Monday, May 19, 2014

Types of People in the AGW Discourse: Revisited

Dear friends and colleagues: this is an updated version of the April 7, 2014 post. The reason we are updating it is that through your comments, we understood important additional categories needed to be added. So, here they are.

The Anthropogenic Global Warming discourse is supposed to be happening between the Deniers and the Believers but this is an oversimplification that does not fit well into the actual reality, so we are presenting below a more useful classification.

1. The Deniers: they don't believe AGW is happening and no evidence will make them change their mind.

2. The Believers: they believe AGW is happening but they have their feet on the ground.

3. The Naivers: they believe Renewable Energy (RE) will replace fossil fuels (FF) and save the day.

4. The Black Swanners: they believe in AGW but at the same time understand that humans will not voluntarily reduce their standards of living. Thus humanity will NOT reduce their FF consumption for many decades to come. The way out? A serious black swan event that will solve the emissions problem "through the back door." Examples:
     a. A gigantic volcanic eruption in Indonesia.
     b. An ebola like virus that drastically decimates human population.
     c. What have you.

5. Gamblers: they do believe AGW is happening but decide to wait and see. There might even be some unintended positive consequences of climate change. If nothing else, their investments in Greenland may become more valuable.

6. Opportunistic: the ones that make loads of money by selling the RE to the Naivers (above).

7. Liars / Lobbyists: what they believe in their heart is irrelevant. They follow the money and fully support their sponsors no matter how much they have to bend themselves backward to seem reasonable.

8. Divesters: believe that once institutional investors divest from fossil fuel stocks the carbon concentration in the atmosphere will return to normal.

9. Defeaters: they believe everything is lost and thus have decided not to do anything and wait quietly for the end to come.

10. Alice in wonderlanders: have confidence that the last freak energy experiment in an obscure laboratory will be massively scaled in a matter of years and come to our rescue.

11. Extreme libertarians: the free market, like magic, will take care of EVERYTHING.

12. Religious zealots: God won't allow humanity to destroy the Earth.

Framing people is never good, but it is certainly better to frame them in TWELVE camps rather than limit them to only two.

We hope the above classification adds something positive to the energy discourse.

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Wednesday, May 14, 2014

Renewable Energy Reduces Emissions

Is renewable energy (solar and wind) the best way to reduce carbon emissions?

At first sight, this question seems almost absurd and we are tempted to say: of course it is the best way!

But, is it? Before jumping to hasty conclusions let's do our homework.

This exercise is going to be a simplification, the purpose is mainly to show us that things in real life are not as simple as in the lab.

So, let's consider a country that supplies 100% of its electricity with coal plants.

According to this table (see link at the bottom of this page), these are the emissions per kWh generated with the different energy sources: **

Thus, if this country generates 100% of its energy with coal, their emissions per kWh would be ~1001 grams.

Now, let's say we install wind turbines (enough to supply 100% of the power when the turbines are producing at full capacity):

Let's say wind capacity factor at this country is 25% (in other words, turbines actually produce 25% of their plate rating on average). It is important to underline that this is not constant power: at some moments the turbines are producing at 100%, at other they produce nothing and at any other moment their output can be anywhere in between these extremes.

So, (simplifying) wind will produce 25% of the energy on an annual basis and the coal plants will produce the rest (75%).

Then we calculate the emissions that are really just a weighted average:

Annual average emissions per kWh = (25% x 12 g/kWh) + (75% x 1001 g/kWh) = 754 g/kWh.

We can see that the emissions of the system did drop, but they are still too high.

What better options do we have?

1. If we replace the coal plants with natural gas plants (which have much higher capacity factors and can be staggered since they are not wind / sun dependent) then the emissions would be:

          469 g/kWh

2. If we replace the coal plants with nuclear plants then the emissions would be:

          16 g/kWh

As we may see from the calculations above, Renewable energy investments are not the best way to reduce emissions.

Arguably, the fastest way to reduce emissions is to replace coal plants with natural gas plants, however, if the higher investment can be made (and the longer lead times are acceptable), nuclear is truly the low carbon energy solution.

Conclusion: Yes, Renewable energy reduces carbon emissions in most systems, however natural gas, nuclear and of course hydro, are better options.

Thank you.

a. In the developed world little new electrical capacity is needed and thus Renewable energy almost directly replaces some other energy source, however in the developing world substantial additional electrical capacity is required and thus a double investment would be required: the Renewable one, plus the reliable one.
b. Sure, Renewables (wind and sun) could be combined to somewhat compensate the fluctuations of the other one. Still, at any particular moment of the year we may have no sun and no wind. At another moment we may have both which could even force us to divert (or disconnect) capacity.
c. To simplify, here we are not considering the possibility of "dumping" energy into another country or using massive storage systems.


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