Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Solar Energy From Space
Alex Ignatiev and Alex Freundlich
Texas Center for Superconductivity and Advanced Materials
David Criswell
Institute for Space Systems Operations
University of Houston
Energy Advancement Leadership Conference
November 17-18, 2004
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
World Electrical Energy Use
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
World Energy Demand
• Global Demand for Energy is Soaring
• Electrical Energy is the Fastest
Growing End Use Energy
• OECD* Nations use more than ½
• By 2020 Non-OECD nations will use
more than ½
* Organization for Economic Cooperation and Development
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
World Energy Needs
• Over 2 Billion people have no access to electricity
• Bring Rest of World to OECD Electrical Power Use
Levels by 2050
• ~2 kW/person
• ~10 Billion people
• Will need 20 TW of capacity
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Solution to World Energy Shortage
• Probably NOT:
Coal
Gas
Oil
• Possibly YES:
Nuclear (fission/fusion) ??
Technology status/politics
Solar
Variable supply on Earth: weather
Solar from Space: Solar Power Satellite
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Solar Power Satellite
• Peter Glaser 1969
Solar Power Satellite Design 1979 – 5 GWe
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
Solar Power Satellite Design 1979
• 60 Units Constructed in Orbit
• 5 GWe
• At GEO
• Deploy Two Per Year
• ~$ 3 x 1013
Why Not Use an Existing Satellite?
The Moon
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
The Moon as a Solar Power Satellite
• Identified First by Criswell and Waldron
• Less Mass to the Moon
• More Direct Logistics – Stand on Solid Ground
• In situ Resource Utilization
• Always Has One Face Toward Earth
• Use Relay Satellites
• Microwave Power Beam
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Spiral Development
• The Moon as a Solar Power Satellite
• How to Establish the Moon as an SPS ?
• Focus Initially on Small Scale Lunar Solar Power
System
• Accelerate Technologies to Larger Scale
• Don’t Bring EVERYTHING to the Moon
• Use the Resource there – “Live Off the Land”
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
Living off the Land – Do This in Space :
In-Situ Resource Utilization (ISRU)
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Electrical Energy on the Moon
• Utilize Lunar Resources to Fabricate Solar Cells on the Moon
• Moon’s Surface is an Ultra-High Vacuum
- ~ 10-10 Torr (day)
- Use vacuum deposition to make thin film solar cells
• Elements Required for Silicon-based Thin Film Solar Cells
are Present on the Moon
- Silicon
- Iron
- Titanium Oxide
- Calcium
- Aluminum
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Typical compositions of lunar mare regolith, anorthite,
ilmenite and pyroxene (weight %)
Apollo 15
Regolith
SiO2
TiO2
Al2O3
Cr2O3
FeO
MnO
MgO
CaO
Na2O
K2O
P2O5
S
Total
46.7
1.7
13.2
0.4
16.3
0.2
10.9
10.4
0.4
0.2
0.2
0.1
100.7
Ilmenite
(FeTiO3)
0.1
52.2
Anorthite
(CaAl2Si2O8)
44.2
35.8
0.5
44.4
0.2
1.4
0.2
99.0
0.2
19.7
0.2
100.0
Low-Calcium
pyroxene
(Ca,Mg,Fe)SiO3
52.4
0.4
1.89
1.0
16.9
23.9
2.6
99.14
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Utilization of Lunar Resources-ISRU
• Past Interest in Lunar Resource Utilization
- Extraction of Oxygen
BUT:
• Number of Chemical Processes Can Yield Silicon
from Regolith
• Number of Chemical Processes Can Yield Metals
from Regolith
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
Chemical Reduction of Regolith
• Carbothermal Reduction
• Hydrogen Reduction
• Fluorine Reduction
• Electrochemical Reduction
• etc. – Identify Best for Lunar Environment
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Fabrication of Solar Cells on the Surface of the
Moon from Lunar Regolith
• Vacuum Deposition
• Thin Film Solar Cells
• Utilize Lunar Resources
Make Solar Cells On the Moon !
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
Fabrication of Thin Film Silicon Solar Cells on the
Moon
• Needs
Top Electrode and
Anti-reflect
- Substrate
- Bottom electrode
n-Si Emitter ~
0.5 m
- p-n junction
p-Si Base ~
20 m
- Top patterned electrode
- Antireflection layer
- Interconnection of
individual cells
Substrate and Bottom
Electrode
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
Substrate
• Use Lunar Regolith
• Fine powder (<100 m)
• softens around 1300oC
• highly viscous state
• some gas evolution
• Melts around 1500oC
• surface smoothes to be very
flat
• high resistivity > 2Mohm-cm
• Excellent solar cell substrate
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
Rest of Lunar Solar Cell
top contact
n silicon
p silicon
back contact
Regolith glass
substrate
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Electrolytic Reduction of Metal Oxides
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Regolith Processing by Electrochemical Means
• Silicon Extraction (R. Keller)
•electrolysis and solidification from a hyperutectic SiAl alloy
• E-beam Evaporation of Thin Film Si in Laboratory
Vacuum Chamber
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Impurity Levels Measured in Starting Lunar-Si
and Si Films Deposited on Al Foil
Impurities
Aluminum (Al)
Impurity
levels
extracted
from
in
regolith*
Si Impurity measured by
SIMS on regolith films
lunar
deposited on 1 mil-thick
Al-foil
240 PPM
Non conclusive due to
(substrate)
Calcium (Ca)
175 PPM
< 1 PPM
Lithium (Li)
31 PPM
< 1 PPM
Copper (Cu)
20 PPM
< 1 PPM
Iron (Fe)
18 PPM
< 1 PPM
(*) As measured by R. Keller from EMC Consultants.
Vacuum Purification of Silicon
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Silicon Solar Cells on the Moon
• Extract Si and Metals
• Bring dopants
• Fabricate Thin Film Si Cells on Regolith Glass
• Microcystalline Cells
• Low efficiency ~5 - 8%
• Make many cells
Initially Take the Raw Materials to the Moon
BOOTSTRAP Follow-on Si Cell Fabrication
Need a Deposition/Fabrication Tool
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Fabrication of Solar Cells on the Surface of the
Moon from Lunar Regolith
• Mechanized Solar Cell Growth Facility – Cell Paver
- ~ 150 - 200 kg
- Evaporation energy from solar thermal collectors
- PV panels for motive/control power
- Continuous lay-out of cells on lunar
surface
- Remotely controlled
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Fabrication of Solar Cells on the Surface of the Moon
from Lunar Regolith
• Solar Thermal Evaporation/Melting of Semiconductor and Metals
-
Solar Concentrators with Fiber Optics Connections
-
Line Evaporators
- ~ 10-100 m/hr evaporation rate  ~1 m/hr linear rate
- ~ 30-300 m2 in 1 lunar day
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Parabolic Concentrators in Conjunction with Fiber Optics
Energy for:
• Melting of Regolith into Glass
• Evaporation of Silicon and Metals
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
Solar Thermal Lunar Regolith Melting
Power required to melt
lunar glass substrate
is 50-70 W/cm2
FIBER OPTIC
LINEAR BUNDLE
ITERMEDIATE
PLATE
RADIATION
SHIELDS (Ta)
REGOLITH
GLASS
15-20 cm
1 cm
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Solar Thermal Line Evaporator
Ta, W, Mo, BN
Crucible
Material to be
evaporated
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
Lunar Solar Cell Interconnection
- Stair-step interconnection
- Serial connections for ~ 100V
- Cell groups fabricated for ~ 5 A
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Fabrication of Solar Cells on the Surface of the
Moon from Lunar Resources
• 1 m2/hr (prototype facility)
• Fabricate ~ 65W/hr @ 5% and AM0 (~1400 W/m2)
• Assume 35% uptime (~3060 hrs/yr)
• Fabricate ~200kW/yr capacity
• Require ~ 100kg of raw materials (Si)/yr
• Continuous Cell Replacement – ‘Self Replicating’ System
- Assume limited cell lifetime
. Radiation damage
. Particle damage
Make More Solar Cells
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Regolith Materials Extraction for Production of Solar
Cells on the Surface of the Moon
• Regolith Processing Facility: Si and Metals Extractor
- ~ 150 kg
- Regolith scoop
- Solar thermal and electric heat (connect to solar cell field)
- Recycle electrolyte
- Transfer oxygen
- Feed solar Cell Paver(s)
. ~ 10 kg reactor  ~150kg/yr @ 500W
. Small Support Rover to feed Cell Pavers
- Possible secondary purification required
. Vacuum purify
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Production of Solar Cells on the Surface of the Moon
• Ultra-high Vacuum on Lunar Surface Allows for Direct Thin
Film Solar Cell Production on the Moon
- Less Mass (cost) to the Moon – 1 MW @ 1/10 Cost
- Lunar Resources Utilized for Cell Production
- Trade-off Cell Efficiency with Quantity
• Industrial Scale Power Generation and Power Grid on the Moon
. 10 Rovers  from 2 to 4 MW/year
. 100 Rovers  Up to 40 MW/year
. 1,000 Larger Scale Rovers  Up to 2 GW/year
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Lunar Solar Cell Cost Projection
Power
item
540 kW
Scenarios
1,800 kW
10,000 kW
10,000,000 kW
Development cost ($/kg)
$100,000,000
$100,000,000
$180,000,000
$20,000,000,000
Transportation cost ($/kg)
$57,000,000
$57,000,000
$114,000,000
$2,100,000,000
Operations cost
$12,000,000
$40,000,000
$80,000,000
$800,000,000
$169,000,000
$197,000,000
$374,000,000
$22,900,000,000
14,904,000
49,680,000
276,000,000
276,000,000,000
$11.34
$3.96
$1.35
$0.08
$312
$109
$27.6
$2.29
Total cost
Total power kW-hr
Unit cost $/kW-hr
Unit cost $/W
May be Cost-Effective for Large Production
NAFCOM
$0.50
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
The Moon as an SSPS
Microwave Power Beaming from Moon
• Beaming Stations at Lim of Moon
• Always ‘see’ Earth
• HTS transmission grid on Moon
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
Collaborators/Contributors:
Dr. Charles Horton
Dr. Donald Sadoway
Dr. Laurent Sibille
Dr. Peter Curreri
Dr. Mike Duke
Dr. Sanders Rosenberg
Dr. Darby Makel
Mr. Jerry Sanders
Mr. Scott Baird
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Additional Need on the Moon: Energy Storage
• Utilize “Water” or Hydrogen at the Poles
a.) Electrolyze Water During “Day”
• Hydrogen/Oxygen
b.) Extract Hydrogen and use Oxygen from Regolith
Processing
• Thin Film Solid Oxide Fuel Cells Operation During “Night”
• High efficiency ~ 60+%
• Low mass
• ~ 20 W/cm3
• ~ 4 kW/kg
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM
Texas Center for Superconductivity and Advanced Materials
University of Houston
NASA Research Partnership Center
TcSAM