production) at the same voltage due to improved reaction kinetics.
System Efficiency Estimation Electrolyser: η = 65.3% electricity (+heat)/hydrogen conversion efficiency (at a current flow of 23,5 A) - Not considered: hydrogen pressure energy output, power consumption of the 12W water pump, heat transfer with circulating water The above efficiencies were calculated using the lower heating value (LHV) of hydrogen. Hydrogen production/consumption was estimated by measuring the pressure increase/drop in the pipe. Alk. FC DCI 1200: η = 41.1% hydrogen/electricity conversion efficiency (at 650 W electrical power output) - Not considered: thermal energy output (approximately 20% combined heat and power efficiency over 60%)
Proven Wind Turbine Rated power output: 2.2 kW Zebedee furl (+ cone) system allows for dynamic balance between the rpm and the pitch of the airfoil. During stormy winds turbine doesn’t stop, instead, keeps generat. at nearly rated power. Drawing: Proven Energy Limited
Electrolyser in the Container Deionisation column Recombiner Flash arrestor Dehydration unit Water pump Electrolyser stack Circulating water reservoir Source: IRL
Hylink Transition to Totara Valley Pipeline mole ploughing (60 cm deep) Electrofusion joint between the pipeline sections MDPE Internal diameter: 16 mm Outer diameter: 21 mm Wall thickness: 2.5 mm Length: 2 km Volume: 402 L Welder for electrofusion Source: IRL
Fuel Cell Connection in the Woolshed IRL controller IRL grid-connected inverter PEM fuel cell ReliOn Independence 1000 (J48C) Pressure sensor Source: IRL The batteries power the control and data logging equipment as well as provide a necessary buffer for the fuel cell and inverter. Operating PEMFC supplies the inverter and the controller as well as charges the batteries. 48 V gel battery bank
Hydrogen Diffusion Rate Estimation The pipeline was pressurised with 4.1 barg hydrogen and then the pressure drop was recorded. Result: Hydrogen loss: 42.5 kPa/week 7.5mol/week 15 g/week 0.5 kWh/week at LHV 3 W Currently, the fuel cell operates at pipeline pressure between 1 barg and 2 barg, so at average 2.5 bar abs. Using: 1.5 W mean power loss due to H 2 diffusion through pipe walls during fuel cell operation
Hydrogen Permeability through PE - Comparison Massey University (at 20°C) : Industry (at 23°C): Totara Valley (at 10°C): General rule of thumb for Arrhenius equation: for every 10°C increase the reaction rate doubles. Or E P and P 0 can be estimated by measuring P at different T and solving:
Frictional Pressure Drop Estimation at Fuel Cell’s max. Output According to the manufacturer, the fuel cell consumes at 1 kW 15 stdL H 2 /min mean H 2 velocity is 1.24 m/s Due to the gas flow is laminar, and hence, the friction factor f independent of roughness. Then the frictional pressure drop can be calculated using the Darcy-Weisbach equation as follows: Considering that the fuel cell requires low H 2 pressure for operation, the calculated pressure drop can be neglected.
HOMER Simulation of the current HyLink System Configuration Selected Results
Data Inputs Batteries’ task is not to store energy to meet community’s load requirements. They cover the system internal electricity needs, and PV panels can be thought as the power source for that. For this reason batteries as well as PV panels were excluded from the simulation. Wind resource data was taken from the NASA website, however the four wind parameters (Weibull shape factor etc.) derive from the previous study at Massey University. The average of one of the eight monitored sites at Totara Valley was used as the primary load data. Furthermore, factual and not projected data was used e.g. for the ReliOn fuel cell the lifetime of 4,000 operational hours and not 40,000 operational hours.
HyLink System Schematics used in HOMER grid-connectedstand-alone
Providing Back-up Power for Peak Loads (May) - Grid purchase capacity constrained at 2.3 kW - max. hourly peak load throughout a year: 3.3 kW - 1 kW fuel cell
Providing Back-up Power for Peak Loads (July) - Grid purchase capacity constrained at 2.3 kW - max. hourly peak load throughout a year: 3.3 kW - 1 kW fuel cell
Providing Back-up Power for Peak Loads Due to small system configuration, esp. wind turbine/electrolyser, very dependent on the prevailing wind conditions.
Daily Pipeline Filling Process Fluctuations due to changing Wind
Scenario for HyLink with added Massey University’s 2.2 kW Wind Turbine and IRL’s 1 kW Electrolyser The previous capacity shortage on 24 th July is compensated due to improved system response.
Scenario for HyLink with added Massey University’s 2.2 kW Wind Turbine and IRL’s 1 kW Electrolyser
Outcomes Low durability and high replacement cost of electrochemical conversion devices represent the main barrier in introducing the HyLink system Small-sized system very dependent on the prevailing wind conditions – low energy buffer capability The 36%-efficient fuel cell/inverter subsystem consumes the full pipe content (3.3kWh at 3bar pressure difference) in ca. 1 hr at 1kW ac output. The wind turbine/electrolyser subsystem needs ~9hrs at its rated power (80 stdL/hr, 360 W) to provide this hydrogen content – at optimal wind conditions Hence, the fuel cell/inverter efficiency (36% electr.) constrains the overall system performance and the small wind turbine/electrolyser size slows the system’s response.
General Outcome Successful demonstration of a new energy concept – in operation since May 2008 The HyLink system reveals barriers and opportunities of hydrogen based energy systems. The HyLink system proves, that an energy carrier can be produced from a renewable resource high efficiently. The HyLink system proves that this energy carrier can be transported via cheap pipelines. The HyLink system proves that this energy carrier can be converted to electricity high efficiently (not Carnot Cycle constrained), carbon neutral and noiseless in fuel cells.
Acknowledgements Prof. Ralph Sims (Massey University) Attilio Pigneri (Massey University) Steve Broome (IRL) Edward Pilbrow and Eoin McPherson (IRL) Jim Hargreaves (Massey University), Phil Murray, Mark Carter Totara Valley residents and many others at Massey