Local utility in the greater Helsinki area of Finland is starting drilling for a 2,000m well to be used for geothermal district heating. The technology will be provided by Finnish company QHeat on – what we assume – is some heat exchange approach.
Vantaan Energia, one of Finland’s largest city energy companies will start work on a geothermal geothermal heating plant in Vantaa Varisto. The renewable heat generated at the plant is directed to the Vantaa district heating network and sold to geothermal customers. Vantaa is a municipality in the greater Helsinki area, the capital of Finland.
Ilkka Reko, Director of Vantaa Energy’s heat business, says that drilling work will begin in August. Prior to drilling in the area, preparations and material purchases are made.
“We should be ready at the turn of the year. In December, trial operation and production should be possible,” Reko estimates.
Quantitative Heat (QHeat) is responsible for the construction of the plant. Quantitative Heat Oy’s or QHeat’s technology is based on heat wells about 2 kilometers deep, which utilize the thermal energy of the soil. The plant will produce about 1,400 MWh of heat, which corresponds to the heat demand of about 100 detached houses.
This corresponds to a volume of about 40 traditional and 300 meters deep geothermal wells [of a traditional heat pump system].
Investment aid for new technology
Vantaa Energy was granted a 35 per cent investment subsidy for the project through Business Finland. The investment support has made it possible to introduce a new type of technology, which, according to Reko, is being tested for the first time in Finland on such a scale.
According to Reko, the new technology separates the Varisto geothermal plant from the Otaniemi geothermal plant in Espoo, whose construction work has caused even small-scale earthquakes. Two holes have been drilled in the Otaniemi geothermal plant, and one in the Varisto geothermal plant.
“This is not fundamentally different from normal geothermal well drilling, which is drilled around the city even in the middle of a settlement. We make a slightly bigger hole and go deeper and the equipment is higher and more robust,” says Reko.
According to Reko, Varisto’s drilling work should not cause any disturbance to the area’s residents. The plot of the Varisto heating center is not located near the settlement.
“We have a different technology in which one hole is drilled inside which a vacuum-insulated collector tube is placed. Cold water is lowered along the outer surface of the hole and warm water is transferred up along the collector pipe. The warm water at the top is heated to approximately 80-100 degrees.”
“When we get experience from this, we will see if we can reproduce this sensibly. And of course, as expertise evolves, costs fall, the heating business manager opens.”
In recent years, Vantaa Energy has invested heat in environmental friendliness. Last autumn, Vantaa Energy announced that it would accelerate the abandonment of coal and that it intends to end its use in energy production in 2022.
Comment: With project like this the lines between traditional heat pump systems and deeper heat-exchange systems are becoming increasingly blurry. Targeting deeper heat resources, these projects – based on heat exchange technology – are not tapping water resources like traditional deep geothermal projects. Exactly, how this works is so far a bit unclear to use, but we are investigating and will be reporting on it.