published in Energy Research & Social Science, the authors found that energy infrastructure construction takes 40% longer than planned – on average, a delay of roughly two years.
Nuclear power plants had the highest cost overruns and delays, with average construction costs exceeding estimates by 102.5%, or $1.56 billion. Hydroelectric projects followed at 36.7%, then geothermal (20.7%), carbon capture (14.9%), and bioenergy (10.7%). Wind projects averaged a 5.2% cost increase, while hydrogen projects came in at 6.4%.
By contrast, PV plants and transmission infrastructure recorded cost underruns of 2.2% and 3.6%, respectively.
