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EIA projects US energy-related CO2 emissions to remain near current level through 2050; increased natural gas consumption

Carbon dioxide emissions from S energy consumption will remain near current levels through 2050, according to projections in EIA’s Annual Energy Outlook 2019. The AEO2019 Reference case, which reflects no changes to current laws and regulations and extends current trends in technology, projects that US energy-related CO2 emissions will be 5,019 million metric tons in 2050—4% below their 2018 value—as emissions associated with coal and petroleum consumption fall and emissions from natural gas consumption rise.


USenergy-related carbon dioxide emissions and fossil fuel energy consumption. Source: US Energy Information Administration, Monthly Energy Review, Annual Energy Outlook 2019 Reference case

Energy-related CO2 emissions generally follow energy consumption trends. In the United States, emissions associated with the consumption of petroleum fuels—motor gasoline, distillate, jet fuel, and more—have consistently made up the largest portion of CO2 emissions. In 2018, the transportation sector’s consumption accounted for 78% of US CO2 emissions from petroleum and more than one-third of all US energy-related CO2 emissions.

Petroleum emissions from other sectors have fallen in recent years as equipment and processes that use petroleum fuels have been replaced by those using other fuels, in particular, natural gas.

In the transportation sector, consumption and emissions trends in the past have been driven by changes in travel demand, fuel prices, and fuel economy regulations. In EIA’s AEO2019 Reference case projection, current fuel economy standards stop requiring additional efficiency improvements in 2025 for light-duty vehicles and in 2027 for heavy-duty vehicles, reflecting existing regulations. As travel demand continues to rise, transportation consumption and emissions increase.


US energy-related carbon dioxide emissions in AEO2019 Reference Case. Source: US Energy Information Administration, Monthly Energy Review, Annual Energy Outlook 2019 Reference case

Natural gas is the least carbon-intensive fossil fuel, and for decades natural gas made up the smallest portion of US energy-related CO2 emissions. However, in 2015, natural gas emissions surpassed coal emissions, and the AEO2019 Reference case projects that natural gas CO2 emissions will continue increasing as natural gas use increases.

The US. electric power sector—now the largest consuming sector for natural gas—has added generating capacity from natural gas in recent years and has used those power plants more often. Natural gas surpassed coal to become the most prevalent fuel used to generate electricity in the United States in 2016.

Other sectors have also increased their consumption of natural gas. By the mid-2020s, EIA projects that the industrial sector will again become the largest consumer of natural gas, using natural gas as a feedstock in chemical industries, as lease and plant fuel, for industrial heat and power applications, and for liquefied natural gas production.

The residential and commercial sectors are also expected to continue using more natural gas. For instance, EIA projects that natural gas furnaces and boilers will be used in 55% of US homes in 2050, an increase from their 49% share in 2018.

Coal CO2 emissions in the United States are almost all from the electric power sector. Only about 10% of coal CO2 emissions came from the industrial sector in 2018, and this percentage is expected to remain the same through 2050. Although the AEO2019 Reference case projects that nearly one-third of the existing coal-fired electricity generating capacity retires within the next decade, the surviving fleet is used more often, meaning coal’s projected decline in electricity generation is less than the capacity retirements would suggest.



You could drop that 50% with a combination of wind, solar, gas, nuclear, hydro and HVDC cables.
It would take a while (say 10-20 years) but it would work.
You could probably get a 70% drop - beyond that, it would get tricky.


Yes mahonj, it could be done. However, there's a lot of commercial, political and individual built in resistance against the use of cleaner energy sources.

The North East States keep on refusing to buy more very low cost (4 cents/kWh including HVAC/HVDC lines) clean Hydro/Wind energy from North of the Border, to keep the local/national Coal and NG industries going, regardless of increased CO2 emissions?

The consequences of GHGs on living creatures and the planet or not (yet) sufficiently known?


The people in West Virginia have been colonized around the coal industry; the entire state is run by coal effect that's all they know. The same is true of Louisiana, which is dependent on the petrochemical interest for their livelihood. The fossil fuel industries have a hundred years of domination and a decided head start on the forces in play for transitioning to clean energy. It will take a concerted effort to educate these brainwashed citizens to accept the idea of change, even when they know the change is in their best interest.

By far the best way to accelerate the transition would be for the Government to get behind the push to the future by creating green jobs and retrain these pollution industry workers for the clean energy jobs; but, that won't happen under Trump and the Republicans. who work for the fossil fuel companies. All the GOP has to do in the coal regions, West, Virgina, Kentucky, Pennsylvania, etc., to get their vote, is threaten their jobs.


Projections that far into the future do not make much sense. In the 1890's people were trying to project how deep the horse manure would be in the streets of America.


ConEdison states that 91% of the steam generated in NYC comes from natural gas (the rest comes from fuel oil).  50% of steam consumed is cogenerated.

ConEd claims 10 million pph of steam and 358°F steam temperature at 165 psig, (181.1 C and about 12 bar absolute, which is actually subcooled water at that condition).  But taking saturated steam at 181 C I calculate 2694.8 kj/kg enthalpy relative to liquid at 20 C so 10 million pph carries 3.39 GW(th).

Why burn natural gas when you can use uranium?

An S-PRISM has a design thermal rating of about 1000 MW(t), so 4 of them should suffice to run the NYC steam systems.  However, the S-PRISM operating temperature is well above the system's steam temperature.  Assuming a Cal Abel-style system with molten salt heat storage for load following with a boiler producing superheated steam at 450 C (842°F) and 200 bar, expansion to 100 bar, reheat to 450 C and exhaust to the steam system at 10.252 bar:

Total heat additions 3369.5 kJ/kg
total work out 760.5 kJ/kg
eff = 22.6%

From 4 GW(th) of heat supply, that's 3096 MW of steam heat plus 904 MW(e).  You could always bypass some steam from the turbines if you needed more heat.  When the full amount of heat was not required, a 90% efficient low-pressure turbine exhausting saturated vapor at 30 C could extract a further 699.2 kJ/kg from the steam and boost the thermal efficiency up to 43.3%.  That would allow up to 1732 MW of electric generation.

I'm wondering if I didn't make a mistake somewhere in the steam calculations, as that efficiency seems rather high.  I'm not seeing anything, though.  Maybe I'm assuming too low a limit on steam quality (fraction of vapor to total mass) in the LP turbine.

So 4 S-PRISM modules could both provide all the heat that NYC's steam systems require and also generate almost as much electric power as Indian Point.

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