We hear a lot these days about our personal carbon footprint. What does that mean? It means the amount of carbon dioxide (CO2), the principal man made greenhouse pollutant, that goes with the energy we use. In some cases, this is very precisely measurable. One such case is with electricity. Have a look at Tables A1 and A2 to the left. The bottom rows give the amount of CO2 per kilowatt-hour of Ontario electricity. If you are in Ontario right now, and using electricity, and can figure out how much electricity you are using, you can figure out instantly your carbon footprint from using that electricity.
At the time I wrote this, ten a.m. on Saturday June 21 2014, each kWh of Ontario grid electricity came with about 24.79 grams of CO2. How much CO2 is that, anyway? Enough to fill about 7 standard 1.89-liter milk cartons.
An average 4-person household in Ontario uses about 800 kWh per month, says the Ministry of Energy. That works out to 26.7 kWh per day. So if the carbon footprint of Ontario electricity—known formally as the CO2 intensity per kilowatt-hour, or CIPK—were to stay at 24.79 grams, an average Ontario household would accumulate over 190 large milk cartons full of CO2 every single day. That is about two and a quarter standard oil barrels.
See Item B1 in the right sidebar for a volume calculation of the carbon dioxide content of Ontario grid electricity, based on last hour’s CIPK.
Over a month, that home’s carbon footprint from electricity use would work out to around 68 oil barrels’ full of CO2.
There clearly is no way any household could store that much waste. It would have to be thrown out. And where? Why, into the atmosphere of course. Out of sight, out of mind.
In fact, that is exactly how CO2 from power generation is dealt with. It is simply dumped into the atmosphere, at the power plant that makes the power. Just as that 4-person household using the 800 kWh per month could not possibly store 68 oil barrels’ full of CO2 every month on the premises, so power plants that produce literally tens of thousands of tons of CO2 every day could not possibly store that on site either. So they simply dump it into the atmosphere. Between midnight and seven a.m. this morning, Ontario power plants dumped over 4,600 metric tons of CO2 (see Table A2 on the left for the most recent running total). That is now swirling in our atmosphere, where we can’t see it. Out of sight, out of mind.
Well, not quite out of sight. All that CO2 we dump into the air shows up in the global concentration of CO2 in the atmosphere is measured, at hundreds of sites around the world. Readings from the oldest of these, the Mauna Loa CO2 Observatory in Hawaii, are published daily by the Scripps Institution of Oceanography. I republish the daily readings on this site; you can see it at the top left of this page. As I wrote this, the daily reading from Mauna Loa was 401.32 parts per million. It went above 400 ppm for the first time in recorded human history, only a couple of months ago.
So, 7 milk cartons full of CO2, every hour (assuming a CIPK of 24.79 grams). If that sounds like a lot, it is actually not a lot. It could be much worse. How much worse? Well, if certain “environmental” lobbies had their way, and Ontario replaced its nuclear generators with ones that run on natural gas, then each kWh of Ontario electricity, instead of coming with 24.79 grams, would have come with 417.3 grams. (See Table A3, in the upper right to compare last hour’s actual CIPK with that of a grid in which the nuclear units were replaced with gas-fired units.) That is enough to fill 227 liters; more than an oil barrel.
All of the CO2 that makes up Ontario’s hourly CIPK comes from plants that, at seven a.m. this morning (June 23 2014), were contributing 15 percent of the generation feeding the provincial grid. The other 85 percent came from plants that emit no CO2 at all. And of these, the biggest contributors by far were the ones that run on nuclear fuel.
Much is made of the waste that accompanies nuclear generation. How does nuclear waste really compare with the oil-barrels’-per-hour worth of CO2 waste that accompanies fossil-fired generation?
Well, imagine that every Ontario resident had to store his or her waste from nuclear generation at his or her residence. Here, unlike the CO2 from fossil generation, it would be easy. If you apportion the total waste from nearly a half-century of nuclear operation in this province to every man, woman, and child who lives today in Ontario, you would have enough to fill less than three large milk containers.
Three milk containers per person—twelve per four-person household—from a half-century of continuous operation, versus seven per hour for the same household (assuming a CIPK of 24.79 grams, which is very, very low).
Which type of generation has the lower waste footprint?