The Environmental Cost of Using Electricity

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Samuel Francis
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1 Calculating Energy Costs The watt (W) is a unit of electrical power, which is the rate at which we use energy. We pay the electric company for the use of energy. A kilowatt (kw) is equal to 1000 watts: kilo is a prefix that means The simplest definitions of kw and kwh are as follows: 1 kw = one thousand watts (and a watt is one joule of energy per second) 2 kwh = using a thousand watts for an hour (3,600,000 joules).! Kilowatts are a unit of power, while kwh is a unit of energy. Think of it this way: kw defines how much energy a device uses or generates in a given amount of time. One kilowatt is the power of one thousand joules (J) per second (s). Meanwhile kwh defines how much energy that device actually used or generates. So, a 100-watt light bulb that is on for 10 hours needs 1 kwh (1,000 watt-hours). This is the same as ten 100-watt bulbs burning for one hour. D Equation: kw x hours = kwh (power) x hours = (energy) P x t = E *(P = E/t!) Example: If a water heater had a 4.5 kw heating element and ran for 1 hour, what amount of kwh would it consume? kw x hr = kwh 4.5 kw x 1 hr = 4.5 kwh In order to determine the COST of energy use you must multiply the kwh by the cost per kwh. The Environmental Cost of Using Electricity Using energy results in pollution of our environment. Energy is used by power plants to make electricity. It is also used when we drive cars, take airplanes, mow the lawn and cook our food. Many types of pollutants are produced by power plants: CO2, particulates (particulates are small particles that can contribute to smog) and oxides of sulfur (Oxides of sulfur contribute to acid rain pollution.)

2 Sample Questions: 1. Complete the chart. Assume 8.5 cents per kwh. Appliance Average Use (hr/ day) Annual Energy Consumption (kw) Annual Cost ($) Vacuum cleaner Hair dryer 0.25 IGNORE 100 Computer Central air conditioning 12 (60 days/year) Mini Christmas lights use about 1/2 watt per bulb. Say you have a string of 100. a. How many watts is this total? 0.5 W x 100 bulbs = 50W = 0.050kW b. If you use these lights for 10 hours a day for 8 weeks, how many kwh is this? kwh = h x kw = (10 x 8 x 7) x 0.05W = 28 kwh c. How much will these lights cost you if each kwh costs 7? 28 kwh x $0.07 = $ A 100-watt light bulb that is on 10-hours a day for 30 days. How much energy will it use? 10 hours per day x 30 days = 300 hours (energy is all about time of operation) 300 Hours x 100 Watts = 30,000 watt hours (energy is also about connected load or Watts) A kilowatt (kw) is 1000 watts 30,000 watt hours 1000 watts = 30 kilowatt hours (kwh as on the electric bill ) 4. If the cost is $ per kwh, how much did it cost to operate that lamp? 30 kwh x $ per kwh = $2.72 cost of operation 5. How much would I save if I replaced the 100-Watt light bulb with a 60-Watt light bulb that would produce the same amount of light energy if the lights were on 10-hours a day for 30 days? 100-Watt original light - 60-Watt Replacement light = 40-Watt reduction 300 Hours of operation (Problem 1) x 40-Watt Reduction = Watts saved Watts hours saved 1000 Watts = 12 kwh 12 kwh x $ (Problem 1) = $1.09 savings $1.09 Savings $2.72 Original Cost of operation =.40 x 100 = 40% 6. he 100-Watt bulb has a life expectancy of 1,000 hours. How much will it cost to burn the bulb for 1,000 hours? 100 Watts x 1000 Hours = 100,000 watt hours 100,000 Watt hours 1000 Watts = 100 kwh 100 kwh x $ per kwh = $ The 60-Watt bulb has a life expectancy of 4,000 hours. How much will it cost to operate during its life? 60 Watts x 4,000 Hours = 240,000 watt hours 240,000 watt hours 1000 watts = 240 kwh 240 kwh x $ per kwh = $21.72

3 Delivery Services: this portion of a bill includes charges from your local distribution company (electric utility). These services continue to be regulated by State Government. These charges are measured per kilowatt hour (kwh), which equals 1,000 watts of power used over a one-hour period. Rate: this lists your delivery service rate. Most customers have a residential rate, which provides for basic power delivery services. Customer Charge: this is a fixed charge that covers a part of the electric company s fixed cost to deliver electricity Distribution Charge: this covers the local, lower-voltage power lines (wires) and associated facilities that transport the electricity from distribution substations to homes and businesses. Substations, owned by local distribution companies (the electric companies), receive electricity from power-generating facilities and distribute it to customers. Transition Charge: this fixed charge allows your distribution company to recover costs incurred before the 1997 Electric Restructuring Act for its: 1) investments in building or operating power generation plants and 2) other activities mandated by that 1997 law. This charge will decrease over time as these costs are recovered. Transmission Charge: this is the cost of delivering electricity via high-voltage power lines (wires) and associated facilities that transmit the electricity from power plants to distribution substations. Energy Efficiency (also called Conservation and Demand Side Management ): this is a fixed charge required by the Commonwealth for all electric ratepayers to help fund programs to improve energy efficiency and/or reduce energy use. Renewable Energy: this is another fixed charge required by the Commonwealth to help fund the Massachusetts Renewable Energy Trust, which finances the development of facilities that produce power from solar, wind and other renewable resources. Supplier Services: this portion of your bill includes charges from a power supplier or aggregator for generating the electricity. This is the only part of the bill that is subject to competition among power supply companies. Basic Service - Fixed: customers may choose a competitive power supplier, the company that generates their electricity. Most consumers have not selected a supplier and are listed as a Basic Service Fixed customer. This rate provides the most stable electric bills rather than a variable rate, which fluctuates monthly based on the current market price for electricity. Generation Charge: this covers the amount of electricity you use the energy that comes from power plants and other facilities that produce the electricity transported to homes and businesses via distribution substations. The generation charge is set through contracts between power generators and distribution companies, as well as the wholesale electricity market, which is under Federal Energy Regulatory Commission (FERC) oversight.

4 Calculating Energy Costs The (W) is a unit of electrical power, which is the at which we use energy. We pay the electric company for the use of energy. A (kw) is equal to 1000 watts: kilo is a prefix that means The simplest definitions of kw and kwh are as follows: 1 kw = watts (and a watt is one joule of energy per second) 2 kwh = using a thousand watts for an (3,600,000 joules).! Kilowatts are a unit of, while kwh is a unit of. Think of it this way: kw defines energy a device uses or generates in a given amount of time. One kilowatt is the power of one thousand joules (J) per second (s). Meanwhile kwh defines how much energy that device actually or. So, a 100-watt light bulb that is on for 10 hours needs 1 kwh (1,000 watt-hours). This is the same as ten 100-watt bulbs burning for one hour. Equation: kw x hours = kwh (power) x hours = (energy) P x t = E *(P = E/t!) Example: If a water heater had a 4.5 kw heating element and ran for 1 hour, what amount of kwh would it consume? In order to determine the COST of energy use you must multiply the kwh by the per kwh. The Environmental Cost of Using Electricity Using energy results in of our environment. Energy is used by power plants to make. It is also used when we drive cars, take airplanes, mow the lawn and cook our food. Many types of pollutants are produced by power plants. In San Diego County, both and are burned during the production of electricity. On average, the following pollutants are produced:, (particulates are small particles that can contribute to ) and of sulfur (Oxides of sulfur contribute to pollution.)

5 Sample Questions: 1. Complete the chart. Assume 8.5 cents per kwh. Appliance Average Use (hr/ day) Annual Energy Consumption (kw) IGNORE Vacuum cleaner Annual Cost ($) Hair dryer Computer Central air conditioning 12 (60 days/year) Mini Christmas lights use about 1/2 watt per bulb. Say you have a string of 100. a. How many watts is this total? b. If you use these lights for 10 hours a day for 8 weeks, how many kwh is this? c. How much will these lights cost you if each kwh costs 7? 3. A 100-watt light bulb that is on 10-hours a day for 30 days. How much energy will it use? 4. If the cost is $ per kwh, how much did it cost to operate that lamp? 5. How much would I save if I replaced the 100-Watt light bulb with a 60-Watt light bulb that would produce the same amount of light energy if the lights were on 10-hours a day for 30 days? 6. The 100-Watt bulb has a life expectancy of 1,000 hours. How much will it cost to burn the bulb for 1,000 hours? 7. The 60-Watt bulb has a life expectancy of 4,000 hours. How much will it cost to operate during its life? 8. What could you do at home to decrease your electricity bill?

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