What I'm writing about here is energy in the technical sense. Energy is what we use to make all our machinery run that makes our lives easier. It is frequently measured in Joules or British Thermal Units (BTU's) or multiples of these units.
Energy Links
http://www.extension.iastate.edu/grain/resources/publications/buspub/baumel01.htm
http://www.bts.gov/press_releases/2005/bts003_05/html/bts003_05.html
http://www.eia.doe.gov/emeu/aer/pdf/perspectives.pdf
http://www.eia.doe.gov/pub/oil_gas/petroleum/analysis_publications/oil_market_basics/graphs_and_charts.htm
http://www.eia.doe.gov/pub/oil_gas/petroleum/analysis_publications/oil_market_basics/petflow.htm#Flow%20of%20U.S.%20Oil%20Sector%20from%20Petroleum%20Source%20to%20End-Use,%20199
http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/atlas/serve.cgi
http://www.uclaextension.edu/arrowhead/ppts/Souten.ppt
http://www.railcan.ca/documents/english_trends_2000.pdf
http://www2.isye.gatech.edu/~jvandeva/Classes/6203/air.pdf
Why is energy important?
Energy makes our society go. The cars, buses, trains and planes we ride in use fuel. The trucks that bring us food and the farm equipment that grow and harvest that food use fuel. Our offices and houses are full of devices that use electricity. Energy gives us our society and quality of life. When we think of an improvement to our lives or a solution to a problem, it usually involves consuming more energy.
Unfortunately, there is also a dark side to our energy usage. It is a resource with limits. We have fought and will probably fight wars in the future over energy. If we run out of easy energy or the cost rises too much or too fast, many of the things that make our society work will be at risk. Without enough energy our quality of life will drop quickly. If you run low on energy, your ability to easily solve problems is reduced, and solutions that worked in the past may fail. Since much of our infrastructure is interlinked, when you lose one solution, you will degrade or lose others. All our eggs are in the same energy basket.
Note that when we “solve” a problem, we tend to use energy to do so. Then we tend to build another solution on top of the first, using more energy. We have done this repeatedly to create the society we live in. If you take away the energy, all the solutions tend to fall apart in short order. A small example is when you have a black out, the gas stations can not pump gasoline, so then there is a fuel shortage.
Thing is, we could solve many of our energy problems. We could do this not only for ourselves, but also for future generations. We could share the technology we develop and remove at least some of the justifications for conflicts. We just need to choose to do so.
The US, being around 5% of the world population uses 25% of the world's energy at this point. What happens when China with 20% of the world's population decides it wants as much energy per capita? What happens when India with another 15% of the world's population wants as much energy per capita? If we are all trying to use limited oil resources, there is going to be a conflict when demand rises by several hundred percent. Resource wars are inevitable unless we find alternative energy sources.
If we wait for a “market signal” of rising prices before acting, the “market signal” we get will hit in so many places it may be overwhelming. It may be more like a sledgehammer to our economy. A sudden lack of energy may force us to choose between bad and worse options. Do farmers get fertilizer or fuel? Do truckers get to bring us food? Do we have to go to war? War will not just be the choice of dumb politicians, it may be viewed as the better of a few bad options.
It is better to prepare alternative sources of energy now. It is similar to preparing for an earthquake. When the ground starts to shake, it is too late to prepare.
What do I need to know about energy?
The best thing to do is to ask questions.
Is there some way of comparing different forms of energy apples to
apples?
As I said before energy can be counted in units such as
Joules.
If I look at a stack of coal and a can of gasoline, I can
ask several questions:
How many joules are there my fuel?
How much does it weigh?
(Energy density in terms of weight)
How much space does it occupy?
(Energy density in terms of volume)
Is it a liquid, solid or gas.
(Liquids are probably the most portable and easiest to move)
In general you want your fuel to have a high energy density and to be easy to put into vehicles. Energy density is evaluated by weight and by volume. Gasoline has a good energy density by weight and volume (several times that of coal). Gases (natural, hydrogen, etc.) have a great energy density by weight, but not so great by volume. In order to fit in a reasonably sized volume gases have to be compressed or put into a matrix. Doing that uses more energy and creates additional problems and hazards. If we go to a hydrogen based economy, the sheer inconvenience is going to make people angry. How would you put fuel in your car if you run out of hydrogen somewhere? No easy, light, gasoline cans.
The fact that gasoline is a liquid makes it pretty darn convenient. You can pump it and pour it. With coal you need a shovel and with gases you need a compressor and high pressure tanks. Every time someone starts talking about an energy alternative like hydrogen, you should ask yourself if it will pass the convenience test. Ethanol and Methanol stand a much better chance of passing that test.
Liquid fuels are a convenient energy storage and transport medium for mobile applications. Electricity is an energy transport medium more suitable for fixed applications (home, office and factory). It is a convenient way to move energy into every room of your home. Imagine carrying a shovel of coal everywhere instead.
Where does energy come from?
Some forms of energy are not available in nature and have to be made. Electricity is not available (unless you fly a kite in a thunderstorm) without a generator which is usually driven by a turbine or engine. So electricity is really just a way of easily moving energy from another source. Similarly hydrogen gas must be made either using natural gas or electricity & water. So hydrogen is just a way of moving energy around. It is not an energy source by itself. Talking about hydrogen powered cars is stupid unless you know how you are going to make the hydrogen. So people who talk about a “hydrogen economy” are either dumb or have a hidden aggenda, such as building thousands of nuclear power plants, burning vast amounts of coal or doubling our natural gas consumption.
There are a few different real sources of energy:
Fossil fuels include oil coal and associated natural gas. Lots of coal. Oil is getting harder to get to and to get out of the ground. The more energy you spend getting your energy, the less net energy you have and the more it costs. Whenever someone comes up with a new way of getting energy (oil shale, tar sands) ask how much energy is used to get the energy into a useable form and what the economics are. The answer is usually not good. We have pretty big coal reserves, but coal is not as convenient as liquid fuels. Fossil fuels also have environmental impacts like CO2 and global warming.
Yeah, a few nuts say climate change isn't happening. Then explain to me why sea level has risen 0.71 ft in Seattle between the 1930's and 2000. It isn't caused by subsidence... Tell me why we are getting longer and longer storm events with more event rainfall, that pushes our storm drainage and sewerage systems harder and harder. Those who don't believe in climate change can delude themselves if they want, but tell them to not bother trying to lie so poorly to everyone else. Climate change is real and we are just starting to deal with its effects.
Nuclear energy can come from fission. Maybe, maybe fusion will be useful in the future. The old joke is that fusion is the energy source of the future, and it always will be. Governments have thrown a fair amount of money at fusion, but it is really hard to get significantly more energy out than you put in. Until you are able to get enough out to sustain the process and to use elsewhere, fusion will not be a viable energy source.
Fission using nuclear reactors produces ratioactive material. Some of that material can be dangerous for a long long time. People also worry about poorly run power plants having an accident. Now, nuclear engineers claim they can make power plants safe. The difficulty in evaluating this is that the risk may be lowered, but the consequences can be pretty high. In fact, since radiation is considered unusual and is invisible, most people view it as being like black magic. People don't tend to do good risk assessments in these circumstances. But when we start running low on energy, people are less likely to care.
The amount of proven uranium reserves is at least 50 and maybe hundreds of years. But, there has not been nearly as extensive a search for uranium as there has been for oil yet. So while the amount of oil reserves is not likely to increase much, the amount of uranium reserves is likely to increase.
Note that the countries with the largest known reserves are Australia (24%), Kazakhstan (17%), Canada (9%), USA (7%), and so on. But what this does show is that if we go nuclear in a big way, we will still have similar foreign policy issues as we do with oil. But, sending money to Australia would be more innocuous than sending money to the middle east.
Then there is green energy like solar, wind and tides and biofuel. Wind and tidal energy are subject to storms, which can destroy the energy collection devices or force it to stop functioning. Solar, wind and tidal sources are intermittent and require some form of equalization to provide stored energy while the primary source is absent.
These forms of energy are more present in some locations than others. The wind blows better in some locations. The sun shines more often in some locations, Arizona, than others, like Western Washington. Also, these forms of energy require collection mechanisms that require energy and money to build and operate. Between the intermittent availability and cost, there are some definite problems. Ask what the life cycle economics are.
Biofuels are a hot topic in the green energy field. Surprisingly, the big biofuel to date has been right under our noses (wood). The thing to remember about biofuels is that they use the same farm and timberland we use to feed and house ourselves. Can we feed, house and fuel ourselves all from the same land? What happens if we only have enough land to do two out of three or 50% of each?
How do we use the energy?
Like any enconomic system there is supply and then there is demand. Lets look at demand.
There is a really great website run by the Energy Information Agency (EIA). It is somewhat confused, but there is a lot of data in there that could lead to better decisions. (Your comment about stupid politicians goes here.)
The single largest sector of energy usage is transportation, 40%. The largest subsector is our cars. But I will cover freight first.
Freight
aircraft 9.1 net ton miles per gallon at 498 mph (747F)
trucks
125 net ton miles per gallon best case, 50 average at 50 to 60 mph
trains 640 net ton miles per gallon best case, 440 average at 20
mph
ships 1000 net ton miles per gallon best case, down to 350
(smaller less efficient) at 10 knots
Trucks and rail are split around 50/50 in ton miles, but in terms of tons it is more like 80 percent trucks, 20 percent rail. So rail is used for long haul stuff.
Railroads are going for their obvious strength, low cost transport of heavy stuff over long distances. If you can improve the load/unload ease and maintain medium haul rail lines you could increase the use of rail further and save energy.
Putting freight on rails cuts energy use by a factor of 8 in medium to long haul transport.
Commuters
In terms of consumption:
Gasoline accounts for 8.8 Million Barrels /Day
Dilstilate Fuel
Oil (diesel) accounts for 3.77 Million Barrels / Day
Diesel usage: 62% highway, 5% railroad, 3% ships, the rest is non-transportation. So of the fuel used on the highway 81% is gasoline (cars) and 19% is trucks and cars with diesel engines.
Cars are the biggest user of the biggest sector (transportation) of the biggest energy slice (petroleum). Cars use around half the petroleum. Petroleum is around 40% of US energy used. So cars consume around 20% of all the energy we use.
Buses get around 3 mpg and a regular size bus can seat 35, more standing, an articulated can seat 64, more standing. So figure a minimum of 105 seat miles per gallon and more like at least 140 seat miles per gallon on a full rush hour articulated bus (even at 2 mpg).
So buses are around 4 to 7 times as efficient as most single occupant cars if the buses are filled with people (unless you car pool).
If we wanted to improve our energy picture we would put as much medium and long haul truck and car traffic on rail instead. By lowering the time and cost of loading and unloading and putting money into medium haul rail infrastructure.
And for urban short haul we'd use light rail and buses and full car pools (3 or 4 people per car minimum).
This would cut energy use by a factor of 8 in long and medium haul transport. In short haul peak hour transport it would improve things by maybe a factor of 4. Of all these, car pooling would be fastest to implement and have the biggest impact. Rail would have the best fuel economy ratio.
So as you can see, there are a few things we can do to reduce our transportation energy consumption significantly.
Electricity
For our homes, offices and factories the most convenient method of delivering energy is via electricity. It is no surprise that electricity is the largest non-transportation means of delivering energy. All that electricity has to be generated from other sources of energy.
About half our electricity comes from coal and about 20 percent each from nuclear and natural gas and the rest from hydroelectric. Of the energy used to make electricity, 2/3 goes to generation, transmission and distribution losses. So if you can encourage people to generate electricity more efficiently and find ways to transmit it more efficiently you will be doing very well indeed. If we are going to generate a bunch of solar power in Arizona, it will be very nice if we can efficiently move it around the country.
Note that one of the significant issues with electricity is that it has been deregulated and turned into a free market. The conservatives say “good, good!” Well, they are likely to find the limits of free marketeering in this arena. The problem, aside from greedy people like Enron, is that there is little reserve capacity in generation or transmission left, and there is little incentive to build more transmission capacity. What economists see as redundancy, engineers know is robustness. In this arena, if we let simple economics rule, we shall just make our society more fragile. This is one example of the limits of economics. Economists are not, by and large, very good at doing risk assessments. If they were, we would live in a more robust civilization.