By Jorlan Peeters | February 2022
Offshore wind energy will make the energy transition possible - provided certain conditions are met
"To make the energy transition possible, renewable energy must be available in vast quantities, at an acceptable price. Offshore wind energy can play an important role in this - but first a number of steps need to be taken."
“Wind is an endless source of energy, and wind turbines do not produce any CO2. However, wind turbines cannot be scaled up indefinitely on land. For example, the turbines will not blend into every landscape. Moving them to sea, where wind speeds are usually higher than on land, is a solution. Fewer turbines are needed at sea to produce the same amount of energy and small increases in wind speed can result in produce greater energy production. Wind speeds and direction is more consistent at sea, and offshore turbines can also be higher, which means they can produce more electricity.”
"The total installed capacity of offshore wind energy in the Netherlands is currently about 2.5 GW. Between 2023 and 2030, 1000 megawatts (MW) is expected to be added each year. The aim is to have wind farms producing 11 GW of electricity by 2030. Offshore wind power plants are linked to mainland connection points via submarine cables, from there they run to the grid, and ultimately to end users. Smart batteries can help match supply and demand.”
“However, experts warn that connecting large amounts of offshore wind energy and storage systems to - often outdated - grids poses a huge challenge. The growth of offshore wind energy therefore calls for expansion and modernization of the electricity grid."
“Wind turbines are connected via inverters (power electronics) and long submarine cables, which can lead to unwanted harmonic voltages. What’s more, new technologies and power electronics are often more sensitive to voltage disturbances. When wind turbines are commissioned, voltage fluctuations in the distribution network must be kept within certain limits. The European voltage standard EN 50160 prescribes a maximum of ±10% for 10 minutes of average voltage at consumers. This is to ensure devices are not damaged or don’t start to malfunction. IEC 61400-21 - the international standard for measurement and assessment of Power Quality of grid-connected wind turbines - recommends load-flow studies to assess the influence of wind turbines on steady-state voltages. IEC 61400-21 also defines power quality characteristics for wind turbines and suggests methods to assess the impact of wind turbines on grid power quality. For example, it defines a flicker coefficient and associated measurement procedures, and specifies methods to calculate the expected flicker emission of one or more wind turbines, based on their flicker coefficients.”
“To ensure voltage quality, grid operators set high requirements for offshore wind farms. Grid codes are also becoming stricter. The requirements for low/low voltage and harmonics are becoming more stringent, making compliance for wind turbines harder.”
“Continuous monitoring and analysis of Power Quality characteristics can play an important role in this.”
“The widespread use of offshore wind makes Power Quality increasingly important. As the wind power market grows, it becomes increasingly important to verify and optimize wind turbine and wind farm power quality performance. The development of huge wind farms over the past decade has brought an increased focus on Power Quality in relation to management and stability of electricity networks. Yet this requires much more attention. That’s a pity, because without attention to Power Quality, the share of offshore wind in the energy transition could be unnecessarily limited.”
"Grid operators and installation managers are faced with numerous challenges related to the unpredictable nature of renewable energy yields. Switching of wind turbines and large variations in generation and consumption of energy can lead to significant voltage fluctuations. HyTEPS provides modelling, simulation and analysis for wind farms to verify compliance with all relevant grid standards, for example to obtain approval from the transmission system operator. This prevents problems within electrical installations, reduces risks, improves efficiency and ensures safety. We have carried out thousands of individual harmonic load ﬂow studies for each harmonic order (including interharmonics) of a 200 MW wind farm. Whether it is voltage quality in distribution systems or solving power system stability challenges, HyTEPS has an answer."