The conditions of attribute aggregation vary by country and legal/regulatory framework for the
electricity sector. Where a single multi-attribute instrument, such as a U.S. REC exists, assurance
of all relevant attribute aggregation is simplified. If separate instruments have already been created
for different attributes of power generation (e.g., carbon attributes), attribute aggregation can be
achieved by bringing these instruments together – by demonstrating ownership and retirement of all
instruments that make up a renewable electricity usage claim. Where there is not an existing
market for renewable electricity, or where electricity is not typically differentiated, attribute
aggregation may require engagement with local electricity suppliers. Companies should also take
account of the in-country policy context of the generation (existing practices, policies, and legal
frameworks that determine how electricity and renewable electricity is or can be transacted in
different markets).
Where certain attributes (e.g. GHG emissions), cannot be owned or are equivalent to zero due to
policy (e.g. the effect of a GHG cap-and-trade program on the avoided grid emissions attribute),
and where attributes are not sold off separately, a renewable electricity usage claim may
nevertheless be possible, provided that the renewable electricity purchaser owns all other
generation attributes and that the remaining owned attributes are sufficient to define use of the
resource according to market development, consumer expectation, and stakeholder feedback.
Companies should disclose any attributes that are not included in the instrument or transaction. In
addition, different standards and certifications (e.g., Green-e) may have different or additional
requirements for a “fully aggregated” instrument or group of instruments. Companies should also
abide by any local laws and regulations pertaining to claims (e.g., the U.S. Federal Trade
Commission’s “Green Guides” in the U.S.).
3 Exclusive ownership
Exclusive ownership of renewable attributes consists of legal enforceability, tracking (exclusive
issuance, trading, and retirement), and exclusive sales and delivery.
3.1 Property rights
Legally enforceable contractual instruments must include “property rights” to environmental and
renewable attributes of generation – that is, there must be a legally enforceable contract in place to
back the exchange of attributes as property rights. Legal enforceability does not necessarily require
governmental programs or legislation to create or recognize a market or energy attribute certificate,
only that the mechanism for definition and conveyance/transfer of the attributes (e.g., contract,
energy attribute certificate in a tracking system, etc.) is legally enforceable.
3.2 Tracking
Claims must be substantiated by attributes that have been reliably tracked from a generator to a
consumer. Where attributes are transacted without energy attribute certificates, the transfer of
attributes must be clearly articulated in a legally enforceable contract or series of contracts that link
the generator to the end user, and claims must be based on the permanent end-use ownership or
final use of those attributes, which also must be specified in a contract. Where energy attribute
certificates are used, the certificates must be reliably tracked. This, again, can be done using
contracts. However, the most sophisticated mechanism for tracking energy attribute certificates is
an electronic attribute “tracking system”, in which certificates are electronically serialized and
issued to generators with accounts on the system, tracked between account holders in the system
where they are traded, and ultimately permanently retired or cancelled electronically by the entity
making the claim or on behalf of an end-user making a claim. Attribute tracking systems provide
exclusive issuance, trading, and retirement of attributes to markets for renewable electricity to
support credible claims. Where tracking systems exist, transactions outside of the tracking system
are usually limited to special cases (e.g., where participation in the tracking system is too costly for
very small generation units).