.RiskBased Assessment of Energy Security A Case from Europe Boyko Nitzov*The European Union's Agency for theCooperation of Energy Regulators (ACER)Ljubljana, Slovenia This paper suggests a riskbased approach to assessing energy security and the cost of its enhancement in the context of the European Union's framework. The paper highlights the inherent costbenefit tradeoff of choosing a certain level of energy security which would satisfy the formal requirements of the regulatory framework and at the same time be costefficient. The suggested analytical framework is applied to the case of a Member State of the European Union. 1. The regulatory framework The European Union's regulatory framework related to its natural gas sector comprises several key elements, namely:
2. Analytical framework To arrive at the required riskbased assessment, a model using a fourstep procedure is applied. First, the capacity needed for achieving compliance to the N1 rule is assessed. Next, the cost of achieving compliance is evaluated. Next, the diversity of natural gas supply, the key element of security, is assessed by calculating the enhanced Shannon index (ESI, cf. Kaderjak et al., endnote 9). ESI is used as a proxy in assessing the magnitude of the loss incurred by a disruption in gas supply. Finally, the probability of interruptions in gas supply is evaluated based on actual events observed over a certain period of time, and the assessed probability is used in conjunction with the ESI as input to a Gambler's Ruin type of analysis (cf. Arps et al., endnote 12). Cost is determined on the basis of investment required to reach acceptable levels of the N1 indicator and the ESI, and benefits are estimated as the avoided cost of natural gas supply interruptions. The analytical frame is at subsector level, i.e. energy security is assessed at the level of a given kind of primary energy (in this instance, natural gas) rather than at the level of the entire energy sector. The approach allows to pinpoint the specific sources of potential threats to energy security and also to gauge the associated costs and benefits on a narrower range of values. The output of the model allows an estimate of the maximum cost of enhancing energy security which would be economically justifiable under the specific conditions of a country or a region, i.e. an assessment of the breakeven point beyond which "buying" more security is not efficient. An example of such a costbenefit assessment of energy security based on the actual case of a member state of the European Union is provided. For the purpose, a software utility is used (cf. Rebecca Byrd, L. et al., endnote 10).
3. A model for assessing efficient levels of energy security a. Additional capacity needed to comply with N1 criteria Regulation 994 requires member states to maintain the value of the N1 indicator at a level of at least 100% (Annex I, p. 4 of the Regulation): Equation 1 where
The N1 formula without demandside measures omits D_{eff }from the equation, but is otherwise identical to the N1 formula with demandside measures. Denoting z for N1 and S_{add}=EP_{m}+P_{m}+S_{m}+LNG_{m,, }in case N1 is less than 100%, the required additional new crossborder supply capacity S_{add} (which may be added by any combination of increasing EP_{m}, P_{m}, S_{m}, and/or LNG_{m}) is given by Equation 2, required additional capacity (mcm/d)
b. Cost of required additional capacity needed to comply with N1 criteria The cost of new capacity, measured in total cost and in cost of service per capacity unit, varies by type of infrastructure. For natural gas pipelines, it is given by the required horsepower of the compressor stations (installed and used), the fuel efficiency of the compressors, the capital cost of constructing the line, the mode of operation (pressure differentials, etc.), the condition of the pipe ("roughness"), ambient pressure and temperature, gas composition, and other factors. In a generalized form, the total cost function of transporting gas via pipeline is[7]:
Equation 3
where c_{1} is the cost of operation per HP/day, c_{2} is the construction cost per inch/mile, c_{3} is the construction cost per installed horsepower and p(r,t) is the imputed daily cost of the pipeline as a function of the interest rate r and project life t. Similarly, the total cost function can be derived for any natural gas infrastructure which requires a certain throughput per given period of time (capacity), for example, daily sendout capacity for LNG terminals or withdrawal rates for underground gas storage. In this paper, we use the above approach to assess the cost of a pipeline or its equivalent in terms of capacity needed to achieve compliance to the N1 criteria. c. Import disruption impact indicator^{[8]} Diversity in meeting the fuel demand of a country or a country group, including imports, is the principal element of supply security. The ShannonWiener index (‘Shannon index’) measures the diversity of meeting fuel use. The general form of the Shannon index is as follows: Equation 4
where p_{i} is the share of fuel type i in gross inland fuel consumption and n is the number of different fuels used. Beyond diversity, import dependence is another major determinant of supply security. To measure the impact of import dependence, an enhanced version of the Shannon index (ESI) is used, as proposed by Hirshhausen and Jansen: Equation 5
where c_{i} is a correction factor for each primary energy source. The correction factor takes into account the share of net imports in total consumption of a given source of energy and the rate of diversification of the import sources of energy. Typically, the five major primary energy sources are considered (oil, natural gas, coal, nuclear, and hydro). For coal, oil, and nuclear fuel, a number of supply sources and routes are usually available, and the correction factor is set at unit. However, the value of the correction factor for these primary sources of energy must be individually assessed in each specific case. For natural gas, the correction factor's value exhibits greater "scatter" and may be anywhere between close to zero and one. For natural gas, the correction factor is calculated as: Equation 6
where m_{gas} is the share of imports in gas consumption, S_{gas} is the Shannon index for gas, S_{max }is the maximum of the Shannon index, and Equation 7
where m_{gasj }is the share of import gas from source j in the total imported gas for the given country. The ESI is used in this paper as a proxy in the calculation of the magnitude of the impact of a disruption of imported gas supply, whereby a level below unit indicates the proportion of consumers who will be impacted by the effects of the disruption. For example, an ESI of 0.6 would mean that 40% of consumers would not be getting any gas for the duration of the gas supply disruption. ESI is a convenient tool for evaluating the magnitude of the gas supply disruption impact, as it may be used to assess the loss due to lack of gas supply. The loss would be comprised of product which has not been produced because of operation interruptions due to lack of natural gas (the unavailable services of natural gas as an input to production and consumption), plus the lost revenue from gas sales. Loss does not include implied cost, such as loss of comfort by customers who use gas for heating and cooking and other similar loss. Equation 8 is used for evaluations of the negative impact of gas supply interruptions.) Equation 8
where I_{gsi} is the value of the negative impact in currency units, GDP is the gross domestic product during the year, d_{d} is the duration of the disruption in days, G_{pf}is the share of gas in primary energy consumption during the year, and SI_{e}is the ESI. d. Probability of natural gas import supply disruption The assessment of the probability of natural gas import supply disruption is purely statistical and requires a sufficiently long period of time. Supply disruption "events" are considered to have occurred if lasting for more than 24 hours, regardless of the reason for the disruption. Only supplyside disruptions are taken into consideration, i.e. unexpected surges in demand are not considered as a reason for gas supply shortfall. Over the last decade, scarcely a member state of the European Union has not experienced at least several natural gas supply disruptions, which means that the probability of supply disruptions over a period of time typically needed for the construction of new gas infrastructure is very high. The issue therefore is not whether such disruptions would occur (they will), but whether their impact merits the construction of new supply infrastructure. Put simply, one has to compare the cost of constructing new gas supply infrastructure with the benefit provided by the infrastructure in terms of ability to avert the negative consequences of gas supply disruptions, over a time frame of sufficient duration. e. Risk and reward: applying Gambler's Ruin analysis to investment decisions on projects for natural gas supply security enhancement For assessing whether the risk to energy security from potential gas supply disruption is of such a magnitude as to merit the construction of new supply infrastructure, we use Gambler's Ruin analysis as described by BDM Petroleum Technologies.^{[9]} An important concern of investors^{[10]} is the possibility of going broke through continuous failure. This risk is similar to gambling and is called “gambler’s ruin.” Investment risk analysis involves these basic parameters:
Based on the Gambler’s Ruin theory presented by Arps and Arps^{[11]}, the minimum acceptable probability (P_{m}) of success for the venture breaking even in the long run is: Equation 9
and the chance (α) of an investor going broke through a continuous string of failures is: Equation 10
The investment analysis will inform the following:
In the case of disruptions of import natural gas supply, we use the following:
4. Facing ruin in the gas business: The case of a EU member state The four elements of the model described above enable the assessment of the levels of risks to natural gas supply security which a given country faces, as well as making the right choice in terms of investing in upgrades of gas import infrastructure. The following analysis refers to one of the member states of the European Union and uses actual data. As the example is for illustration only, we will refer here to that country as "Country Y". a. Calculation of the N1 indicator for Country Y and determination of required new import capacity to achieve compliance to regulation 994/2010 The following actual data is used to calculate the N1 indicator for Country Y:
With the above parameters, the N1 indicator for Country Y calculated by using Equation 1 is 28% without demandside measures and 33% with demandside measures. The required additional gas import capacity calculated by using Equation 2 is about 13 mcm/d, which could be added by constructing one or more new pipelines, LNG, and/or storage infrastructure, or increasing production. Regarding these options, Country Y' gas sector features are the following:
The available options for achieving satisfactory levels of energy security, after exhausting the potential of demandside measures and increasing domestic production, are therefore limited in the instance to either constructing new import gas pipelines or an import LNG terminal. The new infrastructure should be able to deliver 13 mcm/d without demandside measures or 10 mcm/d with demandside measures. In a nutshell, the country needs at least one new 28 inch pipeline or a LNG terminal of similar capacity, from a source, route, and supplier different from the current ones. b. Sizing and costing of the required new gas import infrastructure By using the determined minimum of required import gas capacity, and optimizing for pipeline diameter and horsepower at various pressure differentials, total length of pipeline depending on source of gas, distances between compressor stations and other parameters, the required new gas import infrastructure for Country Y is sized and costed. c. Determining the impact of gas supply disruptions By using Equations 47, the correction factor and the ESI are calculated for Country Y. ESI for 2009 is 1.13 overall and 0.7 for fossil fuels only, well below EU15, where the index is about 1.32. For natural gas, accounting for the complete lack of diversification apart from very modest domestic production, ESI is a dismal 0.02: an interruption in import gas supplies will affect 49 customers out of 50. Country Y experienced a total cutoff of gas imports in 2009 for a period of 14 days. During the year, the country's GDP was $46 billion, the share of gas in primary energy supply was 13%. Given the above data and using Equation 8, the value of the negative impact of the gas disruption is assessed at about $225 million. d. Probability of natural gas import supply disruption Between 2001 and 2011, Country Y experienced two complete cutoffs of imported gas supply, which means that in any given year there is a 20% chance for a major import gas supply disruption. e. Gambler's Ruin: Playing dice with energy security With the results of steps 5a through 5d above, Gambler's Ruin analysis yields a chance of going broke of over 41% and a minimum acceptable probability of success with the acceptable probability of ruin of 78.5%. This means that the current level of energy security in Country Y is much lower than required and, furthermore, that import gas supplies should be diversified within about five years if Country Y is to avoid a loss equal or greater than the available capital for executing gas supply diversification projects. In the case of Country Y, the benefits of diversifying import gas supply clearly overweigh the cost of diversifying.
5. Discourse and conclusions As far as Country Y is concerned, results demonstrate that it cannot achieve compliance to Regulation (EU) No 994/2010 without diversifying gas supply, and that in order to assure compliance, the minimum new gas supply capacity should be about 13 mcm/d without demandside measures and about 10 mcm/d with demandside measures, from a source and via a route which is different from the current import ones. With an ESI of only 0.02, Country Y carries an unacceptably high risk of experiencing a large loss from cutoff of gas supply. In monetary terms, given the history of gas supply interruptions, the size of the economy and its gas business, carrying such risk is equivalent to losing about $70 million every year. Country Y has a fair chance (just under 80%) of "going broke" in five years time if it continues playing dice with energy security. Failing to diversify gas supply and comply to EU regulations within this time horizon is likely to result in spending money on investment in diversification of gas supply later on and still carrying excessive risk of complete cutoff of gas supply at least once in the meantime, i.e. becoming a "ruined" gambler. The results of the analysis also allow projects to be ranked by using multicriteria analysis. For example, in Country Y any economically justifiable diversification project in the light of Regulation (EU) No 994/2010 must meet the following criteria:
Country Y is now considering at least 16 crossborder gas supply and UGS infrastructure projects, only one of which satisfies all criteria. Regretfully, it is not a priority on the government's list. One of the features of the results of our analysis is that they are quite timedependent. For example, if the same analysis is to be carried out in several years time, many of the variables in the model will have different values. It would also be possible to use a different period of time for determining the values instead of the one used in the case (20012011). There are also similar considerations related to the choice of rates used for discounting, a topic which is beyond the scope of this paper. What is probably most important to understand is that energy security is not an absolute value, but one which changes over time. Besides, there are clearly cases where the cost of bringing up energy security to match a certain regulatory requirement may be greater than the benefit provided by achieving improved energy security. For these reasons, discussing energy security without taking into account the specific circumstances of a country or a region in terms of patterns of supply and use of energy, prices, physical deliverability limitations, and other fineprint type of data is prone to making costly mistakes. One may argue, of course, that buying "excess security" by investing in infrastructure that would diversify supply beyond what is actually reasonable in economic terms is still better than underinvesting, which may expose the country or region to bullying by suppliers and dangers beyond the economic remit. Nevertheless, a riskbased assessment of the economic costs and benefits associated with investing in new natural gas infrastructure, for the purpose of contributing to energy security, is a must in an informed decision making process.
6. Notes and References * Boyko Nitzov is TSO Cooperation Officer in the gas department of the European Union's Agency for the Cooperation of Energy Regulators (ACER). The views expressed in this paper are views of the author and do not necessarily reflect the official position of ACER or any of its Boards. [1] Directive 2009/73/EC of the European Parliament and of the Council of 13 July 2009 concerning common rules for the internal market in natural gas and repealing Directive 2003/55/EC (Text with EEA relevance). [2] Regulation (EC) No 715/2009 of the European Parliament and of the Council of 13 July 2009 on conditions for access to the natural gas transmission networks and repealing Regulation (EC) No 1775/2005 (Text with EEA relevance). [3] Cf., for example, a summary of the third legislative package available at http://europa.eu/legislation_summaries/energy/internal_energy_market/index_en.htm. [4] Regulation (EU) No 994/2010 of the European Parliament and of the Council of 20 October 2010 concerning measures to safeguard security of gas supply and repealing Council Directive 2004/67/EC. Text with EEA relevance. The Regulation is available online at http://eurlex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32010R0994:EN:NOT. [5] Regulation (EU) 347/2013 of the European Parliament and of the Council on guidelines for transEuropean energy infrastructure and repealing Decision No 1364/2006/EC. [6] All capacity is in million cubic meter per day (mcm/d) except where otherwise indicated. [7] The derivation of the production cost function of a gas pipeline is published by the author in: Hetland, Jens; Gochitashvili, Teimuraz (Eds., 2004). Security of Natural Gas Supply through Transit Countries. Springer. [8] The method for calculating the enhanced Shannon Index is quoted from: Péter Kaderják, Peter Cameron & András István Tóth (2007). "Unilateral natural gas import dependence: a new supply security issue for Europe".European Review of Energy Markets, volume 2, issue 2, pp. 1315. [9] Cf. L. Rebecca Byrd and Frank TH. Chung (1998). Risk Analysis and Decision Making Software Package (32Bit Version) User Manual. BDM Petroleum Technologies Under Contract to BDMOklahoma, Inc., p. 11. [10] Even when money comes from public funds  B.N. [11] Arps, J. J, and J. L. Arps. 1974. Prudent RiskTaking. Journal of Petroleum Technology 27(7): 711–716, as quoted by L Rebecca Byrd et al., op. cit., p. 11. [12] The importance of time horizons and rates used for assessments are discussed in Section 5.

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