Austria does not agree that natural gas and nuclear power would be considered green energy and that doing so could harm the credibility of the European Union. Austria is taking the European Union to court over plans to characterize natural gas and nuclear power generation as sustainable energies amid efforts to fight climate change. The Austrian government on Friday filed a lawsuit with the EU’s top court over the classification used to define clean energy resources. The EU’s executive Commission plans to add certain nuclear and gas plants next year to a list that helps investors determine which projects are sustainable.