The evidence for wind energy

SEAI programme manager John McCann reviews the academic studies on wind power and its positive endorsement of the sector.

The rapid increase in wind energy in the Irish electricity system is unique, in that it has been the subject of an unprecedented amount of published academic, public and industry research. Analysis of the effects of previous major transformations in transitioning from hydropower, to a fossil fuel dominated system, incorporating in turn, peat, oil, coal and finally gas as the major fuel source, was not widely accessible.

By contrast, the extensive research that has underpinned the initiation of this first step in decarbonising the electricity generating system is in the public domain. A majority of Ireland’s wind energy research funding has been dedicated to examining deployment issues, including costs, electricity system impacts and avoided fuel use and CO2 emissions.

This research might be grouped into two categories. The earlier studies analysed the future potential and system effects of wind energy in the Irish power system. As operational data accumulated, later research studied the actual impacts of wind energy upon power system operation. The high level results of the salient studies are summarised below.

Future potential

The first significant study was the 1990 ESB paper ‘The Case for Wind Energy’ by O’Dwyer, Mangan, Kelleher and Cooke which postulated, that if all of its output must be utilised, the maximum wind energy penetration in the Irish electricity system would be 7.5 per cent. The core assumption underlying this result has since been discarded and in 2013 wind energy contributed 16.3 per cent to Ireland’s electricity demand with a very modest amount of curtailment in periods of low demand.

Further Irish research examined the onshore and offshore wind energy resource potential, the statistical characteristics of the wind resource, the capacity of the electricity networks to accept wind energy, operating reserve requirements, market and support mechanisms for wind energy, the impact of wind energy on conventional power plant and the amount of wind energy in potential future Irish renewable energy portfolios.

The landmark 2008 ‘All Island Grid Study’ was the first study that comprehensively examined renewable energy potential in terms of the resources, conversion technologies, electricity network and generating system impacts. It was recognised internationally as setting a new standard for wind energy techno-economic studies. The study analysed the technical feasibility and relative costs and benefits associated with six scenarios with increasing shares of electricity from renewable sources on an all-island basis, examining the required investment in renewables, the net cost to society and the potential CO2 reductions.

The study found that, while a 59 per cent renewable energy scenario was computationally infeasible, levels of up to 42 per cent were technically feasible, with societal costs increasing only marginally. The principal form of additional renewable generation was wind, the 42 per cent renewable energy scenario required least use of imported fuels and, compared to the “do nothing” baseline, achieved a CO2 reduction of almost 25 per cent. On the basis of the results of the study, a 40 per cent contribution of renewable electricity was allocated within Ireland’s overall 16 per cent 2020 EU renewable energy target.

A follow up study by the all-island regulators assessed the possible impacts of high penetrations of wind on the 2020 Single Electricity Market. The study found that wholesale market prices are significantly lower with high wind penetration, though economic benefits are sensitive to fuel and carbon prices.

In its ‘Facilitation of Renewables’ and ‘DS3’ series of studies, EirGrid assessed the technical implications of this target for system security and reliability, proposing a programme of work to ensure system reliability is maintained and reduce levels of wind energy curtailment by progressively increasing the allowable instantaneous wind energy penetration from 50 per cent to 75 per cent.

The Electricity Research Centre (ERC), involving researchers from UCD, TCD, the ESRI, Maynooth University and University of Limerick, among others, has engaged in detailed research on the technical aspects of incorporating wind energy within power systems and is recognised as a leading international centre for such research.

The body of knowledge available as a result of their research projects is impressive and represents a substantial national resource.

Ireland also participates in international research through collaborations such as the IEA Wind Research, Design and Demonstration Implementing Agreement Task 25: ‘Design and Operations of Power Systems with Large Amounts of Wind Power’. The task work began with a state-of-the-art report that collected the knowledge and results from wind power studies. It developed guidelines on the recommended methodologies when estimating the system impacts and costs of wind power integration and formulated best practice recommendations on system operation practices and planning methodologies for systems with high wind penetration.

System effects

More recently, studies in the latter category, analysing actual impacts, have primarily examined the actual economic, system operation, fuel and CO2 impacts arising from increasing amounts of wind energy.

In 2011, SEAI and EirGrid used detailed system and market modelling tools to assess the expected wholesale prices of electricity during 2011. The study demonstrated that the cost of supporting wind power via the PSO was offset by wind depressing wholesale market prices, resulting in a zero net cost for electricity consumers.

A 2013 Economic and Social Research Institute (ESRI) study found that, from 2008 to 2012, wind depressed hourly market prices by amounts varying from 0.2 per cent to 1.3 per cent based upon monthly averages, a result in line with the prior findings in 2011.

In 2014, SEAI completed detailed dispatch modelling of the real time operation of the all-island electricity system in order to estimate the fossil fuel savings from wind generation and other renewable electricity sources in 2012. Wind energy accounted for 15 per cent of all-island electricity consumption in 2012 and displaced 826 ktoe of fossil-fuel reducing CO2 emissions by 2.33 million tonnes.

Sixty-one per cent of the CO2 savings are due to the displacement of natural gas and 39 per cent due to the displacement of coal, with a displacement intensity by wind generation of 0.46tCO2/MWh. Independently of this work, the ESRI used econometric modelling to derive the CO2 savings for 2008-2012 and also arrived at a result of 0.46tCO2/MWh for 2012.

SEAI’s Energy Policy Statistical Support Unit (EPSSU) is responsible for providing statistics on all facets of national electricity supply and demand. The rising contribution of wind energy to energy supply and emissions reductions can be accessed in the published reports and data. The chart above, derived from EPSSU data, shows the emissions by source and the displaced emissions, in the Irish electricity system.

SEAI has also sponsored a suite of wind energy related research projects under its Renewable Energy Research, Design and Demonstration programme. Studies on environmental and social issues include bird sensitivity mapping for Ireland, greenhouse gas emissions associated with developing wind farms on peatland sites, individuals’ perceptions of wind farm projects, the interactions of bats with onshore wind farms, and social acceptance of wind energy projects from a spatial planning perspective.

The results of the many studies to date have overwhelmingly confirmed that wind energy is, in the near term, Ireland’s most abundant, technologically viable and cost competitive renewable energy resource. They have further confirmed that wind energy may make a major contribution to our 40 per cent renewable electricity target, without compromising a stable and reliable electricity system. It is therefore a policy priority to utilise Ireland’s wind energy resource to the fullest extent possible within a renewable energy portfolio that meets national commitments to 2020 EU renewable energy targets.