Tuesday, December 09, 2014

Technical Feasibility

That something is somehow technically feasible, doesn't mean it makes economic or even environmental sense.

Let's consider the following question:

1. Is it feasible for a country to transition to 100% renewable* electricity? (Assuming there are no financial or material constraints).

The answer is almost certainly yes.**

However, that is not the important question. The important question is:

a. What would be the purpose of generating all the electricity of a country with renewables?

If the answer is: to reduce CO2 emissions, then I think we first need to make our homework.

Off the bat, neither solar PV nor wind are zero carbon emitters (once their lifecycle is considered). Sure, no technology, not even hydro, is zero emissions but according to the IPCC**** utility scale solar PV has a median value of 48 grams of CO2 equivalent per kWh. Low, but not extremely low. Wind clocks in at 11 grams. Much better.

However, the numbers above do not include either the back up plant (usually fossil fuel powered) that is needed most of the time to support the relatively low capacity factors of renewable energy, nor the lifecycle emissions of the massive storage that would be required to somewhat wean renewables from fossil fuel plants.

So say, if on an annual basis wind supplies power 25% of the time and a natural gas power plant the rest of the time, the weighted emissions would be:

          25% x 11 grams/kWh + 75% x 490 grams/kWh = 370 grams/kWh

Yes, it is lower than a natural gas power plant by itself, (reduction of 120 grams/kWh) but are these modest CO2 reductions worth the double investment?

And, more important, is there a better way to invest our limited financial (and material) resources to achieve more bang for the buck?

As an exercise, the replacement of a coal plant with a natural gas plant would result in the following reduction:

          820 grams/kWh (coal) - 490 grams/kWh (natural gas) = 330 grams/kWh

The reduction in emission is almost three times larger and probably with a smaller investment that would last longer. (How long before wind turbines have to be replaced?).

Now, if we replace the coal plant with a nuclear one the numbers look this way:

          820 grams/kWh (coal) - 12 grams/kWh (nuclear) = 808 grams /kWh.

The reduction in emissions is almost seven times larger than with renewables.

Conclusion: technical feasibility by itself does not justify investments in renewable energy. More important is to consider the financial and environmental factors.

Feel free to add to the conversation in Twitter: @luisbaram

* By renewables we mean solar and wind in this article. Hydro is also a renewable but it is in a league by itself and we actually already have countries generating 100% of its electricity with it. Among them we have Paraguay and Albania.

** Sure, the manufacture of the wind turbines and solar panels would require massive inputs of fossil fuels, but for simplification we won't consider them at this moment.


Labels: , , , , , ,

Wednesday, December 03, 2014


For literally thousands of years, humanity made little technical progress at least as it helped to improve the life of millions upon millions of people and then, suddenly, 200 years ago or so our technological capabilities just exploded.

To what do we owe this?

On a first approximation we could say that fossil fuels were the trigger but on second thought, they had already been known for hundreds of years and little was made of them.

No, more important than the fuels themselves were the engines developed:

1. The steam engine.
2. The internal combustion engine.
3. The gas turbine.

These engines allowed coal, oil and natural gas to be converted into movement, into transportation.

Electricity had also been known for a long time but it was not until the electric generator (powered by one of the engines above) provided abundant energy to illuminate and power the world that electricity became overwhelmingly important.

However, electricity was not only power and light, it was also signals, and here the all important developments before 1950 were:

1. The telegraph
2. The telephone
3. Radio and television

Crude implementations of the first two could exist without electronics proper, but radio and television required an amplifier and thus came into being side by side with them the vacuum tube.

Finally, electricity was one more thing: "intelligence." The first fully electronic general purpose computer, ENIAC, came into being in the late 1940s. It used prodigious amounts of vacuum tubes (more than 18,000).

So, by 1950, we had cars, airplanes, trains, air conditioning, elevators, radio, television, telegraph, telephone and even some computers.

Accelerated progress seemed to lay in the past because the vacuum tube required loads of power and was too big and unreliable to be implemented by the thousands in computers and other devices.

Say, a basic cell phone was completely out of the question, let alone a personal computer, tablet or smart phone.

And then came William Shockley and the transistor.

The first transistors were more often than not just (lower power / smaller) replacements for vacuum tubes, but if we wanted hundreds, thousands, millions, billions of transistors in a single device another breakthrough was needed.

And then came Robert Noyce and the integrated circuit. This allowed complex circuits with many transistors to be built into a single crystal of silicon, but if we wanted a full computer to be swallowed in a single integrated circuit, another breakthrough was needed.

And then came Ted Hoff and the microprocessor.

So arguably, our awe inspiring current civilization critically depends on at least the following foundations:

1. Abundant / relatively cheap energy (mainly fossil fuels).
2. Engines that use those fuels to produce useful work.
3. Electricity that, aside from light and power, means signals and "intelligence."
4. The transistor / integrated circuit / microprocessor

The future challenge for our civilization is probably more than anywhere else in point number 1. If fossil fuels won't continue to be forever cheap and abundant, then we'll need other types of energy to replace fossil fuels.

How much time we have is open to discussion, but almost everybody agrees eventually we'll need to massively replace fossil fuels or enter into the twilight of our civilization as we know it.

Are the current alternatives we have today (nuclear and renewables) good enough to massively replace fossil fuels? Probably not.

In the past, technology has always come to our rescue:

Engine technology.
Electricity generation.

Today, once more we need technological breakthroughs, this time to develop cheap / abundant / low carbon energy.

Let's remember that wide deployment of a technology critically depends on cost. The first transistors Fairchild Semiconductor produced for IBM in the 1950 had a price tag of $150 USD each in bulk amounts (1950's dollars). Today the cost of each transistor in an iPhone is around one millionth of a cent (2014 cents).

Thus, if something is going to replace fossil fuels, the cost of that energy is all important (we have to consider the full system, not only a component).

Will humanity rise to the challenge? Let's stay tuned.

Feel free to add to the conversation in Twitter: @luisbaram

Labels: , , , , , , , , ,