Industry
European businesses using renewable energy: ways to buy green power
Certificates, long-term contracts and new wind farms: three ways a company can say its power is green, and the grid behind each of them.
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Unilever made its announcement in September 2019: every factory, office, research site, data centre, warehouse and distribution centre it ran across five continents now used renewable grid electricity. The company had set itself 2020 as the deadline and beat it. Read the fine print of the Unilever statement, though, and the claim splits in two. About 38 % of that grid electricity came through power purchase agreements and green tariffs. The rest was covered by renewable electricity certificates.
Neither half is a trick. They are simply different things, and the difference is the most useful thing to understand about how European businesses use renewable energy.
Three ways to call power green
A company in Europe that wants to report renewable electricity has three main routes, and they do very different work on the grid.
The first is the certificate. In the EU it is called a guarantee of origin: an electronic record that one megawatt hour was produced from wind, sun, water or another renewable source. Producers can sell it apart from the electricity itself. A buyer that cancels enough certificates can report its consumption as renewable. The certificate does not tie a company’s consumption to the hour in which the power was produced, and it rarely changes what gets built.
The second is the green tariff, where a supplier sells a renewable product and backs it with certificates or its own plants.
The third is the corporate power purchase agreement. The buyer signs a long contract with a named wind farm or solar park at an agreed price. That certainty is often what lets the developer raise finance, so a PPA can add new capacity to the system. Of the three routes, only this one reliably puts new turbines or panels on the ground.
SAP: certificates with a label
SAP, the German enterprise-software company, has covered its data centres and offices with 100 % renewable electricity since 2014, and in January 2015 it was among the companies that joined RE100, the initiative for firms committing to fully renewable power. Over the following years it moved its purchases towards EKOenergy-labelled electricity wherever that was available, according to SAP’s own account of the partnership. The label adds sustainability criteria on top of an ordinary certificate.
For a software firm, electricity is mostly a data-centre bill, which makes SAP an early example of a pattern that has since spread: the heaviest corporate users of power in Europe are increasingly the companies that store and process data.
Amazon: the contracts that build plants
That brings the story to Amazon, the American company that has become the largest single buyer in the European market. According to Amazon, BloombergNEF ranked it the largest corporate purchaser of carbon-free energy in Europe for 2025. By Amazon’s count, published in April 2026, it had backed more than 260 projects across Europe and the UK with more than 10 GW of capacity. One example is a 110 MW agreement with RWE for Nordseecluster B, a 900 MW offshore wind farm in the German North Sea.
Here is where the grid comes in. An offshore wind farm in the German sector reaches the mainland through a long export cable, and from the coast the power has to travel south through a national transmission network that is already crowded. The company pays for the output; where the electrons end up is the business of the transmission system operator. When the lines are full, turbines are curtailed and plants further inland are ordered up to cover the shortfall. The site’s guide to grid congestion explains how that redispatch works and who pays for it.
Siemens Energy: the business of the wires
Some European businesses do not buy renewable power so much as make it possible to move. Siemens spun off its energy arm as Siemens Energy in 2020, and the new company took with it a large order book for high-voltage direct current equipment. Siemens or Siemens Energy converter stations sit at the ends of Viking Link between Britain and Denmark, Nemo Link to Belgium, ElecLink through the Channel Tunnel, and the Celtic Interconnector now under construction between Ireland and France. Hitachi Energy, the former ABB power grids business, supplied the converters for NordLink and North Sea Link, both 1,400 MW links from Norway.
Converter stations are the expensive, slow part of any HVDC link, and a handful of manufacturers supply almost all of them. Their order books, more than any sustainability report, set the pace at which offshore wind can be connected.
What limits the pledges
A certificate can be bought in Norway and cancelled in Belgium on the same afternoon. The electricity cannot make that trip unless there is a line with room on it. Between countries, that room is set by interconnector capacity and by how the market allocates it; the directory of Europe’s interconnectors shows how thin some of those connections still are, especially on the Iberian and Baltic edges.
A long-term contract has the same limit in a different form. A German factory can sign a PPA with a Spanish solar park, and the contract will settle perfectly well on paper, with the buyer paying the agreed price and the difference to the market price changing hands each month. Whether any of that solar power reaches Germany at noon depends on the Pyrenean crossings and on the lines through France, and those are among the most congested borders in western Europe. Buyers who sign such deals are, in effect, betting on the grid being built.
That gap between the paper trail and the physical flow is the fair criticism of the certificate route. It does not make SAP’s or Unilever’s claims false, but it means that a company reporting 100 % renewable power may still draw on a grid that runs on gas in the evening. Companies that care about the difference have started to talk about hourly matching, where every hour of consumption is paired with renewable output from the same hour and the same bidding zone.
Hourly matching is far harder than annual matching, because it forces a buyer to care about windless January evenings. How many European companies will sign up for it, and at what premium, is a question their next sustainability reports will start to answer.
Questions
What is a corporate power purchase agreement?
A power purchase agreement, or PPA, is a long-term contract under which a company agrees to buy electricity from a specific wind farm or solar park, usually for ten years or more, at a price set in advance. The contract gives the developer a revenue it can take to a bank, which is often what gets the project built. The power itself still travels through the public grid.
What is a guarantee of origin?
A guarantee of origin is the EU's electronic certificate proving that one megawatt hour of electricity was produced from a particular source. Producers receive them and can sell them separately from the electricity. A company that buys and cancels enough of them can report its consumption as renewable, even if the certificates come from a plant in another country that the company never contracts with directly.
Can a company in one EU country buy wind power from another?
On paper, yes: certificates move freely across borders, and cross-border PPAs exist. Physically, the electricity follows the grid, and it only reaches another country as far as interconnector capacity allows. When the links between two bidding zones are full, the power a company has contracted for elsewhere cannot flow to it, and prices on the two sides of the border separate.
Which companies build Europe's power links?
The converter stations for most of Europe's HVDC interconnectors come from a small group of manufacturers, among them Siemens Energy and Hitachi Energy, while the subsea cables are made by firms such as Prysmian, Nexans and NKT. The links themselves are owned and run by transmission system operators, sometimes together with private investors.