Planning fallacy
The Sydney Opera House was expected to be completed in 1963. A scaled-down version opened in 1973, a decade later. The original cost was estimated at $7 million, but its delayed completion led to a cost of $102 million.
Sydney Harbour Tunnel
The total construction cost of the project was A$554.25 million. $A223 million of this is an interest-free loan from the NSW Government, to be repaid at the conclusion of the operating contract in August 2022 when the tunnel will be transferred to public ownership. The government has also guaranteed an Ensured Revenue Stream (ERS) to the operator, whereby it makes up the shortfall between toll collections and the guaranteed amount. As toll revenues have been below the projected amount, in 2008 for example, the government paid the operator $58.9 million, with the total amount forecast to be $A1.1 billion from 2008 to 2022. The NSW Auditor-General has also raised concerns that the tunnel's expenses may make the operating company default on the $A223 million loan, however the government remains confident in it.