A Light Bulb Shows How Solar And Wind Beat Coal

What would you rather do: burn 714 pounds of coal or  put up 100 square meters of solar power?

Good Magazine performed an interesting experiment which underscores the benefits of renewables while simultaneously showing off the shortcomings of coal, nuclear and natural gas. It calculated how much energy it would take to keep a 100 watt light bulb burning for an entire year. The results are charted in the infographic below but here is a quick rundown:

• Coal: 714 pounds.
• Natural Gas: 143 pounds.
• Nuclear: 0.35 pounds.
• Solar: 8 days, 8 hours and 14 seconds of energy from 100 square meters of solar panels.
• Wind: 2 hours, 20 minutes and 9 seconds from a 1.5 MW turbine at 25% capacity.
• Hydroelectric: 2 hours and 35 minutes.

Granted, this is a purely hypothetical situation. Under the new lighting efficiency regulations, you probably can’t find a 100 watt incandescent bulb in the U.S. You’ll be stuck doing this comparison on a 13 watt LED, but the ratios would stay the same.

While it is challenging to compare apples to oranges, it is somewhat safe to say solar and wind win. Eight days isn’t long and 100 square meters isn’t very much room. Coal, nuclear and natural gas would also require new fuel every year. Sunlight and wind are free. Water for hydroelectric dams is free, but the dams certainly aren’t and in many places drought could make new dams a risky bet.

As far as costs go, you can also pretty much bet solar is the winner. The tab for 100 square meters of panels, even with installation, will measure in the thousands. Everything else on this list would start in the hundreds of millions of dollars.

The thought experiment also highlights the remarkable potential for efficiency. Casual energy consumption--i.e. energy consumption for things like lights or computers in idle that you really don’t think too much about—really adds up, particularly on a global scale. As we noted in this space last year, lighting consumes 19% of world power, or more than nuclear and hydroelectric combined. In the U.S. lighting and nuclear are about equal. Investing in new bulbs and networking for lighting would be far more cost-effective than new reactors, and take far less time.