Providing system level frequency support from wind across the full operating range

Conventional synchronous generation provides inherent frequency support to power networks via the
physical inertial properties of the machines. As the number of these synchronous generators on the network
decreases, and converter-interfaced renewable generation increases, this frequency support must now be
provided from other sources. The use of wind turbines to provide frequency support at the inertial timescale
(roughly 5ms - 2s) has been established as a feasible proposition for some time and in multiple studies.
However, several issues remain for the use of wind power to provide this frequency support:
>Most studies of inertial support from WTs are based on operation at full power. However, grid codes
require inertia provision to be guaranteed at all operating points. How can inertia provision be
extended to be provided at lower wind speeds?
>What is the best way of quantifying inertia provision given the variation across operating conditions?
>What is the optimum strategy for inertia provision across the maximum operating range e.g.,
curtailment versus temporary over-rating?
>How do grid forming algorithms perform in terms of inertia provision in a network with high converter
penetration and how can it best be operated/tuned to provide frequency support?
>To what extent can WTs using Grid Forming control schemes be used to contribute to droop support
over the 2s to a few minutes timescale? What is the cost in terms of lost energy production prior to
an event?
>Inertia support at WT level vs farm level - which is the best control strategy to maximise frequency
support and minimise negative impacts on individual WTs?
This project should review the current control strategies, performance and limitations in the literature for
frequency support from WTs. A range of time and frequency domain modelling techniques should be used to
implement control strategies for frequency support, assess performance across the operating point range and
suggest improvements for providing inertia support at low wind speeds. The impact on WT energy production
and lifetime health and the limitations of WTs for frequency support should also be analysed. The addition of
energy storage to improve performance may also be considered.

This outward-facing doctoral training centre will create impact through knowledge enhancement and leadership development which will have significant benefit for society, people and the economy.

Societal Impacts:
A very large increase in renewable energy generation, mainly wind, wave and tidal, is expected in the coming years and decades to meet the UK Government and international obligations to reducing greenhouse gas emissions by at least 80 per cent by 2050 when compared to 1990 levels. In particular, the Offshore Wind Industry Council is proposing, under a Sector Deal, to deliver 30GW of offshore wind by 2030 and 50GW by 2050, whilst reducing the average price of electricity by 18%. The longer term societal and economic impacts arise from the difference that the CDT programme and its graduates make to the UK realising this medium-term and longer-term target. The societal impact of meeting these targets, over failing to meet them, can be calculated in avoided CO2, increased sustainability, security and resilience of the energy system in a safe, affordable and environmentally sensitive manner.

People Pipeline and Skills:
There is a widely recognised skills gap in renewable energy both in UK and Europe. Hence, the proposed CDT is timely contributing significantly to meeting the sector's skills demand by the provision of highly trained engineering leaders, expert in a broad range of wind and marine energy technologies and engineering. Most of the CDT graduates will be expected to take up posts in the growing commercial wind and marine energy sectors, and quickly rise to positions of leadership and influence. Some graduates will remain in the higher-education sector and develop academic careers providing much needed increased capacity and capability resulting in a positive impact through an expanded research-base and capability to deal with the inevitable research challenges of the sector as it develops further commercially.

Students will be mentored and encouraged to take a proactive role in creating impact with their research whilst observing Responsible Research and Innovation (RRI). All the Universities participating in this CDT proposal have explicit policies and resources in place to support knowledge exchange and impact and also public engagement. These support the students throughout their studies to engage in broader dialogue and deliberation and to be aware of the potential impacts and implications of their research.

Our CDT students will also engage in outreach activities and impact the wider community through the well-established Professional Engineering Training Scheme (PETS): this scheme is managed and directed by the students and provides opportunities to engage in outreach activities and to work with peers. e.g. PETS runs a schools and colleges programme wherein the students organise visits to schools and colleges to provide information about renewable energy and a basic introduction to the technology involved.

Economic Impact:
The low-carbon and renewable energy sector is estimated to increase five-fold by 2030, potentially bringing two million jobs to the UK. In particular, an ambitious Sector Deal for industry proposed by Government as part of its Clean Growth Strategy could see a total installed capacity of 30 GW of offshore wind by 2030 with the potential to create at least 50,000 jobs across the UK. If achieved, this would be a six fold increase from the current installed capacity and would make offshore wind the largest source of domestic electricity. To ensure resilience, it is also important to retain and develop the leading UK Wave and Tidal position. With the direct and indirect value added to the UK supply and installation chain in terms of job creation, intellectual property exploitation, and sales of wind, wave and tidal technology and services, the proposed CDT will make an important contribution through knowledge enhancement and leadership development.