Earlier this week, a report came out showing that some apps on Android use more than twice the power they actually need because they're running ads. Angry Birds in particular was called out, with 70 percent of its power draw dedicated to uploading information and downloading ads. That stark fact may be part of the reason why Angry Birds Space, which was released yesterday, has both a free and a $.99 "premium" version in Google Play.

Although it might not be entirely fair to single out Angry Birds for battery life issues, the app is a common example simply because of how popular it has become. At the center of the Android app ecosystem is a fundamental problem that hasn't yet been solved: paid apps get better battery life but simply don't make much money in Google Play, while free-with-ads apps appear to be much more profitable but provide a much worse experience to the end user.

"I've been waiting for Google to get the Android Market in better shape."If Angry Birds is the cipher through which to understand this problem, the result doesn't look good for Google's store or for Android as a platform. Google Play simply isn't making much money for developers who offer paid apps on Android. Rovio's "Mighty Eagle," Peter Vesterbacka, says that until now "it just hasn't made sense" to offer a paid version of Angry Birds on Google Play:

The top developers offering paid downloads on Android, the numbers are single-digit millions at best. We are in the hundreds of millions on Android, so just it hasn't made sense.

That's why, until now, Rovio only offered the ad-based version on Android Market, though the company did offer a for-pay version on Amazon's Android app store. It's also not as though Rovio was unaware of the battery life issues that come with ad-based apps. The company has been working with Nokia Siemens Networks since last summer to optimize Angry Birds for battery life. However, it's a difficult challenge: the firm found that the ads on the Android version meant that Angry Birds was using 3.5 times more signaling (the total number of network connections) than the iPhone version. Nokia Siemens points out that there's not an easy solution if you need to include ads:

Advertising delivery for Angry Birds is done by Google (Rovio cannot influence this), so any reduction of mobile ad-associated signaling will have to be done by Google, not Rovio.

Angry Birds has since switched to using Flurry for ads, but as the more recent study shows, it presents similar battery life problems. One solution to this conundrum is for Google to emulate an Apple strategy: offer an ostensibly more battery-efficient and unified advertising solution to advertisers, like iAds. Unfortunately, that example isn't entirely promising when it comes to actually bringing in more money. Apple has had to cut rates and ease terms for its iAds offering.

A more obvious strategy, then, is to offer both paid and free versions on Google Play. That's exactly what Rovio is doing, but it's fairly clear that nobody should expect huge numbers from the paid version. Vesterbacka is cautiously optimistic, at best, that Google Play will be able to create real revenue for paid apps:

I've been waiting for Google to get the Android Market in better shape and they're moving in the right direction with Google Play [...] they're making things work better so paid content actually makes sense on the Android side.

Ultimately, the best solution is the most direct: Google needs to find ways to make Google Play a destination where consumers are willing to spend money. Looked at that way, the rebranding from Android Market to Google Play and the increased efforts to offer more types of content to purchase (including, it seems, movies) begin to make more sense.

Until and unless Google can build an ecosystem of consumers willing to part with their money directly, both the company and Android developers will be forced to depend on advertising revenue. In the meantime, Android users would be well-advised to keep a spare battery handy.