A CRITICAL REVIEW OF WIND TRANSMISSION COST ESTIMATES FROM MAJOR TRANSMISSION PLANNING EFFORTS

It is difficult to evaluate the cost of new transmission for wind energy due to the complex and data intensive process of transmission planning. The requirement for wind to be sited in high wind resource areas that are often far from load centers and the low capacity factor of individual wind farms leads to concerns that transmission for wind may have excessive costs. However, regional transmission planning groups are increasingly including wind energy in transmission plans. We analyze 17 transmission plans that include between 500 MW and 25.5 GW of new wind generation to evaluate the range of expected unit costs of transmission for wind. Based on a simplified methodology we find that transmission for wind ranges from $0.40 to 95/MWh or $8.5 to $1,940/kW. However, nearly 75 % of the scenarios studied cost less than around $20/MWh or $420/kW. We find no correlation between the unit cost of transmission and the amount of new wind analyzed in each scenario. We also find that no uniform set of methods and assumptions has emerged for evaluating the transmission requirements for wind energy