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  • 1.
    Norbäck, Viktor
    et al.
    RISE Research Institutes of Sweden, Built Environment, Building and Real Estate.
    Landel, Pierre
    RISE Research Institutes of Sweden, Built Environment, Building and Real Estate.
    Dölerud, Erik
    Modvion AB, Sweden.
    Wickström, Anders
    RISE Research Institutes of Sweden, Safety and Transport, Electrification and Reliability.
    ON-SITE GLUING AND WEATHER EFFECTS ON TALL WOODEN WINDTURBINE TOWERS2023Conference paper (Refereed)
    Abstract [en]

    Modvion develops modular wind turbine towers made of wood. The application requires strong and stiff connections and to achieve the desired performance, a hybrid connection with perforated steel plates slotted into LVL modules is used. The parts will be glued together on site, using a polyurethane adhesive (PUR), providing high strength and stiffness to the connection. This paper presents a preliminary screening on how temperature and relative humidity of the surrounding air during assembly and curing will influence the strength of the bond glued on-site. Static tests were performed on the hybrid connections which were glued and cured in different climates. Tests were also performed at different hardening times to evaluate strength growth in the studied climates. The test results show that at cold temperatures of 9 °C to 12 °C there is a breakpoint where the rate of strength growth starts to decline. The experiments show also that the relative humidity may influence the final strength of the bond. However, the low number of tested specimens brings uncertainties to this observation. High temperatures up to 27 ºC and dry climates down to 20% RH did not impact the strength of the tested hybrid connections.

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  • 2.
    Wickström, Anders
    RISE Research Institutes of Sweden, Safety and Transport, Electrification and Reliability.
    Studie över hur värmeförluster från vätgasproduktion kan bidra till fjärrvärme2023Report (Other academic)
    Abstract [sv]

    RISE leder ett projekt, HyCoGen, som handlar om hur man kan göra vätgasproduktion mer lönsam i Sverige genom sektorkoppling med fjärrvärme. Denna delrapport behandlar hur värmeförluster från vätgasproduktion kan bidra till fjärrvärme genom konkreta förslag på kylsystemets utformning. Ett sätt att tillvarata restvärmen från själva elektrolysör-stacken visas i figuren nedan, en generisk anläggning som producerar 400 kg vätgas per timme vid full last. Den övre separata kretsen (allt utom stacken) leds genom en värmepump istället för att kylas externt. På så vis kan den lågtempererade restvärmen, motsvarande 4.0 MW, nyttjas som värme i ett fjärrvärmenät. Den restvärme som kan tas tillvara på detta sätt blir 6.4 MW (BOL=Beginning Of Life) respektive 9.4 MW (EOL=End Of Life) med en temperatur ut på cirka 70°C. Som jämförelse motsvarar en värmeproduktion på 7.9 MWh/h ca 11 procent av Karlstads Energis fjärrvärmeproduktion under ett normalår. Antingen kan restvärmen ledas direkt till ett modernt lågtempererat fjärrvärmenät eller värmas upp ytterligare med hjälp av en annan panna för att anpassas till existerande fjärrvärmenät där högre temperatur erfordras. Med detta kylsystem kan verkningsgraden för hela processen öka från 70% (BOL) respektive 62% (EOL)till 95%. Detta koncept kräver dock en investering i värmepumpen på runt 30 MSEK, med tillhörande eleffektbehov.

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  • 3.
    Wickström, Anders
    RISE Research Institutes of Sweden, Safety and Transport, Safety.
    Vindkraftens potential och kostnader för att tillhandahålla systemtjänster till elnätet2021Report (Other academic)
    Abstract [en]

    Wind power has an extraordinary ability to contribute with the grid system service FFR (Fast Frequency Reserve). The most cost-effective way to achieve this power reserve is by increasing the rotor speed at low winds in order to store desired FFR capacity in the turbine's rotational energy. The total rotational energy stored in Swedish wind turbines during operation amounts to close to 10% of the existing stored kinetic energy in the Swedish electricity system. But the wind turbines are not synchronously connected to the grid. This means that special turbine control is required to use this energy for grid stabilizing purposes. The strategy for today's wind turbines is to maximize energy production in all wind situations, based on the technical limitations the plant is designed for. This mode of operation does not allow for contribution of system services to the grid. In this project a generic land-based wind turbine of 3.4 MW and 130 m rotor diameter has been modelled in the aeroelastic codes FAST and VIDYN. By upgrading the control system, the turbine operates at higher rotor speeds in low winds. Thousands of simulations have been executed to analyse potential and consequences for different combinations of winds, rotor speed concepts and different degrees of FFR power increases. One proposal suggests that the rotor speed is about 2 rpm higher than the optimal speed for the lowest winds. It generates a power capacity which very quickly can be applied in winds between 3 and 8 m/s in accordance with the requirements for FFR that ENTSOE [13] set up. If this capacity is summarized for all Swedish wind power, the FFR reserve reaches 415 MW. This is quite more than what ENTSOE requires to maintain 49 Hz in the electricity grid in the worst case, a production loss of 1450 MW. The cost of this capacity, ie the increase in rotor speed, is decreased energy production for the wind turbine of 3.4 MW. It will go from optimal 12.716 to 12.556 GWh/year, corresponding to 1.3%. This is a relatively small and therefore cheap reduction. An alternative option to generate FFR is to operate at the turbine with a power curtailment in order to have a power reserve capacity over time. This method is only possible in winds above rated power. However, this strategy is significantly more expensive in terms of production loss. The loss of production costs different depending on when the loss occurs as the energy price varies over time. The next step will be to calculate the production loss in [SEK/year] hour by hour rather than [GWh/year] based on the compensation for produced energy and the compensation for the power reserve. These two market signals become control signals to the turbine control to operate in the most optimal way to maximize revenue and thus benefit.

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