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Sep 3, 2010

Grid Interconnections

How are new power plants interconnected to ERCOT?

Texas is divided electrically among four electrical systems as illustrated below. The Electric Reliability Council of Texas (ERCOT) is the primary grid operator for 85% of the power consumed in Texas. ERCOT has an open access transmission system, meaning that any generator can connect to any transmission line after completing the ERCOT interconnection process. This applies to all types of generators whether they produce power with nuclear fuel, coal, natural gas, or wind.

To interconnect a power plant in ERCOT, the generator must first file an interconnection request with ERCOT. ERCOT produces a screening study identifying key characteristics about the proposed location of the generation facility and its potential effects on the system. The generator will consider this information and decide whether or not to move forward with the proposed facility

Once the generator decides to proceed, ERCOT will schedule a meeting with the owner of the transmission line and the prospective generator to discuss specific electrical and system implications of the proposed facility. The generator then has 180 days to put down a substantial financial deposit (based upon the size of the plant) in order to fund further studies. The transmission line owner then performs a steady state, a short circuit and a stability study on the proposed plant.

If these studies show the project to be capable of transmitting electricity into the ERCOT system, the transmission owner completes a facilities study with detailed engineering requirements necessary to interconnect the project. Finally, the generator, ERCOT, and the transmission service provider (TSP) sign an Interconnection Agreement, which requires the generator to post security for the proposed improvements required to bring the generation facility plant on-line.

The study process can take up to two years and the transmission owners have another 18 months once the interconnection agreement (IA) is signed to complete the improvements agreed to in the IA.