In the year 2000 the UK set a target to secure 20% of electricity from renewable sources by 2020. This was met with widespread scepticism at the time. Yet the actual figure in 2020 was 43%, with 24% coming from wind energy alone. At a global level, in 2002 the IEA predicted that the total installed PV capacity in 2020 would be 20GW. In fact, the capacity was 713GW, with 126GW added in 2020 alone. Similarly woefully incorrect predictions were made about the future cost of renewable energy, the rise of electric transport and the stability of electrical systems when large proportions of renewable generation are connected.
How did these experts get things so wrong? It appears that a great many predictions are implicitly (but seldom explicitly) based on more or less linear rates of change, whereas most technological change is exponential. Once a technology gains a foothold, it’s market penetration becomes exponential, changing so fast it is generally only understood with hindsight. In the modern world, the rates of penetration are becoming faster and faster. As volume rapidly scales, costs decrease, resulting in a virtuous feedback loop, further accelerating the rates of change. Wind energy, and solar PV in particular, are but a very recent manifestations of this trend.
Key learning objectives:
Explain the extent to which predictions and reality have differed for the deployment of renewable energy
Contrast linear and exponential models of technical change
Explain when renewable energy will be cost competitive with other forms of electricity generation
Describe the space requirements for renewable energies