A debate within political circles in the historic town of Marburg, Germany, and its regional government in Giessen pits the environmentally conscious against the very environmentally conscious and highlights the question of where to draw the line when it comes to mandating energy efficiency.

The town council of Marburg in June passed an ordinance that would require solar panels to be installed on all new buildings as well as homes that undergo renovations or get new heating systems or roof repairs. The penalty for noncompliance is a fine of 1,000 euros or about $1,500. The rule as it stands now is set to go into effect on October 1.

The regional government has threatened to step in to nullify the ordinance, prompting a counterthreat from city officials that they would seek to get the state building code changed to protect the ordinance. The debate is not whether solar panels are energy efficient but rather whether such a policy should be forced on the population.

"It's unfortunate that they decided to compel people because I think you breed opponents that way rather than friends of solar energy," said Hermann Uchtmann, an opposition politician and chemist who himself once built a solar-powered desalinization station for the town's sister city in Tunisia. Uchtmann said the demands are too invasive for existing homes, especially those owned by senior citizens who might not live long enough to justify upfront costs. But supporters say that such an ordinance is needed in the town of 80,000 people whose population has remained relatively static and where few new homes are built.

"We have a serious energy problem with the older homes," said Marburg Deputy Mayor Franz Kahle. "Before, solar installations were the exception, and their absence was the rule. ... We want to get to the point where the opposite is the case"