4 ms·

I realize you didn't invent these terms, but is kW/h the right metric? A plain reading of the units provided suggests 700 grams of CO2 is released every hour fo

I realize you didn't invent these terms, but is kW/h the right metric? A plain reading of the units provided suggests 700 grams of CO2 is released every hour for every kW generated, but that seems unlikely. Where does the per hour figure in?

throwaway894345 5y ago
It's almost exactly 1kg per kw/h, at least in the US: https://www.eia.gov/tools/faqs/faq.php?id=74&t=11 https://www.eia.gov/tools/faqs/faq.php?id=74&t=11 But yes, "per hour" is necessary because you can't instantaneously emit a certain mass of co2. You emit over time, just like you generate power over time.
jeltz 5y ago
I suspect it is a typo and that it should be grams per kWh.
Teknoman117 5y ago
I meant kWh. The units derivation is as follows if I remember correctly: The SI unit for some absolute quantity of energy is the "Joule". 1 watt = 1 joule per second (1 J/s) Watts can sort of be thought of as the rate at which some absolute quantity of energy is available or able to be consumed. Since energy sources are usually rated in terms of their ability to supply an instantaneous amount of power, in order to get back to the absolute amount of energy, you need to multiply by the time in order to get back to just some multiple of joules. 1 watt-second = 1 J/s * s = 1 J. So the concept holds that if we are going to measure some amount of something (other than power) produced by a power plant, it should be measured against the absolute amount of power produced. Obviously this doesn't take into account the fact that pollution generated by some forms of power aren't linearly correlated with the power produced - e.g. fossil fuel plants produce less particulate pollution the hotter the fire burns, meaning they get dirtier vs the power output the lower the output power is set. Hence why gas turbines burn cleaner that gas-fired steam generators (hand waving over the efficiency differences of direct fired turbines versus steam generation). Another data point is that natural gas turbines (again, averages from the US) produce 550 grams per kWh, and combined cycle (adding a second turbine that runs off the exhaust heat of the first) are 435 grams CO2 per kWh. But the numbers I posted are what I meant. In the US, an average of one kilogram of CO2 is emitted per kilowatt-hour of energy (3.6 * 10^6 Joules) generated. Nuclear is two orders of magnitude less carbon emission (versus coal), wind and solar are comparable if deployed under ideal conditions. Even under non-ideal conditions, they still offer an order of magnitude improvement.

throwaway894345 5y ago

It's almost exactly 1kg per kw/h, at least in the US: https://www.eia.gov/tools/faqs/faq.php?id=74&t=11 https://www.eia.gov/tools/faqs/faq.php?id=74&t=11 But yes, "per hour" is necessary because you can't instantaneously emit a certain mass of co2. You emit over time, just like you generate power over time.

jeltz 5y ago

I suspect it is a typo and that it should be grams per kWh.

Teknoman117 5y ago

I meant kWh. The units derivation is as follows if I remember correctly: The SI unit for some absolute quantity of energy is the "Joule". 1 watt = 1 joule per second (1 J/s) Watts can sort of be thought of as the rate at which some absolute quantity of energy is available or able to be consumed. Since energy sources are usually rated in terms of their ability to supply an instantaneous amount of power, in order to get back to the absolute amount of energy, you need to multiply by the time in order to get back to just some multiple of joules. 1 watt-second = 1 J/s * s = 1 J. So the concept holds that if we are going to measure some amount of something (other than power) produced by a power plant, it should be measured against the absolute amount of power produced. Obviously this doesn't take into account the fact that pollution generated by some forms of power aren't linearly correlated with the power produced - e.g. fossil fuel plants produce less particulate pollution the hotter the fire burns, meaning they get dirtier vs the power output the lower the output power is set. Hence why gas turbines burn cleaner that gas-fired steam generators (hand waving over the efficiency differences of direct fired turbines versus steam generation). Another data point is that natural gas turbines (again, averages from the US) produce 550 grams per kWh, and combined cycle (adding a second turbine that runs off the exhaust heat of the first) are 435 grams CO2 per kWh. But the numbers I posted are what I meant. In the US, an average of one kilogram of CO2 is emitted per kilowatt-hour of energy (3.6 * 10^6 Joules) generated. Nuclear is two orders of magnitude less carbon emission (versus coal), wind and solar are comparable if deployed under ideal conditions. Even under non-ideal conditions, they still offer an order of magnitude improvement.