How much energy does it take to power those iPads?

If you are like me, then you are constantly using your iPad(s AAPL) all the time. I like to run my iPad at full brightness and I am almost always connected to the Internet. And that means frequent visits to the electrical outlet — at least twice a day. And as result I often fret about how much energy I am using on my iPad and other devices, and how they are impacting my carbon footprint.

Some new research from Palo Alto, Calif.-based Electric Power Research Institute (EPRI) breaks down how much an iPad costs in terms of electricity and how much energy all the world’s iPads consume. EPRI calculations show that the annual cost of charging an iPad every other day is about $1.36 a year.

The analysis shows that each model of the iPad consumes less than 12 kWh of elelctricity over the course of a year, based on a full charge every other day. By comparison, a plasma 42” television consumes 358 kWh of electricity a year. EPRI conducted the analysis in Knoxville, Tenn., at its power utilization laboratory. Costs may vary depending on what region that a consumer resides and the price of electricity in a particular location. The assessment was conducted to determine the load requirements – the amount of power needed to operate the devices — of the increasingly popular iPad.

But when you  multiply those kilowatts by millions of iPads being sold, the energy impact on the planet starts to add up pretty quickly. According to EPRI calculations:

the average energy used by all iPads in the market is approximately 590 gigawatt hours (GWh). In a scenario where the number of iPads tripled over the next two years, the energy required would be nearly equivalent to two 250-megawatt (MW) power plants operating at a 50 percent utilization rate. A quadrupling of sales in two years would require energy generated by three 250-MW power plants

Our measurements indicate that new iPads will consume about 65 percent more electricity per year. Other products that were included in the analysis were laptop PCs, which consume 72.3 kWh of electricity each year and cost consumers $8.31 and 60W CFL light bulbs which consume approximately 14 kWh of electricity and cost consumers $1.61 a year.

They also calculate that the Apple iPhone 3G consumes 2.2 kWh of electricity each year, which results in a power cost of $0.25 annually.