Evanston signed the U.S. Mayors Climate Protection Agreement in 2006, joining hundreds of other American cities that have pledged to “meet or beat” the Kyoto Protocol by reducing greenhouse gas emissions to 7 percent below 1990 levels by 2012. Since then, concerned citizens have joined the City to figure out ways to reach this goal.
This fall more than 200 of their suggestions will be presented to the Evanston City Council in the form of the Evanston Climate Action Plan (ECAP). While most of the ideas aim to reduce carbon output, the renewable energy group focused on ways to produce energy with minimal or no CO2 emissions. Among the energy group’s six proposals, the leader by far in CO2 abatement is an offshore wind farm.
The Wind Farm Proposal
The proposed wind farm consists of a series of ten turbines, arrayed north to south, located three to four miles offshore opposite Northwestern’s two-mile shoreline.
Why This Location?
Unique to Evanston is its two-mile stretch of non-residential lakefront property, the only such expanse at the southern end of Lake Michigan in Illinois. At the proposed wind farm location, Lake Michigan is only 35 to 50 feet deep. (Compare the roof height of a two-story home, generally about 35 feet.) Lake Michigan has fresh water — and relatively small waves. The challenge of setting a foundation in this water, while not insignificant, is nothing like setting one in rolling salt water hundreds of feet deep.
The State of Illinois has established a goal of having a portfolio of 25 percent renewable energy by 2025. It is likely that the most economical renewable solution is wind power. A wind chart of Illinois shows very few areas of class-4 wind (on a scale of 0 to 7) in the state. Most are in Lake Michigan, which is also the only area where the energy produced is very close to its end energy use. The very few areas downstate that have good wind are far from end-users, which means that there is energy loss in the transmission of the power.
Wind Farm Power Production
The farther from the turbulence generated onshore by trees and buildings, the better and “cleaner” the wind is. At the proposed wind farm location and at a height of 220 feet above the water, the wind speed is estimated at 17.5-mile-per-hour, based on the available 15 mile-per-hour average wind speed at Chicago’s water intake cribs, which are only two miles offshore. Because wind power goes up as the cube of wind speed, a small increase in wind speed yields a tremendous increase in wind power. At 15 mph, initial calculations show the wind farm would produce enough power to abate 43,000 tonnes [metric tons] of CO2, roughly equal to the emissions from more than 5,000 Evanston households. At 17.5 mph wind, the CO2 abatement increases to over 80,000 tonnes, which is nearly 60 percent of the CO2-reduction goal of the ECAP.
The first step was for the City Council to review and approve the Climate Action Plan, which they did at the Nov. 10 Council meeting. Then the major stakeholders, including the City and Northwestern, can begin discussions about the wind farm. Funding will be necessary to verify the wind speeds at the proposed wind farm location. Then wind-farm developers can evaluate the feasibility and design the specifics of a long-term power agreement with the City and/or Northwestern.
A longer-term step would be to investigate whether Evanston could entice a wind turbine manufacturer to establish a manufacturing plant in Evanston proper. That would be a great tie-in for Evanston to get a jump on the green economy, providing well-paying jobs and producing local taxes in a growing industry.
As an interesting side benefit, the wind farm could become a tourist attraction similar to Denmark’s offshore wind farms. This would obviously be advantageous to Evanston businesses. The farm could also generate tremendous publicity for Evanston and for Northwestern, producing benefits for both entities by significantly reducing the City’s CO2 footprint and potentially providing major economic benefit to everyone involved.
Wind power provided 19.7 percent of Denmark’s electricity in 2007, a significantly higher proportion than in any other country. This was done in response to Denmark’s goal of reducing its CO2 output by 22 percent of 1988 levels by 2005. Almost half of the world’s wind turbines are produced by Danish manufacturers.
The world’s largest offshore wind farm is the Princess Amalia Wind Farm, located in the North Sea off of The Netherlands and consists of 60 turbines with a total capacity of 120 MW.