Renewable Electrolysis In

System Development and 

Kevin Harrison

National Renewable Energy Laborator

2007 DOE Hydrogen Program Annual Merit 

May 15, 2007

This presentation does not contain any proprietary or confid

NREL/PR-581-41613Presented at the 2007 DOE Hydrogen Program Annual Merit Review and Peer Evaluation on May 15-18, 2007 in Arlington, Virginia.
Overview

Timeline

Project Start Date: 9/2003Project End Date: Ongoing

Budget

Total Project Funding:FY05 - $400KFY06 - $625K DOE

- $1.3M Industry cost share

FY07 - $1M DOE

Production Barriers

• G. Cost• H. System efficiency• J. Renewable integration

Pa

• Xcel Energy

• Distributed • Teledyne E• Hydrogen E• Univ. of No• Univ. of Min• Basin Elect• Ft. Collins U• DOE Wind/H
Project Objective

This project examines the issues with using renproduce hydrogen by electrolyzing water. • Characterize electrolyzer performance under power conditions and develop standard testing • Design, build and test shared power electronicontrollers to reduce cost and optimize system • Identify opportunities for system cost reductiobreakthroughs and incremental improvements integration focused on commercialization and m• Test, evaluate, model and optimize the renewsystem performance for both dedicated hydrogelectricity/hydrogen cogeneration.
Renewable Electroly

Verify DOE goals of:

Distributed electrolysis• By 2012, reduce the cost of distributed production odistributed electrolysis to $3.70/gge of H2 (delivered• By 2017, reduce the cost of distributed production odistributed electrolysis to <$3.00/gge of H2 (delivereCentral Electrolysis • By 2012, reduce the cost of central production of hyelectrolysis to $3.10/gge of H2 at plant gate ($4.80/g• By 2017, reduce the cost of central production of hyelectrolysis to <$2.00/gge of H2 at plant gate (<$3.0
Project Backgroun

Importance and Need – Projec
Project Tasks

Systems Engineering, Modeling, and Analy

Develop concept platforms, develop and va

and system models, system assessment, atools

System Integration and Component Develo

Work with industry to develop new advance

control strategies to couple renewable and systems.

Characterization Testing and Protocol Deve

Equipment installation, performance chara

standard test procedure development
Technical Accomplishm

Systems Engineering, Modeling, and Analy

Summary report of electrolytic hydrogen pDeveloped model and simulation of 10 kW 

PEM electrolyzer stack 

System Integration and Component Develo

Developed and tested second generation p

interface between 10 kW WT and electroly

Characterization Testing and Protocol Dev

Stack and system level analysis of perform
Electrolysis Analys

• Updated “Summary of Electro

Hydrogen Production” report.

• Current cost of hydrogen via ele

Other Variable CostsFixed O&M Capital Costs Electricity Costs
FY07 Technical Accompli

Systems Engineering, Modeling, an

Wind Profile

ABC

abc

Transformer

DC_CurrentDC_VoltWind SpeedVabc

pulses

Rectifier

Control

gABC

+

-

Rectifier

Vabc

ABC

abc

Measure

L 

i + -

Idc

Wind (mph) 

AB

C

 Wind Generator

• Simulated wind turbine to stack system w• Compared model and PE to explore gatdiscrepancies and enhance control algorit
FY07 Gen1 PE Test Re

0

500

1000150020002500

40 60 80 

Fr

Power (W

• Gen1 PE for 10kW WT• Battery interaction at lower frequency and state-of-charge• Big opportunity for optimization

System Integration and Component D
0

2000400060008000

100001200014000

0 5 10 15 20 25 

Calculated Wind Speed (mph)

Power (Watts)

Gen II - DC Power Available WinGen I - DC Power Hydrogen Flow Available Wind Power Curve Fit
FY07 Gen2 PE Interim Tes



0

20406080

100120

1491 1551 1611 1671 1731 1791 1851 1911 1971 2031 2091 2151 2211 2

Time (Seconds)

DC Current (Amperes)

DC Current H2 Flow 

H

System Integration and Component D

Hydrogen Production and Current as a func
FY07 Technical Accompli

Characterization

• Stack level perspective• Current control• Step and frequency response• Polarization curves f(T)

0

20406080

100120140160

0.0

20.8

41.7

66.0

86.8

1

Tim

Stack Current (Amps)

Current from external power 

supplies to stack

Hydrogen flow rate (scfm) (scfh)

012

Tim

Stack Voltage (V)Stack Current (A)

3032343638404244464850

0 20 40 60 80 100 120 140 160

Stack Current (Amp)

Stack Voltage (Volt)

Tavg = 6.8 °CTavg = 14.5 °CTavg = 24.9 °CTavg = 33.6 °C

Cathode pressure range: 179.7 – 166.2 psig
FY07 Technical Accompli

Characterization

• Single electrolyzer system-level perspective • Efficiency suffers at low current• Working with industry to improve opportunity for RE electrolysis

0

102030405060

0% 25% 50% 

% of Full Stack 

System Efficiency (%)
Xcel-NREL Wind2H2 Colla

Wind Turbine

100kW

AC-DC and 

DC-DC 

Converters

Alkaline and 

PEM 

Electrolyzers

Compressor

Storage

Benefits of the Collaboration:• Examine benefit to utility by shifting wind produ• Research optimal wind/hydrogen through syste

• Characterize and control wind turbine and H2-p• Evaluate synergies from co-production of elect

• Compare alkaline and PEM electrolyzer technol• Realize efficiency gains though a unique integr
Xcel-NREL Wind2H2 Colla

Component Integratio

• Ability to accvarying energwind and PV

• Electrolyzers of both PEM and alkaline technologies.
Xcel-NREL Wind2H2 Colla

Direct Coup

• Variable speed wind tur

coupled to the hydrogenstacks of commercially aelectrolyzers.

DC varyin

with wind 

speed 
FY07 Testing
FY07 Testing
Xcel-NREL Wind2H2 Colla

Dick Kelly (Xcel) and Dan Arvizu (NREL) shake hands after pushing button to light H2 sign and dedicate system in December 2006
Future Work 

FY08 Testing
Basin Electric

Univ. of N. Dakota

Added Value from Collab

NREL and

Xcel Energy

University 

of Minnesota

• H• V• H

• Larger Scale “Wind Storage”• Anhydrous Ammonia Production• Vehicle & Hybrid Applications

• Larger Scale “Wind Storage”• Vehicle Applications

• Timetables originally parallel• Inter-project collaboration, 

data sharing and H2 safety

• Welcome additional partners 

to the informal renewable electrolysis collaborative

• C• A• R

Hydrogen Utility 

Group (HUG)
Path Forward

• Design, built and test of PE for 100kW W• Complete standard test protocol develop

renewable-electrolyzer performance and 

• Model/simulation of renewable-electroly

FY08

• Test and validation support for DOE Ele

Hydrogen Production projects

• R&D MW-scale wind to electrolysis com

systems

• Operation of Wind2H2 Project in Grid an• Test high-pressure PEM electrolyzer

FY07

FY09

-

FY10
Summary Slide

• Economic analysis shows that re

electrolysis can meet DOE hydrotargets

• Integrate components and engine

increase efficiency and reduce corenewable electrolysis

• Multi-partner collaborative effort t

renewable electrolysis and share operational experience. (industryutilities, government)

• Work with HUG to examine how u

effectively produce and use hydro
Additional Slides

• The following slides are inclu

supplemental information.
Renewable Electrolysis - Integrated Systems Develo

FY 2004 FY 2005 FY 2006 FY 2007 FY 2008 

5 kW PEM – 5kWPV & 10kW Wind

50kW Electrolyzer & 100 WT Design Testing

500kW Elec & 1.5MW WT Design 

Construction

Characterization Testing and 

Coordination, Planning and Stakeholder Development

System Engineering and Modeling 

System Integration and Comp

Workshops

W

W Hydrogen Utility Interest Group and Renewable Elec

Dev. Current Costs 

and Performance data

Develop Energy System Assessment Tool 

(Combine H2 and Elect. Costs)

Develop Engineering Simulation Tool

5/10kW PE Interface 50kW PE Interface 

Conduct 

Site and System 

Optimal Sy

ElectrolysisUtility 

Integration 

Workshop

Sept 2004

Project Timeline

Key: Reduce cost by combining powerelectronic components, optimize systembased on hydrogen and electricity production
Distributed Electrolysis T
Central Wind Electrolysis 
• Electrolysis: Capital cost reductions and efficie

improvements are required along with the design 

electrolyzers capable of grid integration and comlow-cost, near-zero emission electricity sources.

• Capital Cost. The capital costs of electrolysis sys

prohibitive to widespread adoption of electrolysis hydrogen production. R&D is needed to develop materials with improved manufacturing capability while improving the efficiency and durability of th

• System Efficiency. New membrane, electrode, a

designs are needed to improve system efficiency Development is needed for low-cost cell stack opaddressing efficiency, compression, and durabili

Technical Barriers
Hydrogen Utility Group 

Dedicated group committed to exploring the unique perspective utilities bring to the hydrogenelectric future

Utilities: DTE Energy, Sacramento Municipal Utility District, Nebraska Public Power District, ConnexusEnergy, BC Hydro, KEPRI Nuclear Power LaborPublic Service Company, Entergy, Xcel Energy, California Edison, Fort Collins Utilities, New Yor

Southern Company, and Sempra Energy.Supporting Organizations: DOE, NREL, EPRI, N

This Project has also worked with HUG