INTERNATIONAL WORKSHOP ON OIL DEPLETION
Uppsala, Sweden, May 23-25, 2002
Organized by Uppsala University and ASPO, the Association for the Study of Peak Oil
Considerations on Renewable Electric Energy Systems
by Professor Mats Leijon
Div of Electricity, The Ångström Laboratory, Uppsala University, Sweden
Most renewable electric energy systems of today focus on unregulated energy production like solar and wind power. However, if we still want to use electricity when we need it and not at the will of nature, we must be able to regulate power.
The question of regulating power is of significant importance in all energy systems. Today the only renewable energy that has regulating capability is hydropower provided by river dams or pump stations, and it is used to regulate peak loads. Tomorrow it will have the additional feature of regulating sources like the wind and solar power as well as other unregulated sources. In countries with little or no access to regulating hydropower, gas turbines are used in an equal function.
Therefore it’s important to differentiate between units with peak power/regulating capability and units with only energy production/non-regulating capability since all discussion regarding unregulated renewable energy production will only be theoretical if we neglect the peak power problems.
The other consideration is from a democratic and thereby an economical point of view. In the Nordic grid, electricity prices have been rather low compared to other parts of the world. During the last few years, spot prices have varied between 0.5 cents/kWh to 2.5 cents/kWh. In the search for renewable alternatives, it can easily be argued that sources with low energy production per install power rating always need subsidies to be economically feasible. Is this, at least in the long run, the best way to use taxpayers’ money? Most would think not.
Therefore, the technological development of unregulated renewable sources cannot be driven by political decisions alone. In the long run, it also has to be run by economic drivers. By looking at the utilization factor for different renewable sources, it can, from a purely economic point of view, be concluded that several of the ones that are discussed today, stance a small chance to be successful without subsidies. However, there are several yet undeveloped sources of power like geothermal, sea-based wind (offshore), ocean wave energy, underwater currents and possibly other sources that have a large energy production potential per installed power rating and thereby also satisfying the boundary conditions of future sustainable complement in the electric energy production.