More on the R Factor

I have gotten average data from EIA and an article by Papatheodoru:

Energy-----R------Eff (%)----Eff/R----Cost
Source--------------------------------------$/W

Coal-----------5.9-----70----------12-------1.25
Nuclear------7.5-----90-----------12-------2.10
Hydro---------3.7-----35----------9.5------1.54
Biomass-----6.3-----50--------- 7.9------1.80
Geotherm.---6.4----80----------13-------2.20
Solar-----------1.3----20----------15-------5.00
Wind-----------2.0----25----------13-------1.18
Avg.----12.8

So R is essentially a function of efficiency. As an estimate:
-------------------------R = Eff/13

note: R converts MW to GWh or kW to 1000kWh

Wind Power

I've always wanted a parameter named after me. So I devised the R term to convert electric power into electric energy. Of course, power does not convert directly into energy ( there is no simple multiple between watts and kilowatt-hours), but R can be a useful estimator.

The defining equation is

RP = E

where R is the conversion factor, P is power in MW, and E is electricity in millions of kWh per year. I checked some data and found for wind that R averages 2.25 with most values between 1.9 and 2.6.

So if you want to estimate the annual output of a 1MW turbine, it's about 2.25 million kWh/yr.

I also averaged some cost data for wind power and found that:

C =1.62 - 0.24*lnP

where C is cost in $/Watt and P is Power in MW. So a 2MW turbine comes in at $1.45/watt, which is not bad

Chernobyl

I'm amused at the conflicting results of energy analyses (the current one is on how much energy is needed to produce corn ethanol). I have a suspicion that the analyst first decides on the answer and then looks for support - just as Christopher Columbus did 500 years ago (see the bio by Adm. Morrison).

A good example is Chernobyl:

Deaths Resulting from 1986 Chernobyl Reactor Accident

Deaths Source

56 World Nuclear Association
4,000 U. N. Chernobyl Program
16,000 International Agency for Research on Cancer
30,000 - 60,000 European Green Parties
140,000 Greenpeace

Note that the estimated number of deaths depends strongly on the organization's stance on nuclear power.

(I can't get this table to format correctly! but it makes the point)

Electric-Powered Cars

(Written several months ago - may need updating)

Fuel costs the average driver about a dime per ten miles; a good gas/electric hybrid lowers that to about a nickel. Powering an all-electric car is even cheaper (1). The reverse is true for purchase price. All-electric cars are the most expensive and gasoline-powered ones the cheapest.

Hybrids are generally believed to be important energy savers, which is true if they are compared with gas guzzlers. However comparing the same make and model in both standard and hybrid versions reveals a different story. On average, hybrids cost about $6,500 more than standard versions and only get about ten mpg greater mileage (2). I made some rough calculations and found that the price of gas would have to roughly double to make a hybrid purchase worthwhile economically. With gasoline prices soaring (3) and electricity prices increasing only moderately (4), hybrids should become less of an economic burden. Hybrids also have the advantage over all other new car concepts, in that they can be fueled at any gas station. The gas tank can also be modified to take ethanol blends. There is some demand for them and about there are about 600,000 hybrids on the road now (5).

All-electric cars are not yet commercially available, except in golf-cart size. Conversion kits for full-size vehicles cost around $15-20,000, about half of that price if you install one yourself (6). Even at these prices, the break-even price on gasoline costs is somewhat less than for hybrids. All-electrics are also both the most energy-efficient auto technology and the quietest (7). Because all-electric cars can only go about 100 miles between charges, they can find use as ‘urban cars’, which take advantage of the fact that most cars travel only 40 miles on a typical day and can be recharged after the driver comes home at night.

Both classes of electric car will benefit from advances in battery technology to improve the range of all-electrics and to cut down the time needed to charge them. Plug-in hybrids (8), which are receiving increased attention, suffer from the same problems.

REFERENCES

(1) "Crunching the Numbers on Alternative Fuels", Popular Mechanics, May 2006 [2-42]

(2) Yahoo Autos

(3) Energy Information Administration Petroleum Navigator

[2-110]

(4) Energy Information Administration Average Retail Prices of

Electricity [2-106]

(5) a. R.L.Polk News Index

b. R.L.Polk News Archive

(6) Electric Auto Association

(7) Michelin Challenge Bibendum, Paris 2006

(8) Plug-in Hybrids <www.sheryboschert.com/PowerPoints/florida.ppt.htm>

* Hydrogen-powered cars are sometimes considered electric vehicles. Because of their special problems, I consider them a separate class.