Sports economists have long-known that the economic gold mine predicted to arise from building sports stadiums never actually arises. While some specific people (namely team owners) benefit from the building of stadiums, their effects on local economies as a whole are virtually non-existent at best.
One reason for this is that government funding for sports, funding paid through taxes of some sort, crowds out spending in other industries. Another reason is that consumer spending on sports comes at the expense of spending in other industries. At best, subsidizing a sports stadium is a wash. At worse, government ports subsidies may actually lead to fewer jobs because consumer sports spending is more likely to leave a local economy.
This article in Bloomberg suggests much the same thing about government subsidizing of so-called green jobs (HT Warren Meyer):
For every new position that depends on energy price supports, at least 2.2 jobs in other industries will disappear, according to a study from King Juan Carlos University in Madrid.
U.S. President Barack Obama’s 2010 budget proposal contains about $20 billion in tax incentives for clean-energy programs. In Spain, where wind turbines provided 11 percent of power demand last year, generators earn rates as much as 11 times more for renewable energy compared with burning fossil fuels.
The true cost of anything is its opportunity cost. In terms of jobs, the study suggests that each subsidized "green" job costs 2.2 jobs in other industries. In terms of the Keynesian economics, the jobs multiplier of renewable energy, at least in Spain, is -1.2. There may be other reasons to pursue "green" energy sources, but I am skeptical that job creation is one of them.