2.2.2 Other scenarios: Shell and Greenpeace
In 1995, Shell International Petroleum published two energy-supply scenarios ('Sustained Growth' and 'Dematerialisation'), which contained similar elements to the WEC scenarios. In 2001, however, Shell published two further long-term scenarios: 'Dynamics as Usual' and 'Spirit of the Coming Age' (Shell International, 2001). The former envisages 'an evolutionary progression from coal to oil to gas to renewables (and possibly nuclear)…', whereas the latter is more radical, charting the rise of a new technological system based on hydrogen, aided by developments in fuel cells and sequestration of carbon dioxide. This system, widely known as the hydrogen economy, is described in Section 4.3. Shell's analysis of the global market shares of different fuels in these two scenarios is shown in Figure 10, tracking trends from 1850 through into the future.
Although superficially rather different, the scenarios shown in Figure 10 display several similarities, including a gradual decline in fossil fuels in the 21st century, and a global market share for all renewables of about one-third by 2050. Interestingly, the two earlier Shell scenarios (1995) both predicted a much higher market share (around 50%) for all renewables by 2050, demonstrating how marked changes in forecasts can occur on a relatively short timescale. Another indication of the frailty of forecasts was ironically also provided by Shell, which reduced its own estimates of the company's oil reserves on four separate occasions in 2004, by over 20% overall. Time will tell whether these re-evaluations heralded a hastening of fossil fuel depletion.
One organisation, Greenpeace, spurred by warning signs that conventional energy resources may be unsustainable, commissioned a study by the Stockholm Environment Institute in the early 1990s that proved to be even more optimistic than the preceding examples (Lazarus et al., 1993). With similar assumptions on population increases and economic growth (to allow comparison with other scenarios), the Greenpeace scenario develops to a situation free from fossil fuels by 2100, dominated by solar and wind power (around 75%), with supplementary contributions from biomass, hydropower and geothermal sources. Nuclear power is phased out rapidly (by 2010), whereas the fossil fuels decline gradually through the century. This scenario requires improvements in energy efficiency that actually reduce global demand around 2030, before it rises again towards the end of the century, and hydrogen is used as a transport fuel and to store energy from intermittent sources such as wind.
In all these 'scenario-based' forecasts, as well as the tendency for the 'unthinkable' to happen (as it commonly does — Figure 7), it is important to temper such predictions by bearing in mind the difficulties with adopting alternative energy resources. Achieving the modelled percentage shares of primary energy supply begins at a very low base level, and demands sustained high rates of growth in the alternatives sector; indeed, growth rates that far surpass any that have characterised global economic history during the last century.