Talks

Helping the Sun

 By Eniday Staff

We could start with a paradox, which in the end, is not really genuine. With the exception of atomic energy and the thermal energy in the core of our planet, we owe all the energy we use to the Sun…

Yes, apart from nuclear and geothermal, every time we turn the light on or start the engine of our car, we are using a certain amount of solar energy, which became available in different ways and times so that we can use it according to our various wishes. It is not the primary origin that makes the difference, but the history of that energy.
Let’s look at some extreme cases that, as such, speak volumes. The first case: we produce thermal energy from thermal panels installed on the roof of a house, so thanks to solar radiation, we can heat water for sanitary purposes. This is a fairly rapid process: photons take 8 minutes and 19 seconds to travel from the Sun to the Earth, then it takes a few hours for the water to warm up. Let’s take and even faster case: photovoltaic panels on the roof of a house (in Italy, we’ve installed over 600 thousand) react very quickly to irradiation and produce electricity almost instantaneously. Production time: under 9 minutes.
Now let’s take a few contrasting examples. About 38% of the world’s electricity is produced by burning coal. Where does the Sun come into this? Coal comes from forests trapped under very ancient geological strata, where transformation took place under high temperature and pressure conditions. Again, thanks to the sun, but with a time span of between 280 and 345 million years.

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World electricity production is still dominated by the use of coal with a share of 38%.

Towards new targets

Another case is oil: its origin is still the subject of research, but we know that it derives from organic compounds that are trapped in layers of rock, dating back many thousands, sometimes millions of years. The Sun plays an important role here as well, as prime mover so to speak, its energy leading to the formation of the compounds containing carbon.
Time makes a difference. But there’s also something else, carbon dioxide. As we all know by now, burning fossil fuels results in the emission of CO2 into the atmosphere, the main culprit in global climate change. If we generate electricity with a photovoltaic panel or with a wind turbine (even in this case, the Sun is the prime mover), the only carbon dioxide produced comes from the production and transport of the panels or wind turbine. If we produce electricity or heat by burning coal, an amount of carbon dioxide is emitted that all the plants in the world don’t have the time to reabsorb. This therefore results in increasing global warming.
You can’t just rely on sun and wind though; other means of energy production are also needed for human purposes. That’s why the use of biomass is constantly becoming of greater interest. When it comes to the time needed to make them available, they sit between the very extremely short times needed for photovoltaics and the geological eras for coal (but much closer to the first than the second). Cultivating plants for use as fuel and exploiting the decomposition of vegetable or animal waste materials to produce fuel oil or gas, are now consolidated methods for reducing carbon dioxide emissions and initiating positive circular processes in resource production and use, including a resource that we need to survive: food.

The role of the green

Eni has launched a major investment plan in this area, with the aim of developing a biofuel supply chain. Green diesel is produced from the chemical-biological treatment of dedicated crops, such as palm oil (the so-called first-generation biofuels) or from urban and food industry waste, or agricultural or forestry waste (second-generation biofuels). There’s also production from dedicated crops – that are not in competition with agricultural food production, such as algae – or from using otherwise unused marginal land (third-generation green fuels). According to European regulations, diesel fuel must consist of at least 7% diesel from renewable sources. Eni also offers Diesel+, which contains 15% green diesel.

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The first continuous pilot plant based on Waste to Fuel technology in Gela

Green diesel is produced from the plants or herbivores that ate them. As they were growing, the plants used the carbon from CO2 as a building material (to make the trunk, branches, leaves, flowers, fruit and seeds), extracted using energy from the sun. The carbon that comes out of the exhaust pipe of a car powered by green diesel is the same that the plants removed from the atmosphere a short time previously. Using renewable fuels produces the same amount of CO2 as using of fossil fuels, but there’s a big difference: that carbon dioxide was removed from the atmosphere by the plants a few months or years before and it wasn’t buried underground for tens or hundreds of millions of years.

READ MORE: Sun pumping by Michelle Leslie

about the author
Eniday Staff