AT&T Developer Program contacted me regarding an interesting research article on their web site, ‘A Call for More Energy Efficient Apps’.
A much simplified summary is that changing how much and how often your app downloads data, you can significantly change the battery usage. Allied to this is how much an app pre-fetches. Too much and the app will be slow to start (load) but render subsequent pages quickly. Conversely, more intelligent fetching only ‘as needed’ will be more economical on data use but potentially more battery hungry and cause the user to have to wait for data.
As the article concludes that "there are tradeoffs that prevent making blanket recommendations for all cases". It’s the designer/developer’s responsibility to architect the appropriate solution.
One observation I have is that optimising apps for lower battery usage tends to also favor the server-side. Aggregating up small requests into one large request will provide for a less ‘chatty’ communication that will provide less server requests per second. I have worked on several projects that have used this technique to make the server side more scalable.