ENERGY FROM DEEP DOWN GEOTHERMAL ENERGY

Generating and using energy in such a way that it doesn’t impact the environment has been pursued for many years, but this green future vision now seems more realistic than ever. While a number of sustainable forms of energy have proven successful and are being scaled up in capacity, other forms of energy are still in their infancy. This is the time to join forces, to apply and combine knowledge and expertise from different sectors. Together we are responsible and together we can make a difference. In terms of sustainability and in terms of HSEQ.

Geothermal energy is still relatively new compared to other renewable energy sources, but the sector is catching up. The geothermal sector in the Netherlands wants to grow from 24 installations in 2018 to 700 in 2050.1 It is also possible to extract shallow geothermal heat in the rest of Europe. In countries such as Italy, Turkey and Iceland, there is volcanic activity, so geothermal heat is already available in shallower layers of the earth. In the Netherlands, it is expected that enough geothermal heat will be available to meet 20% of the Dutch heat demand.2

What exactly is geothermal heat?

Geothermal heat comes from water from deep earth layers. Drilling is required from about 500 meters to sometimes a few kilometers deep. But even when you don't drill that deep (less than 500 meters deep) you can still benefit from heat from soil water. This is called geothermal heat. The use of geothermal heat means that less natural gas is used.

Ground source heat

The sun heats the ground and soil water to about 30oC, which produces soil heat. To pump up the heat from the soil or ground, a heat pump is needed, which reduces CO2 emissions (compared to a gas-powered high-efficiency boiler) by about 45%.3

Geothermal heat

Unlike ground source heat, geothermal heat does not come from the sun. This heat in the water is heated by the earth itself. Depending on the depth, the temperature can be as high as about 125oC at 4,000 meters. At 2,000 meters depth the temperature is about 50 oC. Because this heat is not dependent on weather conditions, the temperature of the soil water is very constant.

Advantages and disadvantages

Ground source heat and geothermal heat are both sustainable choices. As mentioned, geothermal heat is deeper in the earth, making it more difficult to access. The extraction process is therefore more expensive than when heat is extracted from shallow soil. Before a geothermal heating system is installed, it is important that there are enough customers to make it profitable.

Sources:

1. Milieu Centraal

2. Alles over Aardwarmte

3. Milieu Centraal

Then there's ultra-deep geothermal heat

The name says it all, in ultra-deep geothermal heat (UDG) the heat comes from deep within the earth. At depths between 4,000 and 6,000 meters, heat of 200oC can be extracted. Interesting! Because these constant high temperatures are suitable for industrial applications and this results in a considerable reduction in CO2 emissions. UDG is not yet applied on a large scale. A lot of research is still needed. In Paris and Munich, however, UDG is already an important heat source for district heating. In fact, Munich aims to supply the entire city with electricity and heat through UDG by 2040.4

"When there are new developments in the energy sector, caution is called for. This applies in any work situation, of course, but especially when research is still being done into possibilities and the associated risks and hazards," says Pier van Spronsen. Pier is founder of HSElife NL and HSEQ Direct, advanced systems that he and his team use to reduce workplace-related accidents worldwide. "Safety first, I can't stress it enough. Extracting heat can pose risks to the environment and to employees. Good preparation and knowledge is then essential."

Why choose geothermal heat?

Both in the summer and in the winter, ground source heat and geothermal heat offer a solution. In the summer, relatively cool groundwater can be used to cool warm air in offices, for example, and the warmed-up groundwater can be pumped back into the soil. In the winter, the warmed water can be used to provide heating in greenhouses, for example. In addition, geothermal heat is a reliable source that is not dependent on weather conditions, for example. Another advantage is that geothermal installations do not take up much space when compared to other forms of renewable energy such as wind farms and solar parks.

Small risk of earthquakes

Heat wells last about ten years. The heat at the site where drilling was done may decrease over the years, requiring new drilling. This type of drilling carries a small risk of earthquakes.

Safety culture in geothermal energy

Working with hazardous substances such as Methane and heavy metals, risk of blowouts,... factors that create potential hazards for professionals working in geothermal energy. "Risks are on the horizon wherever work is done; you must always be aware of that," Pier van Spronsen believes. "Repetition is the power of the message. That's why I think that merely taking periodic training courses is not enough. Knowledge and skills must be continuously at the highest level. Just like awareness and a sense of responsibility. It's simply not possible to say, 'It’s going to be fine'. You must always be alert and work according to rules and guidelines. There are too many workplace accidents worldwide, we cannot let go of the reins. By creating a good safety culture you ensure that working safely and responsibly is in the DNA of employees. It's good to see that it's being looked at properly within the energy sector."

Who can use geothermal heat?

Geothermal heat is mainly used to heat greenhouses, homes and other building. This makes it a good alternative to natural gas and coal. Ground source heat can be used for the same purposes. There are large-scale heat pump systems as well as heat pumps for homes. In this way, you can heat both a house and large greenhouses completely without natural gas.

Source: 4. Bouwwereld