THE ROLE OF MICROGENERATION IN DISPLACING CARBON DIOXIDE EMISSIONS FROM MOTOR VEHICLES IN IRELAND

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1 THE ROLE OF MICROGENERATION IN DISPLACING CARBON DIOXIDE EMISSIONS FROM MOTOR VEHICLES IN IRELAND Gerard T. Wrixon Tyndall National Institute, UCC Abstract Micro generation (MG) in Ireland, generally domestic wind and/or PV plants of less then 6 kw, have a role to play in ensuring that Ireland fulfils its EU commitment of having 10% of its transport energy (excluding aviation and marine transport) come from renewable sources by MG is also of great interest as issues have arisen (IAE Report on Energy Policy, 2011) on the feasibility of having 40% of electricity in the R of I being produced from wind farms by MG plants are particularly suitable in rural locations not well served by public transport and have the advantage of not requiring additional investment in the electricity distribution system. Making the charging of electric/hybrid vehicles a priority energy from such MGs could ensure that a substantial contribution of charging energy comes from renewable sources. It could also make MG an attractive investment option for rural/individual house dwellers were a suitable incentive scheme for the generated RE in place, as is the case in other EU countries. This paper examines the consequences of introducing MG in Ireland and concludes that with current EV growth scenarios, substantial increases could be made both to the RE content of transport energy as well as to the displaced CO 2 emissions over those currently predicted without MG. INTRODUCTION Recent work [1] has indicated that should Ireland achieve its target of having 10% of all vehicles in its transport be electric by 2020, the contribution made by these vehicles in using renewable energy sources (RES) is 1.7% total 2020 transport energy demand, projected to be 5,790 ktoe. This compares to a target of 10%, ie 579 RES. The 1.7% calculation includes the following assumptions: - a grid portfolio which in 2020 has about 42% RES, coming predominantly from wind power - the RES contribution to the electric vehicles (EVs) is weighted by a factor of 2.5 in accordance with Directive 2009/28/EC Article 3.4c. The assumption of 42% of RES of grid electricity by 2020 has been seriously questioned in a recent report [2] by the Irish Academy of Engineering (IAE). They cite the drop in energy demand since 2007 which, coupled with the over-investment in generating capacity in the same period, leads them to the conclusion that there is no requirement for additional generation capacity in the Irish power system for at least ten years. They specifically question the proposal to build thousands of MWs of unnecessary wind power over the next decade effectively stranding already existing (mainly natural gas fired) generating assets. Ironically there was a decline, from 14% to 12%, in the contribution of RES to Ireland s electricity supply from 2009 to 2010 [3]. This was despite an increase in the installed wind capacity and was due to wind speeds in 2010 being below normal across the island. This demonstrates the economic imperative of building future wind farms preferentially in areas of high average wind speed in the West and North West. The predictable environmental

2 31 st August 1 st University College Cork Proceedings ITRN2011 objections both to the siting se wind farms and to their associated transmission lines across to population centres in the East country, coupled with the large (and according to the IAE, unnecessary) capital expenditure involved, would seem to cast doubt on the prediction of 42% RES in our electricity by If this figure were 25% for instance, the contribution made by EVs in using RES would drop to 1% total energy demand in Consequently it is instructive to consider an alternative for charging EVs with the potential of supplying up to 100% RE to the vehicles, namely microgeneration (MG). At a domestic level in Ireland MG refers to the production of RE, normally via small wind generators and/or solar photovoltaic (PV) panels. If these plants are connected to the grid to feed in excess electricity, the maximum currently allowed size is 6kW for single phase and 11 kw for 3 phase. MICROGENERATION Were there an increase in the penetration of microgeneration to supply the energy needs of EVs, it would result in an increase RE content total transport energy demand and a concomitant decrease in the amount of CO 2 emitted. Figure 1 shows, for the high scenario outlined in [1] i.e. 213,561 EVs in 2020, the contribution made by EVs in using RES as a percentage total transport energy demand in 2020 plotted against the percentage of those EVs using microgenerated electricity. Figure 1. The increase in percentage RE contribution to the total transport energy demand in 2020 for the high level scenario in [1] as a function of the percentage of those EVs whose energy is supplied by MG, for RE grid electricity content of 42% and 25%

3 The upper line assumes 42% RES grid electricity in 2020, while the lower assumes 25%. As can be seen from the figure, were only 50% of EVs (~100,000 vehicles) to use MG with a grid component of 25% RES, the contribution of EV s RES to the total transport demand rises from 1% to 2.5%. More importantly perhaps is the contribution of MG to reducing CO 2 emissions. Again, with the high growth scenario as outlined in [1], it is calculated that with 42% RES on the grid, 314 ktco 2 were emitted to charge the EVs, compared to 504 ktco 2 avoided due to displaced petrol and diesel related emissions, giving a net reduction of 190 ktco 2. This contributes 1.4% towards the 20% reduction in Non-ETS emissions (those outside emissions trading) by 2020 relative to 2005 and 0.5% to the 20% Non-ETS emissions reduction target. The equivalent figures with 25% RES on the grid are a net reduction of 100 ktco 2, contributing 0.75% to the 20% reduction on Non-ETS emissions by 2020 relative to 2005, and 0.4% to the emissions reduction target figure. Figure 2 shows the increase in CO 2 reduction as increased penetration of MG is used to provide full RE charging for an expanding number high level scenario vehicles as outlined in [1]. As can be seen, were all se EVs to be charged using MG, the full 504 ktco 2 used by an equivalent number of fuel burning vehicles could be avoided leading to a reduction of 400 ktco 2 for the case where the amount of RES on the grid was 25%. This contributes 3.7% to the 20% reduction in Non-ETS emissions relative to 2005 and 1.3% to the emissions reduction target figure. Figure 2.The lower solid lines show the net reduction in emissions (ktco 2 ) for the high level scenario in [1] as a function percentage of those EVs whose electricity is supplied by MG. For the case of a 6 kw PV system in the S/E of Ireland, the dashed lines in the figure represent the further reduction in CO2 emissions resulting from RE generated by the PV installations in excess of that needed by the EVs.

4 31 st August 1 st University College Cork Proceedings ITRN2011 A bonus resulting from the use of MG to charge the EVs is seen from the dashed lines in the figure which show the further reduction in CO 2 emissions, in excess of that used by the EVs, resulting, in this instance, from the use of a 6 kw PV system in the South/East of Ireland. Such a system produces 1100 kwhrs/installed kw/annum. A typical EV (Leaf) uses ~0.15 kwhrs/km and using an average annual journey length of 14,500 km [1], each EV uses 2175 kwhr/annum leaving an excess of 4425 kwhr/annum. With 42% RE in the grid, giving an electricity emission factor of 283 gco 2 /kwhr and assuming all EVs in the high level scenario [1] were charged with similar PV systems, an additional reduction of 267 ktco 2 would be achieved. This would increase to 346 ktco 2 with 25% RE on the grid as a consequence of the increased electricity emission factor of 366 gco /kwhr PV and MICROWIND In the South and East of Ireland PV systems produce about 1100 kwhrs/annum/installed kw i.e kwhrs for a 6 kw system in a year, and outputs of as high as 1200 kwhrs/annum/kw have been reported from a system in Wexford [4]. These values are unexpectedly high compared to values of about 1000 kwhrs/annum/kw obtained in Germany [4] and can be explained by recent, more accurate solar radiation data, obtained by satellite observations (rather than interpolation of ground based data) [5], which show that SE coastal regions have about 10% more insolation then hitherto believed. The lower ambient temperature in Ireland, which leads to a lower module temperature, also plays a role, as module power decreases by ~ 0.4%/ o C above the rated temperature of 25 0 C. Currently PV system prices are approaching 4,000 Euros/installed kw and are expected to keep decreasing over time as manufacturing costs decrease. The advantages of PV are low/no maintenance and long (greater than 25 year) life. It s principal disadvantage is the 3:1 variation in energy delivered between summer and winter months. To maximize the amount of RE used to charge an EV from a PV system it is consequently necessary to ensure that different charging rates are available in summer and winter. The16 Amp specially installed domestic EV charger is suitable in Summer, however an 8 Amp charger is more appropriate in winter, especially if the current 6 kw limit on domestic MG installations is to remain. A 6 kw micro wind generator [6] produces 11,000 kwhrs/annum and costs 30,000 Euro. Few domestic and not all rural sites are however suitable for such an installation. In addition, maintenance, lifetime, noise and visual impact are all issues compared to PV. Nevertheless in the Midlands and West, where PV outputs of 850 kwhrs/annum/kw have been measured [4], wind MG, where it can be used, has obviously a decided advantage. Ideally, especially in rural/farm settings it would seem to make sense to increase the single phase 6 kw MG limit, as is the situation in other EU countries. This would allow the installation of hybrid systems (e.g. 6 kw wind and 5 kw), especially in the Midlands, North and West, as well as larger PV systems in the East and South. This would not only increase the amount of RE available for vehicle charging but would also obviously result in a further reduction in CO 2 emissions. This reduction can be calculated from Figure 2 by scaling the dashed lines upwards for PV systems larger than 6 kw or, for hybrid systems, by allowing for the larger annual energy output of wind per installed kw. DISCUSSION As is seen from the above, with current EV growth scenarios [1], MG has the potential of making substantial contributions both to the RE content of transport energy as well as to the

5 displaced CO 2 emissions over those currently predicted without MG, especially in a situation where installed RE capacity in the grid may be less then is currently predicted. MG is also particularly well suited to powering EVs in Ireland due to the large number of one-off houses in rural/semi-rural locations where MG systems can be easily sited and which, by definition, are not well served by public transportation. In addition the components for MG systems, small windmills [6], electronic controls and PV modules (which can be made in a double glazing factory) can all be manufactured in Ireland. This contrasts with the current situation where all wind generation capacity is imported. MG in fact represents a genuine opportunity to develop a unique technological capability with both domestic demand and export potential. To realize these benefits, the penetration of MG into Ireland will need to be encouraged. Current REFIT levels are not at all adequate and do not reflect the many advantages, outlined above, which increased use of MG would bring to Ireland. Increased REFIT, in line with practice in other EU countries; Green Certs issued on the basis of kwhrs produced to be sold on to power companies to increase their RE contribution; capital tax incentives based on the wider societal benefits arising from the use of MG (import substitution, job creation etc) could all justifiably be used to create a situation where it made economic sense for farmers/homeowners to invest in MG. Keeping the size of MG systems to a modest 11 or 12 kw level would also have the advantage of not requiring any additional investment in the electricity distribution system. Some larger (20-50kW) demonstration systems could also be built at schools, community centers, health clinics etc both to provide EV charging and as a way of sensitizing society to the need to diminish our dependence on imported fuel as well as well as the imperative of cutting our CO 2 emissions. REFERENCES [1] A.M. Foley, H. Daly and B.O Gallachoir, Quantifying the Energy & Carbon Emissions of a 10% Electric Vehicles Target, International Energy Workshop 2010, KTH, Stockholm. [2] Irish Academy of Engineering Report, Energy Policy and Economic Recovery , Feb [3] CER Information Document CER/11/129, Fuel Mix Disclosure and CO 2 Emissions 2010, July [4] J. Cotter, Private Communication. See also Micropower.ie [5] Photovoltaic Geographic Information System [6] cfgreenenergy.com