This one's really off the radar.

Wind farms, along with solar power and other alternative energy sources, are supposed to produce the energy of tomorrow. Evidence indicates that their countless whirring fan blades produce something else: "blank spots" that distort radar readings.

Now government agencies that depend on radar -- such as the Department of Defense and the National Weather Service -- are spending millions in a scramble to preserve their detection capabilities. A four-star Air Force general recently spelled out the problem to Dave Belote, the director of the Department of Defense’s Energy Siting Clearinghouse.

"Look there’s a radar here -- one of our network of Homeland surveillance radars -- and [if you build this wind farm] you essentially are going to put my eyes out in the Northwestern corner of the United States,” Beloite related during a web conference in April.

Spinning wind turbines make it hard to detect incoming planes. To avoid that problem, military officials have blocked wind farm construction near their radars -- and in some cases later allowed them after politicians protested.

Shepherd’s Flat, a wind farm under construction in Oregon, was initially held up by a government notice that the farm would “seriously impair the ability of the (DoD) to detect, monitor and safely conduct air operations."

Then Oregon’s senators got involved.

“The Department of Defense's earlier decision threatened to drop a bomb on job creation in Central Oregon,” democratic Senator Ron Wyden noted in a press release.

Beloite told FoxNews.com that the project was given the green light by the military only after scientists at MIT’s Lincoln Laboratory assured the Department of Defense “that there were algorithms and processors they could design for not too much money that would mitigate the problem.”

Beloite said that the MIT technology has proven successful in the last few months.

"[The problem] has been addressed. And I have a letter from the deputy director of operations from U.S. NORAD that says 'step one of the two-step fix worked so well that we recommend we don't spend any more money on step two.'"

The fix the MIT scientists came up with tells the radar not to pay attention to signals in a very small area.

“You just tell the radar processor, ‘you're going to have clutter here. Don't display it.’ You create a tiny blank spot [in the radar map] directly above the turbine,” Beloite told FoxNews.com.

In addition to the cost of the radar development, taxpayers are on the hook for more than $1 billion in subsidies for the construction of the Shepherd’s Flat wind farm, according to a 2010 memo from Larry Summers and two other White House economic advisors.

The fix for military radar doesn't work so well for weather forecasters, however.

“It's a lot easier to filter out interference for aviation,” Ed Ciardi, a meteorologist at the National Weather Service Radar Operations Center in Norman, Okla., told FoxNews.com. “The real problem is when rain and the wind turbines are mixed together [on the radar map.] And it's all confusing… sometimes [forecasters] throw up their hands and say, ‘who knows?’”

When the situation is unclear, Ciardi said, “they'll play it safe and maybe extend a warning.”

Ciardi said there have been occasional false alarms due to wind farm interference, but the Weather Service hasn't failed to issue any storm warnings yet.

“We're more worried about the future ... we've seen quite a few proposals for wind farms around our radars. And we have been ... trying to convince them to stay a good distance away,” he said.

One strategy is to ask wind farm owners to turn off the propellers during storms. Another is to convince them to install devices that measure wind speeds and rainfall, so that there would no longer be much need for radar there.

“It all comes down to money and who's going to pay for it,” he noted.

Meanwhile, top radar scientists are working on developing a fix that works for weather radar.

“It's slow progress, and they say it's extremely difficult -- that they need more money and more time. The solution, I would say, is probably five years down the road," Ciardi said.