Gareth Brown explains how to navigate an ocean of offshore unknowns

uropean offshore wind capacity has grown sevenfold since the end of 2010. Tis brings today’s total capacity to 22GW, of which 3GW was installed in 2019. Recent figures from WindEurope indicate that offshore wind is now on course to supply 50GW of renewable energy to Europe by 2030 – the equivalent of more than 6% of the continent’s total energy supply. Crucially, the level of investment required to facilitate this boom in development depends on operational projects bringing in forecasted returns. However, to date, the offshore wind

industry has struggled to meet forecast energy production. Tis has a dramatic impact on revenue, as a drop in energy yield of as little as 2% could result in a shortfall of millions of dollars. Although the causes of

underperformance onshore are well understood and easily identified through in-depth, highly contextual data analysis techniques, the causes of underperformance offshore continue


can reach in excess of 100m in length allow offshore turbines to produce twice as much energy as the average onshore turbine. Taller towers also enable the blades to interact with the stronger, more consistent winds typical of higher altitudes.

Long blades and tall towers that reach higher altitudes might have the advantage of access to greater wind speeds, but the increased blade length combined

to remain something of an unknown. Even the effects of known causes of underperformance, such as heavy rain or hail, cannot be gauged accurately for an offshore site due to a lack of data properly illustrating the effects of harsh offshore conditions on new turbine technology.

HEAD IN THE CLOUDS A key driver for offshore wind development has been the technology’s supersize potential – both the size of turbine technology itself and its resulting generating potential. Larger rotors powered by blades that

with lighter and lighter blade design and increased tip speed lead creates a higher risk profile. Although heavy rain is known to cause leading edge erosion, there is not yet enough data available on how the constant interaction of water droplets at these high wind speeds with new leading edge protection may influence the lifespan of this new turbine technology and the propensity of the blade surface to wear-and-tear. To ensure projects achieve maximum generation, owners must invest in comprehensive, in-depth analysis of both turbine performance data and environmental conditions. By monitoring when turbines are underperforming and charting this against environmental data, it is possible to develop a complete understanding of the impact of offshore conditions on their turbines and act on any faults as soon as possible.

OUT OF THE BOX ASSUMPTIONS Te annual energy production (AEP) forecasts that project owners and investors rely on are often calculated using the power curve for a given turbine out of the box. A power curve is based on a highly specific set of site conditions, with performance modelled against a given temperature range, air density, and turbulence. However, if the site conditions fall outside of those modelled for in the power curve, the turbine may only produce a fraction of the power expected of it. As


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