The first grid-connected hybrid flywheel project in Europe could potentially be rolled out across the rest of the European Community once it initially gets off the ground in Ireland.
Frank Burke, Technical Director at Schwungrad, the company behind the flywheel project told Power Engineering International that the Irish experience in using the technology to maintain a stable grid as more and more renewable power is loaded on will serve to inform other member states.
“With the Irish context there is the pretty high target of going 40 per cent renewable by 2020 which is only a few years away now. One of the problems at the moment is that the system can’t allow more than 50 per cent of non-synchronous renewable generation at any one time; it’s not just renewable, that also applies to the interconnectors because those interconnectors are DC and are not synchronised. The problem is growing every year where a renewable plant is having to be curtailed because they can’t allow more than 50 per cent on.”
“At times there’s no wind and that means at other times you have to have up to 75 per cent renewables on the system, and if the system operator needs to be able to raise the bar from 50 per cent renewable to be able to accommodate 75 per cent renewable they need more system services and that’s where we come in with the flywheels and batteries.”
Flywheel technology has no direct fuel use or related emissions, and no water consumption. It simply absorbs power, stores it and is continuously ready to respond to any grid requirements to rapidly inject power. It is not a power plant in the conventional sense, but operates as a shock absorber and dynamic energy support system, absorbing and re-injecting small but highly flexible amounts of power to suit grid requirements.
Burke predicts that the Irish case will later be applied across the union, especially in countries whose targets for renewables are presently relatively modest, but bound to increase over time.
“Ireland is ahead of the curve because we are already at over 22 per cent renewables last year and 20 per cent the year before. So we moving towards that 40, some countries only have a target of 20 per cent. So we are seeing problems on the Irish electrical system that other countries are going to see in five to 15 years as they increase their targets and aim for higher percentages of renewables.”
“The other thing that makes Ireland unique I that we are an island and not very strongly interconnected with AC interconnectors, in fact having none at all.
So problems are more acute in Ireland than in continental Europe so that’s why (Grid operator) Eirgrid are to the fore over the last five years.
Eirgrid recently introduced a programme called DS3. DS3 stands for delivering secure sustainable electricity system and part of that is agreement that some additional system services such as flywheel technology would be paid for by the system operator.
The value or the payment for system services at the moment are about €60m a year but the Irish regulator has agreed that the value of system services can increase up to €235m by 2020. There is a growing market for system services and that’s a reflection of the needs of the grid.
€2.55m from the European Commission Horizon 2020 was received in December of 2014 to support the work. SchwungradEnergie Limited is the prime mover in tandem with the Dept. of Physics and Energy at the University of Limerick and US company, Beacon Power.
So, with flywheel already a proven technology, what is this project’s USP?
“It is about proving the application of using flywheels and batteries for short term system services, what we’re calling dynamic energy storage as distinct from the longer term energy storage that batteries are normally associated with being able to facilitate.
Those projects are where you have maybe four to six hours of full load energy storage for when there’s maybe not much wind. That not our business. We are using flywheel and batteries from the first milliseconds out to 20-30 minutes. That very fast initial response.”
With 2020 fast approaching the need for rapid frequency response and voltage control, contributing to system stabilisation is growing in urgency. Burke says the timeline is first directed at Ireland, and later further afield.
“We will place the flywheels in the summer, batteries in the autumn, both separately tested before combining them at the end of the year tested as a hybrid and after an additional control algorithm it will be continuously tested into 2016. In 2017 under the DS3 programme there’s a plan to offer out long term contracts to people who can provide system services in Ireland, though we would be bidding in for the long term contract in 2017. If we win that we will build one or more 20 MW plants if we get the contracts. We are also in discussion with the National Grid in the UK, and are looking at other countries around Europe.”
“Flywheels are being used for this purpose already in the US but not so far in Europe so we are the first in Europe.”
Burke provided further details to Power Engineering International on the key attributes of the technology so sought after as the world grows its share of renewable power generation.
From a starting point, traditional power plants would have comprised heavy turbines and generators with lots of steam, hence a very stable system, with lots of inertia on that system.
The advent of renewables means generation that’s not synchronised, is very light and doesn’t contain the same extent of inertia.
“What we are trying to do is bring back some of that heaviness to the system by having flywheels that will be able to respond within hundreds of milliseconds. The flywheels store kinetic energy at high speed and we are also storing it as chemical energy. In both cases we should be able to respond in a couple of hundred milliseconds to start feeding power back out to the system if the system frequency suddenly drops.
“With flywheel we can continuously regulate the system frequency. You can charge and discharge them millions of times whereas with batteries you wouldn’t connect it continuously as you’ll wear out the battery.
Beacon Power President & CEO, Barry Brits is optimistic about the prospects for the technology.
“We see the potential in Ireland and Europe for short-duration flywheel energy storage as a key tool to help address the grid system stability impacts of leading implementation of renewable energy sources.
“In this ‘new’ energy storage marketplace, we have been providing these kinds of services in the US for over seven years, have accumulated over eight million flywheel operating hours and delivered more than 300 gigawatt-hours of service to electric grid operators.”
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