Power Purchase Agreements (PPA) in Mexico: how AWS, Google and Microsoft buy renewables for their data centers

Power Purchase Agreements (PPAs, long-term energy purchase contracts) are the central piece of the business model that has allowed hyperscalers (operators of data centers at massive scale such as AWS, Google, and Microsoft) to approach their carbon-neutral goals in Mexico and other markets. A PPA is not a conventional electricity purchase contract: it is a 10 to 20 year financial commitment that finances the construction of a renewable generation plant in exchange for receiving electricity at a fixed price throughout the term.

This article describes how the PPA model works in Mexico, what actors participate, why hyperscalers use it instead of buying electricity at wholesale, and what lessons a medium-sized data center can take to participate in or approach the model. The regulatory part of the Mexican framework (CRE, CENACE, SENER) is covered in another article; here we focus on the business model.

What a PPA is and why it is not a conventional electricity contract

A PPA is a bilateral contract between an electricity generator (typically a solar or wind park developer) and a buyer with consumption volume sufficient to absorb the project’s production. The buyer commits to buy a minimum volume of energy at a fixed price for 10, 15, or 20 years, and the generator uses that commitment as collateral to finance the plant’s construction with bank debt.

The difference with a conventional electricity contract is structural. In a conventional contract, the buyer pays the wholesale market tariff or the CFE (Federal Electricity Commission) tariff according to actual demand; the price varies hour by hour and can double at peaks. In a PPA, the price is fixed throughout the term, the volume is contractual (with shortfall penalties), and the market risk is assumed by the generator. This converts electricity into a predictable cost, similar to a capital quota, rather than an operational variable.

How AWS, Google, and Microsoft use it in Mexico

Hyperscalers arrived in Mexico between 2017 and 2020 with a common goal: operating their cloud regions with 100% renewable electricity in the shortest possible time. The PPA was the vehicle that allowed them to achieve it. The mechanism is the same in all cases: the hyperscaler signs a PPA with a solar or wind park developer in Mexico, commits a multi-year purchase volume, and the developer uses that commitment as underlying collateral to obtain bank financing and build the plant.

What varies between operators is the coverage strategy. Some prefer to sign virtual PPAs (financial contracts without physical delivery, where the difference between agreed price and market price is settled) to maintain operational flexibility. Others prefer physical PPAs (direct supply from a specific plant) to guarantee real additionality. The choice depends on the maturity of the local electricity market, on the availability of generation in the data center’s zone, and on the sustainability strategy that the company wants to communicate.

The aggregate numbers that the industry reports are eloquent: hyperscalers have signed PPAs for tens of gigawatts accumulated globally between 2015 and 2024, which has financed the construction of a significant part of new renewable generation in markets where they operate. In Mexico, public reports from IEA and CENACE show that corporate PPAs represent a growing fraction of new renewable capacity installed, although not all of it goes to data centers.

Why PPAs are not accessible to all data centers

PPAs were designed for consumers with large and predictable load profiles. A hyperscaler in a cloud region consumes between 100 MW and 500 MW, with a constant load profile 24/7, which allows absorbing the production of a 200 MW to 500 MW solar plant with margin for variability. A corporate data center of 5 MW to 20 MW does not have the volume to justify a bilateral PPA with a developer, and much less the financial capacity to commit to 15 years of minimum volume.

This asymmetry explains why the PPA model in data centers continues to be hyperscale territory and of a few large operators in Mexico. For medium data centers, the alternatives are: buying renewable electricity through I-REC certificates (International Renewable Energy Certificates) issued by generators in Mexico without long-term financial commitment, or participating in demand aggregators that negotiate virtual PPAs on behalf of a group of consumers. Neither of the two options finances new generation with the same multiplier effect as a direct PPA, but they bring the medium data center closer to the renewable electricity goal without the 15-year commitment.

Business model: why it works for all parties

The PPA works as a business model because each party solves a different problem. The generator solves the financing problem: without a long-term purchase commitment, a solar or wind project does not qualify for bank financing because future cash flow is uncertain. The PPA converts that future flow into predictable and allows the developer to obtain debt at 15 or 20 years with attractive rate.

The buyer solves the price problem. Instead of paying the market tariff (which in Mexico has high peaks in peak hours and dry season), they pay an agreed fixed price throughout the term. For a data center with constant load profile, that predictability is worth more than any percentage reduction: it allows budgeting electricity as a fixed cost, not a variable, which changes the financing structure of the entire data center.

The electrical system as a whole benefits because the PPA finances new capacity that otherwise would not be built. Without corporate PPAs, new renewable generation in Mexico would depend exclusively on CFE auctions and on public investment, with the deployment rate that each one determines. With corporate PPAs, there is a second financing route that complements the first.

Four risks of the PPA that should be documented before signing

Four risks are typical in any PPA, and a data center considering signing one should have them documented in its financial model.

• Counterparty risk: the park developer may default on the delivery commitment due to financial, technical, or regulatory problems. A PPA with bank performance guarantees reduces this risk; a PPA without guarantees leaves it on the buyer.
• Shadow price risk: the agreed price may end up being higher than the market price if wholesale prices drop significantly during the term. The buyer pays more for the electricity than the market equivalent in some years.
• Volume risk: if the data center consumes less than projected (improved operational efficiency, migration of workloads to cloud, closure of operations), the buyer continues paying the committed minimum volume or incurs penalties.
• Curtailment risk: in zones with high renewable penetration, the system operator may cut renewable generation at hours of high production and low demand. The data center may receive less renewable energy than agreed, while still paying the volume.

Sources

[1] IEA — Data Centres and Data Transmission Networks (energy consumption) — https://www.iea.org/energy-system/digitalisation/data-centres-and-data-transmission-networks

[2] Wikipedia — Power purchase agreement (background reference) — https://en.wikipedia.org/wiki/Power_purchase_agreement

[3] IEA — Renewables 2021 (global renewable energy trends) — https://www.iea.org/reports/renewables-2021

[4] The Green Grid — Data center efficiency industry resources — https://www.thegreengrid.org/

[5] Wikipedia — Electricity sector in Mexico (background reference) — https://en.wikipedia.org/wiki/Electricity_sector_in_Mexico