Potential role of space in 21st century energy systems
- Paper number
IAC-05-C3.1.05
- Author
Dr. Leopold Summerer, European Space Agency (ESA)/ESTEC, The Netherlands
- Coauthor
Dr. Tiziana Pipoli, European Space Agency (ESA)/ESTEC, The Netherlands
- Year
2005
- Abstract
The 19 th century has brought the most dramatic change in the energy system fuelling human activities after the discovery of fire: from an almost entirely biomass burning society at its beginning to a society obtaining almost 80% of its primary energy from fossil fuel (coal) burning at its end in western economies. The 20 th century has seen two further radical changes: the introduction of two other forms of fossil fuel, oil and gas, enabling the emerging transport industry and the introduction of nuclear power, both together reducing the share of coal to less than 20% at the end of the century.
An energy system based on burning of fossil fuels with lifecycles of thousands and millions of years is inherently unsustainable. The accompanying environmental aspects ( CO 2 emissions), issues of health in agglomerations and the increasing energy import dependence on few, largely unstable supply regions indicate the need for another substantial change in our energy system for the 21 st century.
We are still in the fossil fuel age, but first signs are pointing towards its end. Space might in three respects play an important role for the new, still to be defined energy age. The present paper tries to focus on three aspects: space as an efficient tool for energy management of decentralised networks of small renewable power plants, energy systems for space as precursors for terrestrial systems and finally energy from space via space based power generation plants.
Space in the service of energy grid management
Currently, the average share of wind and solar generated electricity in IEA member countries is only 0.4%. High growth rates in some countries and fast technical evolution will continue to increase their share over-proportionally (e.g. 60% average wind generation growth in Germany between 1990 and 2001). The extrapolation of these average growth rates will lead to electricity generation shares of solar and wind plants to levels, requiring reliable generation prediction capacities. In order to avoid the necessity of additional backup generation capacity, their real-time monitoring and forecasting becomes essential. Space assets are best suited to provide such regional and global monitoring and forecasting services.
The further decentralisation of electricity generation plants, the combination of public and small-scale private generation units (e.g. households) and the ongoing European integration of regional and national electricity grids will require a more and more sophisticated management in order to achieve reliability (avoidance of propagating blackouts) and efficiency.
Space technologies can contribute to such a complex energy grid management with Earth observation and telecommunication satellites providing real time information about the power plants and grid elements status, generation capacities and consumer needs and at the same time enabling immediate data transmission and communication to and among an intelligent information network.
Space power solutions as precursor systems
Sufficient power supply and efficient power management are among the primary concerns of all space activities. The absence of hydrocarbons required power generation systems relying on the only two energy sources available for sustainable operations: solar and nuclear energy. Both have been used in space for almost 50 years. Mass constraints and raising power demands have driven the development of reliable and ever more effective photovoltaic cells for the conversion of solar radiation to electricity. Eclipse and peak power demands have enhanced the development of efficient secondary energy storage systems.
On Earth coal, oil and gas are used at the same time as energy sources and energy carriers. Fossil fuels can however not be the basis for a long-term sustainable energy system, therefore leading inevitably to the separation of energy sources and energy vectors (electricity or hydrogen). Due to the absence of fossil fuels, this separation was implemented for space systems right from the start of space activities.
Therefore, space energy systems provide valuable information and experience for future, sustainable terrestrial energy systems and should thus be considered as precursor systems.
Solar power from space
Solar power plants are among the promising long-term energy options, principally able to cover humanities ever increasing energy need in a sustainable way free of greenhouse gas emission. About 30 years after their first use in space and benefiting from research and development for space, terrestrial solar power is one of the fastest growing energy sectors with high growth rates sustained over more than a decade (especially in Europe) and very promising forecasts.
While the first photovoltaic cells for space delivered just a few mW of electric power, modern telecom satellites operate with about 20 kWe and the panels of the ISS are planned to provide around 100 kWe in its final configuration. Extrapolating this trend and adding the ever increasing array efficiency and kW/ kg ratio lead to visionary concepts for solar power satellites, producing solar-generated power to be transmitted to the Earth surface. Compared to terrestrial solar plants, the advantages of permanent illumination by the sun (limited storage needs), no weather and climate effects have to be weighted against space transportation costs, in space operations, safety aspects and conversion losses in the wireless transmission system.
All studies concluded the principal technical feasibility of the concepts and gradually improved their power to mass ratio. No substantial development efforts were undertaken however since with current technology space generated electricity costs would still be too high, upfront costs prohibitive and the launcher sector not mature enough to reduce Euro/kg to orbit costs by the required order of magnitude.
In the past space concepts were mainly compared to traditional energy systems. Based on this background, the Advanced Concepts Team (ACT) at the European Space Agency started a three-phased programme in 2003. The first phase of the programme, the Validation Phase, focused on a comparison of space solar power plant with comparable terrestrial solutions on the one hand and the assessment of the potential of SPS for space exploration and space application on the other. Based on the findings of this phase, this paper describes the next steps currently undertaken in Europe.
- Abstract document
- Manuscript document
IAC-05-C3.1.05.pdf (🔒 authorized access only).
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