Economic Analysis: Co-generation Using Wind and Biodiesel-Powered Generators

This study was undertaken to determine the economic feasibility of complementing electricity generated by wind with electricity generated by diesel gensets using various blends of biodiesel. An investment model was developed to estimate whether adding a genset, which increases the investment, revenue and operating costs will enhance the economic viability of generating electricity with a wind turbine. The investment model provides a tool that can be used to answer this question for sites with various wind characteristics and with alternative sources of revenue. Existing regulations and tariffs in Minnesota and other parts of the U.S. establish preferences for power generated from wind and other renewable sources. The price typically paid for wind energy in Minnesota is $.033 per KWH, but owners of wind turbines are eligible for several additional sources of revenue. The federal Production Tax Credit (PTC) of 1.9 cents per KWH is a second source. Utilizing this credit may require an investor/partner on a wind project with sufficient passive income tax liability to utilize this credit over the first ten years of the project. In addition, a Minnesota state incentive payment of 1.5 cents per kilowatt-hour is available for ten years on wind projects of 2.0 Megawatts or smaller, subject to statewide subscription levels. Production of electricity from wind may also result in the creation of tradable renewable credits or "green-tags," which may have value to utilities subject to state renewable energy standards. The variable nature of electrical power capacity from wind has been problematic for utilities, which try to meet the variable loads required by the summed demand of their customers. In addition to payments per kilowatt-hour produced by wind or other renewables, attractive capacity payments are offered by utilities when renewable sources can supply 65% "firm" power during "On-Peak" hours which are typically 9:00 a.m. through 9:00 p.m., Monday through Friday, excluding holidays for the months June through September. The key task of this project is to determine if electricity derived from wind can be economically complemented with electricity generated by diesel generators or gensets using biodiesel, another renewable fuel. Biodiesel is a fuel that can be derived from vegetable oils or animal fats and can be used neat (100%) or in various blends with petro-diesel. With the passage of the Energy Bill of 2005, the federal biodiesel tax credit has the effect of lowering the price of biodiesel blends to the price of petro-diesel through 2008. Without the biodiesel tax credit in 2009 and beyond, the cost of B55 and B75 biodiesel blends (required to qualify as renewable power) will increase substantially. Electricity produced by diesel generators or gensets is typically much more expensive than electricity produced from wind or other sources; however, the electricity produced by the combination of wind and biodiesel generators may qualify as "firm" power and be eligible for capacity payments if considered a single "qualifying facility."