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Bursting Cuba’s Sugar Cane Biomass Bubble

 

What’s really going on with renewable sources of energy in Cuba?  The island’s official press is brimming with optimism in this connection, but, do we actually have reason to be so positive?

I will start this post with one of the most widely divulged “half-truths”. According to Conrado Moreno, a high-level Cuban government expert and official, “during 2011, 78.4 percent of the total primary energy output came from fossil fuels and 21.6 percent was produced using renewable sources of energy.”

During a presentation on the subject, Projects Vice-President for CUBASOLAR Julio Torres Martinez said:

“In Cuba, sugar cane is an ideal means of intensively exploiting renewable sources of energy. This is owed to the high caloric content of bagasse, which has met as much as 30 percent of the country’s energy demand.”

After reading these two comments, one walks away with the reassuring sense that we’re on the right track, as deriving 30 percent of the country’s primary energy from renewable sources is a magnificent ranking. It is so magnificent, in fact, that it is a little hard to believe. How did humble Cuba achieve this, when countries with the highest indices of development in this area barely make it to 10 percent? I smell a rat here, and we’re going to find it.

To discover where the trick is, we’ll have to wade through some data published by Cuba’s National Statistics and Information Bureau (ONEI) and crunch some numbers. The first step is breaking down the percentage of energy produced in Cuba using renewable energy sources (RES), on the basis of a report for 2010 (1).

RES Contribution (thousands of tons of oil) %
Biomass 938.5 97.7
Others 20.9 2,3
Total 959.8 100

The percentages column (courtesy of yours truly) immediately raises suspicions. The amount of energy derived from biomass is so huge compared to all other sources that it could only be the result of fraudulent information.

We know that Cuban biomass is primarily made up of sugar industry (SI) sub-products. Let’s follow that trail.

Sugar Industry Energy Balance

Is so much energy actually produced using sugar cane biomass? The only way to find out is to draw up an energy balance for Cuba’s sugar industry.

Don’t worry, it won’t be complicated. We will arrange the system’s inputs and outputs in such a way as to arrive at a simplified and general formula.

We’ll start with the inputs, the energy consumed by the SI:

  • Fossil fuels. In 2010, the SI consumed some 190 thousand tons of oil (2). Let us assume we are dealing with tons equivalent (Tep), which is a standard energy unit.
  • Electricity. ONEI reports that, during this period, the SI consumed 295 Gw.h.
  • We mustn’t forget the contribution of the sun (we won’t need to quantify it, in our case).

Let us now look at the output:

  • Most of the energy produced by the SI is contained in sugar. We’re not going to quantify it either.
  • Then we have electricity, produced using biomass. According to ONEI, the said industry generated 446 GW.h. that year.

Let us now introduce these data into an equation. The inputs are on the left and the outputs on the right. Here it goes:

Sun + 190 thousand Tep + 295 Gw.h = sugar + 446 GW.h

We have electricity at either side of this equation because the SI both consumes and produces electricity. Placing all of the units of GW.h on one side of the equation and then subtracting, we get:

Sun + 190 thousand Tep = sugar +  151 GW.h

Those eager to present us with optimistic results stop precisely at this point. The trick consists in presenting the 151 GW.h as net electrical energy produced using biomass. That trickle of electricity that sugar refineries afford the country’s electrical network has been milked for all its worth – but let us look at the balance to understand where it is really coming from.

Tep and GW.h are two different ways of expressing energy amounts, and each can be converted into the other unit. Since every GW.h is equivalent to 86 Tep, 151 GW.h represent some 13 thousand tons of oil equivalent. Introducing these numbers into our equation, we get:

Sun + 190 thousand Tep = sugar + 13 thousand Tep

13 represents 6.8 percent of 190. That is to say, a very small percentage of the energy invested is recovered from biomass.

Let us now place all of our Tep numbers on one side of the equation and simplify the formula one last time. The final equation is:

Sol + 177 thousand Tep = sugar

Interpreting the Results

After converting our units and simplifying the equation, what we find is that the only net energy produced by the SI is that contained in its sweet sugar crystals, no more, no less. The energy produced using biomass, derived from the sun and oil invested, is reintegrated entirely into the system.

Bursting the Bubble

To arrive at the highly inflated figure of 21 to 30 percent of primary energy produced using renewable sources, experts have lied in different ways.

They are deceiving us, conceptually, by including industrial biomass as a primary source of energy, when, in truth, it depends in great measure on oil (making it more of a secondary source of energy).

They are lying in the same way when they include it among renewable sources of energy – the clean, environmentally friendly kind that do not emit greenhouse gases, I mean.

They are deceiving us at the quantitative level when they claim that all of the sub-products of the harvest are optimally exploited as a source of energy – when we know this is not the case.

The crudest and most propagandistic lie, however, is that the sugar industry is self-sufficient and even produces energy. We’ve demonstrated that this is entirely false. The percentage of sugar cane biomass that is actually used to produce energy covers only a miniscule percentage of our energy spending.

We thus arrive at our conclusion. After clearing away the straw and bagasse, we’ve come upon the raw reality: in Cuba, not even 3 percent of the country’s primary energy is produced using RES. Is this the figure the experts and press hope to conceal under a pile of sugar cane?

I am not bursting this bubble out of sheer pleasure. My intention, rather, is to demonstrate how precarious the situation is in this area.

When fossil fuel shortages and/or the political crisis in Venezuela hit our fuel supplies, we’re going to have a really tough time. So, isn’t it better to know the truth and act accordingly?

Notes:

  1. I used ONEI data for 2010 because this is the last report that has the tables I need up to date. The situation hasn’t changed considerably since.
  2. According to ONEI, 102,600 tons of diesel and 87,900 tons of fuel oil were used by the sugar industry. Adding these two figures, we get 190,400 tons of refined oil, which I rounded off to 190 thousand to simplify calculations.

Source: http://www.havanatimes.org/?p=102637#sthash.H54QTKZC.dpuf



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