CONTEXT

Since 2011, more than 100 gigawatts of new renewable capacity has been installed year on year, surpassing the capacity added every year by fossil fuels and nuclear power. The market share of renewables increased to 29% in 2020, in comparison with 27% in 2019.  The International Energy Agency (IAE) estimates that electricity from renewable sources in 2021 will grow by more than 8% to reach 8,300 TWh, the strongest inter-annual growth since the 1970s. Two-thirds of this growth will come from photovoltaic solar and wind power.

The grid connection of renewable energy sources involves major challenges due to the intermittent nature of supplies. In a market in which the market share of renewables is estimated to reach 40-70% by 2050, electricity market operators and power generators need to get actions under way to ensure the stability of operations and energy supplies. 

In this context, grid codes appear as a vital element for the integration of variable renewables, as they set the rules under which the electric power system operates. These take the form of a series of guidelines and requirements that solar and wind power generation plants have to comply with to connect to the grid in each region.

OPPORTUNITY

In the case of wind farms, compliance with grid codes is a complex undertaking, as the changes in available capacity due to fluctuations in the wind resource can create problems in terms of the quality of the energy.

ACCIONA has more than 8,700 MW of wind power capacity under its ownership in 14 countries (Spain, the US, Mexico and Australia, among others). The functioning and operation of each wind farm needs to be compatible with the security and stability requirements established by grid codes. These codes are specific to each country or region, as they respond to the particular nature of each electric power system. They are also subject to continuous review, as they need to evolve to adapt to the changing needs of each system.

Compliance with grid codes has a direct impact on the profitability of renewable assets. For example, in Australia compliance with grid codes is regulated by law and non-compliance is considered a civil offence and is subject to sanctions. Therefore, it is essential to have tools that allow us to ensure that the operation of a wind farm is in line with the stability and security requirements laid down in each place in order to maximise its performance.

WHAT ARE WE SEEKING?

ACCIONA is launching this challenge to identify the tools and/or technologies that will allow us to improve grid integration and compliance with grid codes for wind farms consisting of doubly-fed turbine technologies (type 3). The proposed solutions should:

• Be able to be modelled and simulated in software such as PSSE, digsilent and pscad
• Analyse and manage the performance of generation assets under real conditions at the turbine and wind farm levels
• Allow, define and automate strategies to maximise the performance of plants, ensuring compliance with the grid codes in force
• Include control algorithms with the parameters defined in grid codes to ensure that the operation of plants complies with established stability and security requirements. In this respect, one of the aims is to improve, in weak grid situations (SCR lower than 5), aspects such as fast voltage control at the point of connection (response time below 5 seconds), fast frequency control at the point of connection (response time below 5 and 1 seconds) and the input of reactive and active current at the wind turbine and wind farm levels (POC) at aggressive (high droop) and fast (response time below 70 microseconds) levels, and control during voltage dips
• Be adaptable and scalable for deployment in different target markets.

Tools with different degrees of technological maturity will be taken into account. The proposed solution does not need to be fully developed at the time of presenting a proposal.

SDG 7. Affordable and clean energy