Drilling work to construct five geothermal energy boreholes going down 500 meters is set to begin in Roosna-Alliku, Järva County. The Estonian Geological Service's research project will culminate in an experimental geothermal energy plans that will provide environmentally friendly heat for several locals buildings.
It takes engineering bureau Steiger between four and six weeks to drill a single 500-meter borehole. Project geologist Hardi Aosaar said that the drill head will be lowered using six-meter interconnectable rods.
"You just hook up the next rod every six meters until you get to 500. Of course, things are a little bit more technical than that as we also need to install mantle-pipes to protect groundwater and also mantle the top part of the holes. We will be pouring the mantle in concrete to ensure groundwater layers remain separated," Aosaar said.
In addition to the boreholes, a geothermal energy plant will be constructed in Roosna-Alliku that will heat the local kindergarten, school, municipality government building and an apartment association. At a meeting with the construction company Tuesday, local residents said they hope buildings that are currently not hooked up to the district heating network could join at a later date.
"There is no local resistance. Rather, people are curious and glad that our village has been selected for such a special project," Sille Pudel, Roosna-Alliku village elder, said.
The work was commissioned by the government and the Estonian Geological Service to look into the potential of geothermal energy in Estonia. Aivar Auväärt, head of the service's geothermal energy department, said there is little in the way of existing research.
"We should get 12-13 degrees from the earth, which will then be heated to 65 degrees using heat pumps," he explained.
The price of geothermal heat will depend on the so-called political decisions of the local district heating service provider, while the cost price should be half of what district heating costs in the region now.
Because there are no other boreholes in Estonia that go as deep, the cost-effectiveness of the project remains to be seen. But it will provide valuable experience.
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