WESM 101: What is the Wholesale Electricity Spot Market?

Learn more about the role of the WESM in our daily lives with our educational series: WESM 101!

The Wholesale Electricity Spot Market (WESM) is a centralized venue for fair and competitive large-scale electricity trading where the price is based on the interaction of supply and demand. In our WESM 101, we aim to illustrate the electricity delivery process by likening it to the distribution of water to homes, with DUs and RES handling the logistics, bringing the water to the Philippine customers. Mabuhay Energy, as a participant in the WESM, plays a key role in providing competitively-priced electricity to contestable end-users in the Philippines through RCOA.

The WESM offers several features and functions.

Gross Pool

Liken the WESM to a pool of water where the market operator monitors the production of water into the tub (power plants), the amount of water that is being given to the participants like RES and DUs, and what price it is sold at, and more!

Locational Marginal Price

Marginal price is computed at each location to reflect transmission loss and/or congestion.

Net Settlement

Bilateral contract quantities transacted in the pool are settled outside the market. A bilateral contract quantity is the quantity in
Megawatt-hour (MWh) of energy sold by one Trading Participant to another through a bilateral contract that is declared in the WESM.

Mandatory Market

To engage in the market, electricity buyers and sellers must register with WESM.
Grid-connected entities such as electric cooperatives and DUs must also register to inject or withdraw power.

Sources: IEMOP.PH, Philippine Electricity Market Corporation