Act 28/2014, dated 27 November [PDF] (Spanish version) establishes that, as from 1 January 2015, customers who use electricity for the purposes set out below may be entitled to an 85% reduction of the tax base for the Electricity Tax:

• Chemical reduction and electrolytic processes.
• Mineralogical processes. 'Mineralogical processes' shall mean the processes classified in Division 23 of Regulation (EC) No 1893/2006 of the European Parliament and of the Council of 20 December 2006 establishing the statistical classification of economic activities NACE Revision 2 and amending Council Regulation (EEC) No 3037/90 as well as certain EC Regulations on specific statistical domains.
• Metallurgic processes. 'Metallurgical processes' shall mean the processes relating to metal production and its preparation, as well as the production of forged, pressed, embossed and stretched pieces, laminated rings and mineral powder products, treatment of surfaces and heat treatment casting, coking, priming, stress-relieving or other heat treatments.
• Industrial activities when electricity consumption accounts for more than 50% of the cost of a product.
  'Cost of a product' shall mean the addition of total purchases of goods and services plus personnel costs plus the consumption of fixed capital. This cost is calculated per unit on average.
  'Cost of electricity' shall mean the actual purchase value of electricity or the cost of production of electricity if it is generated in the business, including all taxes except deductible VAT.
• Agricultural irrigation.
• Industrial activities when purchases or consumption of electricity accounts for at least 5% of production value. For these purposes:
  • Purchases or consumption of electricity shall mean: the actual cost of electricity acquired or consumed, including all taxes except deductible VAT.
  • Production value: it shall be comprised of the net revenues, plus the change in stocks, partly-finished and finished goods.
    'Cost of a product' shall mean the addition of total purchases of goods and services plus personnel costs plus the consumption of fixed capital. This cost is calculated per unit on average.
    'Cost of electricity' shall mean the actual purchase value of electricity or the cost of production of electricity if it is generated in the business.

It also establishes that the following shall be exempt:

• Electricity supplied in the context of diplomatic or consular relations.
• Electricity supplied to international organisations recognised as such in Spain, and by members of such organisations, within the limits and under the conditions laid down by the international conventions establishing such organisations or by headquarters agreements.
• Electricity supplied to the armed forces of any State party to the North Atlantic Treaty, other than Spain, for civilian staff accompanying them or for supplying their messes or canteens.
• Electricity supplied in the context of an agreement concluded with non-member countries or international organisations, provided that such an agreement is allowed or authorised with regard to exemption from VAT.
• Electricity consumed by the owners of electricity production facilities covered by the specific remuneration scheme in accordance with sectoral legislation.
• Supplied electricity that has been generated by fuel cells.
• Electricity consumed at electricity production, transport and distribution facilities for the sole purpose of such activities.

The Act 1074/2014, dated 19th December 2014 [PDF] (Spanish version) and Order HAP/2489/2014, dated 29 December 2014 [PDF] (Spanish version) provide that beneficiaries of the reductions and exemptions set out in Act 28/2014 must ask to be included in the territorial registry of the State Tax Administration Agency's Special Taxes Management Office corresponding to the place where their establishment operates, or at the Department of Special Taxes of the competent District Council if their establishment is located in the Basque Country or the Provincial Government of Navarre State Treasury or District Councils.

Once you have completed all the procedures, the corresponding tax authority will provide you with a Registration Card which, for each facility, shall state the CUPS, date of application, CIE (Electricity Identification Code), information identifying the owner of the facility and, when applicable, the percentage of electricity to be used in the activity receiving the tax benefit.