Monday, June 16, 2008

Some interesting energy facts

I was looking into some more specifics about energy savings in regards to using CFLs and LEDs for the lighting and I found some statistics that were quite startling. The Energy Information Administration website (Official Energy Statistics from the US Government) has a lot of great information about all kinds of power related issues. Check out the section on Potential Savings related to lighting. Here are just a few of the things they talk about:

The overwhelming majority of lights in residential households are incandescent--the least energy efficient of all light types . If households replaced the most intensively used bulbs with compact fluorescent bulbs, they would see a sizable savings in their electric bills. The total U.S. household energy that would be saved by replacing all incandescent bulbs used 4 or more hours per day would be 31.7 billion kilowatthours (kWh) annually, or 35 percent of all electricity used for residential lighting. ...
compact fluorescent bulbs pay for themselves in 1.7 years.

The life-cycle cost of a light bulb includes the cost of the bulb itself, as well as the cost of the electricity required to power the bulb. Electricity costs are a large percent of the life-cycle cost of incandescent lights. Depending on the electric rates, electricity costs account for 78 to 91 percent of the life-cycle cost of incandescent lights, but only 37 to 63 percent of the life-cycle cost of compact fluorescent bulbs.

Compact fluorescent bulbs need about one-third of the power required by incandescent bulbs to emit the same amount of light. If one wanted to replace a 75-watt incandescent bulb, a 26-watt compact fluorescent would be an appropriate choice. Therefore, regardless of electricity costs, compact fluorescent bulbs offer a three-fold increase in efficiency. If compact fluorescent bulbs, by virtue of their high cost, do not produce large dollar savings to individual households, they still result in large savings of electricity and the fuels required to produce electricity.

Of course, one of the biggest issues related to compact fluorescents these days is that they contain Mercury and how does one properly dispose of them. I found the following information (from another bloggers website) to be fairly helpful:

You should consider that mercury emissions from power plants get into rain clouds and come down in lakes and rivers, poisoning fish and the people who eat them. Coal-fired power plants in the US are the largest source of mercury, spewing 50 tons a year into the air -- about 40 percent of the total.

While the amount of mercury used in production a CFL bulb is at most 6mg, the average mercury content is 4mg. The total emissions of mercury created by a CFL bulb from electricity consumption over its lifetime is about 2.4mg of mercury. In comparison the emissions from an incandescent light bulb is about 10mg. Therefore overall CFLs result in a reduced amount of mercury emitted over the lifetime of a CFL bulb. The real gain is the reduction of 38kg of Co2 per CFL per year and an overall saving of 14% on your electricity bill.

To ensure the safe disposal of CFL bulbs you should return them to the retailer, manufacturer or to an appropriate recycling facility. Once collected the bulbs are crushed in a machine that uses negative pressure ventilation and a mercury absorbing filter allowing the mercury to be reclaimed. Therefore if you use a CFL with renewable energy and recycle it, the mercury emission level is actually negated.

If you break a CFL, clean up broken bulbs with care. Open windows and allow to circulate to the affected area. Do not allow children or pregnant women to enter the affected area. First sweep up all of the glass fragments and phosphor powder (do not vacuum), then place in a plastic bag. Wipe the area with a damp paper towel to pick up stray shards of glass or fine particles, and place the used towel in the plastic bag as well. For proper disposal of broken bulbs, the best solution is to save them for a community household hazardous waste collection. Also, you can now get CFLs with ultra-low mercury levels.

The other hazard I recently discovered relates to LEDs
(Light-Emitting Diodes) . It is not widely known to the basic consumer (yet) that LEDs contain Arsenic (a metalloid) that, although a naturally occurring element, has many negative connotations. Again, the main concern here is not that you will be exposing yourself to Arsenic if you install LED fixtures (which you are not), the main concern is about how to properly dispose of the lights if they break or when they die out. And hey, the amount arsenic used in the pressure treated wood deck that your dad built out back when you were growing up greatly exceeds the amount used is LEDs anyway. So by outlawing Arsenic in PT wood, we're much better off these days.

But keep in mind that Arsenic is commonly used in the electronics industry (as well as some cures for diseases) and I would not be sitting here typing on this computer if it wasn't for Arsenic. As far as LED lights dying out...let's keep in mind that the lifespan of a typical LED downlight is about 50,000 hours (CFL about 30,000; incandescent about 2,000) . Given that the average percentage of light usage in a home is around 2,500 hours per year, you will not have to be concerned with changing that LED light for about 20 years! By then, I would imagine we will most likely have addressed many of these concerns, if we haven't already moved on to more advanced lighting technology (and you will have long moved out of your house, anyway). The main disadvantage of LEDs (at this time) is that they cost considerably more than other lights and often have special power requirements. But in the end, the pros definitely outweigh the cons.

Advantages of LEDs:

Produce more light per watt than incandescent bulbs and can be up to 80% more energy efficient

Capable of emitting light of an intended color without the use of color filters and can be designed to focus its light. Other light sources often require an external reflectors

When dimmed, LEDs do not change their color tint, unlike incandescent lamps, which turn yellow

Ideal for use in applications with frequent on-off cycling, unlike fluorescent lamps that burn out more quickly when cycled frequently

Difficult to damage with external shock. Do not contain Mercury

Can be very small and light up very quickly


T.B.DEV said...

Excellent and balanced exposure of facts; please visit my blog for certain startling medical facts about exposure to CFL bulbs, and a representation submitted in this regard. You mention about arsenic in LED bulbs, startling me further

Anonymous said...

This is some very helpful information! We all know the advantages of CFL's, but we should be thinking about their life-cycle which includes when they stop working.

Home Depot just started a CFL recycling program, see link:

T.B.DEV said...

It is in fact the complicated methods and measures involved in safe disposal of tiny quantum of mercury present in CFL bulbs, apart from lack of recycling facilities that is mentioned frequently as dissuading people for going in for CFL lamps. I feel that just a statutory warning on a CFL bulb pack will not do; there is need for a comprehensive education/publicity in this regard

Southern Liberties, LLC - Phila, PA said... you for your interest in this topic. It is a very important issue that I am sure will continue to be addresses in more detail as time goes on. With huge companies like Home Depot (as "anonymous" cited) getting on the band wagon and helping with the proper recycling of CFLs, hopefully we can keep it under control. Thanks again for the great comments!