What do gigajoules, kilowatts and BTUs have in common, and why should you care? A joule is the force needed to move one kilogram one meter in one second. A gigajoule is a billion (109) joules.
A watt is a unit of electricity, one amp (a huge number of electrons) moving in a conductor that has a resistance of one ohm, driven by a force of one volt, (one watt is also one joule). A kilowatt hour is 1,000 watts used per hour.
The BTU (British Thermal Unit) is the amount of heat needed to raise the temperature of one cubic foot of water one degree Fahrenheit.
What they have in common is that they are different measurements of the same thing, energy.
You should care because all are involved in your home heating bill. If you live in Edmonton your home is almost certainly heated by natural gas, you may also be using gas for heating water, cooking or drying laundry.
Natural gas sold in Edmonton is billed as gigajoules, home gas meters read in cubic feet, gas furnace size is rated as BTUs per hour, electric heaters use electricity measured by kilowatt hours, but are typically sold by BTU output.
One kilowatt hour is 3414 BTU.
A cubic foot of natural gas produces 1000 BTU of heat energy.
A gigajoule is 947,817 BTU (pretty close to a million BTU).
277.8 kilowatt hours is also one gigajoule.
Electric heat from the grid in Edmonton will cost consumers roughly ten times more than using gas. The reason it costs more in Edmonton is that 89% of Alberta’s electricity is generated from fossil fuels, coal (50%) and natural gas (39%). If electricity is generated using fossil fuel it will always cost more than using fossil fuel directly for the same reason a pound of potato chips will always cost more than a pound of potatoes.
Using a months bills from Epcor for electricity and Direct Energy for natural gas for February 2020 at the regulated rate for domestic consumption, the delivered cost of a gigajoule of natural gas was $7.34 vs $61.90 for a gigajoule (277.8 kilowatt hours) of electricity, including all the administrative, fixed and variable delivery costs charged by these utilities. The regulated rate varies, fixed rates are available month to month, but do not expect the overall ratio of electricity costing roughly ten times more than gas to change as long as Alberta uses gas to generate electricity.
The future of fossil fuel energy looks dim, as it should. Climate change and greenhouse gas emissions notwithstanding, fossil fuel is a non renewable resource. Since the 1970’s people who know have been predicting that fossil fuels will eventually be used up. So far they have been wrong about when, but few could deny that eventually they will be right. As to what will replace it, a betting person should put their money on solar energy.
Sunlight is a safe bet, as nearly every type of energy we use today is converted solar energy, including fossil fuels. Hydroelectric, wind generation and of course, solar panels are fueled by the sun’s heat. What is needed to replace fossil fuels is an effective, economical way of storing solar energy to cover the periods of the day or season when it is not directly available. This is not an insurmountable goal, fossil fuel began as photosynthetic organisms converting sunlight into chemical energy at an efficiency of maybe 3-6%. Most of that energy was used for the life processes of the organisms that stored it and the organisms that fed on photosynthesizing organisms, as well as the losses that occurred over millions of years.
As for being greenest today, the more people in Edmonton can use natural gas for heating homes or water, cooking or drying laundry instead of electricity from the grid, the less impact their energy use has on the environment, given that 89% of Alberta’s electricity comes from fossil fuels 50% of which is coal. And using natural gas directly costs a lot less money than using electricity.
Every time energy is used a little bit of it escapes, not all of it is used for its intended purpose. Most of the electricity that arrives in your home was produced in a power plant that burned either gas or coal to make heat. Most, but not all of that heat was used to turn water into steam. Most (60%) of that steam energy was not used directly for turning the generator, as 40% efficiency is the limit for steam power. Most, but not all of that generator motion was used to push electrons back and forth in our grid. Some of the electrical energy was lost as heat when it was transmitted, and more was lost, as in not used as intended, when it was used for all the things we use electricity for. Lighting is particularly inefficient.
If there is any good news, it is that much of the electricity we use for all the things we use electricity for, like lighting, computers, TVs, refrigerators and vacuum cleaners ends up as heat inside our homes, which is good news for Edmonton, as our furnaces do not have to work as hard, but not so good news for Miami where it makes their electrically powered air conditioners work even harder.