Renewables consultancy OWC has produced a white paper to encourage developers to consider high voltage direct current (HVDC) as potential export systems for offshore Polish wind farms.
Poland has nine offshore wind projects under development with combined capacity exceeding 8GW, with first power generation expected in 2025.
In addition, there are 11 other offshore wind farm sites waiting to be awarded to the developers competing for them.
All these projects may result in around 18GW of installed offshore wind power.
Contrary to some other markets, in Poland the developer is responsible for the grid connection, including the offshore substation, offshore and onshore export cable and onshore substation, with the grid operator virtually providing the grid capacity and connection point only.
The two major types of technology used for generation export are high voltage alternating current (HVAC) and HVDC. Until recently, HVDC has not often been considered in Poland.
Compared to HVAC, HVDC is able to export much larger capacities with fewer cables and has lower transmission losses over long distances. Therefore, HVDC technology is generally more applicable for the projects of larger capacity and longer cable routes.
However, HVDC, due to its complexity, still has considerable costs and supply chain constraints.
“Selection of the transmission system technology of the offshore wind farm export system with associated grid connection application are therefore one of the most important decisions driving the design process of Polish offshore wind farms,” said principal electrical engineer at OWC and co-author of the white paper Bartosz Hunek.
“It will have a great impact on project performance such as the production, availability, capital and operational costs.”
In its white paper, OWC has conducted an analysis of the main HVDC technology features together with their impact on offshore wind farm development, construction and operation.
OWC has also developed a technical and cost model of the export systems of Polish offshore sites, comparing both technologies.
“There are multiple good reasons for developers to consider HVDC technology for Polish wind farms, but they need to be aware that HVDC also brings its own set of challenges,” said electrical engineer at OWC and co-author of the white paper Piotr Jedrzejewski.
“Nevertheless, the main conclusion from our analysis that certain wind farm areas at Polish Baltic Sea may use HVDC export technology and that we encourage more discussion about this subject in the Polish offshore wind market.”