Determining how much of the problem your organization is contributing...and what you can do!
Thomas Sigmund Warda
Conscious Capitalistic ENVIRONMENTAL ENGINEER - Purveyor of Life and Planet Saving Technologies
How much carbon dioxide is produced per kilowatthour of U.S. electricity generation?
#1) The U.S. Energy Information Administration (EIA) publishes average annual carbon dioxide (CO2) emissions factors for U.S. electricity generation in the State Electricity Profiles. Table 1 of each profile has the factor for the most recent year available. There are historical annual factors dating back to 1990 in Table 7. To find Table 7, see the link under Table 1 for: Full data tables 1-12. The factor is in pounds of CO2 per megawatthour (MWh). Divide the factor by 1,000 to convert the factor to pounds per kilowatthour (kWh).
You can calculate an average annual CO2 emissions factor for electricity generated in each state by type of fuel/energy source by dividing estimated CO2 emissions from electricity generation by type of fuel in each state by the amount of electricity generated by type of fuel in each state.
Data sources for the calculation are available in the state-level historical data files (xls):
- U.S. Electric Power Industry Estimated Emissions by State includes estimates for CO2 emissions by type of energy source in metric tons. You can convert metric tons to short tons by multiplying the number of metric tons by 1.1. Multiply the result by 2,000 to convert to pounds.
- Net Generation by State by Type of Producer by Energy Source data are in MWh. Multiply by 1,000 to convert to kWh.
You can calculate the pounds of CO2 produced per kWh for specific types of electricity generators (prime movers) using different fuels by multiplying the heat rate of a generator (in British thermal units (Btu) per kWh generated), by the CO2 emission factor for the fuel (in pounds of CO2 per million Btu), and dividing the result by 1,000,000.
Data sources for the calculation are in the Electric Power Annual:
- Table 8.1. Average Operating Heat Rate for Selected Energy Sources ( xls )
- Table 8.2 Average Tested Heat Rates by Prime Mover and Energy Source ( xls )
- Table A.3. Carbon Dioxide Uncontrolled Emission Factors ( xls ) (There are about 2.205 pounds in a kilogram.)
So....1,558.8 lbs CO2/MWh × (4.536 × 10-4 metric tons/lb) × 0.001 MWh/kWh = 7.07 × 10-4 metric tons CO2/kWh
#2) "Cold Plus is a chemical additive to improve the energy efficiency of HVAC systems, typically at commercial units. The compressor is the principal rotating shaft device in this system. The coolant (R22 in older units or R-410A or similar in newer units) is compressed into a nearly 100% liquid stream that moves across an evaporator heat exchanger and is partially vaporized as heat is removed from the room or building. The two-phase vapor-liquid stream then travels to the compressor inlet and is re-compressed and condensed. Compressors are predominantly lubricated with oil, categorized broadly as mineral oil or synthetic oil. The rotating seals of the compressor allow a small leakage of oil into the coolant. The oil slowly forms a boundary layer coating on the heat exchanger and other metal surfaces. This predominantly oil boundary layer lowers the heat transfer, requiring longer compressor run times to remove the building heat load and maintain the set temperature.
The Cold Plus, a multi-component suspension is a once-per-HVAC mechanical system-life additive that displaces much of the oil from the inside boundary layer of metal surfaces and reestablishes a low friction (slippery) polymer (PTFE) to stabilize the metal surfaces. PTFE has a higher thermal conductivity of about 2.7 W/m K while oil is in the range of 0.15-0.25 W/m K. Cold Plus conceptually also reduces fluid drag for coolant flow and improves the heat transfer thus reducing the compressor run time, which at the power (kW) usage reduces energy (kWh) consumed." -this was written by the energy efficiency department at Wichita State University funded by the Boeing Corporation Endowmment
The result is less friction, elimination of oil-fouling and higher operating efficiecies resulting in lower operating costs. Typically an 8% to 18% reduction in kWh.