What are the effects of the energy transition on electrical installations?
On December 21, Prof. dr.ir. Sjef Cobben gave a lecture on the effects of the energy transition on electrical installations during a knowledge session entitles “’Inspansion’ and the energy transition” at Eindhoven University of Technology, initiated and organized by HyTEPS. A brief overview of the content can be found in this article.
Until recently, the stability of our electricity grid was guaranteed by large power plants, responding to fluctuations in demand. However, these types of power plants are slowly disappearing as a result of the growth of wind and solar energy. These renewable sources are less flexible and that, in turn, has consequences for grid stability. We see new requirements and conditions being applied to renewable sources, which include various types of energy ‘self-producers’. This is already taken into account in the network code. ‘Requirements for generators’ must ensure that renewable sources, from relatively small to very large, also contribute to grid stability. For example, by dealing with excessively high frequencies, voltage limits, and dips in a smart way and by looking for ways to feed in more power.
Dedicated plan of attack
We’re not only seeing these developments within the high-voltage segment, but also at low and medium voltage levels. The integration of renewable sources is driving (faster) sustainability of grids, along with the growing number of electric vehicles, the development of energy prices, the construction of new grid infrastructure, and adjustments in regulations. However, the shortage of technical staff is a hindrance. Techniek Nederland, the Dutch trade association for the installation and technical retail sector, has indicated that a dedicated plan of attack is required to fill thousands of vacancies. Over the next ten years, 1 billion euros will be invested in, among other things, new intake, certification of craftsmanship, and continuous education.
In the longer term, various solutions for future-proofing infrastructure and improving grid stability are conceivable. For example, through grid reinforcements (although this can’t be repeated indefinitely) and using existing grid structures in different ways (which takes time). Congestion management and releasing spare capacity can offer provide solution. Smart networks are also part of a solution – providing these are connected to smart installations.
High, medium and low voltage networks are increasingly intertwined. More and more heat pumps are being connected to medium and low voltage installations along with far more solar panels than we could ever have predicted. On the other hand, the electrification of homes and transport is creating greater demand for electricity. There is greater voltage variation, but the supplied voltage must always remain within a certain bandwidth: a challenge for grid operators. For example, a smart transformer can help by controlling the voltage.
‘Thinking back to front’: an important part of the solution
Until now, more energy was generated temporarily to cope with larger loads. However, the yield of solar or wind energy can’t simply be scaled up. It is better to look for controllability in the load and adaptation to demand.
In the Netherlands, regulation NEN 1010 part 8, regarding efficient installations, shows how to think back to front’. Installations are becoming increasingly complex, which places greater demands on people and processes, and leads to more risk and failure. The energy classification electrical installation (NEN 1010-part 8-1) strives for greater efficiency through minimal consumption and a high efficiency level. Processes, in which a great deal can often be gained, are not taken into account. NEN 1010 part 8 mainly deal with ways in which everything can be connected as efficiently as possible and how you can best deal with power and loads. For example, you can place an infill point in the center of the load to minimize losses. It can also pay to use a thicker pipe because losses are quadratic to power – with long operating hours, a thicker cross-section pays for itself!
Determining the efficiency level
The efficiency level of an installation can be determined using a qualification system described in NEN 1010. Depending on six criteria, the installation is assigned a label. In the design principles of this standard, the following aspects are considered:
Guarding Power Quality
The intention is ultimately to reduce maximum load so that peak load remains within contracted values. Eventually, the contract value could even go down. Ultimately, the quality of service and performance of the electrical system should not suffer. How to achieve this? Adjustable load and storage systems play an important role, as does measuring and improving Power Quality aspects. ‘Power Quality’ can affect energy efficiency performance in several ways, for example by preventing additional losses or excessively rapid ageing of equipment.
Designers and installers should develop a strategy for measuring and monitoring key parameters including:
For example, reducing harmonics at the level of the load reduces thermal losses in the wiring. Possible solutions include reducing harmonics by installing harmonic filters on the respective load groups or reducing the effect of harmonics by increasing the cross-sectional area of the conductors.
Measurement = knowledge
Overloading capacitors, pipelines, drives and other components in an installation leads to unnecessary energy losses! However, there is often insufficient knowledge about these losses, or opportunities to address them. Measuring is not difficult – but absolutely essential.
Integrating renewable energy and controlling the load based on demand management are important for grid stability (and for achieving relevant standards), but a large number of factors must first be considered. For example:
Storage is relatively expensive – it should not only be used for “demand response” but also for improving voltage and plant continuity.
‘Inspansion’ can also play an important role. Through ‘inspansion’, capacity can be created behind transformer(s) in electrical installations. In this way, more yield can be obtained from existing systems in a safe, smart and sustainable way.
Installations are becoming larger and more complex as renewable sources and growing demand need to be balanced. Part 8-2 NEN 1010 looks at functional aspects and electrical installations for low voltage prosumers. Strategies for building such installations are being examined, including interdependencies and distribution/transfer points. When defining a solution, we need to look carefully at a number of factors:
Where are we now when it comes to realizing stable, flexible, future-proof grids? More efforts should be made to save energy and grow the use of renewable energy sources. Load must be more “flexible” (storage) and there needs to be optimization per customer/neighborhood/area. This requires more sensors and therefore more measurement and better use of all data. And in addition, broad support and awareness are vital.