Author: Dr James G Carton, technical director, TUEN Ltd Dr Carton is set to speak at 'Independent Energy, 24/7', an event being held on Tuesday, 18 February in Room 134, DIT, Bolton St, Dublin 1 (enter via King’s Inn Street). The event is being hosted by the Institution of Mechanical Engineers and is Engineers Ireland CPD approved. Contact Prof A.G. Olabi at With a global backdrop of peak oil production, increasing emissions, climate change and the increasing cost of energy, renewable energy is increasingly important for Ireland. Ireland presently has over 2040 MW [1] of installed wind turbine capacity. With a capacity rating of about 31%, there is approximately 630MW or 5518GWh/yr of power available. This is equal to approximately 15% of national demand. Under Directive 2009/28/EC, EU Member States have been set renewable energy targets. Ireland has adopted ambitious renewable energy targets to be achieved by 2020. The National Renewable Energy Action Plan (NREAP) has set a target of 40% electricity and 12% heat from renewable energy, as well as 10% electric vehicles, by 2020 [2]. Wind power is expected to form the largest component of these targets. It is estimated that at least 6000 MW of wind will need to be installed by 2020 to ensure that these targets are achieved. This amount of wind powered generation will, on average, represent in excess of 50% of national power demand. EirGrid and SONI, the Irish & Northern Irish Transmission System Operators (TSOs) have published reports on the consequences of this amount of renewable energy and how it can be facilitated on the national grid [3]. Findings concluded that up to 50% of wind energy can be accommodated by 2020. However, a conservative cut-off of 60% of peak wind (6000MW) could be required to ensure grid stability. This could indicate that in instances where wind generation approaches greater than 4000MW, the excess would simply be wasted. To put this in context, 1MW has the capability to power 1000 Irish homes. Large percentages of renewable energy that are inconsistent and weather-conditions dependant, and are from locations that are geographically far from regions of high demand, pose huge engineering challenges and economic risks, as well as installation, management and control difficulties for the grid operators. The inconsistency of renewable energy sources means that traditional, fossil-fuelled electricity generating stations need to be on stand-by, as sources, such as from wind, can suddenly cease production. According to a report by EirGrid, SEMO & SONI [4], approximately 2.4% of all wind produced in Ireland is curtailed. Curtailment generally arises during night-time hours (between 11pm and 9am) when demand levels are lower. Using present figures, curtailing 2.4% of produced wind energy is equivalent to 132,000,000 KWh/year. This amount could power 15,000 homes, which at a cost of €0.17/KWh, equates to a loss of over €22,500,000. After decades of improvements in renewable energy technologies, globally more than 80% of energy is still produced from traditional fossil-fuel sources. So what is limiting the advance of renewable energy? Predictions by IEA World Energy Outlook estimates that by 2035, the demand for electricity will be more than 70% higher compared to current demand. Therefore, Ireland and every other country must find solutions to this potential energy crisis. ECONOMIC ENERGY STORAGE AND ENERGY ON DEMAND Storing energy generated during off-peak times and retrieving it as electricity during peak demand times, even if the wind has dropped, will increase efficiency and eliminate the need to have fossil-fuelled generating stations continuously in stand-by mode. Presently, the lack of renewable energy storage is seen as one of the main constraints that stop renewable energy generation from reaching its full potential. In a recent report from the market research firm IHS, the energy storage market is set to grow from its present base of 0.34GW to 6GW in 2017, and to over 40GW by 2022 [5]. Energy storage can be divided in two types: portable (electric cars, mobile devices, etc) and stationary (including grid scale energy storage). In Ireland, pumped hydro is the only energy storage that is presently in operation at national grid level. Investigative work into additional pumped hydro sites and compressed air storage are being completed. Batteries can be used to store energy, but batteries are generally large, heavy and costly. And due to charge/recharge cycle limits, they have a relatively short life and have scalable limits that not always suit large kW or MW systems. Many storage options exist, however there are a number of important requirements:
  • Rapid response and fast on/off capability;
  • Capability to react to frequency and transient instability;
  • Not geographically dependant;
  • Distributed where required;
  • Scalable and flexible;
  • Secure
  • Future proof/upgradeable/recyclable;
  • Long life;
  • Low maintenance;
  • Low cost/transparent payback.
Hydrogen and hydrogen technologies satisfy the above list of requirements [2]. In addition, hydrogen is mentioned in the EirGrid Annual Renewable Report 2013 [6] as a technology that will be required in managing the increasing complexity of our new future energy challenges. TUEN LTD – TECHNOLOGY START-UP [caption id="attachment_11524" align="alignright" width="905"] Prototype TUEN system, showing solar panels and tanks for hydrogen storage[/caption] TUEN Ltd is a technology start-up that is in the process of developing, commercialising and marketing energy technologies, which enhance and increase the efficiency of renewable energy resources. TUEN aims to bring cohesion, coherence, and strategy to the development of renewable energy technologies. The TUEN System is a new type of distributed power generator that offers clean, reliable and affordable energy. The system is capable of complementing previously intermittent renewable energy sources to provide consistent energy to clients by means of energy storage. The TUEN System will improve cost-competitiveness, reduce complexity and increase reliability of supply. It aims to produce, store and deliver hydrogen as a commodity, for combustion, as well as for regenerating electricity on demand by means of a hydrogen fuel cell. The benefits of the TUEN System include:
  • A ‘plug and play’ system;
  • A fully integrated energy system;
  • All energy needs accommodated;
  • Combined heat and power (CHP);
  • Incorporating energy storage technology;
  • Developed to complement renewable energy sources;
  • Developed for independent on/off grid needs;
  • Controlled, consistent, reliable energy;
  • For home, business, universities or niche applications;
  • Scalable for grid integration
The PSO (Public Service Obligation) levy was introduced to support certain peat, gas and renewable energy generation plants. The PSO levy is designed around providing a minimum level of revenue to generator operators, so that such generators are not wholly reliant on prevailing prices in the wholesale electricity market. The PSO levy is currently €3.57 per month (excluding VAT) for all domestic customers (price correct as of 1 October, 2013) [7]. Customers are effectively paying to conserve the unsustainable burning of fossil fuels. Bridging the gap between the present shortcomings of renewable energy, and a future sustainable, clean energy economy is not as intractable as it seems. It will, however, not take a leap of faith, but a leap of fact. For more information, see or email References:
  1. Irish Wind Energy Association
  2. Carton JG, Olabi AG. Wind/hydrogen hybrid systems: Opportunity for Ireland's wind resource to provide consistent sustainable energy supply. Energy 2010;35(12):4536-4544
  3. All Ireland TSO Facilitation of Renewables Studies EirGrid & SONI
  4. 2011 Curtailment Report EirGrid & SONI
  5. Grid- connected storage market set to explode PV Magazine
  6. Annual Renewable Report 2013 EirGrid, SEMO & SONI
  7. PSO Levy 12/13 Decision Paper – CER/12/121 Commission for Energy Regulation
Dr James Carton graduated with BEng in Manufacturing Engineering from Bolton Street Dublin Institute of Technology in 2005. Following several years of industrial manufacturing experience, Dr Carton carried out PhD research in Dublin City University, focusing on the research, design and development of hydrogen and fuel-cell technology, and graduating in 2011. During and following his PhD research, Dr Carton gained many years experience in leading edge technology, completing projects with the European Space Agency and National Aeronautics & Space Administration, and the International Space Station. More recently, he developed heat shield technology with an Irish Space company for the Solar Orbiter Satellite. Currently, Dr Carton is prototyping his patented fuel-cell technology with Dublin City University and is technical director of TUEN Ltd.