Common mistakes suppliers make when buying renewable energy

There is increasing pressure on companies to decarbonise their Scope 3. Sustainability standards are focusing on supply chains as a source of greenhouse gas emissions, while companies are becoming aware of the enormous potential to curb CO₂ output beyond their own operations.

For suppliers, this might come in the form of requirements from their clients to purchase renewable energy, with a range of criteria to fulfil. But how can suppliers ensure that they source renewable electricity correctly and, most importantly, in a way that is efficient and cost-effective for them?

In this article, we have compiled our recommendations for companies that source Energy Attribute Certificates (EACs) to cover their clients’ Scope 3 emissions, to help you make the most of the transition to renewables.

Megawatt-hours (MWh) or kilowatt-hours (kWh): get your units right

This may seem obvious, but mixing up units is a very common mistake. When you obtain the electricity consumption data you need to cover, make sure it is in MWh, rather than kWh. One MWh is equal to 1,000 kWh. Failing to make the correct conversion might result in vastly under-procuring—which could lead to missed targets or requirements—or over-procuring, which can prove costly.

Energy Attribute Certificates (EACs) represent one MWh of renewable electricity. There are multiple active EAC systems worldwide. However, most of them, including national systems, use MWh as their unit of measurement.

Be clear on the consumption year

A year isn’t always a year. At least not in terms of the energy reporting calendar.

Consider your own financial year and that of your clients. If, for instance, the company you supply to closes its fiscal year each March, it might allow you to cover consumption for the first quarter of the calendar year with certificates from the previous year. This kind of flexibility may also result in more cost-effective sourcing opportunities.

Additionally, some countries may have annual reporting schedules for renewable energy consumption that do not match the calendar year. In Great Britain, for example, the reporting calendar is tied to the national Fuel Mix Disclosure, which runs from 1 April to 31 March. In Japan, some certificates issued in one year may still be valid for consumption until June of the following year, with different purchasing and reporting deadlines for different EAC systems.

To understand the rules and reporting dates in different countries, make sure to consult with an advisor. Ecohz offers complete guidance and can get the best EAC mix for your company in all your locations.

Round up to make sure you cover 100%

When buying EACs, it is better to buy slightly too many than slightly too few, so always round up. Sometimes, procurement teams will omit decimals from their electricity consumption figures. This often happens when converting kWh to MWh, which, as we mentioned, is a common hurdle. So, for example, if your consumption is 1 300 kWh, it is better to purchase 2 MWh.

Falling short in your purchasing can cause you and your clients to miss targets. When submitting documentation to sustainability standards such as CDP, entities that leave a gap may receive lower scores, while insufficient coverage can also cause problems with auditors reviewing renewable energy use claims.

Additionally, since most companies that fail to procure enough EACs only notice the shortfall very close to reporting deadlines, buying the missing certificates can be much more expensive than it would have been otherwise.

Cover your entire consumption, not just a fraction for a single client

It is, of course, not a mistake to buy renewable energy exclusively to cover the share of consumption that corresponds to one of your clients. However, there is a solid case for sourcing a larger volume of EACs and even covering the entire electricity consumption of a factory.

Firstly, assigning EACs to an individual client is not always straightforward. Calculations can be made using the share of revenue generated by that client or the percentage of units purchased. However, the necessary figures are not always available, while factories might produce multiple products, making the calculation more complicated and potentially leading to costly errors.

Additionally, purchasing EACs for a factory’s entire electricity consumption makes it much more attractive to source from. Large manufacturers in industries as diverse as automotive and consumer IT products are setting renewable energy consumption targets for their suppliers and prioritising working with companies that use renewable energy. Now more than ever, sourcing renewable electricity can be an asset in winning market share.

Buying EACs through the Ecohz Supply Chain Portal

The Ecohz Supply Chain Portal makes it easy for suppliers to purchase EACs through a series of simple steps:

• When one of your clients invites you to join their renewable energy purchasing programme, you will receive and email to log into the Portal for the first time and set up your company information. You can also use the portal without the need for an invitation to cover your own Scope 2 energy consumption.
• After setting up your profile, you can make requests for renewable energy. Just click Request to get a price quote on the EACs you need. Acceptance of any offers and delivery of the certificates (EACs) are done directly in the portal.
• Select the year you are covering with renewable energy. If most you’re your consumption occurred in 2025 then select 2025. You are also able to input your fiscal year. Our advisors will deliver the best EAC mix available, or you can contact them to get advice.
• Fill in the amount of MWh needed for a client’s share of your electricity consumption.
• Once an offer is ready, you will automatically get an email containing the validity time of the offer.
• After you click Review offer, you will be directed into the portal to see all details of the offer and simply click Accept Offer to proceed with the purchase.
• Once the offer is accepted, a contract for that individual transaction is sent to the designated signatories.

What support do suppliers get when using the Ecohz Supply Chain Portal?

Ecohz advisors guide suppliers through the entire EAC purchasing and reporting process, helping them build the necessary knowledge and capabilities.

Personalised onboarding: Ecohz runs a customised enrolment programme, including platform setup and start-up webinars.

End-to-end management: We handle the entire procurement process, from request to cancellation.

Streamlined communication: Ecohz manages all information flows and transactions directly with the client requesting you to purchase renewable energy.

Upskilling: Ecohz can educate your procurement teams on the benefits of switching to renewables and conduct webinars for suppliers presenting EACs and the functionalities of the platform.

In-house procurement: EACs and other sustainability solutions are sourced directly from our portfolio, allowing us to guarantee the integrity of the certificates.

Customised technical support: You have access to updates and new functionalities, as well as technical assistance in English and Mandarin.