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Balancing California's Energy

How much energy does the California economy use, how is the energy supplied, and what is it used for? For economic, environmental, and energy security reasons, many people are interested in the answers to these questions. The California Energy Commission (CEC) recently funded scientists in the Environmental Energy Technologies Division (EETD) at Lawrence Berkeley Laboratory (Berkeley Lab) to help find the answers. The results are the California Energy Balances Database (CALEB) and a report that features the California Energy flow chart as its centerpiece.

To compare energy sources, researchers converted them all from the units in which they are typically expressed-e.g., kilowatt hours for electricity, therms for natural gas-to trillions of British thermal units (Btus).

One reason for the state's interest in these questions about energy use is that accurate energy consumption data are prerequisite to an accurate inventory of California's greenhouse gas emissions and emissions inventory is currently being conducted by the CEC. The data are also prerequisite to developing effective plans for reducing those emissions. California Governor Arnold Schwarzenegger recently issued an Executive Order requiring the state to develop such a plan.

This is not the first time that someone has looked at how California's energy supply is used. However, this comprehensive effort attempts to resolve gaps in our knowledge about energy flows. These gaps are a result of different methods of gathering statistics.

CALEB's data are largely based on statistics gathered by such agencies as the CEC, the U.S. Department of Energy's Energy Information Administration, the U.S. Geological Survey, and the California Air Resources Board. Because different counting methods can lead to slightly different results, it is essential to make data from these different sources compatible. For the EETD study, all the basic inputs-coal, petroleum, natural gas, nuclear, and renewable sources-had to equal all the outputs, plus losses caused by the basic physics of energy conversion and transmission.

The flow chart presented here is Berkeley Lab's answer to this problem. "We had to make sure there was no glaring inconsistency on the supply side compared to the figures the state is using on the demand side," says Scott Murtishaw, primary author of the study.

The sizes of the colored bars in the chart and where they start and end reveal a lot about energy in California. A quick look at the chart confirms some expected results and yields some surprises.

One fact that's not surprising is that in a state with so many motor vehicles (nearly 30 million registrations, of which more than 18 million are automobiles), petroleum and miniscule amounts of other transportation fuels, mainly ethanol and natural gas, account for half of the state's total energy use.

What may be surprising, however, is how much of that is figure is accounted for by marine bunker fuel, used by maritime vessels-just under one-fourth of the petroleum input. "That's a consequence of having three of the United States' largest ports [Long Beach, Los Angeles, and Oakland] in California," Murtishaw points out.

Another interesting observation is that burning of natural gas provides a substantial amount of electricity in California. This is shown by the yellow bar at the top of the chart, which branches out and merges into the blue "Total Electricity Supply" bar that goes from left to right.

"This large dependency means that a rise in natural gas prices will not only affect winter heating bills but electricity prices as well," says Murtishaw.

Also worth noting is that, for reasons of basic physics, large energy losses result when fuel input is converted to electricity, for example by burning coal or gas. This is evident in the light blue bar on the center-right labeled "Transformation Loss." At an estimated 2,280 trillion Btus, transformation losses represent more than half of the total electricity supply. Consumers don't get to use the lost energy, but they still pay for it in the sense that the cost of building power plants is embodied in the utility rate structure, and laws of physics limit the efficiency of energy conversion in these power plants.

There are still some statistical uncertainties, indicated by flows into the "Statistical Differences" box. Negative numbers indicate instances where consumption appears to be greater than supply, for example in petroleum and natural gas use. These uncertainties need to be researched further.

Some features of California's energy balance are only evident in comparison to energy use in other states. For example, California's mild climate means that less energy is used for space heating in the winter than is true in colder states. The bar on the top right labeled "Residential and Services" is proportionally smaller than it would be for a state with harsh, cold winters. And because California, relative to Midwestern states for example, does not have much energy-intensive heavy industry such as steel, concrete, or aluminum manufacturing, the "Industrial" energy bar is also proportionately smaller.

Murtishaw notes that the bar representing energy from "CA Utilities Out of State" in the far left center of the chart, although small, is interesting. "California investor-owned utilities are among the few that own large out-of-state power plants," he says.

The study, "Development of Energy Balances for the State of California," was prepared by Scott Murtishaw, Lynn Price, Stephane de la Rue du Can, Eric Masanet, Ernst Worrell, and Jayant Sathaye.

— Allan Chen

For more information, contact:

  • Scott Murtishaw
  • (510) 486-7553; Fax (510) 486-6996

Download the study from the Public Interest Energy Research Program (PIER) web site.

This research was supported by the California Energy Commission's Public Interest Energy Research program.

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