D2Grids: seeds planted for 5GDHC grids
Posted on 07-12-2023 by Stichting Warmtenetwerk
The D2Grids project has planted seeds in Northwest Europe for fifth generation heating and cooling networks. A white paper with principles and calculation formulas is on the way.
Scaling up fifth generation heating and cooling networks (5GDHC). That was the idea behind D2Grids. A European subsidy project of Interreg NWE in which more experience has been gained with this type of heating and cooling network in which heat and cold can be exchanged between buildings. Goals, among other things: to convince suppliers to make good products, with ultimately lower prices, but also to create more certainty for investors.
Heerlen
What has been done in Heerlen by MijnWater since 2004 should also be possible in other places, thought Herman Eijdems (Tri-Es Consultancy and former director of innovation and strategy at MijnWater). "In fact, in Heerlen we have connected the heat pump to a network on two sides. So we didn't think from the idea that one pipe supplies energy and brings back another than the water, but from two pipes with which you supply energy. Only one tube brings cooling and the other tube heat. You can then exchange energy between those two tubes. So with each connected building, the temperature in those pipes improves, because we cool the cold pipe for heating and heat the hot pipe for cooling. That is a substantial difference with the traditional conventional heating and cooling networks."
That worked well in Heerlen – "we also saw more and more scientific substantiation" – and could also be suitable for projects in Paris, Glasgow, Bochum and Plymouth. "If we jointly scale up to a total of 50,000 connected homes, producers will be alert to make those products that fit well in such a system. And they could then become cheaper."
On the other hand, Eijdems saw that these projects are often 'moving trains', where a copy paste approach is difficult. "That is not necessarily necessary, was our idea, if we could formulate the principles from which the successful network in Heerlen originated."
Principles
The D2Grids consortium has thus drawn up five design principles for 5GDHC systems:
- Closing energy cycles as well as possible
- Use low-value sources for low-value demand
- Decentralised and demand-driven energy supply
- An integrated approach to the different energy sectors
- Local resources as a priority
Eijdems mentions the formulation and application of these principles as one of the important results of D2Grids. Subsequently, calculation rules (KPIs or key performance indicators) were developed to determine how well these five principles have been applied. Spider diagrams have been rolled out here for the European projects participating in D2Grids. "For example, some projects score very well on the circular principle, but worse on local energy sources. The diagrams make that clear."
Most effect
The nice thing, Eijdems continues, is that the principles and formulas drawn up show which measures have the most effect. "Suppose you consider building a heat buffer or investing in (thermal) solar panels, what will bring you closer to the fifth-generation ideal? One of the formulas then quickly shows the extent to which the peak loads on the electricity grid decrease."
In Brunssum, Paris and Glasgow – in an expansion of the D2Grids project – additional measures were applied in this way, with which the realized 5GDHC networks could be improved. "So we have developed a method with which you can test what you have to do to get there. Ultimately, you want to build 5GDHC nets because they offer many advantages in the urban environment. The KPIs help to secure this in the design and realization of these systems."
Substantiating choices
The principles and formulas will also help in other projects where this type of heating and cooling network is discussed. "They are universal principles to help steer the energy transition. I haven't come across anyone who has said that following these principles is not good."
They help to substantiate choices, Eijdems thinks. "The advantages of a fifth-generation heating and cooling network can be tested against the KPIs. This offers a big stick during the complex process. You make it visible that if you make a dent in the spider diagram, you lose an advantage. On the other hand, if it turns out that such a solution requires an extra investment, you know why you are doing it."
By formulating KPIs, the fifth generation concept can be tested.
Whitepaper with results
A whitepaper on D2Grids is on the way. This book of about 25 pages explains the principles of a fifth generation heating and cooling network and the associated formulas for calculating it. "In it, we show how it has worked out on the various pilots and what kind of results you get."
There will also be a scientific paper from the Open University. "We see that many projects now claim 5GDHC, but it is not a product, like a Tesla that you can apply for a patent on. More of a vision that you follow to achieve a good product. Nevertheless, it is important to record that vision and to be able to test the result against it. Such a scientific article is a good tool for that."
The building blocks in a 5GDHC system.
140 coal mines
In many places in the Netherlands, 5th generation grids are an option or under development. Eijdems himself is involved in projects in Tilburg, Helmond and Culemborg, among others. He also mentions Germany: "I am very happy that I got them into the D2Grids project, because North Rhine-Westphalia is home to the largest heat network in central Europe: 2,500 kilometers of pipes. Most of it at high temperature from cogeneration plants. The Germans see that they have to make a change. They have renounced nuclear energy, renounced coal and now have to get rid of lignite. A real seed has been planted there. Stadtwerke Bochum – the energy company – has now gone through this project and tapped into a coal mine as a source where they can get hot water from a depth of 800 meters. Despite some setbacks and delays in the project, that source is now working well. We have learned from that and there are still 140 abandoned coal mines in the Ruhr area."
Speed
It is not all fast, Eijdems has figured that out. "We did not connect 50,000 homes as intended. Bochum now has the source in place and can start connecting customers, but that will soon take a number of years."
These are complex processes with many stakeholders. The challenges lie in technology, but certainly also on a financial and organizational level and in laws and regulations. "Clarity about the right choices, the concept to be followed, the vision and the course help enormously."
There are also still steps to be taken in pure technology. "Such a booster heat pump, do we switch it properly in the larger system? Due to the time pressure and the lack of staff, there is now a need for plug and play and foolproof products. There is still a way to go. In addition, we want these products to be able to communicate with each other in a smart way, so that we can ensure optimal performance in an integrated energy network, but also efficiently guarantee maintenance and safety."
Author:
Paul Diersen
