IEA Training Manual - Module 5

4.4.2 Identifying and explaining trends

Once you have developed potential indicators, and have collected relevant data, it is possible to begin to analyse those data to identify and demonstrate trends. Readers with little or no experience with indicator development and data collection are encouraged to take time now to review Module 4 on Data and Indicators.

The integrated story, illustrating causality among key drivers and environmental states, is just the outer layer of the analysis. Beneath this high level integrated story are other stories more intimate in detail, which help us better understand what is happening to the environment and why. Getting to this next layer of information requires analysing the indicator to identify correlations, and to explain key temporal and spatial patterns.
A good place to start is the analysis of the state indicator to get to the core of the issue. The example below illustrates such an analysis for automobile fuel efficiency.

Case Example: Advanced

Figure 12: Historical analysis of
on-road vehicle fuel efficiency in

Source: IISD and TERI 2002.

Identifying and explaining trends in on-road automobile fuel efficiency in Canada

Travel by automobiles is one source of emissions in Canada. The fuel efficiency of the fleet of automobiles on the road in Canada is one good indicator of this pressure. Figure 12 presents on-road fuel efficiency data for the period 1970 through 1994, along with data for vehicle stock and average vehicle fuel efficiency.

Consider a historical analysis as a first step in identifying and explaining trends in a pressure indicator. The sudden improvement in fuel efficiency realized in the late 1970s as illustrated in Figure 12 below, can be explained by the Corporate Average Fuel Economy (CAFE) standard that was adopted in the United States in 1975, following the 1973 Middle East oil embargo. In Canada in the 1980s, voluntary industry fuel efficiency targets were put in place through the federal government’s Company Average Fuel Consumption (CAFC) programme. Through the 1980s, a 55 percent improvement in on-road fuel efficiency was realized in Canada.

But, there was a sudden halt in fuel efficiency improvements in the 1990s. In looking at an indicator of the vehicle stock, we see a change from small and large cars to light trucks that were used as personal vehicles, and often called sport utility vehicles. In fact, it would also appear that the change in the vehicle stock during the 1980s (more small cars and fewer large cars) was a factor in the longevity of the on-road fuel efficiency increase experienced during the 1980s, aided by increases in the on-road fuel efficiency of both small and large cars during this time.

It would appear that the lack of improvement in on-road fuel efficiency in recent years late is due to society’s preference for larger, less fuel-efficient light trucks and sport utility vehicles.


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- - 08 Aug 2012
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- - 05 Aug 2012
I'm looking to buy a car here and was doing the rcraeseh. The Cost to Own of Hybrids was consistently more than similar (or same) model non-Hybrids. The only advantages Hybrids have is with the fuel costs over the life of the car, and the Hybrid tax credit. But, they're at a disadvantage with almost everything else. And, they're killed by the depreciation, due it seems to the high invoice price. (O.K. I think I just unintentionally made a really good argument for buying Hybrids Used.)But, just to compare the two cars I'm liking, the Honda Civic super-basic trim has a CtO of $24,200 and the Honda Civic Hybrid $26,900. And, the Civic Hybrid is actually way more affordable and closer to the CtO of its non-Hybrid sister model than the other Hybrids I've been looking at.Here's what I'm thinking. The projected Cost to Own is based on a few guesses, like how much mileage you're likely to have, and the price of gas pretty much staying where it is.Now I don't want to read doomsday predictions about how we're going to go all Mad Max. I don't. But, it's natural to suppose the trend of gas prices going up is going to continue.I mean the reason it happened in the first place is because people in developing countries have been buying cars, so the demand for gas has gone up. These countries aren't done developing. Or, to put it another way, there's alot of people in the world who haven't bought a car yet.Back to the Civic I figure with the differences in CtOs not including the cost of gas ($4,300), the cost of gas would pretty much have to double ($4,300/($8,600-$6,200)=~1.8). And, that's pretty much just for the Honda Civic. I'm having a real hard time imagining a horrible nightmare scenario where the Ford Fusion Hybrid New would be a better buy than the Ford Fusion New.I guess I've pretty much already answered my own question. But, I have another scenario for all of you. If someone starts mass producing Hydrogen Fuel Cell cars for mass sales, what's that going to do to the price of gas? I'd expect it to go down partly because the demand for gas would be stemmed somewhat, but mostly just because the gas companies would want to incentivise their consumers keeping combustion cars.I guess the big question there is, how likely is that to happen in the next 5 years? Or however long? Isn't it odd how these alternative cars have the potential to sabotage each other?And, how competitive is hydrogen with gas as a fuel? Obviously, there's the old issue that hydrogen would have to build their distribution from the ground up. But, once that's done, how much would a mile fueled by gas cost vs. a mile fueled by hydrogen?Gas comes out of the ground with it's energy already in it. Petroleum pumps try to be (and are) highly energy efficient. But, pumping a liquid out of minerals Well, isn't that like squeezing blood from a stone?Hydrogen you have to use up energy to electrolyze it or refine it from fossil fuels. I'm not bothered so much by the greenhouse implications. From an engineering standpoint it's an energy storage device. What's the cost? Electricity is cheap. Right?Then there's the comparative fuel economies of fuel cell and combustion cars. Hydrogen is more energy intensive than gas. A full tank is lighter. The lightening of the cars load would give it a slight advantage in fuel economy. Wouldn't it? (Get the image of hydrogen making balloon floaty cars out of your head please. It so doesn't work that way.) Also, since the internal drag is on a much shorter drive train, wouldn't that give Hydrogen Fuel Cell cars a tremendous advantage in fuel economy?So an swers, are you saying that if I asked these other questions separately you WOULD answer them? Besides I'm dubious of that on it's own, it kind of sounds like Y!A points farming to me, at a cost to me!Beyond that it's occurred to me you don't have to double the price of gas. For vocations that involve alot of driving you could easily more than double the mileage and the fuel consumption. Like I imagine Taxi companies, if they're not using Hybrids are pretty much losing money.From the National Hydrogen Association: The estimated costs for producing and delivering hydrogen to thefueling station using today’s technologies vary from $2.10/gallon of gasoline equivalent (gge) to $9.10/gge. These hydrogen costs do not include highway taxes and do include the increased fuel efficiency of fuel cell vehicles compared to gasoline-powered hybrid electric vehicles. So best case scenario hydrogen is just competitive with gas.An swers, sorry you did write that mileage can make a Hybrid worthwhile first. But, I still don't like the other thing you wrote, if only because that means flooding the latest question pages with spam questions. There's enough inane crap on here as it is.On the other side of things, saying hydrogen as a fuel isn't going to happen in a big way tomorrow is not the same as saying it's never going to happen. The price of gas will go up, not least of all because people consider it to be an essential consumable. People don't just use less simply because demand outstrips supply, so the price has to go way up to be prohibitive. Next we'd need to see a big drop in the price of electricity. Maybe when they mine the moon for tritium for fusion power, though the new fusion powerplants and the power infrastructure will still cost money on top of the price tag of a commercial lunar space program. I think the big energy conglomerates like GE can afford to do it easy. But I've never been a big fan of electric cars. I don't think the oil companies are trying to keep them buried because they threaten their monopoly. I just don't think they've ever really been any good. Granted tremendous advances in battery technology have given them a huge step forward. But, even with that and regenerative braking (an old technology which has gained new interest) electric cars' ranges just aren't very good. I know that sound like a strawman attack, like the old one that electric cars can't make it up hills. But, it's true. At the least, going on a roadtrip in an electric car is out of the question. It doesn't help there the batteries are pretty dang heavy. But again the weight is less important than internal drag on the drive train, as well as regenerative braking. (Batteries are also expensive, but not more so than engine blocks and full drive trains, and definitely not more than hydrogen tanks and fuel cells.)
Module 5 - Integrated analysis of environmental trends and policies
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