[Greenbuilding] cost of electric versus natural gas and gasoline

[Mike O'Brien]

Hi, all--

All good points for Ben's calculus.

One more would be the respective carbon content of each fuel.

Burning natural gas produces about 11 pounds of CO2 per therm or  
100,000 Btu.

As others have noted, gas and coal are used to generate electricity.  
Here in Portland, our local utility estimates that they produce about  
one pound of CO2 per kiloWatt-hour, or about 29 pounds per 100,000  
Btu--more than double the direct combustion of gas. Our coal-based  
utility is around 64 pounds per 100,000 Btu. What will be the effect  
on costs of reducing this carbon?

Future price increases in electricity will be directly affected by  
the cost of fossil fuels, of course, but also by "shoes waiting to  
drop", for example the cost of cleaning up the smokestack mercury and  
acid pollution of coal-based utilities in the Midwest.

Here in our region electricity prices have been increased  as a  
result of deregulation, which opened the door to many scamsters like  
Enron.

At one time the biggest municipal bankruptcy ever was the Washington  
Public Power Supply System, or "WHOOPS", which spiked electric costs  
for all the participating utilities and left us unfinished nuclear  
power plants.

What I am saying is that electric costs are a function of many  
variables, including human incompetence and cupidity, that are hard  
to predict but tend to produce big jumps in consumer prices.

Best,

Mike O'Brien



On Mar 9, 2008, at 8:18 AM, Reuben Deumling wrote:

> On Sun, Mar 9, 2008 at 5:10 AM, Ted Inoue <tedinoue at gmail.com> wrote:
>
>> Ben,
>> For a comparison like this, one must also consider the  
>> efficiencies of the
>> energy conversions involved as that makes a substantial difference  
>> in the
>> outcome of the comparisons.
>>
> This is a very important point, and doing so will reveal that the 100%
> efficient electric energy (measured at the level of your house)  
> must--as
> others have pointed out on this list in the past--be multiplied by the
> efficiency with which coal or natural gas or oil was burned at the  
> power
> plant where the electricity that is delivered to your house was  
> produced.
> Commonly this is assumed to be somewhere around 35% or .35.   
> Transmission
> and distribution losses are commonly also tallied in the case of
> electricity.
>
>>
>> For example, if you use electric baseboard heaters to heat a  
>> house, that
>> delivers "electric heat" at essentially 100% efficiency. Every  
>> kilowatt
>> hour
>> of electricity pumped into the baseboards delivers the full 3413  
>> BTUs of
>> heat.
>> On the other hand, a natural gas furnace will have a combustion  
>> efficiency
>> that diminishes the actual BTUs delivered to heat the home. If you  
>> buy one
>> therm and that is combusted at 85% efficiency then you've lost 15%  
>> of the
>> energy right off the bat, and have to figure that in.
>
> Including the losses at the source then would suggest a rather  
> different
> comparison between electricity and natural gas as a heating fuel:
> electricity: 35% (not counting T&D losses) vs. natural gas or propane:
> 65-85%
>
>
>> Next, you typically wouldn't run straight electric resistance  
>> heat, but
>> instead would use a heat pump. A good heat pump delivers 8-9 BTUs  
>> of heat
>> for every one watt put in (see the HSPF rating). This effectively  
>> improves
>> the comparison in favor of electric heat by a factor of 2+.
>>
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