For a smart grid future

EirGrid is implementing a three-pronged strategy to develop a smart grid for Ireland.

With the Government aiming to achieve 40 per cent of electricity from renewables by 2020, EirGrid is rolling out new infrastructure, technologies and solutions to deliver a smart grid. Its Grid25 plan, the ‘Delivering a Secure Sustainable Electricity System’ (DS3) work programme and demonstration projects are the central planks.

Smart grid technologies, says Fintan Slye, EirGrid’s Director of Operations, will enable Ireland to achieve high renewable penetration “with the optimal set of investments.” Without them,“we’d have to put in more infrastructure.”

He explains: “So what smart grid technologies allow you to do is to push the system closer to its limits, but be confident about where you are and keep it within those limits, and ensure that you can maintain reliability of supply.”

While wind can presently meet up to 50 per cent of total load on the system, it will have to rise to 75 per cent to meet the Government’s target.

Infrastructure

Grid25, the TSO’s €4 billion roadmap of grid development to 2025, involves 1,150km of new power lines and upgrading 2,300km of existing lines. This represents a doubling of the bulk transmission system’s capacity.

Areas with good renewable energy resources and high levels of grid connection applications (i.e. the west and south) currently do not have extensive grid infrastructure. Extending the network to these areas forms part of the plan. Major power corridors will be built from Cork to Dublin, via Waterford; from the midlands to the west; and in the Cork-Kerry area.

EirGrid is also building the East-West interconnector between Ireland and Wales. The 500MW HVDC interconnector (between Deeside, north Wales and Woodland, County Meath) is due to become commercially operational in September. The first capacity auction for the interconnector took place on 19 June.

Work examining the feasibility of future interconnection with either the UK or France is underway, and it expects to publish the results of preliminary analysis by the end of the year.

The TSO is also involved in work on other potential interconnection projects. The ISLES project envisages an offshore transmission network and subsea electricity grid in the Irish Sea-North Channel area and off the west coast of Scotland. The North Seas Countries’ Offshore Grid Initiative involves nine EU countries and Norway.

DS3

EirGrid and SONI’s DS3 programme is addressing the operational challenges in integrating very high levels of instantaneous renewables penetration on the grid. Managing system frequency and system voltage, balancing the system in real time and ensuring the compliance of plant with grid code requirements are the main challenges.

The programme aims to maintain security of supply standards in the context of changing plant portfolio and assist in delivering the 2020 EU targets (for Ireland, 16 per cent of all energy from renewables). Facilitating the renewables target also requires minimising curtailment of renewable electricity, as required by the EU Renewable Energy Directive 2009/28/EC.

Curtailment occurs when high levels of wind generation meets insufficient system capacity. Though it usually occurs at night when there is low demand and high winds, it is expected to become a more common occurrence during daytime.

DS3 contains three main work areas: system performance; system policies and system tools.

The system performance strand aims to provide certainty around current and future plant performance capability. It also involves reviewing system services arrangements.

In order to manage the voltage and frequency on the power systems in both jurisdictions, DS3 is analysing and adapting system operational policies through data collation and analysis. Policies for ramping, reserve and standards of rate of change of frequency (ROCOF) for plants connected to the system are being reviewed.

EirGrid and SONI are developing system tools to manage increased operational complexity. The tools are aimed at assisting operators in the support centres. They are updating system models with actual plant performance capability.

A tool already in use is WSAT (wind security assessment tool). It provides dynamic stability analysis in real time and tells the operator how close the system is to its limits.

DS3 contains eleven workstreams and runs until 2014. The communications component of the work programme entails consultation with stakeholders, such as an advisory council.

Among the issues the council has discussed is the ROCOF standard on the power system. The current grid code in Ireland requires generators to be able to ride though ROCOF of 0.5 Hz/s. However, EirGrid’s research on facilitating renewables shows that the standard will have to move up to accommodate higher levels of wind energy on the system.

Slye says that the industry is “struggling” with how to get original equipment manufacturers that commissioned generation in the past to certify that a generator will ride through a fault. The industry “needs to do a good bit of analysis” to resolve this, he says.

Demonstration projects

EirGrid and SONI are also partnering with industry on new technologies and ideas for the power system. This work involves trialling and proving new solutions and technologies and building shared learning. Smart grid concepts of interest to the system operators include demand side management and transmission technology such as dynamic line rating.

Dynamic line rating is already being employed by EirGrid in a pilot project on four lines. It can measure in real time the actual current flow on the sag of the line. EirGrid is currently assessing the results and considering where next to deploy it.

Smart grid technology, according to Slye, holds great potential for Ireland. “There’s a huge opportunity here for us to solve some of those problems that other countries haven’t even seen yet,” he states, “and then export that technology, that expertise, to other countries”.

To the extent that Ireland is “ahead of the curve”, Slye believes that Ireland can “build an ecosystem nearly, that will be self-sustaining and will work here but that then does have that opportunity to just effectively market itself externally.”