Al Slavin distributed this handout at a recent workshop at Trent University. It shows some basic facts about energy and energy usage on a personal level as applied here in Ontario.
- watt (W): Energy per second (“power”) used by an electrical device.
- kilowatt (kW): 1000 watts.
- To get the total energy used, multiply by the number of hours the device is on.
- kilowatt-hour (kWh): Energy use in 1 hour. E.g. a 1-kW heater run for 2 hours uses an energy of 2 kWh.
- Note: A high-power device, such as a kettle, does not use much energy if it is on for only a few minutes per day
- 1 tonne = 1000 kg
- In Ontario, about 13 cents for 1 kWh of electrical energy.
- (8.7 cts 7 PM-7 AM, 13.2 cts 11 AM-5 PM, 18.0 cts 7-11 AM & 5-7 PM).
- Devices that cause heating/cooling use the most energy.
- Example: a hair dryer uses 1500 W on hot and 70 W cold
- GHG’s generated per kWh of electricity:
- In Ontario, about 31 g CO2-equivalent, or 0.031 kg/kWh.
Examples of energy use:
- An electrical heater needed to heat a single room is typically a 1 kW heater, as recorded on the plate on the heater. To run this for 1 h costs about 13 cents. To run continuously for a day requires 1 kW x 24 h = 24 kWh of energy. Cost 24 kWh x $0.13 per kWh = $3.12 per day, or $94 /month.
- An incandescent light bulb Typically is 100 W = 0.1 kW. Cost to run per hour = 0.1 kWh x $0.13 per kWh = $0.01 = 1.3 cent. These bulbs are very inefficient for light production, with about 90% of the electrical energy lost as heat.
- LED light bulb with same light output as a 100 W incandescent bulb requires about 10 W of power (LED) and last 40 x longer. They cost more to buy, but use much less energy and produce only about 10% of the GHG’s of the incandescents. Also, are cheaper over the lifetime of the bulbs. Buy LED bulbs rather than Compact Fluorescents (CFL): LED’s are 2x more efficient, and CFL’s contain mercury and so require special recycling. Go to “saveonenergy.ca” for discount coupons.
- Refrigerators: Buy Energy Star appliances only. Check label inside for efficiency (see sample Energuide label on right). Cost to run this fridge per year, about 554 kWh x $0.13 = $72. Save more than $140/yr and 1,774 lbs of greenhouse gas emissions annually when you switch to an ENERGY STAR certified refrigerator from a model over 15 yrs old. By properly recycling your old refrigerator you can save another 10,509 lbs of greenhouse gas emissions.
- Washing machines: Today’s clothes washers are at least 68 percent more energy efficient than those produced in 1990. Typical Energy Star energy is 100 kWh/yr (GHG = 3.1 kg/yr). Washing on a warm cycle uses 10 times as much energy as a cold wash.
- Computers: Desktop about 100 W + 30 W for LCD monitor; laptop about 40 W. Tablets much less. These are small compared to heating and lighting, IF you set your computer to auto-sleep after 10 minutes or so of inactivity.
- House heating: (48% of GHG in Peterborough) Depends on your heat source. GHG in kg per kwh of heat: electric in Ontario 0.031 (will fall as more renewable energy used); heating oil 0.250, propane 0.215; natural gas (methane) 0.181; geothermal about 0.01 kg/kWh from electricity for the heat pump. If you switch from oil heat to gas you save twice: lower cost and 28% less GHG. Heat loss depends on (inside temp – outside temp). If 0oC outside and 20oC inside, turning thermostat down by 1oC saves 1/20 =5% of your heating cost for those conditions.
- Eating beef: Livestock produce 14% of global GHG’s, of which cattle contribute about 65%.Cows (and sheep, goats) produce methane by burping. The average beef-eater is responsible for 0.35 tonnes of greenhouse gases (as CO2 equivalent) a year.
- Car: GHG about 0.255 kg/km (1 kg GHG in 4 km!).
- Buses/trains: much less GHG, because is shared among many.
- Air travel: 1 transatlantic flight (return) generates your entire year’s per-capita allotment of GHG’s. Buy carbon offsets.
- Low-income assistance to buy efficient appliances: 1-877-688-3089 or email HomeAssistance@summerhill.com