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Example of the Final Project. Possible Reduction of Greenhouse Gas Emissions by Replacing Incandescent Lights with Compact Fluorescent Lights (CFL). Outline. Introduction What are CFLs and why are they more efficient than incandescent bulbs?
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Example of the Final Project Possible Reduction of Greenhouse Gas Emissions by Replacing Incandescent Lights with Compact Fluorescent Lights (CFL)
Outline • Introduction • What are CFLs and why are they more efficient than incandescent bulbs? • How much energy can be saved per year in British Columbia of all incandescent light bulbs are replaced with CFLs? • What is the effect on the CO2 emissions?
Introduction • Government web pages and media suggest replacing incandescent light bulbs with compact fluorescent light bulbs to save energy. • We want to know how much energy is saved per household and estimate the energy savings in BC if all the home lights were replaced by CFLs. • We also estimate the corresponding reduction in CO2 emissions. • In our estimates, we take into account energy used to manufacture incandescent bulbs and CFLs. For the estimate of the BC energy savings, we assume that ½ of all lights could be replaced by CFLs on average.
What is a CFL? • Ordinary incandescent light bulbs emit light due to electrical heating of a thin tungsten wire. They convert only a few % to visible light (Lab 8). 90% – 95% of the electrical energy is converted into heat. • A CFL is based on light emission from a gas discharge: An electric current is driven through a gas ionizing the gas molecules. The recombination of ions and electrons results in light emission. • For the same light output as a 60 W light bulb a CFL needs only 13 W of electrical power. • (Source: Wikipedia)
How much energy would be saved annually due to replacing these bulbs? • Assume each bulb is switched on an average of 4 hours/day • Average power 60 W. Replaced by 13 W CFL= Savings of 47 W per bulb replaced • Each home would save10 47 W (4 h/d 3600 s/h 365 d/y) ≈ 2.5109 J per household per year. • For the whole province:2.5109 J 1 600 000 households≈ 41015 J per year
What would be the total reduction in CO2 Emissions? • CO2 emissions in the US are 1.34 pounds (0.608 kg) of CO2 per kWh averaged over all methods of generating electricity • (1998 – 2000, Source: US Government, DOE). • Conversion between kWh and J1kWh = 1000 J/s 3600 s/h 1h = 3.6106 J • Annual reduction in CO2 emissions is: 41015 J per year (1kWh / 3.6106 J) 0.705 kg/kWh= 8108 kg of CO2 per year in BC
What would be the percentage decrease in energy consumption? • Total BC power production ≈ 53 000 GWhours ≈ 53109kWh3.6106 J/kWh≈ 21017 J • (http://www.bchydro.com/rx_files/info/info46749.pdf) • The savings of 41015 J by switching to CFLs would decrease our provincial energy consumptions by 2%
Conclusion • Replacing incandescent bulbs with CFL leads to significant savings in energy (and money). • BC’s energy consumption would decrease by approximately 2% if all households would replace. • Higher production cost of CFLs are offset by much longer lifetime. • Concerns about mercury content in CFLs could be addressed by mandatory recycling programs.