In recent years, many companies in Thailand have begun installing renewable energy systems, particularly solar power, to control rising electricity costs and increase their corporate renewable energy share. However, as corporate environmental targets become stricter—especially under Market-based Scope 2 reduction goals—many organizations find that on-site solar generation falls short of their ultimate targets. This raises a frequently asked question:

"If we already have a solar system installed, do we still need to buy RECs? And can they be used together?"

The answer is yes, they can be used together. Combining both is standard practice among medium-to-large organizations, particularly those with physical space constraints or growing energy demands. This article explains how Solar and RECs complement each other and highlights key precautions before submitting disclosures to your corporate Head Office.

What is a REC and How Does It Relate to Solar?

A Renewable Energy Certificate (REC) is an official document verifying that 1 MWh of electricity was generated from verified renewable sources. Organizations use RECs to lower Market-based Scope 2 emissions in compliance with global standards like the GHG Protocol and RE100.

If an organization self-invests and installs its own solar system, the electricity generated and consumed onsite counts directly as renewable energy without purchasing separate RECs. Self-installed solar results in key operational impacts:

1) Significant reduction in grid electricity (kWh) purchases:

For many factories, grid consumption drops by 20% to 50%, depending on system capacity and load profiles. Companies must provide operational evidence and logs explaining the decrease in grid power usage during audits.

Why Solar Alone Is Often Insufficient for Renewable Energy Goals

Although installing solar panels delivers long-term electricity bill savings, relying solely on solar energy does not always fulfill every corporate requirement due to key operational constraints:

• Insufficient roof or ground space relative to total factory power load.
• Weather and seasonal variations causing intermittent solar generation.
• Escalating annual RE target requirements set by multinational parent companies.
• Urgent mandates to reach 100% renewable energy within a short timeframe.

For these reasons, purchasing unbundled RECs bridges the annual "gap" between actual onsite solar generation and total corporate renewable targets.

What to Do When Using Solar via PPA and Wanting Additional RECs?

Many companies choose Solar Power Purchase Agreements (PPA) over direct investment. However, claiming energy attributes requires reviewing contractual terms regarding who holds the Environmental/Energy Attributes:

• If the contract assigns attributes to the electricity user:

  The company can report renewable usage by attaching the PPA contract as evidence. If formal certificates are required by auditors or corporate headquarters, the company can request to officially register and issue RECs from the system.

• If registering RECs from an investor-owned Solar PPA system:

  Negotiation with the investor is necessary because legal ownership of the power plant belongs to the investor. Official REC registration guidelines dictate that registration must be executed by the project owner or an authorized agent via a Letter of Authorization. Required documentation typically includes project specifications, proof of ownership, and potentially additional administrative fees unless pre-negotiated in the original PPA contract. Additional administrative fees apply when issuing official certificates or executing redemptions.