Proposed Indiana (Midwest) Feed-in Tariffs 2009

By Paul Gipe


This is a brief explanation of the proposed feed-in tariffs provided to the Indiana Renewable Energy Association and Representative Matt Pierce.

The tariffs suggested are applicable throughout the Midwest and not solely to Indiana.

The tariffs, or prices paid for renewable generation per kilowatt-hour, are based on my professional judgment of current best practice worldwide and best practice specifically in North America.

In large part the tariffs are based on those implemented October 1, 2009 in Ontario, Canada. The Ontario Power Authority derived a system of tariffs for renewable energy following the most rigorous and, equally as important, the most transparent price-setting process yet conducted in North America. The Ontario tariffs were converted to US dollars.

Because of lucrative federal subsidies in the US, there are two tariff tracks: one without federal subsidies, and one with the subsidies.



Two Tracks (with & without Federal Tax Credits)

There are two tracks because not every potential generator can fully use the federal tax credits. If the program is to be equitable, that is, if the program is to provide equal opportunity to all Indiana citizens, it must not be limited to only those with substantial federal taxes. Thus, even those who do not have substantial federal tax liability can take advantage of the program by using the tariffs.

While it would be technically more correct to run a full financial model taking into account the discounted effects of the federal subsidies, this was determined to be unnecessary. Instead, the proposed Indiana tariffs derived from Ontario’s current rates were simply reduced 30 percent, representing the equivalent benefit of the federal tax credits.


Wind Energy

Wind energy is a special case and was treated separately and in much more detail. There are four classes of wind energy tariffs: two tariff classes for small wind turbines, an offshore class, and a tariff class for onshore, commercial-scale wind turbines.


Small Turbines

Tariffs for small wind turbines are divided by the area swept by the wind turbine’s rotor. This measure allows inclusion of both conventional horizontal-axis wind turbines as well as novel vertical-axis wind turbines.

The smallest class is representative of household-size wind turbines. These are currently more expensive and less productive than commercial-scale turbines and, consequently, the tariff needed is much greater. The tariff proposed for household-size wind turbines is comparable to that in several European countries and to that proposed in Great Britain.

The second small turbine class is for wind turbines considered suitable for small businesses. With the federal tax credit, the tariff proposed is similar to that proposed by Indianapolis Power & Light in its filing with the Indiana Utility Regulatory Commission (IURC) for wind turbines less than 100 kW in capacity.


Commercial-Scale Turbines Onshore

The price necessary for profitable operation of commercial-scale wind turbines is highly dependent upon the wind resource and the resulting productivity of the wind turbine. To spread economic opportunity to a greater percentage of Hoosier farmers, rural landowners, and small businesses it is necessary to offer a range of tariffs to reflect the different wind resources available.

When a single wind energy tariff is used for commercial-scale wind turbines, some generators will be overpaid and others underpaid. Both to avoid overpayment at windier sites and to enable profitable wind development at less windy sites it’s necessary to calculate a range of tariffs.

There are two techniques currently in use to accomplish this task: the German system, and the French system. Both systems use a trial period of five to ten years. All turbines are paid the same price during the trial period. After the trial period, the tariff payment changes, reflecting the site’s productivity. The German system (it is also used in Switzerland) is more unwieldy than the French system and less adaptable to North America.

The French system bases the post-trial tariff on a measure of the wind turbine’s productivity.

The proposed Indiana tariffs are similar to those proposed in Ontario by the Ontario Sustainable Energy Association. They have been specifically adapted to the North American wind resource and costs.


The proposed Indiana tariffs are derived from the Profitability Index Method developed by Bernard Chabot for the French equivalent of the National Renewable Energy Laboratory.

This method incorporates average installed costs, annual expenses, inflation, the cost of capital, and so on. Most importantly, this method enables simple recalculation of the tariff needed as the wind resource and turbine productivity vary.

The two most important parameters are the installed cost relative to the area swept by the wind turbine rotor. In this case, the installed cost is approximately $2,400/kW for a 2 MW wind turbine with a 90 meter diameter rotor.

The base productivity is set at a minimum average annual specific yield of 650 kWh/m2/yr. This yield is equivalent to a wind resource of 5.5 m/s (12.3 mph) at hub height. The calculation results in a tariff of $0.14/kWh without tax credits and $0.098/kWh with the federal tax credits.

The base tariff is paid for the first five years to all turbines installed under the program. Turbines with a productivity of 650 kWh/m2/yr or less will be paid the base tariff for the full 20 years.

At the end of the first five years, the yield for each year is determined. The year with highest yield and the year with the lowest yield are discarded. The productivity of the turbine is calculated from the yield of the remaining three years.

The profitability index is limited to 0.55 at an annual yield of 1,200 kWh/m2/yr. This eliminates overpayment for development at windy sites where the wind resource is equivalent to 7.4 m/s (16.6 mph) at hub height. The calculation results in a tariff for years 6 through 20 of $0.084/kWh without tax credit, and $0.059/kWh with federal tax credits.

Note that because there are two tariffs (for years 1-5, and for years 6-20), the average or equivalent tariff is somewhat more than the second period tariff. Thus, at a site with an average yield of 1,200 kWh/m2/yr, the average or equivalent 20-year tariff is $0.104/kWh without tax credits and $0.073/kWh with federal tax credits. The latter equivalent tariff is nearly identical with that proposed by Indianapolis Power & Light to the IURC for wind turbines larger than 1 MW of $0.075/kWh.