The isolated Faroe Islands in the North Atlantic has an ambitious goal to become the world’s greenest group of islands. That means by 2030, SEV, the islands’ power utility, will be using 100% green electricity from hydropower, solar and wind and potentially tidal streams. As well as being an important climate change initiative, this will bring economic benefits as the Faroes will no longer rely on expensive fossil-fuel imports.
However, switching off the existing diesel-fueled generating plant could impact the stability of SEV’s grid. This is because the large rotating equipment provides vital “spinning inertia” that keeps the system in balance. Any grid instability could affect the fish processing and aquaculture industries that contribute some 20% of the Faroese GDP.
To tackle this challenge, ABB is working with SEV to deliver innovative technology in the form of synchronous condensers (SCs). These large rotating devices effectively put inertia back into the grid to keep it in balance.
The first SC installation is at the 6 megawatt (MW) Porkeri Wind Farm on Suðuroy, the southernmost electrically isolated island of the archipelago. This unit, manufactured at ABB’s specialized factory in Sweden, is scheduled to be up and running in the first half of 2022. Together with battery energy storage, the SC could enable 100% of the island’s demand to be met with wind energy at times with good wind conditions.
Figure 1 – An SC will help the island of SuĂ°uroy meet 100% of its energy needs with renewables.
Magnus Rasmussen, Faroe Islands Minister of Environment, Industry and Trade, said:
“We want to harness our natural sustainable energy resources so we can stop using oil. The challenge is that we are an isolated island with no power cables connecting us to our neighboring countries. That means we need to use innovative technology such as synchronous condensers to stabilize our grid and ensure security of supply for 2030 and beyond.”
SCs explained
An SC is not a motor since it does not drive anything. Neither is it a generator since there is no prime mover. It is a large rotating electric machine, deployed traditionally to produce reactive power, balancing out highly inductive loads, like electric motors.
Many decades ago, SCs were deployed widely by electrical utilities and heavy industries that operated transmission, distribution or industrial power grids. However, this function was superseded by new developments in power electronics.
In recent years, the more decentralized nature of grids, combined with concerns over the loss of inertia, have stimulated new interest in SCs. This is because they can provide the stability associated with large generating plant by providing an alternative source of spinning inertia. SCs can also supply and absorb reactive power and deliver voltage support and dynamic regulation.
SCs are proving to be a very cost-effective and reliable way to maintain power quality and provide the fault current protection essential to strengthen a weak grid. This factor is key to increasing the penetration of renewables within the energy mix while maintaining grid reliability.
Modular concept aids flexibility
Modern four pole SCs are typically available in ratings up to 80 megavolt amperes of reactive power (MVAr) and 3 to 15 kilovolt (kV) system voltages. Higher outputs are reached by using several units in a standardized modular concept. This configuration offers better redundancy and availability compared to one large unit.
SCs are tailored on the basis of network studies for the specific location where grid support is needed. This enables the creation of pre-designed SC packages that are easy to transport, install, commission and integrate. They are small or medium sized units that can be strategically sited for optimal results – providing an ideal decentralized solution to increase grid strength and stability.
SCs are not only for islands
SCs have a much broader range of applications than islands. Currently, ABB is delivering a contract for Statkraft, Europe’s largest renewable energy producer, to design, manufacture and install two high-inertia SCs for the Lister Drive Greener Grid park in Liverpool, England. They will play a key role in stabilizing the local grid to handle more wind and solar power. This will help the UK’s National Grid meet its target of operating a zero-carbon electricity system by 2025.
Figure 2 – The high-inertia concept combines a mid-size synchronous condenser with a flywheel.
Lister Drive is the first ABB project anywhere in the world to feature a high-inertia configuration. This couples an SC with a 40-tonne flywheel that increases the instantaneously-available inertia by 3.5 times.
SCs are set to grow in importance
The world’s electricity networks are undergoing fundamental change as the grid penetration of renewables increases while fossil fuel power plants are decommissioned. This is creating a growing need for networks to be supported by decentralized solutions that ensure grid stability and resilience. Synchronous condensers can play a vital role in strengthening weak networks, especially in remote areas. Their advantages include inertia support for frequency stability, fault level contribution and voltage regulation – all functions that are challenging to achieve with power electronic systems alone.
In addition to the latest deployments in Liverpool and the Faroe Islands, SCs have already helped reinforce power networks in Australia, Canada and elsewhere in the UK. The expectation is that network operators worldwide will adopt SCs in ever-increasing numbers as the urgency to decarbonize electricity production continues to gather momentum.
For further information: https://new.abb.com/motors-generators/synchronous-condensers
Kristina Carlquist is General Manager, Synchronous Condensers, ABB.
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