Over the past week, mobile phones have been the subject of a host of green moves, from new phones made from recycled materials to ambitious goals for recycling and recyclability of discarded phones. At the same time, European companies announced a major step forward in energy efficiency: a universal standard for chargers.

It started last week when Samsung and LG both announced solar-powered phone models, even though those models are likely a long way from the market. Soon after, at the Mobile World Congress in Barcelona, the Chinese company ZTE announced that it had partnered with Digicel, a Latin American telecom, to produce a low-cost solar cell phone.

And Motorola unveiled its plans for the Renew, an easily recycled carbon-neutral cell phone, made of plastic recycled from water bottles -- and designed to be easily and completely recyclable.

Although announcements of ever-greener tech products are far from earth-shattering, one announcement out of the Mobile World Congress does promise to have big effects across the tech world: the GSM Association, the industry body behind the Congress, said that it would embrace a universal charger standard by 2012. The new charger, which will use a Micro-USB connector, will be compatible with the majority of new phones on the market by the beginning of that year.

Creating a universal power standard -- not just for mobile phones but for all tech devices -- is one of the biggest obstacles to making significant cuts in the overall energy consumed by consumer and commercial electronics, as well as a major contributor to the growing issue of e-waste. The GSMA's planned universal charger will be around 50 percent more efficient in its standby energy use than existing chargers, and will help eliminate an estimated 51,000 tons of e-waste from duplicate chargers.

Commercial electronics are often more energy-efficient than consumer gadgets -- the problem of green power supplies has been on our radar since we launched GreenerComputing in 2007 -- but there is always room for improvement. ChannelWeb yesterday offers a quick overview of Green Plug, a California-based company that is working to spread the word about the benefits of just such a universal power standard for all electronics. See also this feature from October looking at the green power supply problem.