Utility Rate

I would use the latest utility rates. The metric for LEED is US dollars.

You have options relative to the rate you use. The most accurate is to contact the utility in question and model the entire rate tariff. The next best is to obtain an average cost/unit from a similar building within that utility's service territory. The other option is to find an average cost/unit that has been published in the political jurisdiction in question. In the US the Department of Energy surveys each state and regularly publishes the average cost/unit for most fuel types. I am not aware of a web site that publishes country energy cost data for Europe. Perhaps the EU publishes such data. If not perhaps the individual country does.