Stock Changes

Stocks are quantities of energy products held on the national territory that can be used to: (a) maintain service under conditions where supply and demand are variable in their timing or amount due to normal market fluctuations, or (b) supplement supply in the case of a supply disruption [IRES, Ch. V, para. 5.16, PDF p. 70, 2018]. Stocks held to manage a supply disruption may be called “strategic” or “emergency” stocks and are often held separately from stocks designed to meet normal market fluctuations, but both purposes are covered by this single definition [IRES, Ch. V, para. 5.16, PDF p. 70, 2018]. In economic statistics and national accounts, this notion corresponds to what is referred to as inventories [IRES, Ch. V, para. 5.16, footnote 43, PDF p. 70, 2018].

Stock changes are defined as the increase (stock build) or decrease (stock draw) in the quantity of stocks over the reporting period, and are thus calculated as the difference between the closing and opening stocks [IRES, Ch. V, para. 5.16, PDF pp. 70–71, 2018].

Transfers

Transfers are statistical devices to overcome practical classification and presentation issues arising from changes in the use or identity of a product. They comprise two kinds:

• Products transferred — the reclassification (renaming) of products, necessary for example when finished oil products are used as feedstock in refineries.
• Interproduct transfers — movements of fuels between product categories due to reclassification of a product that no longer meets its original specification. For example, aviation turbine fuel that has deteriorated or been spoiled may be reclassified as heating kerosene.

[IRES, Ch. V, para. 5.17, PDF p. 71, 2018]

Transfers are grouped here with stock changes because both are bookkeeping devices for reconciling reported quantities rather than physical flows across the territory boundary. Chapter VIII gives both fuller treatment as balance-construction mechanisms: stock changes feed the top block’s total energy supply formula (with a balance sign convention opposite to the definition above — a stock build is shown as a negative value) [IRES, Ch. VIII, paras 8.17–8.18, 8.22–8.23, PDF pp. 118–119, 2018], and transfers open the middle block [IRES, Ch. VIII, para. 8.26, PDF p. 119, 2018].

Related

• IRES Chapter V — Energy Flows — the chapter digest this page supports
• Production — one of the flows that stocks can be built from
• Imports and Exports — the other flows that stocks are drawn against
• Energy Balance — the balance-construction treatment of stock changes (total energy supply formula, sign convention) and transfers (middle block)