I can still remember the analogue days of travel, when I backpacked through Europe and Asia with no more electronics than a couple of Double-A batteries (at best). I only needed them if I wanted to use the flash on my camera. That was less than fifteen years ago.

Now I don't even go to the zoo without my laptop and my digital camera. When the battery runs out, it's time for coffee. And then I make sure I sit near a power outlet in the nearest cafe.

But what do you do when there are no power outlets? If you are kayaking in the middle of the Atlantic, climbing Mount Everest, or just on a local camping trip in the wilderness, what do you do when the batteries run out?

Some say "just bring extra batteries." That might work.

But what if you have several different electronic items, and you don't want to buy spare batteries for each of them? What if you'll be away from civilization for an extended period of time, and the spare batteries just won't last?

A solution for this can be portable solar power. Devices exist which will charge your electronic equipment, using the power of the sun.

Not all portable solar power devices are the same. Some provide enough power to charge a laptop, some can be used for smaller devices such as cameras, and some can only be used for devices that use very little electricity - like MP3 players.

The amount of power that a solar device provides depends mostly on the size of the device. Bigger solar panels generally provide more power. Other factors influence the amount of electricity produced by a solar power device. These factors include the strength of the sun, the length of exposure to the sun, the obstruction to sun (mist, cloud cover, dust, etc.), and the location of the equipment on the Earth.

Different solar power devices provide different amounts of power, and are therefore compatible with different types of equipment.

Portable Solar Power devices also exist in a variety of forms. Some are light and flexible, while some are contained in durable units that look like a small suitcase or radio. There are waterproof varieties, as well as solar panels built into bags and backpacks.

When you are away for a few days, extra batteries may suffice to keep your camera or phone going. But if you will be away from civilization for weeks? Or even months? Ironically, escaping from the modern world can also involve modern solutions. Far and alone on the Patagonian plains, with nothing but the wind and the horses to keep you company, you may feel like you're living six centuries into the past. But that doesn't mean you will never want to access your email or take a photograph.

So don't cancel that 45-day mountain trek. And don't leave your digital camera behind.

We don't all have to be tethered to the power lines.