Creativity and Invention

Invention is the act of making something entirely new or of discovering an entirely new way of accomplishing something, and so often this is a result of trying many different approaches. For me, when one method doesn't work or achieve the results I need, I just try something else. Yet what will make an approach different from someone else's approach is the spark of creativity. To solve the problem, try applying a technique or a principle that, at first glance, doesn't seem to apply.

When I invent things, I know I'm trying to solve a problem. I'm exhausting all of the possible ways to solve it. I'm looking for an efficient way to make use of the information or progress that has been made so far. I'm finding a better way to do it. Or a way to do it at all.

Try Something Unlikely

In ancient Egypt, blacksmiths were good at forming swords other rudimentary tools by holding a piece of iron into a fire to make it malleable and beating it with a hammer. The hammer and anvil had been used for many years, having been invented in the iron age. But sometime around 1450 BCE in ancient Egypt during the reign of Twthomosis III somebody decided that a leather bag could serve as a bellows, and that the increase of forced air would make the fire hotter. Because of this, metal became more malleable, and could even be melted.

This is a clear example of using an unlikely object in common use for something else entirely. A leather bag, used for carrying things, becomes a bellows for metallurgy. Many inventions, in fact, require this kind of discovery.

To make these kinds of discoveries, we must learn about as many things as possible, but perhaps not in depth. Absorbing a little about plenty of subjects is food for invention. It helps you make connections between things that are, for all intents and purposes, not connected in the first place.

For instance: knowing about Voronoi diagrams helped me figure out how best to render fascinating patterns like those produced by raindrops on a windshield. My blog post on where ideas come from is helpful in understanding how to exercise your brain to make such connections.

Try Try Again

But even more discoveries happen a small bit at a time. And the light bulb is the perfect example. Most people associate Thomas Edison with the discovery of the light bulb. But really, he only participated in part of the invention: the part that made it practical.

In 1800, Humphry Davy, in Britain, discovered that applying electricity to a carbon filament could make it glow, demonstrating the electric arc. Some 77 years later, American Charles Francis Bush manufactured carbon arc lamps to illuminate Cleveland, keeping the filament in a glass bottle. Two years later, Thomas Alva Edison discovered that filaments in an oxygen-free bulb would still glow. Then he tried literally thousands of materials before settling upon carbonized bamboo for the filament. The new bulb could last 1200 hours. And it had a screw-in base! But it wasn't until 1911 when modern sintered ductile tungsten filaments were invented at General Electric, that their useful lifetime was increased substantially. Then, in 1913, Irving Langmuir started using inert (electrically nonconductive) gases like argon (instead of a vacuum) inside the bulb, which increased luminosity by a factor of two and also reduced bulb blackening. Nitrogen, xenon, argon, neon, and krypton are routinely used inside bulbs today. However, when mercury vapor is used, the gas itself is the conductor, producing blue-green electric arc.

Of course, light bulbs are being reinvented every few years now. Fluorescent bulbs are used in businesses largely because they are four to six times the efficiency of incandescent bulbs. Then there were compact fluorescent light (CFL) bulbs, sharing the same efficiency advantage, but in a compact light bulb form factor. And now light-emitting diode (LED) lighting. These new bulbs save about 80-90% of the energy (over incandescent bulbs) required to illuminate us. And they last about 25 times longer than CFL bulbs.

The future is going to be just as much about conserving energy as it is about producing it.

Try Harder

The main use for creativity in invention is simply so you can solve the hardest problems of all. These are the problems that don't have an apparent solution.

Two supreme examples of this kind of problem are computer vision and computer cognition. Teaching a computer to understand everyday objects like faces, kinds of clothing, the make and model of a car, and even something as simple as a tree is incredibly difficult. Humans do this very well, of course, and this belies its complexity. Teaching a computer to read and understand a book is also hard beyond comprehension. Small parts of this, like optical character recognition and a small amount of natural language processing have been accomplished. But for the computer to actually understand the subject matter and discuss it, or even better to learn from it, is practically impossible. People dedicate their lives to solving this problem.

A small example of the problem of computer cognition is what I once dreamt about: subject space. I envisioned a space where all concepts are related in different ways. Each concept is a node in the graph of subject space and arcs between the nodes relate them.

Here I show is-a relations as a green arrow between two objects. So the green arrow between FLEA and BUG represents the information that a flea is a kind of bug. Similarly meat, rice, and carrot are a kind of food. This is a subset relationship. Another kind of relationship has to do with ownership or possession. A cyan arrow from one object to another means that the source object can possess the destination. A dog has legs, and so does a bug. A has relation can have other information associated with it. For instance, a dog has 4 legs and a bug has 6 or 8 legs. Any relation, which generally is where the verbs live in this space, can have additional information associated with it, in the form of an adverb. For instance the eats relation can have quickly associated with it.

Action relations concern a direct or indirect object. These are shown in indigo. Legs walk on the floor. A human buys food, and a dog eats the food. A flea lives on the dog. In this way buys, walk-on, lives-on, and eats are relations. And by definition, those relations can have a timestamp associated with them. The sequence in which actions occur affect the semantics. Sometimes in a causal way.

Very complicated relations are two way arcs, like the dog-master relationship. There are other obvious relationships, like is-an-attribute-of, where appropriate adjectives may be associated with subjects. Even idiomatic expressions get their representations here. For instance hair of the dog is slang for an alcoholic drink.

Note that a human has legs but I didn't include an arc for that relationship. This shows that subject space is not planar. In fact, it is n-dimensional.

Such a graph is useful in understanding and parsing the grammar of text or spoken language. A sentence can then be encoded into a series of factual semantic concepts. For instance, if you know the man buys food, then you will have to determine what the food consists of. Based on this graph, it could be meat, carrot, or rice, or some combination of them.

Also, the relation eats really means can eat. When parsing text, the fact that a given dog is eating or has eaten food is yet to be discovered. Once discovered, this subject space graph helps the semantic understanding system codify the actions that occur.

Sometimes the solution, however complex, can come to you in a dream. And this shows a creatively-applied technique, graph theory, and how it is applied to a nearly impossible problem, computer understanding.

Trial and Error

It is quite remarkable when a discovery gets made by accident!

Physicist Henri Becquerel was looking for X-rays from naturally-fluorescent materials in 1986. He knew that phosphorus would collect energy by being exposed to sunlight. And he had a naturally-fluorescent material: uranium. But there was one main problem: it was winter and the days were all overcast.

So the put his materials together in a drawer, including a bit of uranium and a photographic plate, and waited for a day when the sun would come out. When that day came, he removed the materials from the drawer and soon found that the photographic plates were affected by the uranium without being first exposed to sunlight.

And radioactivity was discovered.

My point is that sometimes a discovery is the result of unintended consequences. As for me, I have invented a few effects by accidentally creating a bug in a program I wrote. This is part of the pleasure of working in graphics. In fact, the cool visual effect in my Mess and Creativity post was discovered as the result of a bug in a program that computed image directions.

Trials and Tribulations

One problem, the lofting problem, was an elusive problem to me for years. I spent a lot of time constructing better and faster Gaussian Blur algorithms over the years, and even learned of a few new ones from such people as Michael Herf and Ben Weiss. But it wasn't until late 2004 that Kok Chen suggested that I apply constraints to the blur. And an iterative algorithm to solve this problem was born. This is detailed in my Hard Problems post.

Disruptive Technology, Part 2

The times, they are a-changin', and maybe it's time to change the batteries as well. In the first installment of disruptive technology, we talked about brick-and-mortar disruption by internet commerce, the disruption of books by digital media, the constant revolution in data storage, and the disruption of several markets by smartphones and tablets.

Now we will talk about some another market currently undergoing disruption.

Internal Combustion Engines

Most people would think that the internal combustion engine is here to stay. This is almost certainly true because of the near-impossibility of replacing aircraft engines with anything else at present. But with cars, some leaps and bounds have occurred. And the market is beginning to see the effect of technology disruption.

Hybrids

Hybrids are here and are rapidly maturing as a market. The revolutionary vendor Toyota farmed out an entire market and became the Apple of hybrid vehicles with its Prius. Now most manufacturers have a hybrid car and this is increasing the average efficiency of petrochemical fuel usage. Which has been lowering the demand for three years now. But hybrids are still dependent upon gasoline. Is it possible to dispense with the petrochemical use and make a vehicle that only uses batteries?

Electric Cars

Electric cars do exist and are in common use already. The Chevy Volt, the Nissan Leaf, and the Tesla Roadster are examples of all-electric cars (except the Volt, which has a range-extending internal combustion engine, of course). Electric cars provide zero pollutants (and no tailpipe). The engines are quiet, and efficient, providing better acceleration than internal combustion engines. And they don't use foreign resources. So they can reduce the dependence upon an imported consumable.

But there are issues with electric cars: maximum distance traveled, charging, acceleration, batteries, the carbon footprint of making the electricity in the first place, and of course payoff.

Maximum Distance Traveled

The Tesla Roadster travels 244 miles between charges, but costs $104,000. The new Tesla Model S is coming out this summer with 160 miles between charges and has an extended-range model that can go 320 miles between charges. And the price, at about $40K to $60K comes down to less than half that of the Roadster. But it has about the same acceleration capabilities.

Other electric car offerings, such as the Chevy Volt (40 miles between charges, but with a range-extending internal combustion engine), and the Nissan Leaf (100 miles between charges) are extending the options for prospective customers.

But the scoop is that the Volt is really more like 33 miles between charges.

Charging

Charging one of these cars is actually quite cheap: somewhere between $2 and $4 per "tank". That's certainly encouraging, given that a tank of gas cost me $80 this morning. Yet it took me about 4 minutes to fill up.

But wait, how long does it take to charge these cars? On a 110-volt outlet it could take as long as 20 hours! With a 220V outlet, this goes down to 8 hours. You might be installing one of these in your garage. It's not really too foreign since your dryer has the same basic hookup.

But the huge amount of time it takes to charge is still reducing the usefulness of these devices. I have heard of quick-charge stations; couldn't we just use those?

Practically all of the "quick-charge" stations are in Southern California. So much for going to the gas station! Even a quick-charge to 80 percent capacity is an agonizing 30 minutes of time.

Yet, Nissan seems to have come up with a ten-minute charging solution by changing the material of the electrode in the battery. This could be just what is needed. Or at least it's a start. And it may not appear in use for quite a while, as is typical for battery advancements.

Acceleration

These cars will have to be as ballsy as mine before I buy one. Well, in some cases they actually are! The Volt goes from 0-60 MPH in about 8.5 seconds, 10 seconds with four occupants. The Nissan Leaf goes from 0 to slightly over 60 MPH in 11.9 seconds. Ho hum.

But the real surprise is the Tesla Roadster with 0-60 MPH in 3.7 seconds! And the Tesla Model S approximately matches this. So there are some more expensive options out there for those of us who like to drive fast and feel the torque.

The improvement in acceleration was achieved by replacing lead-acid batteries with lithium-ion batteries. Now, the amount of energy per pound matters almost as much as the total amount of energy stored.

Batteries

The main issue with electric car batteries is how much power they can store per weight. Lead-acid batteries (used in traditional internal combustion engine cars) can store 30-40 Watt-hours per kilogram. If we use a Nickel-metal hydride battery, we can get 30-80 Watt-hours per kilogram. If we step up to Lithium-Ion batteries, though, we can get 200 and more Watt-hours per kilogram, though typical Lithium-polymer batteries are at about 100-130 Watt-hours per kilogram.

But each of these technologies has a different issue: how many charges it can withstand before requiring a replacement. On the Tesla electric cars, a "blade" technology allows part of the batteries to be replaced in the shop on a need-be basis.

Some new Lithium-ion battery types can withstand 7000 or more charges, which means they could practically last more than ten years.

The idea of swapping out batteries for freshly charged batteries is a possible solution to the charging problem, and it can also alleviate the problem of the lifetime in terms of the number of charges. Then you could go to the gas station (actually a battery swapping station) and get an instant refueling. The time to refuel the batteries would then be spent in the charging stations themselves. Hmm.

So what we need is a standard battery type that is shared between all electric cars. Right now, the battery is really one of the major advantages that each electric car vendor actually has. With the right standard (that had the right flexibility), though, the research on batteries could go on in parallel to the electric car manufacturers and improve incrementally over time. It would create a new industry.

Carbon Footprint

These cars are electric, right? They are totally green with no emissions! Oh, wait... where does their fuel come from?

Really, the carbon footprint of an electric car is the footprint of the creation of the electricity used to charge the batteries again and again. So, where does your electricity come from?

In China, the explosion in electric and hybrid cars has led to an interesting problem. It turns out that the carbon footprint of making the electricity is much worse than that of using internal combustion engines in the first place. This is because they use coal to make 70 percent of their electricity (cough).

Payoff

These cars will certainly pay off over time, since we won't be buying gasoline, right? It turns out that electric cars are quite expensive compared to their internal combustion and hybrid cousins. Well, the payoff probably won't be there until oil gets to about $300 a barrel.

As for the Tesla Roaster: payoff isn't really the right word. It's about the satisfaction of driving one, I hear. Payoff is getting better for the Tesla Model S, though.

Their recently introduced (but yet to be manufactured) Model X is more of an SUV when compared with the Model S's sedan format.

Planes, Trains, Trucks

The larger hauling capacity of trains and the extreme energy requirements of aircraft are in another league from the hauling and energy requirements of personal transportation. Diesel fuel, Jet Fuel, and gasoline is used for these situations because the energy density of petrochemical fuels is about 35 times the energy density of the best batteries in use with electric vehicles today.

Currently only Hydrogen has the possibility to displace it, when compressed. But even Hydrogen uses up more space: it takes six times the volume to store an equivalent amount of Joules of energy using Hydrogen than when using gasoline.

So, perhaps the internal combustion engine is here to stay for a while. At least for the heavy lifters of industry and travel.

What Needs To Happen?

Can technology overcome the problems with electric cars? To some extent and within a limited usage constraint, it has already. But to get to the point where even aircraft can practically become electric, some changes are going to have to occur.

We need a serious advance in battery energy density. If you consider that the efficiency of the electric motor is about 75% compared with the 20% efficiency of the internal combustion engine, and if you consider the factor of 35 of energy density between the best batteries and gasoline, the energy density will have to go up by a factor of at least about 11 or 12 before we can see batteries powering Dreamliners. But is that all that's needed?

No.

The amount of time it takes to draw a given amount of energy from a battery must also go down, so you can increase the work temporarily for harder tasks. And the charging time will have to go down, even if battery swapping stations can become the standard.

This means that batteries and capacitors are going to have to merge. A capacitor can be charged in very little time, hold its charge for a very long time, and discharge almost instantly. If a battery can be switched into capacitor mode, this will go a long way to improving the usefulness of batteries for driving mechanical systems that require a large amount of work.

Energy, Part 1

As the world moves closer to fossil fuel depletion and global warming seems to be increasingly caused by carbon dioxide emissions, sources of green energy have become more and more important. But what are green energy technologies and how far have they gone towards adoption? What hold-ups are there in relinquishing fossil fuels? What can satisfy humanity's diverse and enormous requirements for energy? To even start to answer these questions, we need to know how energy is harvested, stored, and consumed.

Harvesting Energy

Since Einstein we have known that energy is contained in all matter, and his famous formula represents an upper limit on how much energy can be harvested. And in a few cases, we have determined how it can be extracted, with varying efficiencies. Let's look at a few. The first method of energy extraction is from an exothermic (heat-producing) chemical reaction. This method is used in internal combustion, and it releases heat, measured in Joules. For example, when combusted with oxygen the following fuels release this much energy in kiloJoules per gram:

• Acetylene 11.8
• Ethanol 27.3
• Coal 17-21 (sub-bituminous) 29-33 (bituminous or anthracite)
• Kerosene (Petroleum) 43.1-46.2
• Methane 50.6
• Gasoline 51.6
• Hydrogen 120

The reason Hydrogen has so much promise is due to its clean-combustion: water is the only by-product of combustion with oxygen. The other fuels release CO2 in varying amounts per kiloJoule of heat produced: gas is the least at 1.2 moles of CO2 per megaJoule and coal is the most at 2.0 moles per megaJoule.

The conversion of harvested heat into electricity or mechanical motion is quite a different matter.

Most people know that internal combustion engines are really controlled explosions. The addition of heat to a gas causes a significant change in its density. This change is implied by the law of ideal gases:

PV = nRT

Here, P is the pressure, V is the volume, n is the amount of the gas, R is a constant, and T is the temperature.

From this, we can see that when you increase the temperature, while keeping the amount of gas and the volume it is contained in constant, then you must increase the pressure proportionally. A massive increase in heat and a chemical reaction can create an explosion, which is a massive increase in volume. This is what happens in an internal combustion engine: the gas explodes, the massive increase in pressure drives a piston, and the motion of the pistons drives a cam shaft.

In modern cars, this is used to propel the car forwards, as work.

This can also be used to move a rotor and generate electricity through electromagnetic induction. Many power plants work this way, including the Moss Landing power plant in California.

Chemical reactions, to generate heat and drive turbines, generate about 65% of the world's electricity requirements today.

The second method of energy extraction is the harvesting of kinetic energy from matter that is already moving, such as water and air. This energy is almost always harvested using a turbine.

Have you seen the wind machines dotting the hillside near you? Those are wind turbines that harvest electricity from the wind itself, with very little effect on the environment. This is commonly called wind power, and is a renewable energy source, powered indirectly by the sun with the process of convection, and the turning of the earth, through the Coriolis force. Wind power currently generates about 1% of world electricity requirements, though the cumulative output is growing exponentially, suggesting in 20 years that an 8-fold increase will occur.

Another kind of kinetic energy that can be harvested is moving water. This is commonly called hydroelectric power. I'm sure you have noticed that water runs downhill. Here gravity itself is harvested because of the inexorable tendency of water to find a common level. Water, usually stored in a reservoir (fed by rain or snow melt) is stopped up at a dam. Some of the water is allowed to flow into a river, and in between the reservoir and the river is a turbine that runs a generator. About 1.5% of world electricity requirements are generated using hydroelectric power.

What happens when you mix exothermic reactions with turbines? The heat produced by chemical reactions is often used to heat water to produce steam. The state change that occurs when water is converted to steam means an increase in volume by a factor of approximately 1700 times. The increase in pressure means steam can be used to drive a turbine to generate energy, in a technology known as steam turbines. This process is used in aircraft carriers to great effect: it can drive a steam catapult to propel planes from its deck, or it can be used to drive the main screws to propel the carrier through the water. This process is also extremely well-suited to energy generation via electromagnetic induction. About 90% of all electrical power in the US is generated using steam turbines both in conventional coal, natural gas, fossil-fuel, and also through nuclear power plants.

A third method of energy extraction is via the photoelectric effect. This is the method that solar cells employ to harvest energy directly from sunlight. The efficiency of this technique is determined by how many photons are required to generate a single electron. Modern solar power plants, however, usually employ a different method to harvest energy. The technique is known as solar collection. In this technique, mirrors and lenses concentrate the sunlight from a large area to a small area. Once in a small area, the sunlight can be used to heat water in a closed steam system, as in solar towers. This steam is then used to drive a steam turbine, which drives a generator, which generates electricity. Usually the mirror is shaped like a parabolic trough, and instead of heating water directly, it heats molten salt and then the molten salt is used as a heat source for the power generation system.

Solar power is considered to be renewable since it harvests energy directly from the sun, the effectively continuous free energy source.

The largest solar power station in existence, in the Mojave desert of California, generates 354 MW of power. In comparison, the Three Gorges Dam hydroelectric power station located on China's Yangtze river, generates 18.5 GW of power, and, when finished, is intended to generate a total of 22.5 GW of power. As of yet, solar power hasn't yet reached a generating level of even 0.1% of the world's electricity requirements.

A fourth method of energy extraction comes from the energy contained in matter itself. Nuclear power currently works by exploiting the chain-reaction properties of U-235, an isotope of Uranium. In a nuclear power plant, the runaway chain reaction is usually moderated by water and other slow-neutron absorbing substances, like graphite. Nuclear reactors generate heat in abundance. This heat is used to heat a second, insulated water cycle and generate steam, which then drives a turbine and a generator to make electricity. But it is also possible to use molten sodium, an excellent neutron absorber, to transfer the heat of the nuclear reaction, in a so-called liquid metal reactor.

Uranium is about 40 times more commonly occurring naturally than silver, and so it is hard to prevent technologically advanced nations from acquiring it. For instance, in Israel, the sands of the Negev desert contain trace amounts of Uranium. The separation of U-238, the isotope of Uranium that makes up 99.3% of naturally-occurring Uranium, from U-235 (that makes up the rest) is complicated.

The Diablo Canyon nuclear power plant
Source: PG&E via Power Plants Around the World

Nuclear power presently generates considerably more energy than solar power. For instance, the Diablo canyon nuclear power plant in California generates 2.4 GW (7.5x the largest solar power plant) and makes up about 20% of the Northern California power grid.

Nuclear power accounts for 14% of the world's electricity requirements today.

However, nuclear power has some serious drawbacks. The disposal and storage of radioactive waste (particularly spent nuclear fuel rods) presents problems that, while they can be solved, are nonetheless controversial. The Östhammar facility in Sweden shows promise for treating this problem with the proper respect and care required for 100,000-year storage systems. The site was chosen partly because the rock at the waste-storage level is relatively free of fractures. After the rock is excavated, two tons of spent fuel is stored in 25-ton copper canisters. Each copper canister is then welded shut using a special robotic welder and robotically deposited in an individual tunnel in the repository. Then, bentonite clay is injected into the tunnel, mixed with water, to expand into place. This forms a watertight barrier that is essentially earthquake-proof. The storage repository is scheduled to open in 2025.

Portable Energy Storage

Once energy is harvested and converted to electricity, it may be stored for later use and carried around. You can consider fuel to be a portable energy storage system also, although usually fuel needs to be combusted and this makes it normally unsuitable for battery usage. But even this axiom is being challenged by the fuel cell.

Portable energy may be stored in several ways. The first is a battery, which generates electricity through electrochemistry. The second is a capacitor, which stores energy in its electric field. The third is a fuel cell, which, similar to a battery, uses an electrochemical reaction to generate electricity.

We grade portable energy storage systems on:

• capacity, which is the amount of electric charge they can store
• charge time, the amount of time required to return the device to full or substantial charge
• discharge rate, the maximum amount of constant current the device can produce
• energy density, a measure of how much energy the device will produce by weight

Each characteristic is useful for different uses. For instance, in an electric car, the energy required to start the engine and move the car from a standing start is related to the discharge rate. Also, a device must be light in relation to the amount of energy it contains, and thus energy density must be high for an electric car battery.

On Hydrogen Fuel Cells as an Energy Source

The energy density of hydrogen gas is the highest of all chemical sources, in excess of 120 kiloJoules per gram. The energy density of a lithium-ion battery, in contrast, is only about 0.7 kiloJoules per gram. Of course, nuclear material such as U-238 has an energy density of 20 gigaJoules per gram. Antimatter contains a theoretical maximum of 180 teraJoules per gram. Presently, nuclear material and antimatter are unsuitable for portable energy storage systems due to the weight of a nuclear reactor and the general unavailability of antimatter.

All above considerations point to hydrogen fuel cells as the most likely successor for portable energy systems. Per weight, hydrogen fuel cells are about three times the energy density of gasoline. The volume of hydrogen, even stored as a compressed gas, far outstrips that of gasoline for comparable amounts of energy generation. This makes hydrogen use a bulky problem.

Also, most all the world's hydrogen production emits CO2, since it uses the steam methane reforming process. So some improvement is needed to cut down on its carbon footprint.

Improving Batteries

The characteristics of a capacitor are short charge time and fast discharge rate, really the opposite of a typical battery. This is why several companies are trying to merge the two technologies to get the best of both.

Supercapacitors are a new technology which promises to replace the battery as we know it. One valuable attribute of supercapacitors is the apparent ability to charge and discharge thousands of times, making the device stable enough to outlive the device it is intended to power. The main problem with super- and ultra capacitors (battery-capacitor hybrids) is the energy density. The capacitance of these devices is directly proportional to the electrode surface area. The use of materials like activated charcoal (with its unbelievably large surface area) have increased the energy density into the usable domain. The promise of nanotechnology, such as nanotube carbon filaments, also can lead to high surface-area solutions and still greater energy density.

How Energy is Consumed

The amount of electricity used per year by humanity is in excess of 20 petaWatt hours per year. The US uses about 20% of that, and China uses another 20%. This doesn't include the energy produced by internal combustion engines, or by burning coal, wood, and kerosene for heating. When all energy consumption is added up, total annual consumption is 474 exaJoules.

It is interesting that world energy consumption decreased 1.1% in 2009, due mainly to economic downturn in North America. But that trend doesn't seem to be a continuing story, since in 2010 world energy consumption grew about 5%. In particular, China's energy consumption did not decrease in 2009, and consequently it is now the world's largest energy consumer, at about 18% of global energy consumption.

What's Next?

In part 2, we will drill down farther into how energy is consumed, and discuss what we can do to cut down on energy consumption, and what is already happening in that regard. We will also discuss the thorny issues surrounding fossil fuel usage. Also, the carbon footprint of energy production and consumption will be discussed. Which energy sources have the smallest carbon footprint? It's not obvious at all.