Is Article 56(1)(a) of Council Directive 2006/112/EC to be interpreted as meaning that an allowance under Article 3(a) of Directive 2003/87/EC of the European Parliament and of the Council of 13 October 2003 establishing a scheme for greenhouse gas emission allowance trading within the Community and amending Council Directive 96/61/EC which confers a right to emit one tonne of carbon dioxide equivalent during a specified period is a ‘similar right' within the meaning of that provision?