Where CO2 comes from

This post will deal with US emissions for 2006. Again, things can be divided into three major parts. Electrical generation accounts for 40% of all US CO2 production. Transport accounts for at least 33% of CO2. Everything else emits the remaining 27%.


Electrical Generation

This sector is the leading emitter of CO2. Furthermore, CO2 emissions from this sector are dominated by coal burning power plants. Coal plants alone account for 33% of all US CO2 production. Mostly, they run base load.

Replacing these coal plants with something else is, in my view, the easiest way to battle global warming. Nuclear power would be an ideal replacement for this coal. This one simple move could cut US CO2 production by one third without anything else having to be done. France already gets all its base load from nukes. Unlike wind or solar, nukes have a proven capability to generate massive quantities of power dependably and at an economical price.

The remaining emissions from this sector come from natural gas. Much of this is used to produce peaking power. Because of high capital costs, nuclear power is not a suitable replacement. Hydroelectric works very well, but is limited by availability of sites. Wind and solar can make a contribution here, if costs are competitive and if ways can be found to manage their fluctuating output.


Transport

Emissions from this sector come entirely from burning oil, mostly in the form of gasoline, diesel and jet fuel. It accounts for 33% of US CO2 production. I believe there is a strong case for including emissions from oil production and refining, which are usually counted under industrial, as transportation. These account for 5% of America's total emissions and bring transportation's share up to 38% of total emissions.

Cutting emissions from this sector is problematic. There are no easy substitutes for oil. Natural gas is a proven alternative, although it adds a few thousand dollars in cost to a car. There are natural gas burning buses on the road and Honda sells a natural gas powered Civic. Natural gas cuts CO2 emissions by 25% on an energy equivalent basis. Unfortunately Natural gas is not abundant and the biggest reserves are in the Middle East and Russia.

Biofuels work best for tropical countries. Brazil's sugar cane ethanol program seems to work well. America's corn to ethanol program requires lots of natural gas for ethanol production and is best analysed as a way to turn natural gas into a liquid fuel. There is little, if any, energy gain over burning the natural gas directly.

The best strategy here is conservation. European cars use much less than their US equivalents because they are smaller and diesel engines are much more common. The new CAFE standards approved by Congress should reduce the consumption of the average American car by 29% by 2020.

I believe that a great deal of the CO2 reductions in transportation will be driven by Peak Oil rather than by concerns over global warming.


Everything else

This accounts for 22% of US emissions if oil refining is excluded. Industrial emissions account for 12%, residential for 6% and commercial for 4%. This excludes the CO2 emitted to produce electricity which is used by these sectors. Industrial emissions would be higher if we didn't import many goods from overseas. Industrial emitters can often relocate overseas to escape heavy handed US global warming rules.

Looking at "Everything else"

I my previous post I pointed out that:

• Transport = 35% of energy use and almost all of the oil


• Electrical Generation = 40% of energy use and almost all of the coal, nuclear and renewables


• Everything else = 25% of energy use, much of which natural gas.

I will split "Everything else" into "Materials", "Winter heating" and "The rest."

Materials

Manufacturing the materials our economy needs accounts for 11% of our energy use. Materials include:

• Wood


• Paper and paperboard


• Plastics


• Glass


• Cement


• Metals


• Fertilizers


• Chemicals

Approximately 60% of the energy required comes from natural gas and natural gas liquids (NGLs). NGLs can be a byproduct of oil refining but most are produced along with natural gas. Coal and miscellaneous things like forestry wastes provide almost all of the rest of the energy. Apart from NGLs, little oil is used.

Winter heating

Winter heating accounts for about 6.5% of total energy use. Residential consumption surveys show that over 70% of residential heating is provided by natural gas, and the proportion for commercial buildings is similar. Much of the rest is from oil. Winter weather has a substantial impact on energy prices.

The rest

This accounts for about 7.5% of total energy use. A little under a third is energy used in natural gas production and distribution. Another third is general manufacturing excluding materials manufacturing. Residential water heating, which accounts for 1.7% of total energy use, also falls in this category.

A New Way to think about Energy

In my opinion, the way energy is discussed today is unnecessarily abstract and muddles together several separate activities that really should be kept separate. In today's post I'm going to introduce a new way of thinking about energy which will make it easier to think about long term plans for our energy future.


As a first approximation I will divide energy use into Transportation fuels, Electrical generation fuels and Everything else. I'm in the US, so I'm going to deal with this from a US perspective. I may get around to the international picture in a later post. All data is from 2005.



Transportation Fuels

Transportation fuels are gasoline for cars, diesel for trucks and railroads, jet fuel for airplanes and residual fuel oil for large ocean going ships. Note that all these fuels come from oil. Is there any transportation that doesn't run on oil? Not a lot. There are electric rail systems, mostly outside the US. There are a few natural gas powered trucks and buses. Finally, some pipelines are electrically powered and natural gas pipelines are usually powered by natural gas. That's pretty much it. Everything else, freeways, cars, trucks, airplanes and container ships runs on oil. To a good approximation:


Transportation fuel = Oil


The reverse is also pretty much true. In the US, 69% of oil goes into transportation fuels. Another 3% goes into asphalt to pave the roads. 1% goes into lubricants, many of which are used by vehicles. Another 4% is used to power the refineries. About 5% emerges as petroleum coke, which is a low value waste product of refining.

It's fair to say that over 80% of oil in the US is used to enable transportation. Some of the rest is supplied as heating oil and propane. About 2-3% is used for Electrical generation. Only 4% is used for chemicals and plastics.



Electrical Generation Fuels

There are several important energy sources which are exclusively used for electrical generation. Nuclear, hydroelectric, geothermal, and wind are never used for anything else. Wind and solar are not a solution to running out of oil, unless transportation switches to electric vehicles. 92% of all coal is used for electrical generation and coal accounts for 50% of all electricity generated. Adding up these "Power generation fuels":

• Nuclear generates 19% of electricity


• Conventional hydro generates 6.6% of electricity


• Other renewables generate 2.3% of electricity


• Coal generates 50% of electricity

These total to 78%.

Electrical generation fuel = Coal + nuclear + renewables

Most of our electricity is generated from fuels which are dedicated to power generation. Only 3% comes from oil. The remaining 19% comes from natural gas.

As a percentage of total energy use:

• Transportation = 35% (including asphalt and energy used in refining)
• Electrical Generation = 40%
• Everything else = 25%

In my next post, I will take a closer look at "Everything else."