We can use half by utilizing more efficient technologies in all areas of our economy
Energy Consumption By Sector
Energy Consumption By End Use (source: DOE)

Using half the energy in the transportation, residential and commercial areas that make up 68% of our energy consumption is easy with today's technologies.

In each area there are Quick Wins that are cheap, easy to install and pay back their cost in less than a year. An example is CFL lightbulbs which can cut home and workplace energy use by 15% and pay for themselves in one year.

More costly items require Replace-Over-Time (ROT) approach when the asset needs replacing or upgrading. ROT candidates include vehicles, appliances & equipment, heating, cooling & insulation, and more efficient industrial processes. In many cases, Federal, State and local governments give tax credits to assist. Check here to find credits for your location.

Sometimes more efficient processes work. Can a web video conference substitute for a business trip?

The commercial & industrial sector is more challenging because industrial processes such as steel making are usually expensive to replace, however plants are upgraded each year which is the right time to become more effficient. And c ompanies that invest in efficient technologies will gain as energy costs rise.