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	Knowledge - Wind energy and hybrid systems


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Knowledge - Wind energy and hybrid systems

Contents

1. Small wind turbine consumer label
2. Combination of uninterruptible power supply and small-scale electricity generation
3. Load control
4. 3D printing of small wind turbines

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1. Small wind turbine consumer label

Text last revised 2021-05-18

TEROC has for a long time worked to create an international consumer labeling of small wind turbines. For this, TEROC's Sven Ruin has participated as a Swedish representative in IEA Wind Task 27 and IEC TC88 MT2.

In March 2011, the Task 27 working group agreed on a so-called "Recommended Practice" for the consumer label, which was adopted by IEA Wind ExCo in June 2011 and is available for download on IEA Wind.

The work on consumer labeling has been done in collaboration with the revision of the international standard for small wind turbines, IEC 61400-2. At the end of 2013, the new edition IEC 61400-2 Ed. 3 was published, which includes a basically identical method of consumer labeling.

Sweden's participation has been with the support of the Swedish Energy Agency and previously also Bixia (formerly Östkraft) Environmental Fund.

For some time, there have been some wind turbines with consumer label according to IEC on the market. These are published with associated reports on the WWEA small wind turbine website, www.small-wind.org/labels, among other places (the standard allows different websites to be used, but in order for the label to be valid, proper documentation must be found at the URL stated on the consumer label in question). In the book Small-Scale Renewable Energy Systems, there is a table showng small wind turbine test results for consumer labels. Here a table updated 2021-04-30 is available for download . One of the advantages with IEC consumer labeling, which is based only on testing, is that it can be used for all small wind turbines – even self-built. In other measurements, also some self-built small wind turbines have achieved rather good test results, but I have not seen any of those completing consumer labeling.

In the Swedish Wind Power Association's latest market overview of small wind turbines, you can find, among other things, guidance on how to interpret the information on the consumer label. This is possible to download from the Swedish Wind Power Association's web page about small wind turbines, where there are also films about small wind turbines in Swedish.

See the Swedish Wind Power Association's web page about small-scale wind power (in Swedish) »

As a supplement, it can be mentioned that the label does not concern whether a wind turbine is approved to be connected to the public electricity grid (since there are different requirements for it, depending on where you are). In Sweden, Energiföretagen sell the publication Anslutning av elproduktion till lågspänningsnätet - ALP.

2. Combination of uninterrubtible power supply and small-scale electricity generation

Text last revised 2012-02-16

Many may wonder what the benefit really is with the most small-scale electricity generation, such as setting up a small wind turbine or solar PV connected to the public grid. There can, of course, be several answers to that question. However, if you compare the investment with other alternatives, you will often find that it would provide much more renewable energy for the money if you instead bought a part of a medium or large wind turbine, for example. through shares in a wind cooperative.

However, there is a unique advantage that can be achieved by small-scale electricity generation near the place where electricity is consumed: It can in many cases be supplemented with special equipment that gives uninterrupted power in the event of a power failure on the public grid. Unlike an engine-driven generator set, which can only be operated as long as there is fuel in the tank, wind or solar power can last for a long time - if you just do not consume too much electricity!

One problem in this context is that the electricity consumption in an ordinary home or business is often so large that it can be very expensive to create a solution that is able to supply everything you can possibly plug in. To solve this problem, we at TEROC have developed complete system solutions that include our load control. Load control enables prioritization of loads and thus meets the most important needs, while the less important ones are disconnected in case of power or energy shortages.

The combination can, among other things, provide superior security of supply and income, as the surplus from the renewable electricity generation can normally be sold.

3. Load control

Link added 2019-10-30

Among other things, TEROC develops systems for load management (demand management, demand side management), which can provide benefits in several contexts.

For example, in isolated electricity grids supplied by solar and wind power, costs can be reduced by moving electricity consumption over time so that efficiency increases and the risk is radically reduced for complete power failure in the event of a shortage.

When networking small wind turbines and the like, you may want the electricity you generate yourself to be used directly to a greater extent, instead of being sold.

Charging electric vehicles is another area of application. The power used for charging or other purposes can be continuously adjusted so that, for example, the main fuse does not trip, while avoiding the cost of a more expensive grid subscription or reinforcement.

One technology we use for load control is the open and proven LonWorks technology, which was chosen by Vattenfall and Enel, among others, for "smart" electricity meters. Then the existing power grid can be used for communication, so you can reach every electrical outlet, even in situations where wireless communication has its limitations. The load control system can easily be integrated with other systems, for example for power plant control, electricity measurement and alarm systems, which means that plants can be remotely monitored and maintained in a coordinated and rational way.

Load control is also used to some extent in the public electricity grid, but the economic benefits are often less there than in the small energy systems that we focus on.

Read more about load control eg at Power Circle (in Swedish). It is also possible to see how load control can work in practice in our projects, e.g. "Hus Utan Sladd" (in Swedish).

See our software download page for some of the free software we have developed »

4. 3D printing of small wind turbines

Text last revised 2020-04-27

Two students at Halmstad University, Rand Abbas and Ammar Maqsood Ahmad, have in a thesis work made a 3D model of blades for a wind turbine with 1.2 m rotor diameter, among other things. It is based on Hugh Piggott's A Wind Turbine Recipe Book (2013 metric pdf edition). The 3D model is in the public domain and can be downloaded here. In connection with that thesis work, Sven Ruin from TEROC made a calculation of the mechanical loads, to compare with the students' results. A load calculation (in Swedish, updated 2020-04-27), can be downloaded here. It was made with Mathcad 2001i professional and can probably be used also with more modern versions of the Mathcad software. The result of the calculation is also available for download in Rich Text Format. You will probably need IEC 61400-2 to understand the calculation.

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