They come from all over the world to talk about the power of wind - and an industry that is no longer just an illusive goal of starry-eyed environmentalists. It's an industry that's making money.
"We had no idea of the extent of the interest and how it would hit," said Doug Hicks, Endurance Wind Power.
Five years ago, Doug Hicks co-founded a Canadian-based manufacturer of mid-sized wind turbines for farms, businesses, schools and homes. Last year, they produced about 200 turbines. This year it'll be five times that amount.
The big manufacturers are cranking them out too. Forty percent of the country's new electricity generation is coming from wind. And one of the big reasons for that are financial incentives in the Obama stimulus package. Developers are getting tax credits or cash that can cover up to a third the cost of putting up a turbine.
"Energy is a policy driven business - no matter what energy you're in," said Declan Flanagan, E.On Climate and Renewables.
On Wednesday, some of the leaders of the wind power business used the occasion to call for national renewable energy standards. It's one thing, they say for the President to set a goal -- 20-percent of our energy from renewable resources by 2030-- but they want a law requiring it.
"We're talking about big capital developments here. These companies need time to factor in economics and they need to work it. That doesn't happen overnight," said Gen. Wesley Clark (Ret.), Emergya Wind Technology.
"If we don't have renewable energy standards, we really would not see the full potential of renewable energy. We would not see half - not even a quarter," said Mike Polsky, Invenergy, Chicago.
Critics though say a law is not necessary because the free market is working fine and the wind power industry is just looking for a ticket to fatten its wallet.
At least, for now, the wallets are growing, and so too are the number of players in the wind power business.
"As North Americans, we think the Europeans are ahead of the curve, but they're interested in our technology which is quite interesting to me," said Hicks.
Twenty eight states - Illinois among them - have their own renewable energy standards. There is a bill in the U.S. Senate, in committee now, that propose national standards --25 percent of the nation's energy by the year 2030 would have to come from renewable resources.
There are many costs connected to that - not least among them the billions of dollars it'd take to build up a national electrical grid. Proponents say the cost would ultimately be greater if we don't do that.