The Member State of the supplier is the one that decides to apply rules about the moment of invoice issuance.
Member States may impose on taxable persons an obligation to issue an invoice in respect of supplies of goods or services made in their territory, other than those referred to in Article 220.
EU VAT directive 2006/112/EC, Article 221, 1).
WindEurope is based in Belgium, and Belgian authorities say the VAT for intracommunity services is chargeable only once the service has been delivered or payment has been received.
Every taxable person shall ensure that, in respect of the following, an invoice is issued, either by himself or by his customer or, in his name and on his behalf, by a third party:
(1) supplies of goods or services which he has made to another taxable person or to a non-taxable legal person;
(5) any payment on account made to him by another taxable person or non-taxable legal person before the provision of services was completed.
EU VAT directive 2006/112/EC, Article 220
The chargeable event shall occur and VAT shall become chargeable when the goods or the services are supplied.
EU VAT directive 2006/112/EC, Article 63
Where a payment is to be made on account before the goods or services are supplied, VAT shall become chargeable on receipt of the payment and on the amount received.
EU VAT directive 2006/112/EC, Article 65
WindEurope Membership is a continuous service and the chargeability of the VAT for continuous supply of services depends on the supplier’s Member State. WindEurope is based in Belgium, and Belgian authorities say that continuous services are considered as supplied at least once a year, on 31 December.
Member States may provide that, in certain cases, the continuous supply of goods or services over a period of time is to be regarded as being completed at least at intervals of one year.
EU VAT directive 2006/112/EC, Article 64, 2).
Les prestations de services pour lesquelles la taxe est due par le preneur de services en vertu de l’article 51, § 2, alinéa 1er, 1°, qui ont lieu de manière continue sur une période supérieure à une année et qui ne donnent pas lieu à des décomptes ou à des paiements durant cette période sont considérées comme effectuées à l’expiration de chaque année civile, jusqu’à ce qu’il soit mis fin à la prestation de services.
English translation: Supplies of services for which VAT is payable by the customer pursuant to Article 51, § 2, paragraph 1st, 1°, which are supplied continuously over a period of more than one year and which do not give rise to statements of account or payments during that period, shall be regarded as being completed on expiry of each calendar year until such time as the supply of services comes to an end.
BE VAT code, Article 22.