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28 February 2013 | 0
The need for an affordable and reliable supply of energy is as important for our future well-being as the need for good quality air, water and food. Climate change considerations have now imposed a further condition that our energy must be reasonably low in carbon dioxide (CO2) emissions. Concerns over anthropogenic global warming have led Ireland to adopting a target of 40% electricity generation from renewable sources (predominantly wind energy) by 2020.
However, meeting this challenging target may not be sufficient to enable Ireland to meet an associated 2020 commitment of reducing CO2 emissions by 20%. And, even if we achieve these 2020 targets, a power generation portfolio consisting mainly of wind and gas will not enable us to achieve an 80% reduction in CO2emissions by 2050 (figure 1, below), the target suggested in the 2010 EirGrid study by Poyry. This is especially true if we are to maintain an affordable and reliable supply of electricity over the coming decades.
Concerns such as these have led to calls from diverse sources, including ESB, EirGrid, Forfás, IBEC and ICTU, to consider properly the role that nuclear powered electricity might play in our future energy mix. Emerging nuclear technology, ready for deployment in about 10 years, makes this a particularly appropriate time to evaluate this role.
Nuclear power has long been contentious in Ireland with organised opposition existing since the 1970s, when ESB proposed a nuclear plant at Carnsore Point, Co Wexford. Arguments were put forward that nuclear power plants were too expensive and too big for Ireland; that we couldn’t build them; the waste is too dangerous and they’re not safe. More recently, it is claimed that we don’t need nuclear because we have renewables.
While the expense and size of certain modern reactors precludes them from serious consideration in Ireland, there is a new breed of nuclear reactor being developed that removes the most popular of the reservations people have about nuclear power. Rather than being seen as a threat, there is now an opportunity for Ireland to make nuclear power work to our advantage.
It is important to first address the useful but limited role that renewables can play in our future energy mix. After all, if renewables could supply sufficient clean and affordable energy, why bother considering the problematic nuclear, pumped storage and CCS (carbon capture and storage) alternatives?
We have seen from the Poyry study that a renewables and gas portfolio will not be sufficient to allow Ireland to meet its greenhouse gas reduction targets. Poyry also shows that residential retail prices from all the very high renewables portfolios are significantly higher than for the CCS or nuclear alternatives (figure 2, below). It is notable that the subsidies that form a significant portion of the total costs included in each portfolio arise from the large renewable capacity (mainly wind).
In addition, EirGrid say that, in order to meet the “challenging” target of an average of 40% wind-generated electricity, wind must be permitted occasionally to generate up to 75% of demand. The instantaneous limit on the allowable penetration of wind is 50% currently, although much groundbreaking work is being done to try to increase this.
So, it is clear that renewables can reduce our greenhouse gas emissions but not sufficiently to meet our targets post 2020. Renewables can also reduce the wholesale price of electricity but will increase the retail price and this is the more significant indicator. And, even if we succeed in generating 40% of our electricity from wind, from where do we source the remaining 60%?
One real possibility is the new breed of small modular reactor (SMR) being developed in the US and elsewhere.
These new reactors will be much smaller than the large reactors currently being built or proposed in Finland, France and Britain. With an output of around 200 MWe, they would be smaller than some existing generators here. Crucially, daily load follow can be performed from 100 percent to as low as 20 percent power at a linear power ramp rate of 5 per cent per minute, making them ideal for our grid which includes a large quantity of intermittent wind generation.
The modular aspect allows factory fabrication and delivery that guarantees quality control levels not available with on-site construction. This allows improved build reliability and project certainty, and reduces project finance costs. Economies of scale are achieved from the multiples of SMRs required as distinct from the one-off nature of the larger alternatives (such as the 1650 MWe EPR).
Because they are quick to build (three years), the first one can be up and running (and bringing in income!) while the second one is under way, thus reducing the total sunk capital requirement considerably. As a result, they are expected to bring the capital spend required down to levels affordable by privately owned utilities – no State investment would be required.
SMRs take account of the incidents at Chernobyl and Fukushima and have “passive safety”, making them even safer than existing reactors. For example, no operator intervention is required for 7 to 14 days even if all backup power is lost. And, because there is a long time between refueling (three-to-four years), the reactor will have very little downtime, so it will provide cheap and clean electricity for over 90% of the time.
Siting: There are many existing power stations in Ireland where these safe reactors would fit with little or no modifications to the high voltage connections to the national Grid. It would thus be possible to have a number of these plants providing jobs and safe, clean environments to a number of areas of Ireland. A specific option could be to replace the coal-fired plant at Moneypoint with five to six SMR machines.
Many County Councils would be delighted to have the secure rates that would be levied on these plants and to be certain of the rates for 60 years or more.
Opportunities: An Irish university close to an SMR site could develop a training college for nuclear engineers, operators, maintenance staff, environmental monitoring and protection staff and so on. There would also be the possibility of good jobs in the areas of simulator training, foreign consultancy, civil defense, communication and marketing, finance and so on.
There would be many service jobs in these communities also and the prosperity of the entire region would be enhanced by the presence of the SMR plant. National competitiveness would also receive a boost through lower guaranteed cost of power for businesses throughout Ireland.
Suitable reactors: Babcock and Wilcox (B&W) have stepped up development of their 180 MWe SMR called mPower. The Tennessee Valley Authority utility in the USA has expressed an interest in acquiring 6 of these SMRs by 2022. Significantly, the United States Government are granting up to $450 million to assist with the licensing of this project.
Westinghouse is also producing a pressurised water SMR with integral steam generators and primary coolant system all within the pressure vessel, which can be designed for more than its nominal 225 MWe. Fuel is initially similar to modern Light Water Reactors with 5% enrichment and burnable poison – in fact fuel assemblies are “identical to those … in the AP1000”. These would have burn-up of 60 GWd/t (Giga Watt days per ton) with fuelling interval of three to 3.5 years. Other SMRs could be designed ultimately for fuel with 10% enrichment and 80 GWd/t burn-up with an eight-year cycle, or equivalent MOX core. The core has low power density.
COST OF NOT GOING NUCLEAR
To illustrate the long-term effects of national energy policy decisions, consider the cases of Ireland and Finland. Both these countries proposed the Nuclear Non-Proliferation Treaty in the 1960s and were the first signatories of this treaty when it came into being in 1968. Within 12 years, Ireland had rejected nuclear power generation while Finland adopted it.
Now, Finland has a balanced portfolio of fuels in its generation mix, producing around 30% from each of nuclear, hydro and coal, with the remainder mainly coming from gas. Ireland, on the other hand, has over 60% from gas, 15% from renewables and the remainder is from coal and peat. As a result, Finland emits only marginally more CO2 per head of population than Ireland while using twice as much energy as us.
Critically, electricity is 50% more expensive for Irish households and 100% more expensive for Irish industry than for their Finnish counterparts. This is a clear and practical illustration of the economic and environmental benefits that Ireland is passing up with its current prohibition of nuclear power.
To conclude, our current Energy Policy is inadequate. If we are to facilitate the competitiveness required into the 2020’s to attract and maintain industry while meeting our environment targets, we will need a mix of generating technologies including renewables, gas and nuclear. To achieve this, we must engage in active study with the aim of introducing nuclear, and particularly SMRs, without delay.
Denis Duff, C Eng, has over 30 years’ experience in both renewable and thermal electricity generating systems. He is a founder member of the voluntary group BENE (Better Environment with Nuclear Energy), www.bene.ie.