From Models of Doom, the Sussex critique of the Limits to Growth:
Real challenges will no doubt arise if world energy consumption continues to grow in the long-term at the current rate, but limited reserves of non-renewable energy resources are unlikely to represent a serious threat on reasonable assumptions about the ultimate size of the reserves and technical progress. …
It is not unreasonable to expect that within 30 years a breakthrough with fusion power will provide virtually inexhaustible cheap energy supplies, but should this breakthrough take considerably longer, pessimism would still be unjustified. There are untapped reserves of non-conventional hydrocarbons which will become economic after further technical development and if prices of conventional fossil fuels continue to rise.
At AAAS in 2005, a fusion researcher pointed out that 1950s predictions of working fusion 50 years out had expired … with fusion prospects still 50 years out.
Expert: “I’m 100 Percent Confident” Fusion Power Will Be Practical
Companies chasing after the elusive technology hope to build reactors by 2030.
Is fusion finally just around the corner? I wouldn’t count on it. Even if we do get a breakthrough in 10 to 15 years, or tomorrow, it’s still a long way from proof of concept to deployment on a scale that’s helpful for mitigating CO2 emissions and avoiding use of destructive resources like tar sands.