Tesla vs. Edison in Buffalo

It was the late 1800s and there was a two-way war for monopolistic reign over the electricity market. Thomas Edison’s direct current (DC) against Nicola Tesla’s alternating current (AC) (yes, these inspired the classic rock heroes, ACDC). Edison lit New York with his direct current, but Westinghouse (who owned Tesla’s patents) won the opportunity to light the Chicago World’s fair of 1893. Locally, both were impressive feats of science that baffled spectators, but shortly thereafter there would be the ultimate challenge of scale: Using Niagara Falls to power Buffalo, NY.


It was well established that there would be an enormous project that would include power generation at Niagara Falls with transmission to Buffalo, NY. The world was not yet accustomed to the concept of electricity, nor its transmission. There was comfort in mechanical technologies and it was uncertain which would win out.

On the committee, seven of the 14 votes were in favor of electricity, while the others composed of water mains or steel cables on posts with pulleys that would span the 22-mile distance to Buffalo. Finally, the most likely alternate technology was in the form of compressed air as (ironically) recommended by Westinghouse, who was heavily invested in Tesla’s technology, but did not believe in its ability to handle the scale of such a project (we’re going to go ahead here and say that Westinghouse was the business mind, not the scientist), but Tesla knew better.

For a short time, they tried to bring Buffalo to the power. There a tunnel that was built to harness the great power of the river by locating mills and factories on-site, but due to large risks and an unfavorable IPO, it became increasingly clear that the energy needed to be transmitted over distance to Buffalo.

Over time, technology was improved and ultimately, Edison’s DC power could not compete with Tesla’s AC power in the fundamental issue of transmitting the electricity efficiently. Both forms of power, AC and DC, could be transmitted at high voltages, which allowed for greater efficiencies as the current can be increased while resistance remains constant, but the fundamental difference was in transformation. DC could not be transformed to a lower voltage that people could use in their homes and thus could not transmit its current over long distances without huge losses of power.

To review some of the proposed technologies:

  • Water mains would have allowed them to bring the flow/hydraulic energy to be transformed near Buffalo, but this could be difficult, costly, and high-maintenance.
  • Steel pulleys would likely require less maintenance than water mains (yet, still higher than electricity), but would decrease the efficiency to an even greater extent with an extra transformation. Finally, 22 miles would result in a lot of frictional inefficiencies and a long distance to protect.
  • Efficiency of compressed air would be inversely proportional to its power as greater power would cause greater heat to dissipate and this would require a very effective system of sealants, which likely weren’t as effective in the late 1800s as those we have today. So they would have lost energy through lost heat and the loss of compressed air.

As it became evident that electricity may really be the most feasible proposal, AC and DC stepped in the ring. There were two proposed methods of transmitting DC power at high voltage and stepping it down to a lower voltage for residential and commercial use in Buffalo:

  1. They could use the DC over long distances to then power a motor in a separate building to produce a smaller voltage to transmit to commercial and residential buildings. This however, requires multiple conversions and, in the end, proved to be less efficient than AC due to losses.
  2. The other was for 5000-volt transmission to charge storage batteries in Buffalo for redistribution. Again, extra conversions will cause losses in power and 5000V is not high enough to render negligible the resistive heat loss.

In the end, Tesla’s alternating current won out because it could be transmitted at high voltages over long distances and subsequently stepped down to tolerable voltages when it reached buffalo without layers of inefficient transformations.

Today, the two work harmoniously to fulfill different roles. The AC power is often used to transmit over long distances, and to power your lights, but is often transformed to DC to charge your phone or run electric motors that require direct current.

Can wind power the world?


You’ve likely seen wind turbines that are used to collect power for communities. To some, they’re monstrosities; to others, graceful; but with all the attention around global warming, let’s forget about the aesthetics and see just why these turbines are popping up like weeds.

Wind is a renewable resource and the marginal cost is essentially zero. Once the equipment is up, it’s free to collect and it never runs out. Also, unlike energy produced by burning, it produces zero emissions and thus has practically no contribution to global warming.

Sounds great, right? Why don’t we just  set up wind farms to power the whole world? Well, assuming we could somehow seamlessly transition to all-electric cars, planes, etc., let’s dig a little deeper.

Now what is wind power? Wind is essentially the movement of tiny gaseous molecules such as nitrogen, oxygen, and carbon dioxide caused by pressure differentials that occur due mostly to temperature fluctuations and earth’s movement and physical composition. In other words, warm air rises, cool air sinks, so other air moves to fill in the spaces, thus creating wind. Earth’s rotation and structures such as mountains, land, and sea can also affect wind patterns.

Each of these molecules has a tiny mass, but there are A LOT of them. Because it would be nearly impossible to measure the effect of each molecule, we measure fluid movement (air is considered a fluid because it does not have a macro-rigid shape) in a more general sense. The power carried as kinetic energy by any moving fluid is expressed as

Power = (1/2)*A*ρ*v^3

where “A” is the cross-sectional area of the circle created by the blades (essentially a very short tube), “ρ” is the density of the fluid, and v is the velocity. As you can see, Power is proportional to velocity to the 3rd power, so the speed of the wind is vital. The same concept can be applied to water, which is also a fluid.

According to Betz’s Law, no turbine can physically capture more than 59.3% of the kinetic energy in wind and in a practical sense, the best turbines max out at about 50%. Unfortunately, wind is also inconsistent, so we measure the “capacity factor” to be about 30%, which gives us an overall efficiency of (.5)*(.3)=0.15 or 15% of energy captured as electricity.

Now, since the energy is captured, the wind behind the turbine is much slower (and remember the importance of velocity), so in order to maximize the utility of a wind farm, it is suggested to build turbines 3 diameters apart along the direction facing the wind and 10 diameters behind each turbine for the wind to recover. A common rule of thumb for determining the fitness of land for wind farms is measuring the average velocity to be at least 8 meters per second and I’ve taken the average diameter of a turbine to be 60 meters. I’ve drawn out the space required for each turbine below.

FullSizeRender 3

If each turbine is 60m wide, then they must be 180m apart horizontally (relative to the wind) and 600m apart vertically. The vertical distance needed is 600m, but the horizontal distance must include the diameter of the blade as well, so this area must be 240m wide. That gives us a total area of 144,000 square meters for a single turbine.

 Now let’s calculate the power/square meter taking radius to be 60m, density to be 1.2 kg/m^2, and velocity 8 m/s.

Power = (1/2)*A*ρ*v^3 = (1/2)*(pi*r^2)*ρ*v^3 = (1/2)*(3.14*(30m)^2)*(1.2 kg/m^3)*(8m/s)^3 = 868,588 [(kg*m^2)/s^2]/s= ~870,000 Joules/s= 870,000 watts per turbine.

That gives us 870,000W/144,000m^2 = ~ 6 W/m^2. Previous articles show us that the average american uses 10,000 W and globally, we can allocate about 25,000 m^2 per person. With wind power at 6 W/m^2:

10,000 W/(6 W/m^2) = ~1670 m^2

and 1670m^2/25,000m^2 = 6.7%

So 6.7% of our land would have to be dedicated to wind power.

This, however, is an ideal situation. In reality, wind does not have sufficient velocity in most areas to meet these demands. The midwest has among the strongest wind in America and is thus home to the most wind farms. Efforts are being made to harness off-shore wind, but they are largely stifled by the extreme costs of building turbines in deep waters.

Similarly to solar, wind costs are being driven down by competition and technological advancements. At the end of the day, wind power will not be a standalone answer to enable a clean energy future, but it will be a vital component. While both wind and solar power are intermittent, meaning they’re inconsistent energy producers, they serve as compliments to each other as wind power is strongest at night, while solar power is, of course, strongest during the day.

We will attempt first to replace our current electricity usage with clean energy, but if we are to achieve that, there is far more incentive to initiate infrastructural changes for industries such as travel, which currently rely on gasoline. It is unlikely that we’ll completely ditch our consistent power sources, such as coal and nuclear, but their footprints can be greatly reduced.

Can solar energy power the world?

A new form of the American dream: We go to work, heat our homes, turn on the lights, keep our food cold… all by the power of the sun?

Seems like a pipe dream. Gasoline drives us to work and coal powers our lights, kicking out gigatons (science talk for “a lot”) of greenhouse gases. That’s just how it is. Or is it?


Every once in a while, you’ll hear a little more about solar energy, and maybe your tree-hugging neighbor even put some panels on his roof. You may have flown over “solar farms” in the southwest, yet you still pay the same gas bill month to month…

Well get ready for it. Solar is reaching a tipping point. It’s costs have generally exceeded the financial benefits, but with government subsidies, competition has driven the cost down and efficiencies up. On the whole, it is still doesn’t beat some traditional options on price, but it’s edging close enough to consider the positive externalities it may impose and brace ourselves for a clean-energy future.

So how much solar energy do we really need? Let’s make some assumptions and run some numbers. Most people reading this will have a similar lifestyle to the average american, which we’ve already found to be about 10,000 Watts per person while the average global citizen only uses about 2,500 Watts. So let’s assume we want to support a world in which everyone lives at the same energy standards as the average American: 10,000 W

We discussed earlier that there is about 25,000 square meters per person on this earth. How much of that land are you comfortable allocating to solar panels? Remember, you can put them on your roof.

On average (day & night), the sun is providing about 200 W/m^2 to Earth. Currently, affordable solar technologies offer about 15% efficiency, so with 200 W/m^2 beating down on average, our solar panels will capture about 30 W/m^2.

If we each want to use about 10,000 W to heat our homes, cool our beer, and move us from A to B, we’ll need to allocate about (10,000(W)/30(W/m^2))= 333 square meters. Like I said earlier, you’ve got 25,000 square meters to play with…

Come on folks, we’d need to use about 1.3% of our land.

The contingent United States has buildings that cover roughly the size of the state of Ohio (~1.15*10^11(m^2)), which is about 1.15% of the country (10^13(m^2)).


So, in theory, we could cover almost 100% of our energy needs just by covering the rooftops that already exist. The distribution of land in the US is a little different than globally and of course, there’s much else to consider: costs, infrastructure, inconsistency, etc., but hey, there’s hope!

In reality, we’ll need other sources of energy to fill in the gaps for some time to come, but I hope I’ve shown you that solar energy is not a fantasy; It can make a huge dent in the way we use energy globally and will allow for cost-effective advances in transportation (see Tesla), lighting, and many other industries.

How Big is My Back Yard?

When approaching some of the world’s most pressing energy questions, it’s easy to say, “Hey, the world is huge; There will always be enough space and resources.” Let’s do the math.

We currently have about 7 billion humans living on earth. We need to figure out how much land is on earth (assuming it’s all habitable):

The radius of earth is about 6.37 million meters, so the surface area is:

SA= 4(pi)(r^2)= 4*(3.14)*(6.37*10^6m)^2= ~5*10^14(m^2)

But only about 1/3 of it is land, so…

(5*10^14m^2)*(1/3)= ~1.7*10^14(m^2)… That’s 170 trillion square meters of dry land.

If we divide that equally among the 7 billion people, we get:

(1.7*10^14(m^2)) / 7*10^9(people) = ~25,000 (m^2)/person

25,000 square meters per person. That’s your back yard if we distributed our land equally. That’s about the size of 5 football fields. Could you live off it? Can it provide enough energy, food, and water to keep everyone alive? What if the population keeps growing?

Stay tuned for later articles to find out…


2,000 Calories/day? Try 200,000.

You’ve all probably heard that an average daily diet consists of about 2,000 calories to keep your body running as it should. These calories are forms of stored energy that your body has chemically converted to keep your heart pumping, your body warm, and your muscles moving (among other things). What if, however, I told you that you’re actually consuming over 200,000 calories every day…

As I mentioned in an earlier post, the average American uses about 10,000 watts of energy at any given time. This can be broken down to calories/day.

  • 10,000 W/day
  • 1W = 1(Joule/s)
  • 1 Calorie = 4,000 Joules
    • (There is a different scientific definition for “calorie,” but we’ll ignore that for now)
  • So 10,000 W/day= (10,000 J/s * 60 s/min * 60 min/hr * 24 hr/day) / (4,000 J/Calorie) = 216,000 calories/day

Now of course you’re not eating 200,000+ calories/day… but you are USING it. Driving your car, heating your house, cooling your food… it all takes energy. Energy is energy is energy. There’s no real difference between the gas in your car, the food on your plate, or the charge in your phone’s battery.

It can all be broken down into whatever units of energy you’d like, but at the end of the day, the food you eat is less than 1% of your daily calorie intake.

Your life, measured in Horse-Power


You wake up in a warm bed on a cold winter day. You switch on the lights, shower, make breakfast, check your e-mail, and drive to work—all without thinking. On the surface, we define luxury as: cars, clothes, and mansions. In reality, luxurious economies are supported (and intrinsically defined) by their energy consumption (and thus, infrastructure) above everything else. Yes, resources, exports, etc. are more explicitly connected to our wealth, but hear me out.

Your heater burns natural gas all night to keep your house (and shower) warm. Miles away, someone burns coal or nuclear reactors to send electricity to your lights, refrigerator, and even phone charger (which sends energy to the battery in your cell phone). Your car burns gasoline, being pumped and processed all around the world. Your morning walk requires fuel in the form of food—to keep your body moving. Your clothes, your house, your food, even the water you drink requires energy in ways that we’re fortunate enough to ignore—apart from a few bills each month. The wealthier the economy, the more energy said economy uses; The more energy an economy uses, the wealthier said economy can become. It’s a cycle, and we are far more dependent than we’d like to believe.

One understandable way to measure our constant energy consumption is in Watts. There is already a measured unit of energy, per unit time, seconds, that is a Joule. So when your light bulb says 60 Watts, that means it is using 60 Joules of energy every second.

The IEA estimated that, in 2012, the world used about 156 TWhs (TeraWatt-Hours) of energy. This is a redundant way to measure energy, so let’s break it down.

A Watt-hour is the amount of energy used by just 1 watt (J/s) over the course of one hour. So the “Wh” usage of a 60-watt light bulb would simply be 60 “Wh” per hour (…thus, redundant).

Tera= 10^12= Trillion, so 156 TWhs (the global usage) is equal to 156 trillion watt-hours and 5.6*10^20 Joules. This gives us 17.8 trillion watts, which, when divided amongst the ~7 billion humans, equals about 2,500 watts per person. If that didn’t make sense, just bear with me.

The average American uses about 10,000 watts, which is 4 times the global average we just calculated. So, if we were to compare it to light bulbs, the amount of energy used by the average American could power 10,000(watts)/60(watts/bulb)= 167 light bulbs turned on around you day and night. It would be like trying to sleep at the gates of Heaven. That’s also equal to about 14 horse-power. That’s 14 horses walking day in and day out to keep you warm. That’s the amount of energy you’re using to maintain a comfortable lifestyle.

There is a definite correlation between energy consumption, national wealth, and standard of living. Energy infrastructures allow us to delegate production responsibility and drive down prices through competition and efficiency. So next time you wake up without frost on your eyelashes or enjoy a glass of cold orange juice, remember the hypothetical light bulbs.

Why Drive Thru Science?


The purpose of this blog is to address a crossroads I witness at the University of Chicago, where I am soon to graduate with a degree in Physics and Geophysics.

Basically, I want to eliminate the confusion of important scientific concepts that allow companies, governments, etc. to hide from the public behind jargon and numbers. Let’s make science simple.

There’s an unnecessary disconnect between students of different majors. Now of course there are many exceptions, but far too often, they want nothing to do with the subject matter outside of their own field of study.

I’ve been fortunate enough to take courses in economics, public policy, language, sociology, etc. in addition to the maths, physics, chemistry, biology, and statistics and computer science courses that define my major.

An abridged definition of “synergy” describes it as “the creation of a whole that is greater than the sum of its parts.” Cross-functional education is not simply the sum of what you learn, but rather a synergy of the skills, experience, and frames of thought that drive the greatest progress.

I.e. a physicist may request funding for a huge breakthrough without realizing that the benefits of such a breakthrough still would not cover the costs of discovery. An economist might propose a system that maximizes profits for an industry while overlooking the fact that they are polluting the environment and may just kill the goose that lays its golden eggs.

Together though, we can optimize our output and scientific progress in a sustainable way such as carbon credits, environmental data collection/interpretation, and patents on scientific discoveries.

Again, my expertise is in the sciences. I want to convey important information that is often twisted, hidden, or ignored by policy makers, companies, economists, etc. in a simple and interesting way to create synergies between the areas of study that we often confine ourselves to without external exploration.

You’ll learn to question the world around you with full knowledge that you can have an impact. If such questions arise “how does this work?” or “why does that happen?” or “what does he mean?,” please feel free to contact me and I’ll write a blog post on your behalf!