Mobile Hydrogen Generation Providing Lifting Gas for Aerostats


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Mobile  Hydrogen  Generation  

Providing  Lifting  Gas  for  

Aerostats  

 

Robert  Schluter  

President  

Element  1  Corp  

 

 

 

There  is  considerable  interest  in  adapting  the  benefits  of  Unmanned  Aircraft  Systems  (UAS)  and  Lighter-­‐

than-­‐air   (LTA)   platforms   proven   in   military   applications,   towards   real   world   uses   including   precision  

agriculture,  natural  resource  management,  emergency  response,  and  forest  fire  suppression.    UAS  have  

proven  to  be  an  excellent  sensor  platform  where  high  mobility  is  desired.    Alternatively,  LTA  platforms  

have   been   used   to   success   as   a   tactical   tower   when   low-­‐cost,   long-­‐endurance,   surveillance   and  

communication  is  required.    

This  white  paper  focuses  on  the  benefits  of  using  distributed  hydrogen  generation  on  a  mobile  platform  

to  deliver  lifting  gas  for  LTA  aerostats  providing  fire  detection  and  monitoring.      

Why  Aerostats?    

New   generations   of   small   aerostat   systems   are   commercially   available   from   a  

number  of  companies,  and  are  an  excellent  platform  for  sensor  packages,  which  

show  tremendous  promise  in  solving  real  world  problems.      

Mobile  towers  are  height  limited,  providing  only  short-­‐range  coverage.  Aircraft  or  

UAS  are  expensive  and  have  limited  endurance.  The  new  generation  of  aerostats  

provide   coverage   of   a   large   area,   comparable   to   aircraft   or   UAS,   but   with  

persistence  of  days  and  weeks  instead  of  hours,  at  a  fraction  of  the  cost  of  Aircraft  

or  UAS.        

Aerostat   systems   consist   of   a   small   specially   designed   tethered   blimp,   a   launch  

platform  mounted  on  a  skid  or  single  axel  trailer,  and  a  sensor  or  communications  

package.      The   launch   system   is   comprised   of   a   winch   &   powered   tether,   small  

electrical  generator,  and  lifting  gas  for  initial  fill  and  “top  off”.  Depending  on  the  

size  of  the  Aerostat  the  system  is  operated  by  a  two  or  three  person  crew.      

 

H-­‐Series  Hydrogen  Generator  



 

 

 



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The  aerostat  can  be  flown  at  several  hundred  to  several  thousand  feet  altitude,  provides  coverage  24  

hours  a  day  for  up  to  two  weeks  without  maintenance  or  downtime.  Surveillance  versions  up  to  1,000  

feet   can   cover   a   20-­‐mile   radius,   depending   upon   terrain.   An   Aerostat   with   a   communications   relay  

payload   at   4,000   feet   altitude   provides   extended   communication   coverage   up   to   60   miles   from   its  

location.    

FAA  Safety  

As   a   ground   based   system,   aerostats   do   not   require   the   complicated   flight  

clearances  needed  for  UAS  deconfliction  with  manned  aircraft.  The  FAA  requires  

tether  banners,  lights  and  a  system  to  automatically  deflate  the  aerostat  if  the  

tether  breaks.  Simple  “pop  valves”  which  activate  when  an  errant  aerostat  rises  

to  a  high  altitude  can  meet  this  requirement.      

Aerostat  Capabilities  

   


   

Capabilities  

Mission  

*  


Long-­‐Endurance  tactical  sensor  platform  from  200  to  4,000  feet  

Mission  Duration  

*  


24/7  up  to  14  days  before  a  60  minute  "top  off"  is  required  

Coverage  Area  and  

Capabilities  

*  


Variety  of  payloads:  surveillance,  communications,  NDVI  (<  20  lbs.)  

*  


Limited  by  camera  resolution  and  mission.  (1  <  10+  miles)  

*  


Communications  relay  range  limited  by  height,  terrain  (<  60  miles)  

Operating  

Restrictions  

*  


No  COA  and  minimal  FAA  restrictions  allowing  for  rapid  deployment  

*  


No  noise,  unobtrusive,  no  danger  of  falling  on  civilians  

Deployment  

Requirements  

*  


Rapidly  deployed  from  either  a  truck,  trailer  or  helicopter  in  under  4  

hours  


*  

Can  launch  and  recover  in  low  to  moderate  winds  (<25  mph)  

*  

Can  operate  in  challenging  weather  conditions  (winds  <  90  mph)  



Manpower  

*  


Very  simple  operation  with  high  reliability  

*  


Only  two  or  three  person  crews  to  launch  and  retrieve  the  Aerostat  

*  


Communications  and  sensor  operators  can  also  serve  as  launch  crew  

*  


Lower  level  of  skilled  personnel  required  than  UAS  

Acquisition  Costs  

*  


$50,000  (for  smaller  versions)  to  $250,000  (for  midsize  versions)  

*  


Total  costs  depends  on  the  payload  and  other  options  

Operating  Costs  

*  


Minimal  manpower  costs.    No  pilot  proficiency  flying  etc.  

*  


Low  operating  costs  with  lifting  gas  produced  from  mobile  hydrogen  

generator  (<$35  per  fill)  

High  Cost  of  Helium  is  Limiting  Adoption  

The  Aerostat  is  made  of  a  large  fabric  envelope  that  is  filled  with  helium  or  hydrogen,  which  are  lighter  

than  air  and  provides  the  lifting  force  together  with  the  aerostats  lifting  surfaces.    Despite  the  success  in  

military  applications,  widespread  adoption  of  LTAs  for  commercial  uses  is  limited  without  the  availability  

of  low-­‐cost  and  easily  transported  lifting  gas.  

Aerostats  and  other  LTA  platforms  have  historically  been  filled  with  Helium,  an  expensive  gas  that  is  in  

short  supply.    Helium  must  be  drilled  from  a  limited  finite  supply  in  the  earth  and  is  regulated  by  the  US  


 

 

 



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Government.      In   addition,   because   helium   is   a   compressed   gas,   it   is   stored   in   heavy   and   bulky   steel  

cylinders  making  transport  of  helium  both  difficult  and  expensive.    

Hydrogen  as  a  Lifting  Gas    

Hydrogen  is  a  plentiful,  cost  effective,  versatile,  and  safe  (see  Appendix)  alternative  to  Helium.    e1  has  

developed  a  small,  portable  hydrogen  generator  that  is  capable  of  filling  aerostats  with  hydrogen  at  a  

much  lower  cost  while  overcoming  the  logistic  challenges  of  handling  compressed  helium.    A  variation  of  

the   field-­‐transportable   hydrogen   generator   could   also   support   fuel   cell   powered   UAVs   when   they   are  

commercially  available  in  2015.  

Benefits  of  Hydrogen  

Hydrogen  is  a  plentiful,  cost  effective,  versatile,  and  safe  alternative  to  helium.      

Operating  Costs  

*  


Hydrogen  lifting  gas  can  be  produced  economically  

Easier  Logistics  

*  


Liquid  feedstock  is  hydrogen  dense  and  easily  transportable  

Greater  Lift  

*  


Hydrogen  has  12%  greater  lift  capacity  than  Helium  

Hydrogen  Generators  for  On-­‐Site  Production  of  Lifting  Gas  

e1   is   an   Oregon   Corporation   dedicated   to   developing   advanced   hydrogen  

generators  that  are  compact  in  size  and  affordable.  Our  H-­‐Series  hydrogen  

generators   combine   a   chemical   reactor   with   hydrogen   purification—the  

product  stream  is  >97%  hydrogen.  The  standard  product  covers  a  range  of  

sizes  delivering  up  to  150  standard  liters  per  minute  (5.2  ft3/m)  of  purified  

hydrogen   from   a   convenient,   safe,   biodegradable   blend   of   methanol   and  

water.  

Currently   e1   offers   a   commercial   version   of   its   patent-­‐pending   hydrogen  

generator  that  is  designed  for  telecom  equipment  cabinets.      e1  is  offering  a  

mobile  version  of  this  hydrogen  generator  to  support  aerostat  and  fuel  cell  

UAV’s.      

Benefits  of  Mobile  Hydrogen  Generator  

•  Significant  O&M  cost  savings  vs.  compressed  gas  cylinders    

•  Stand  alone  operation  

•  A  higher  degree  of  ruggedness  (especially  over-­‐road  shock  and  vibration)  

•  Simple  and  safe  manual  user  interface  

•  Improved  on/off  cycling  durability  

e1  hydrogen  generators  are  currently  undergoing  field-­‐testing  in  the  U.S.,  China,  Taiwan,  Indonesia,  and  

India,   providing   high-­‐purity   hydrogen   to   support   the   operation   of   fuel   cells   in   critical   backup   power  

applications  in  the  telecom  industry.  e1  has  also  produced  a  prototype  military-­‐specific  version  H-­‐Series  

hydrogen  generator,  the  AHG110  currently  being  tested  by  the  US  Army.  

 

 



 

 

 



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A  comparison  of  hydrogen  versus  helium  as  the  lifting  gas  is  presented  in  Table  1.  



Table  1.  

Lifting  Gas  



Hydrogen  

Helium  

Fill  Volume  

969  cubic  ft.  

969  cubic  ft.  

Payload  (min.,  sea  level,  no  wind)  

41.4  pounds  

38.4  pounds  

 

Supply  Method  



Hydrogen  Generator  

Steel  cylinders  (qty.  4)  

Volume  

1.2  cubic  ft.  (8.9  gal.)  

13.5  cubic  ft.  

Weight  


Approx.  65  pounds  

Approx.  880  pounds  

 

Cost  


Initial  fill  

$35.6  ($4.00/gal)  

$740  ($185/cylinder)  

Make-­‐up  (3%  loss  per  week)  

Approx.  $1.00  /  wk.  

Approx.  $23.00  /  wk.  

Forest  Fire  Management  

Aerostats   have   the   potential   to   provide   valuable   services   in  

wildfire   detection   and   monitoring   as   well   as   aiding  

communications   in   remote   areas   lacking   cellular   or   IP   coverage.    

Forest   fires   are   highly   complex,   non-­‐structured,   difficult  

environments  that  cause  billions  of  dollars  in  damage  to  property  

and  the  environment  every  year.  The  2014  fire  season  is  forecast  

to   be   severe   with   drought   conditions   existing   in   much   of   the  

western  United  States.  To  combat  wildfires  effectively,  their  early  

detection   and   continuous   tracking   is   vital.   Communications   plus   multispectral   imaging   are   extremely  

important  to  early  detection  and  reporting  of  wildfires,  as  well  as  managing  the  locations  of  fire-­‐fighting  

personnel  to  maximize  human  safety  and  minimize  property  loss.    

Fire  fighters  need  frequent  and  high  quality  information  updates  on  the  progress  of  fires  to  effectively  

and  safely  fight  them.  Piloted  aircraft  are  expensive  to  operate,  stressing  limited  fire  fighting  budgets.  

Fixed-­‐wing  and  rotary-­‐wing  UASs  have  limited  application  in  the  near  term  until  the  FAA  relaxes  COAs  

for  commercial  applications.  Aerostats  can  provide  significant  benefits  to  fire  fighters,  and  are  likely  to  

see  field  adoption  this  year.    

Before  the  Fire  

Forest   fire   lookout   towers   are   located   on   mountain   summits   or  

other  high  vantage  points  in  order  to  maximize  viewing  distance,  

spotting   early   stage   forest   fires.   Early   detection   is   critical   in  

retarding   the   spread   of   forest   fires   that   cause   tremendous  

damage.   The   disadvantage   of   ground-­‐based   lookout   towers   is  

they   require   constant   manpower   and   provide   incomplete  

coverage  of  the  forest.      

Unmanned   aerostats   can   be   remotely   deployed   across  

mountaintops   providing   persistent   high-­‐resolution   imagery   and   geo-­‐mapped   data   back   to   a   centrally  

manned  location.  This  saves  manpower  expense  while  effectively  extending  and  expanding  the  coverage  

of  forest  fire  ground  stations.  Modern  UAS  automated  sensor  packages  have  enough  computing  power  

for  early  detection  and  assessment  of  wildfires,  a  key  step  in  reducing  risk  to  life  and  property  loss.  



 

 

 



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During  the  Fire  

Fighting   wildfires   is   a   complex   science,   since   the   direction   and  

intensity   of   the   massive   blazes   can   change   in   minutes.  

Additionally,   spot   fires   can   ignite   behind   fire   lines   when   ambers  

carried   into   unburned   fuel   providing   additional   danger   to   fire  

crews.      

Aerostats   can   be   rapidly   deployed   as   mobile   lookout   towers  

behind   fire   lines   to   assist   in   the   management   of   fires,   gather  

information  about  changing  weather  and  fire  conditions,  and  help  

monitor  for  spot  fires  outside  of  fire  lines,  providing  real-­‐time  alerts  to  fire  crews.      

Communications  Relay  

Another  important  function  of  aerostats  is  use  as  a  voice  and  data  

communications  relay.  Firefighters  are  often  sent  out  with  tablets  

and   smartphones   so   they   can   be   updated   about   conditions.  

Internet-­‐based  tools  can  help  calculate  the  risk  of  a  fire  reaching  

homes   or   other   structures,   and   they   can   predict   how   fires   may  

move,   depending   on   the   weather   conditions.   The   aerostat   will  

provide  a  wireless  “hotspot”  where  ground  service  is  weak  or  non-­‐

existent,   often   the   case   as   wildfires   typically   occur   in   rural   areas  

where  rough  and  remote  terrain  keeps  firefighters  out  of  signal  range.      

After  the  Fire  

Even  after  a  fire  is  contained  and  controlled,  there  will  be  areas  inside  the  fire  control  line  with  active  

flames  or  smoldering  materials.  Aerostats  can  also  be  used  for  post-­‐fire  analysis  to  detect  the  presence  

of  active  fire  embers  during  mop-­‐up  activities.      

Conclusion  

Aerostats  have  great  potential  to  as  a  high-­‐altitude  platform  for  various  communications  relay  concepts,  

local   area   security   /   surveillance   and   other   missions.      It   can   provide   low   cost,   highly   mobile   platform  

with  mission  duration  of  a  week  or  more.  It  can  operate  in  weather  conditions  too  severe  for  many  UAVs  

or   aircraft,   and   does   so   without   endangering   an   aircrew.      Perhaps   the   most   compelling   argument   in  

favor  of  aerostats  is  in  detection  and  fighting  wildfires  where  persistent  surveillance  can  lead  to  early  

detection  of  fires  and,  most  importantly,  protecting  the  fire-­‐fighting  crews  who  often  work  dangerously  

close  to  a  rapidly  moving  (and  unpredictable)  inferno.  

However  the  adoption  of  aerostats  will  be  limited  due  to  the  cost  and  logistic  challenges  related  to  using  

helium  as  a  lifting  gas.      However,  with  training  and  adoption  of  standard  industry  precautions,  hydrogen  

is   a   safe,   cost-­‐effective   alternative   as   lifting   gas   for   aerostats.      Mobile,   on-­‐site   hydrogen   generators  

eliminate  the  logistical  challenges  related  to  using  bottled  gases  and  can  provide  a  low  cost  source  of  

hydrogen  that  will  enable  aerostats  to  reach  their  full  potential  in  commercial  applications.      

 


 

 

 



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Appendix  

Hydrogen  Safety

 

The  hydrogen  industry  has  an  enviable  safety  record  spanning  more  than  a  half-­‐century.    Any  fuel  can  be  



hazardous  and  needs  due  care,  but  hydrogen’s  hazards  are  different  and  generally  more  tractable  than  

those   of   hydrocarbon   fuels,   like   natural   gas,   diesel   fuel,   and   gasoline.      Unlike   natural   gas,   however,  



leaking   hydrogen   encountering   an   ignition   source   is   far   likelier   to   burn   than   explode,   even   inside   a  

building,  because  it  burns  at  concentrations  far  below  its  lower  explosive  limit.    In  the  vast  majority  of  

cases,  leaking  hydrogen  if  lit,  will  burn  and  not  explode.    And  in  the  rare  cases  where  it  might  explode,  

its  theoretical  explosive  power  per  unit  of  volume  of  gas  is  22  times  weaker  than  that  of  gasoline  vapor.  

Thus,  with  proper  handling  procedures  and  training  similar  to  many  of  these  common  fuels,  hydrogen  

can  be  safely  deployed  as  a  lifting  gas.        

Hydrogen  is  extremely  buoyant  and  diffuses  rapidly  

•  Hydrogen  released  into  an  open  environment  rapidly  disperses  up  and  away  from  its  source    

•  Hydrogen  is  14.4  times  lighter  than  air  and  thus  dissipates  quickly    (45  mph;  20  m/s)  

•  Hydrogen  rises  2  times  faster  than  helium  and  6  times  faster  than  natural  gas  

Hydrogen  is  flammable  only  under  specific  conditions  

•  Hydrogen  must  be  contained  to  become  a  fire  hazard  

•  Hydrogen  is  flammable  in  air  at  concentrations  between  4%  and  74%  

•  Optimal  combustion  condition  is  29%  H2-­‐to-­‐air  ratio  

•  Outside  of  optimal  H2-­‐to-­‐air  ratio,  combustion  profile  is  similar  to  other  fuels      

A  Fire  Requires  

•  Hydrogen  gas  leakage  

•  Confinement  of  a  hydrogen-­‐air  mixture  at  combustion  ratio  between  4%  and  74%  

•  An  ignition  source  

•  Prevention  focuses  on  avoiding  these  three  conditions    

First  Layer  of  Defense  

•  Ventilation  if  hydrogen  generator  used  indoors    

•  Inert  gas  boundary  bags  

•  Lightning  &  static  electricity  protection  

•  Electrical  distribution  safety  systems  

•  The  safest  approach  to  flammable  gas  handling  is  “keeping  it  in  the  pipe”  

Hydrogen  Safety  Resources  

•  http://h2bestpractices.org/default.asp    

•  http://www.arhab.org/pdfs/h2_safety_fsheet.pdf  

•  http://www.hydrogenandfuelcellsafety.info/resources.asp  

•  http://www.globalsecurity.org/military/world/airship-­‐hydrogen.htm      



•  http://www.rmi.org/Knowledge-­‐Center/Library/E03-­‐05_TwentyHydrogenMyths    


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