Global green energy producer Enel Green Power is heading the project called DESCRAMBLE (Drilling in dEep, Super-CRitical AMBients of continentaL Europe), where the aim is to extract the maximum possible energy from the geothermal well.
The extreme heat in the rocks deep beneath northern Italy means that both pressures and temperatures will be right at the limit of what even innovative technologies can currently cope with. However, such conditions also mean that the energy output from such a well can be as much as ten times greater than for standard geothermal wells, and will help to ensure that the new well will be very profitable if the project succeeds.
At depths of two to three kilometres in the Earth’s interior, ambient physical conditions change dramatically. Temperature increases. And so does the pressure. Something very special happens when temperatures reach 374 degrees and the pressure 218 times the air pressure at the surface. Project persons encounter what we call supercritical water.
The aim of the project is to achieve a ten-fold increase in output compared with traditional, shallow geothermal wells. For comparison, the Krafla geothermal energy plant on Iceland generates 480 GWh annually. This is equivalent to the electricity consumption of a town the size of Lillehammer.
Participating countries: Italy, Germany and Norway.
Duration: 36 months following project kick-off in May
Total budget: EUR 16,615,957, funded via the EU programme Horizon 2020.
The project was launched in Pisa in Italy in mid-May, and drilling is planned to start in autumn 2016. If everything goes as planned, this well once completed will provide ten times the output of a standard shallow geothermal well.
The project will give a radical boost to the competitiveness of green, geothermal energy because the drilling costs for a well of this type are between 30 and 50 per cent of the total costs.
BASIS OF PROJECT
Low-temperature geothermal energy involves the extraction of geothermal heat from between 150 and 200 metres below the surface. At these depths, the temperature is between six and eight degrees Celsius. Such energy is extracted using ground source heat pumps combined with energy wells, and is currently produced in large volumes.
High-temperature geothermal heat has tremendous potential because it represents an inexhaustible, and virtually emissions-free, energy source.
Heat energy can be found in a variety of rocks in the Earth’s crust. The deeper we drill, the hotter it gets. About half of the heat at depth originates from primordial heat derived from the Earth’s mantle (the layer immediately below the crust) and core.
The remaining fifty per cent is derived from the continuous breakdown of radioactive material in the Earth’s crust. All this heat is transported towards the surface through the overlying formations.
Oil companies are currently making healthy profits from the recovery of oil from reservoirs at depths of 5,000 metres, where temperatures can reach up to 170 degrees Celsius. At deeper levels, drilling operations and materials integrity are faced with major challenges. Steel becomes brittle, and materials such as plastics and electronics either fail or start to melt.
Countries currently leading the way in the generation of electricity from geothermal sources are the USA, the Philippines, Mexico, Indonesia and Italy. Iceland is lower down the list at number eight.
There is an infinite amount of energy lying right beneath our feet. It is a renewable and stable energy source – free of CO2 emissions. Researchers are now planning to drill deep into the Earth to extract it. If they succeed it will be a major technological breakthrough.
Ninety-nine per cent of planet Earth has a temperature in excess of 1,000 degrees Celsius as a result of residual heat inherited from the Earth’s primordial origins and the breakdown of radioactive materials. This heat can be transformed into energy – and there is more than enough to go round.
Today, five years later, researchers and technologists from all over Europe are joining forces to pursue a common cause – to make sure that the world’s potentially most energy-rich geothermal well becomes a reality. The well will be drilled in Larderello in Tuscany, and EUR 15.6 of research funding has been earmarked for the project.
This isn’t the first time that researchers and geologists have been looking deep into the Earth’s interior to extract the inexhaustible amounts of energy it contains. Iceland has been exploiting geothermal heat for many years. The power station at Krafla has been using steam from below ground to generate electricity since 1977. Its annual production is 480 GWh, which is approximately equivalent to the annual electricity consumption of a town the size of Lillehammer.
In fact, twenty-five per cent of Iceland’s energy needs are sourced from geothermal heat, while the remainder is hydroelectric.
In 2009 a team of Icelandic researchers set up some drilling equipment on the volcanic island. Their aim was to drill to 4,000 metres and establish the world’s most effective geothermal well. In a frenzy of creativity, they named it DDP-1. Unfortunately, things didn’t go to plan – the geologists encountered lavas as shallow as 2,000 metres depth.
But, after two years of tests and studies the well had to be shut down, without having generated any electricity at all. However, the Icelanders learned a great deal from their attempt, and have not given up in their efforts to win the race to drill the world’s deepest geothermal well. They are currently planning a new well, with a new name – DDP-2.