August 31, 2022
Toscana Economia – IL TIRRENO
SKIPPING EXPENSIVE ENERGY
by FRANCESCA FERRI
 |
| Living without paying for gas: in Grosseto the condominium that heats up with “do-it-yourself” geothermal energy. What it is and how it works… |
| Not all Italians look at their gas bill with terror. There are some, indeed, who do not even receive such a bill, yet still manage to heat the house without even being attached to the methane network. This is thanks to a sort of “green energy self-sufficiency” that exploits a resource so abundant that it is considered infinite, but little used, if not completely ignored: the heat of the earth. It is the so-called low enthalpy geothermal, that is a “do-it-yourself” geothermal system which with a home system in the cellar, allows us to draw on the immense basin irradiated by the earth’s core. Today this heat is being captured with probes at a depth of 120-150 meters, where it is around 15-16 degrees celsius (59-61degrees fahrenheit), and is being made available to citizens. We are not talking about creating a power plant, that’s true; for that, high enthalpy geothermal energy is needed, which requires wells up to 4,500 meters deep that suck geothermal fluid and vapors. However, the low enthalpy is enough to warm up in winter and, with an inversion mechanism, to have fresh air in summer. All without paying anything other than the initial installation and maintenance of about 400 euros per year for 150 square meters. “In Italy we have an energy resource under our feet and we don’t want to see it,” explains Giacomo Biserni, geologist, and owner of the Ecogeo studio in Grosseto, one of the five-six companies in Italy that deal with low enthalpy. “In Italy we have from 5,800 to 116 thousand Terawatt / hour – depending on the technologies used to extract it – of energy, against a requirement for all of Italy of 330 Tetrawatt / hour per year. I repeat: 5,800 / 116 thousand against 330.” This means only one thing: “In Italy, thanks to this heat, we are already independent from an energy point of view,” explains Biserni. Indeed, “we would be because in reality it is a road that is not being traveled. In Italy geothermal energy is practically only the high enthalpy one, the most profitable, but even with that, just 6 Terawatt per hour are produced.” He continues: “In Italy, gas is purchased from abroad for 85% of the country’s requirements, equal to 80-85 billion cubic meters per year. Of these, 45% are used to warm up [buildings]. Well, low enthalpy geothermal could completely eliminate this [gas consumption].” But does it really work? The answer is yes. In Grosseto it has been done since 2017 in a condominium, designed by Ecogeo and built with the company CbNext. It is the Palazzo Convivere, located between the train station and the historic city center. Classified in energy class A4 – that’s right: A4 – it is connected only to the aqueduct. For the rest, it has geothermal probes that heat it and, thanks to a ‘motor reversal’ mechanism, cool it in the summer. The mechanism is powered by electricity, but this is produced ‘at home’, or rather, on the roof with solar panels, which also serve to power the cooking hobs (burners), to heat the water and to recharge electric cars and bicycles in the garden. The walls of the building are insulated, the windows are draft proof and so no heat is wasted. “The gas bill, in short, never arrives here. Not to mention the savings for the environment: 23 tons of Co2 are saved per year,” says Biserni. Obviously, there is an initial expense. “The plant costs about 12 thousand euros, but you can take advantage of state incentives that make up 50% to 65% of the cost” says Biserni. And, importantly, this form of energy plant construction can be done anywhere. Yet this solution struggles to make its way. “The explanation,” says Biserni, “is simple: the 40-43 billion cubic meters of gas used by citizens earn the state as many as a billion euros in excise duties. If everyone did their own heating, the state would lose a lot of money. This is why, in order not to take this path, they are introducing the concept of ‘safe nuclear power’ in a soft way. But nuclear is never safe”. |