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military/geo-political implications which are further discussed in the following subchapter.
Generally, even if n possible failure paths are considered a n+1 attack pathway is likely to
exist.
b)
Military utilization of space
Space was always and first of all of military interest and only partially started to become
also commercially interesting. Outer space offers high capabilities for military operations
and high threat potentials against other nations. As ‘area of responsibility’ space is
identified as a ‘resource’ which is highly vulnerable for civil applications in space due to
animus foreign actors but offers also high potentials for military operations like the
implementation of new military measures for protection, military deterrence, ‘information
superiority’ and ‘military superiority’ in and through outer space. The ‘Quadrennial
Defense Review 2001’ of the U.S. Department of Defense depicts the importance of space
for the U.S. military: “Technological advances creates the potential that competitions will
develop in space and cyber space. Space and information operations has become the
backbone of networked, highly distributed commercial civilian and military capabilities.
This opens up the possibility that space control – the exploitation of space and the denial
of the use of space to adversaries – will become a key objective in future military
competition.”[TAB 2003a, p 26]
Some 170 military satellites operate in earth orbits. Numerous nations see in the potential
growth of military operations and systems in outer space an increasing risk for the
international stability. The majority of the UN members warn of an ‘arms race in outer
space’.
Space is a geo-politically sensitive subject. The United States of America clearly classified
space as a national top priority. ‘Space superiority’ is seen as an important U.S. target as
well as a key aspect for the transformation of the U.S. military forces. U.S. interests
include the full integration of aerospace capabilities into the U.S. military to maintain
‘space/information superiority’. As also described in the ‘Transformation Study Report –
Executive Summary, prepared for the U.S. Secretary of Defense, Washington D.C., April
2001: “Space capabilities are inherently global, unaffected by territorial boundaries or
jurisdictional limitations; they provide direct access to all regions and, with our advanced
technologies, give us a highly asymmetrical advantage over any potential adversary.”[TAB
2003a, p 41].
In general, any large-scale space developments may evolve in two opposite pathways.
The development of e.g. frequent and cheap access to space could 'civilize' outer space by
allowing for many commercial applications, thus providing a higher transparency on space
activities and creating economically powerful groups with an interest in preventing peace
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in space. On the other hand, the realization of a SPS scenario would require the
improvement of existing technologies and the development of new technologies
particularly for launching (‘Space Support
20
’), space system installations in orbit (including
systems for SPS maintenance such as micro-robotic satellites), new satellite concepts and
microwave technology. These technological improvements would also offer direct and
indirect options for an increase of military weapon forces. For policy and military new
options for actions would be given.
The following potential capabilities of SPS systems need further consideration:
– jamming of civil and military communication [ICNIRP 1997]
– “detonation of electro-explosive devices (detonators)” ([ICNIRP 1997], p 515)
– “induction of fires and explosions resulting from ignition of flammable materials by
sparks caused by induced fields, contact currents, or spark discharges” ([ICNIRP
1997], p 515)
– environmental warfare by means of weather conditioning [ICNIRP 1997]
– development of launch infrastructure for military purposes
– service robots or micro-satellites developed for SPS operation and maintenance could
be modified for military use
– use of SPS infrastructure as basis for military facilities and operations or ‘force
multiplier’ such as for communication or navigation for military purposes.
– development of microwave/laser technology for military purpose.
Since a blockade of the ‘Conference on Disarmament’ and the ‘Ad-hoc-committee’ for the
‘Prevention of an Arms Race in Outer Space’ in the mid 1990ies, no instrument for an
arms control in space does exist today. Space-based solar power systems require a multi-
national alliance for research, development and operation. The alliance has to be
embedded in a strong legal framework which is transparent and also internationally
accepted by third-party states.
Some of the recent and ongoing work towards a proposed new international treaty
banning weapons in space are described in the following:
20
‘Space Support’ defined in the ‘Strategic Master Plan for FY ’02 and Beyond – Executive Summary’, Air Force Space
Command, 2000: capability and capacities for launching and positioning of hardware in space orbits as well as
operation of space vehicles for military purposes. [TAB 2003a, pp. 38]
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Continuing efforts over the past few years to achieve a new, unanimous, world-wide
agreement banning the use of weapons in space centre on the draft document Prevention
of an Arms Race in Outer Space (PAROS). A major starting point for this work was the
presentation to the U.N. Conference on Disarmament in Geneva, on June 27, 2002, by
representatives of the governments of Russia and China, of draft documents intended to
lead to a new treaty.
These efforts both to reinforce the existing ban on space-based weapons of mass
destruction and to form a new treaty, led by China and Russia and supported by a great
number of countries, are described in [www.china-un.ch/eng/30622.html]. Recent steps
include the adoption of resolution A/RES/58/36 by the U.N. General Assembly on
December 8, 2003: "Prevention of an Arms Race in Outer Space" [Text at: http://ods-dds-
ny.un.org/doc/UNDOC/GEN/N03/455/07/PDF/N0345507.pdf?OpenElement].
A more recent activity was a meeting on June 3, 2004, at which representatives of 18
countries supported the PAROS initiative. An interim goal of the ongoing activity is
apparently to formally re-establish an ad-hoc Committee on PAROS in the U.N.
Conference on Disarmament.
The subject of PAROS is due to be discussed again at the next session of the U.N.
Conference on Disarmament from July 26 through September 10, 2004.
Supporting activities by the Canadian government in February 2004 are described in
[www.cndyorks.gn.apc.org/yspace/articles/canada8.htm]. A notable point in the Canadian
position is expressed as: "...putting weapons into space that could blast apart satellites
will only make it more difficult for countries who want to use space for commercial
purposes...".
Thus, the very limited scale of space-based commercial activities today makes
weaponisation of space easier, due to lack of economically motivated opposition. Having
large-scale business operations in space would create strong interest groups against
weaponisation. Both China and Russia hope to reap economic benefits from their large
investments in space technology development, and thus might have also economic
reasons for initiating the PAROS activity.
10.3 Comparison of system characteristics
Table 10-7 gives a brief overview over some system characteristics.
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PV
SOT
SPS
Economic risk
per single plant:
150 GW non-base load
500 GW base load
very low
0.0007
3
– 10
4
million EUR
–
medium
–
0.67
1
- 0.73
2
bEUR
very high
15.2
5
bEUR
33.3
6
bEUR
System vulnerability
very low
(medium with large-scale
storage and for large
scale area installations
like in North Africa)
low
(medium with
large-scale storage)
high
Single power loss
very low
(< 1 MW
e
)
medium
(£ 153 MW
e
)
high
(£ 10 GW
e
)
Technical hurdles
solar-grade silicon
none
launch
(space
transport)
, power
transmission to earth
Development stage
operational / market
phase in
operational / MW
scale demonstrators
research / laboratory-
scale demonstrators
Hurdles to
economic viability
medium
medium
high - very high
(above all launch costs)
Social acceptance
risks
very low
(medium for large-scale
greenfield installations
and in North Africa)
low - very low
(medium for large-scale
installations in non-aride
areas and in North Africa)
high
Military risks
very low
very low
undecided
(potential to 'civilize'
outer space as well as
potential to facilitate
military utilization of
space)
1
Data for 220 MW
e
SOT with pumped hydrogen storage (@ 1,000 GW
e
installed capacity
2
Data for 220 MW
e
SOT with hydrogen storage (@ 700 GW
e
installed capacity)
3
Data for 1 kW
p
PV system with pumped hydro storage (@ 2.2 GW
p
installed capacity)
4
Data for 1 MW
p
PV system with hydrogen storage (@ 588 GW
p
installed capacity)
5
Data for 10 GW
e
SPS system (@ 50 installed SPS systems = 500 GW)
6
Data for 5 GW
e
SPS system (@ 30 installed SPS systems installed capacity = 150 GW)
Table 10-7: Risk matrix
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11 S
TUDY CONCLUSIONS
Terrestrial and space-based solar power supply systems are fundamentally different in a
number of ways. They are to a considerable extent independent, due to geographical
separation, and therefore largely not subject to the same risks. System unit sizes are
significantly smaller with SOT compared to SPS and even more smaller with PV. Moreover,
whereas terrestrial solar energy is most economical for supplying power at relatively low
(PV) to medium/high load-factors (SOT), space-based solar power is better suited to
supplying continuous power and power at high load-factors. As the respective
technologies of the two systems improved, terrestrial solar power would become
economical at higher load factors, and space-based power would become competitive at
lower load factors.
In the following chapters the prerequisites and results of the study are summarized in a
comprehensive form and discussed in a broader context. Finally, future fields of research
are presented.
Data basis
The scenario calculations aim to provide specific energy costs for the comparison of
various terrestrial and space-based technologies. However, due to the different
technological maturity, data certainty varies to some extend:
– Space-based solar power system (SPS) calculations are predominantly based on NASA
Freshlook Study [NASA 1997]. The three key elements for the space system are
launch, photovoltaic system and power transmission. Neither of these elements have
ever been built on an industrial scale. Due to very vulnerable availability of launch
cost data the launch is considered as a parameter. For the energy payback – different
from the Fresh Look study's assumptions – the Koelle's Neptune space vehicle concept
was taken into account.
– Solar thermal (SOT) assumptions are based on 20 years of experience in operation and
successive progresses in research. This experience is analyzed in various recent studies
which are used for the preparation of this report.
– Photovoltaic (PV) calculations are based on almost 40 years of research experience.
Learning curves are based on more than 20 years of industrial experience. Basic data
are taken from various state-of-the-art publications combined with expert knowledge
of the consortium members.
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An error analysis was not in the scope of this study. Thus, a sensitivity analysis remains to
validate the resilience of study results.
Power demand
Considering the potential electricity demand of EU-30 in 2030, 150 GW is the probable
maximum supply share which might be gained by the power generation means discussed
in this report for both base load and non-base load power supply schemes. A 500 GW
base load scenario was considered in order to gain knowledge about cost degression and
to give room for potential energy demands in energy sectors apart from direct
consumption of electricity. Further energy demand could e.g. stem from the need of a
sustainable transportation fuel, such as hydrogen produced via electrolysis.
Terrestrial scenarios
Solar thermal power plants are selected for base load scenarios due to highest load
factors. All SOT plants can be sited in the ‘European sunbelt’ zone 1 apart from the largest
base load scenario for 500 GW continuous power supply. There, 100 to 200 GW of SOT
plants are installed in zone 0 ‘North Africa’ depending on the storage technology applied.
The 100 to 200 GW could have also been supply from decentralized PV installations in
Europe. However, for scenario design and cost optimization reasons, the North African
sites with a higher solar irradiation were chosen to complement the required power
generation capacities.
PV plants – selected for non-base load scenarios – demonstrate the potential of cost
reductions by up-scaling of production volumes. Furthermore, abundant potentials exist
for their installation on roofs, facades, and other areas which are not under competition
with alternative ways of area utilization.
For both scenario types the cost of storage make up a significant share of the overall
costs. These cost results are based on isolated scenario considerations, i.e. not combining
electricity produced by PV/SOT plants with other supply technologies such as wind,
biomass, geothermal or hydropower. A mix of various renewable energies would allow
the use of each technology’s advantages. Therefore, the calculated costs, especially for
PV, are worst-case cost considerations. Costs would be reduced by the cost share of the
storage with other technologies if integrated into a more complex (and more realistic)
energy supply chain.
Space based scenarios
Up to a scenario size of 50 GW, rectennae may be sited in the European sunbelt ('zone
1'). With scenario sizes of 100 GW and above the potential of land area for rectennae'
siting in zone 1 is exceeded. Thus, rectennae also have to be sited in zone 2 ‘Rest of
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Europe’. Potential off-shore installations are discussed but were not selected for the
scenarios.
For SPS systems no operation and maintenance costs could be considered because data
were not available. Also not included is the decommissioning of the space installed
plants. These expenses would have to be added to the levelized electricity cost calculation
(LEC) stated in this report. The influence of the electricity storage is marginal for the SPS
scenarios as only considerably small storage capacities are required to cover the energy
mismatch during the eclipse seasons.
For the largest SPS scenario of 500 GW around 6.7 million tons of payload must be
transported into orbit. The Koelle space transportation vehicle with a projected capability
to transport 350 tons of payload to LEO per flight was assumed for the calculation of
launch costs and transportation related energy efforts. For comparison the US space
shuttle has a transport capacity of 20 tons, the European Ariane 5 can transport up to 5
tons of payload to GEO. Considering the 500 GW base load scenario, carrying 350 tons
per flight would require 19,000 flights over an assumed time horizon of at least 25 years
(provided that transport capacities and launching pads are constructed fast enough). Even
with the 5 GW-scenario about 175 flights are required with Koelle's space vehicle (some
1,000 flights with the US Space Shuttle and 12,200 flights with the European Ariane 5
respectively).
Electricity storage
Various means of energy storage are examined in this study. Two types of energy storage
were selected for scenario calculation – pumped hydro storage and hydrogen production
with subsequent re-electrification.
On one hand, concepts with hydrogen storage are less efficient and more expensive than
concepts with pumped hydro storage if hydrogen re-electrification is considered only. On
the other hand hydrogen storage shows several advantages against pumped hydro
storage. It offers great potentials for cost reductions as well as further strategic synergies.
Pumped hydro storage strongly depends on geographic conditions and requires
considerable land areas for storage lakes. If only centralized pumped hydro storage plants
were applicable due to geographic limitations, additional high voltage DC (HVDC) lines
would be required.
On the other hand, hydrogen can be stored flexible due to the high modularity of
hydrogen storage vessels. On-site energy storage via hydrogen reduces the need of HVDC
lines. Off-shore rectennae may use surplus electricity to generate on-site hydrogen. In
grid-connected applications, the re-electrification of hydrogen on a 'power-only' basis is
usually not economically viable.
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For stationary applications, such as household, commerce and industry, hydrogen is most
efficiently utilized by means of combined heat and power (CHP) production. Yet, CHP was
not in the scope of the study as only costs were assessed and no heat credits.
Hydrogen as transportation fuel could be another potential market. The hydrogen storage
could be used for electricity/CHP production and transportation purposes at the same
time. This would improve the utilization of hydrogen storage and thus improve the overall
economic of a hydrogen storage system.
Comparison of base load / non-base load scenarios
Under the given scenario conditions, terrestrial solar power plants are most economic
with pumped hydro storage at sites where this is available.
The cost of space transportation is excluded in SPS cost calculations due to the high
uncertainty of future space transportation costs. The cost of space transportation is kept
parametric for a separate launch cost reduction analysis. No dump credit was attributed
with excess power in any scenario.
SPS systems for base load scenarios cannot compete with the combination of terrestrial
solar power plants which comprise pumped hydro storage under the assumption scenario
as listed in chapter 7.1. Yet, space systems eventually may be competitive to SOT plants
with hydrogen storage for power levels larger than 50 GW.
Non-base load SPS systems may be competitive to SOT plants for power levels equal or
larger than 100 GW (independent from the type of terrestrial storage facilities applied).
Details on the resulting target launch costs of initially cost competitive SPS scenario are
presented in the following subchapter.
Levelized energy costs (LEC) for SPS systems with rectennae installations in North Africa
are lower compared to systems with off-shore rectennae siting; but more expensive than
for SPS systems with rectennae installed on-shore in Europe.
Launch
Launch (i.e. space transportation) is the principal and most critical cost issue for SPS
systems. The required learning curve targets are calculated for SPS launching in order to
become competitive with terrestrial scenarios. Figure 11-1 and Figure 11-2 show the
results for base load and non-base load scenarios.
Launch fuel costs which base on natural gas as primary energy source will not follow the
learning curve for SPS launching but are forecast to increase until 2030. Thus, targeted
launch learning curves for launch costs do not include fuel costs. Fuel costs are calculated
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with 64 EUR/kg
payload
based on a tripling of natural gas prices until 2030. However, this
increase in energy costs is not included in the calculation of terrestrial and space based
hardware costs. Today’s launch costs are assumed with 10,000 EUR/kg
payload
at current
transport mass capacities of 100 tons per year. This represents the lower end of the
current range of space transportation costs of 10 - 20,000 EUR/kg
payload
. The learning
curves base on the assumed learning effect of cost reduction for payload transportation of
20% with each doubling of mass capacity. This learning curve was agreed by the various
parties involved and is not based on historical experience. An analysis on the viability of
the assumed learning parameter values was not in the scope of the study, yet is critical to
the overall viability of SPS scenarios discussed therein. However a change to new launch
technology would shift to a different learning curve.
10
100
1000
10000
10
100
1000
10000
100000
1000000
Cumulative launch [t]
Target specific launch cost without propellant
[EUR/kgpayload
500 GW
100 GW
50 GW
5 GW
Comp. With SOT-Hydro:
500 GW
100 GW
50 GW
10 GW
5 GW
Comp. With SOT-H2:
Not
competitive
Not
competitive
Today
Figure 11-1: Calculated target learning curves for the launch cost (without
propellant) in order to become cost competitive with the terrestrial base load
scenarios based on pumped hydro storage and hydrogen storage respectively
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