By Amanda Durish Cook

CARMEL, Ind. — MISO will publish a guide describing its cost estimation process for competitive transmission projects by August, according to RTO staff.

“We’re going to really document how we create our cost estimates,” Alex Monn, MISO senior substation design engineer, said during a June 13 Planning Subcommittee meeting.

The RTO has also changed some aspects of its original cost estimation proposal based on stakeholder input.

With the emergence of competition to build transmission under FERC Order 1000, MISO had to begin providing cost estimates for competitive projects in order to protect the confidentiality of developers’ bids. The RTO wants to put a more transparent process in place before the next competitive project is opened to bidding. (See “MISO Seeks to Improve Tx Cost Estimates,” MISO Planning Subcommittee Briefs.)

MISO plans to release both a planning-level cost estimate process and a more final scoping-level one. Stakeholders will review the RTO’s procedures on an annual basis, with the first review scheduled for January 2018.

“We’re going to make this a yearly cycle,” Monn said.

Stakeholders generally agreed on MISO’s new 20% project cost contingency allotment, up from an earlier 15% allowance: “Twenty percent is where everyone landed, so that seems like a good estimate for us,” Monn said.

However, MISO will keep overhead project cost allocation at 10% of the total project cost despite some stakeholder discord.

“In talking to stakeholders, everyone had a different basket of overhead costs,” Monn said. He said MISO staff still believe 10% is the most reasonable figure.

MISO transmission design engineer Devang Joshi said the RTO has increased its planning-level cost estimate for transmission line length to the straight distance between substations plus an additional 30% of the length. Stakeholders asked for more leeway after the RTO originally proposed a straight-line length plus a 20% adder. For scoping-level cost estimates, MISO will create a “reasonable proxy route for the purposes of determining a line length.”

The RTO has also simplified terrain and grading project cost impacts into three categories apiece. Terrain types include flat lands with light vegetation, forested areas and wetlands, with each represented by cost per acre and mile instead of MISO’s originally proposed terrain multiplier. Grading types are identified as “typical” (with the land being less than 30% sloped), “rough” (30 to 50% slopes) or “mountainous” (greater than 50% slopes).

At stakeholder request, the RTO has also added a cost estimate for constructing access roads to substation construction sites, but it reduced transformer cost to a simple unit cost of the transformer instead of a “turnkey” cost that would have provided for other construction materials.