A stroke of serendipity, courtesy of the weather gods, will save the Norwegian offshore wind sector from the intermittent moods of windpower. But only if wind farms are distributed across large geographical areas.
An analysis of wind statistics that we have recently carried out shows that there is no systematic correlation in time between the occurrence of windy oceanic conditions in southern and northern Norway There is also little covariance between periods of windy conditions in southern and northern Norway.
This is good news for Norway’s ambitions in the field of offshore windpower development. Our findings serve to increase the likelihood that when electricity customers demand power, the wind will always be blowing at least somewhere along the Norwegian coast.
This will boost the value of Norwegian offshore wind energy and reduce the need for balancing measures in the electricity supply system. However, all this is contingent on not clustering wind farms too closely together.
Our findings serve to increase the likelihood that when electricity customers demand power, the wind will always be blowing at least somewhere along the Norwegian coast.
Our study was based on 29 years of chronological wind data taken from 15 areas previously identified by the Norwegian Water Resources and Energy Directorate (NVE) as potential wind farm sites.
The areas are spread from the ‘Sørlig Nordsjø II” concession in the far south to Sandskallen offshore western Finnmark in the north. We have also included three areas located off the coasts of other countries bordering the North Sea. These are the UK Dogger Bank, a location close to the coast of Jutland in Denmark, and another in the German sector of the Baltic Sea
Our aim has been to look for possible relationships (statistical correlations) between when the wind blows and where.
Our main finding is that ocean winds in the north and south of the area under investigation exhibit no systematic covariation. This means that overall offshore wind energy generation in Norway can be regarded as more stable, thus potentially enabling us to avoid the incidences of intermittent production that are very demanding to manage.
If the wind was always blowing (or not blowing) at the same time all along the coast, the wind farm operators would be faced with a ‘big squeeze’. In such a situation, they would all be feeding the energy into the market at the same time
Why wind farms must be widely distributed
The terms ‘covariation’ and ‘correlation’ are virtually synonymous. A correlation of 1 between two variables is the equivalent of full covariation. In our case, if the wind is blowing in the south, it will always be blowing in the north as well. A correlation of zero means that there is no such relationship.
If the correlation is minus 1, then the relationship is the opposite. If the wind is blowing in the south, it can never be blowing in the north at the same time. And vice versa.
Our findings demonstrate the following:
- There is statistical covariation between the occurrence of ocean winds in southern Norway and at the aforementioned locations in UK, Danish and German waters, but the correlation is closer to one half than 1.
- There is almost no statistical covariation between the occurrence of ocean winds in southern Norway/northern Europe and between that in mid-Norway and further north. Here, the correlation is close to zero. The division runs approximately west of Stadt on the coast of Vestland county.
These relationships explain why it is so important that wind farms should be geographically spread.
Output close to existing hydropower generation
Our findings are the result of ongoing studies being carried out at the FME Northwind research centre, which is one of the Research Council of Norway’s Centres for Environment-Friendly Energy Research (CEER) programmes, and the Norwegian research project Green Platform Ocean Grid.
The results are extremely relevant in the light of the plans for offshore wind announced by the Norwegian government this summer. By 2040, Norway is intending to award offshore windpower exploitation licences with the potential to generate a total capacity of 30 gigawatts (GW).
This will mean a total offshore windpower capacity that is close to the sum of all existing Norwegian hydropower facilities. Nothing less.
Saving windpower operators from the ‘big squeeze’
In such a massive industrial sector, future wind farm operators would be faced with a ‘big squeeze’ if the wind was always blowing (or not blowing) at the same time all along the coast. In such a situation, they would all be feeding the energy into the market at the same time During such periods, the electricity price would fall, reducing the potential revenues earned by the operators.
Without the welcome lack of covariation between wind conditions in the north and south, offshore windpower generation would become more intermittent. This in turn would increase the need for balancing measures, involving the use of hydropower or other flexibility built into the power system in order to ensure that consumption and generation keep pace with each other.
Our study demonstrates that if wind farms are geographically spread, the need for balancing measures will be reduced.
Another important observation from our studies is the nature of seasonal variations. In all of the aforementioned areas, the wind tends to blow harder in winter (when the demand for electricity is greatest) than in summer.
This means that the need for balancing measures will arise primarily for short periods, or in other words from hour to hour or day to day, and to a lesser extent from season to season or from year to year.
Demand in the north
Some people may object that there is no need to develop offshore windpower in northern Norway because of the low electricity prices currently prevailing in this region. However, a recent power system study carried out by SINTEF for the energy cluster Energi i Nord has demonstrated that northern Norway will be experiencing a power deficit as soon as in the early 2030s unless electricity generating capacity is expanded.
Offshore wind power in northern Norway may thus offer a key to the realisation of a number of industrial development plans and a green energy transition in that part of the country.
What about an offshore grid?
Our findings also have a bearing on what is currently a major debating issue surrounding the lack of power exchange within Norway. Massive levels of grid expansion in Norway are constantly being obstructed by controversies surrounding ‘monster pylons’ in the landscape.
So why not start calculating what it would cost, and what could be gained, by linking the electricity distribution infrastructure by means of an offshore grid that can transport electricity generated by offshore windpower in submarine cables along the Norwegian coast?
This article was first published in the daily Dagens Næringsliv on 24 November 2022 and is reproduced here with the permission of the paper.