Danish Transport Minister Hans Christian Schmidt tabled a bill to widen a container terminal in Copenhagen's northern harbour, which would in effect block the construction of four planned flagship wind turbines.
A parliamentary debate has been scheduled for next week (22 March).
"The national strategy on promoting renewable energy is not comprehensive," said Copenhagen's mayor, Bo Asmus Kjeldgaard. "On the one hand the government keeps talking about CO2 reduction and the building of wind farms. On the other hand they boycott concrete actions."
Copenhagen had planned to slash its carbon emissions to 20% of 2005 levels by 2015 through a move to renewable energy sources.
But objections about the windmills' alleged unsightliness were raised by wealthy residents in nearby Gentofte region, supported by vice-mayor and MP Eyvind Vesselbo.
In August 2009, the city council passed the Copenhagen Climate Plan, which includes 50 specific initiatives to reduce carbon emissions, 34 of which were launched in 2010.
Greenhouse gas reductions were to be made by renovating public buildings, commissioning zero-carbon new city structures, encouraging electric vehicles, promoting bikes and improving public transport and, crucially, the utilisation of wind power.
Standing at 150 metres high, the Northern Harbour wind turbines were each slated to produce 3 MW of electricity. The Northern Harbour itself would have become the initiative's showcase, providing renewable electricity for the area's 40,000 inhabitants and beyond.
At present, Copenhagen has seven onshore wind turbines with fourteen more due to come online by 2013. But the plan would have created an additional 130 wind turbines by 2025, generating 360 MW of energy, on land and at sea.
"If we are not going to be able to build the windmills in the harbour, it will be difficult to find new locations, since the possibilities are restrained," Kim Pind, a spokesperson for Copenhagen Energy, the city-owned company responsible for building the turbines, told EurActiv.
Other green measures planned by Copenhagen City Council include increasing the share of electric, hydrogen or hybrid cars owned by the city to 85% in 2015, through tax incentives.
The city has already acquired 33 electric cars, and around 100 to 150 private electric vehicles are on Copenhagen's roads.
But this alone will provide little more than green window-dressing.
"I don't think the city of Copenhagen will be able to achieve the aims of CO2 reduction in the transport sector if they are not allowed to use tolls and other taxes," Martin Lidegaard, chair of environmental think-tank Concito, told EurActiv.
"The present government is not supporting any strong commitments in the transport sector."
To meet the zero-carbon goal, Copenhagen "has to move very quickly," he argued, namely by reducing emissions and building more wind capacity.
"The more you take energy efficiency into account, the cheaper and realistic the reaching of the goal will be."
The Danish wind turbine industry is the world's largest and wind power already provides Denmark with 18.9% of its electricity production and 21.4% of its generation capacity.
With its green initiative, Copenhagen had aimed to pioneer still further by transforming the capital into what Lord Mayor Frank Jensen called "a lab for green urban development".
For now though, grey clouds of political doubt hang over the Northern Harbour which environmentalists hope wind power will light up.