An interesting article from Pat Swords:
There is now in 2019 approximately 3,700 MW of wind energy installed in the Republic of Ireland with an additional 1,300 MW installed in N. Ireland. As can be seen from the Figure 1 below, for extended periods there is little or no wind power output, and then when a low pressure system moves in, the wind turbines all rush on to the grid at the same time.
Figure 1 Pat
Figure 1: All island electricity demand and wind energy output for week 7th Jan to 13th Jan 2019 (Eirgrid Data)
This is also clearly demonstrated in Figure 2 overleaf showing electricity demand and wind power output from early September 2019 to early October 2019. For large periods of the time, there was simply little or no wind energy, which when it was available generally rushed on to the grid for a short period, as a low pressure system moved through. During these periods of peak output, the wind energy output was at times nearly equal to the troughs occurring in system demand, i.e. each night time period.
Figure 2 Pat
Figure 2: All Ireland electricity demand and wind energy output for period 8/9/2019 to 7/10/2019
1.2 Impact of Intermittent Wind Energy
This irregular supply of wind energy causes huge problems with the existing generators on the grid, as they have to reduce their output or even cease generating for the period in which the wind energy rushes on to the grid, a procedure called curtailment. The “Impact of Wind Power Generation In Ireland on the Operation of Conventional Plant and the Economic Implications”, published in 2004 by ESB National Grid, was written at a time when there was an indicative target being considered by the EU that 13.2% of Ireland’s primary electricity would come from renewable sources by 2010. Currently in 2019 the percentage of electricity in Ireland, which comes from wind energy is reported as 30%. As that 2004 report points out, increasing the percentage of highly variable and intermittent wind energy on the grid cause conventional generators to operate in an increasingly inefficient stop / start manner.
- The adverse effect of wind on thermal plant increases as the wind energy penetration rises. Plant operates less efficiently and with increasing volatility.
This increases costs and reduces the effective emissions savings. An analogy can be to consider conventional generators as like vehicles now driving in a congested urban environment, with frequent stop / starts and acceleration and deceleration to compensate for the highly intermittent and variable wind energy input, while previously they were operating on a steady load like driving on the motorway.
Indeed, this is the reason why the simplistic carbon saving calculations completed by wind farm developers and claims made by the Irish state, such as in its National Renewable Energy Action Plan progress reports; do not reflect actual real world emission savings. While a MW of electricity generated by wind energy, in the limited periods when it is available, will replace a MW of electricity, which would have otherwise have been generated primarily by fossil fuelled thermal plants, it does not displace the emissions associated with otherwise generating a MW of electricity in a thermal plant. This is because of the intermittent wind energy input to the grid, those thermal plant are now operating in a more inefficient stop start manner with increased emissions per unit of electricity generated. .
As that 2004 ESB report went on to conclude:
- The EU target for Ireland, from all renewable sources, is 13.2%. Therefore it can be estimated that, in the long term, using WPG [Wind Power Generation] to comply with the EU target will increase electricity generation costs by 15% (€196m as a percentage of €1.28bn). This translates to a CO2 abatement cost in excess of €120/tonne.
- The cost of CO2 abatement arising from using large levels of wind energy penetration appears high relative to other alternatives.
In 2019 we have reached a 30% input of wind energy to the grid (penetration), which is far in excess of the figure being considered above in 2004. As thermal plant inefficiencies increase as more wind energy is added to the grid, the relative abatement cost highlighted above is a significant underestimation of the situation pertaining in 2019.
1.3 Economic Cost of Carbon Reduction with Different Renewable Energy Sources
Furthermore, as the renewable energy programme has proceeded in Ireland without any form of supporting analysis, there has never been a proper economic assessment of the cost of reducing carbon emissions, using wind energy or any of the other ten sources of renewable energy listed in renewable energy Directive 2009/28/EC. A Directive which defines:
- ‘energy from renewable sources’ means energy from renewable non-fossil sources, namely wind, solar, aerothermal, geothermal, hydrothermal and ocean energy, hydropower, biomass, landfill gas, sewage treatment plant gas and biogases;
Many of these eleven different sources of renewable energy are of a diffuse nature and more suited to being applied for heat energy rather than the generation of electricity. An example of this being the use of solar energy for water heating, which is a simple technology approach, such as circulating water through evacuated glass tubes.
- Typical well-installed systems provide up to 60% of hot water demand over 12 months.
The cost effectiveness of this approach can be determined from the fact that such solar hot water heating installations were in use even before grants for their installation became available. As could also be said in relation to biomass (wood based) heating systems and aerothermal and geothermal systems for space heating. If we consider a Waste to Energy plant, the municipal waste is combusted at a minimum temperature of 850 ⁰C producing in the boiler high pressure steam for electricity generation and hot water for use in district heating. Some 50% of the waste is of biogenic origin (biomass) and therefore 50% of energy produced is from a renewable source.
If this waste had instead gone to landfill, the biogenic fraction would have rotted and produced methane, which is a global warming gas with a Global Warming Potential (GWP) of 28 – 36 over 100 years. In other words it is some 28 to 36 times more potent than carbon dioxide. While the landfill gas collection system would have captured some of this methane for combustion in gas engines, figures show that of the order of 40% is directly released to atmosphere. In a Waste to Energy plant, the heat and mass balance shows 810 kWh of electricity produced per tonne of Municipal Solid Waste combusted with about 0.72 kg biogenic CO2 and 0.53 kg fossil CO2 per kWh of direct emissions.
In the same timeframe that the Irish report was stating that utilising a low penetration of wind energy to reduce a tonne of CO2 emissions was €120, it was being reported that the cost to avoid a tonne of CO2 utilising Waste to Energy technology was about €43, whereas the costs to avoid 1 tonne of CO2 with (other) biomass was €80. Indeed, if district heating systems are used in addition to solely electrical outputs, then this Waste to Energy CO2 avoidance cost reduces to the range €7 to €20.
1.4 Adverse Impact on other Renewable Generators
The capacity factor is the actual power generated divided by the rated peak design power. The capacity factor for the Indaver Waste to Energy plant in Co. Meath and the Irish wind energy sector is show in Figure 3 overleaf for the period of the 12th to 13th January 2019. This Indaver Waste to Energy plant treats some 200,000 tonnes of Municipal Solid Waste per annum, with an electricity output of 18 MW, which was until recently a continuous output, with over 50% being classified as renewable.
Figure 3 Pat
Figure 3: Wind Energy Capacity Factor and Capacity Factor of Indaver WtE for the 12thand 13th January 2019 (Data from Eirgrid)
Clearly a low pressure system passed through on the 12th and 13th January 2019 and as a result considerable wind energy was inputted to the grid, such that other generators had to be taken off line and kept on hot standby ready to ramp up, when the inevitable happened and the wind dropped. This can be clearly seen in Figure 3, where the Indaver Waste to Energy plant had to be taken off the grid for extended periods. However, such a waste to energy plant can’t be simply throttled back, the waste is still arriving and the furnace temperature has to be kept at a minimum of 850 ⁰C to avoid dioxin formation in the off-gases. Instead the steam generated simply has to be dumped into the plant’s cooling system rather than be used to generate steam. Not only is this a loss of revenue to the Waste to Energy plant operator, but it is reflected in resulting higher costs for waste disposal of those using that facility.
Indeed, an examination of pages 43 and 44 of 55 of Indaver’s Annual Environmental Report for 2018 gives a curtailment figure of 6,550 MWh. Dublin Waste to Energy was also curtailed in 2018 by 30,550.8 MWh representing about 7% of the electricity it generated that year for the grid. See page 10 of 28 of its 2018 Annual Environmental Report as submitted to the Environmental Protection Agency.
In total both Irish Waste to Energy plants in 2018 curtailed 30,551 + 6,550 = 37,101 MWh of useful electricity. As the municipal waste keeps coming in and the furnaces have to be kept at a minimum of 850 ⁰C, the steam generated in the boilers has to be sent to bypass the generators and be dumped to the cooling system. In the case of Dublin Waste to Energy, this dumped heat ends up in Dublin Bay at Ringsend.
So what is that in real money? Iarnrod Eireann used 25,240 MWh of electricity for traction on its Dart network in 2017. So the amount curtailed from the Waste to Energy plants in Ireland in 2018 to facilitate increased wind energy on the grid is 1.5 times greater than what the Dart used in 2017. As more wind energy is installed, this situation is worsening, while as has been previously pointed out, some 50% of the energy output from such waste to energy plants is classified as renewable, because the incoming waste is some 50% of biogenic origin.
1.5 Authorisation Procedures which are Discriminatory
The Renewable Directive 2009/28/EC, while defining some eleven different sources as renewable, also places an obligation in its Article 13 on “Administrative procedures, regulations and codes”, which requires that:
- 1. Member States shall ensure that any national rules concerning the authorisation, certification and licensing procedures that are applied to plants and associated transmission and distribution network infrastructures for the production of electricity, heating or cooling from renewable energy sources, and to the process of transformation of biomass into biofuels or other energy products, are proportionate and necessary.
- Member States shall, in particular, take the appropriate steps to ensure that:
- (d) rules governing authorisation, certification and licensing are objective, transparent, proportionate, do not discriminate between applicants and take fully into account the particularities of individual renewable energy technologies;
Authorisation clearly means the granting of planning permits, which is what this planning procedure entails. Furthermore, proportionality is a key aspect of EU jurisprudence, and the principle of proportionality is one of the key principles of Community law and given this pivotal status, it has been the focus of many judgments of the European Court; where the following principles have been repeatedly expounded:
- “….according to settled case‑law, the principle of proportionality, which is one of the general principles of European Union law, requires that measures adopted by the European Union institutions do not exceed the limits of what is appropriate and necessary in order to attain the objectives legitimately pursued by the legislation in question; when there is a choice between several appropriate measures, recourse must be had to the least onerous, and the disadvantages caused must not be disproportionate to the aims pursued.”
From a legal perspective, the situation has already arisen in Ireland that the excessive granting of planning permissions and grid connections for wind farms is clearly discriminating against other renewable sources, in particular that of Waste to Energy facilities. As previously highlighted utilising a low penetration of wind energy to reduce a tonne of carbon dioxide was €120, while the cost to avoid 1 tonne of CO2 with Waste to Energy technology was about €43, whereas the costs to avoid 1 tonne of CO2 with (other) biomass was €80. Indeed, if district heating systems are used in addition to solely electrical outputs, then this Waste to Energy CO2 avoidance cost reduces to the range €7 to €20.
In other words, this discrimination is clearly illegal, as it is occurring in a manner which is discriminating against a renewable energy source, which is of significant lower cost, and is therefore a clear breach of legal requirements related to proportionality. However, this discrimination has a wider impact than solely the two Waste to Energy plants installed to date in Ireland. On the 24th July 2018 the following reply was provided in the Oireachtas by the Minister for Communications, Climate Action and Environment:
- The Lough Ree and West Offaly plants will no longer receive support for their peat production under the PSO from the end of 2019. Both plants have been approved under the REFIT 3 scheme for PSO support for co-firing 30% of total capacity out to 2030, and it is expected that these plants will begin co-firing on biomass in 2019. These two plants require the relevant planning permission to operate beyond 2019. The Edenderry plant has been approved for 30% co-firing support out to 2030, subject to renewal of planning permission.
Therefore three peat fired power stations representing a total output of 370 MW of electricity, will potentially have 30% of that output originating from renewable sources. Furthermore, if one consults the Gas Networks Ireland website, then this explains:
- Renewable gas will be available on the gas network from late in 2018 and Gas Networks Ireland aims to supply 20% of Ireland’s gas from renewables by 2030. This equates to 15% of electricity generation demand or the heating requirements of up to 1,000,000 homes. EU reports have indicated that Ireland has the greatest potential for renewable gas deployment of any of the EU 27 countries. It is estimated that the roll out of renewable gas in Ireland will support 6,500 jobs, mostly based in rural Ireland.
While in addition to the two existing Waste to Energy plants, additional Waste to Energy capacity is required for waste management in the South East, South and West of the Country.
The only conclusion one can draw from the increasing number of partly biomass fuelled power generation plants on the grid, is that if Irish authorities continue to authorise more and more wind energy in a uncoordinated manner without any proper analysis, then considerable discrimination of these other renewable energy sources will occur, as they are curtailed to facilitate the increasing peaks in wind energy output. This is a failure of transparency and proportionality and is discriminating against other renewable sources. Hence by its nature it is a fundamental breach of Article 13 of Directive 2009/28/EC on “Administrative procedures, regulations and codes”.
 See Section 10 of the NREAP progress reports:
 See for example Table 4.10: https://www.epa.ie/pubs/reports/research/climate/CCRP_3_Timoney_MethaneLandfill_web.pdf
 Consonni et al 2005
 https://www.powerengineeringint.com/articles/print/volume-15/issue-5/features/waste-to-energy-energy-no-time-to-waste.html and Section 7.7 of:
 See page 8: http://www.irishrail.ie/media/2017-iarnrod-eireann-annual-report.pdf
 For example ECJ, 07.03.2013, T-370/11, Poland v Commission
 Renewable gas is made using grass and other natural feedstocks using a process called anaerobic digestion.
 1,000,000 homes is based on typical domestic gas consumption per CRU decision paper: https://www.cru.ie/wp-content/uploads/2017/07/CER17042-Review-of-Typical-Consumption-Figures-Decision-Paper-1.pdf and is therefore based on total gas consumption.
 Optimal use of biogas from waste streams. An assessment of the potential of biogas from digestion in the EU beyond 2020 (European Commission)
 IrBEA – Irish BioEnergy Association.