Maurice Gravot

Subject choice and abstract: The Irish electrical mix

I have chosen to look at the Irish electrical mix for several reasons:

- now that the technologies used to exploit renewable energies (such as wind, solar, wave...) are almost mature the new challenge is to integrate them into the energy mix of the different countries
- in addition I think that comparing choices made by Ireland and France, to satisfy their electricity needs, could be interesting

This page is oranized in three sections:

- the different sources of electricity: it consists in a description of the energy sources. This chapter details the advantages/drawbacks, the estimated world stock, the CO₂ emissions linked to each source. This presentation of the different sources will allow to understand, in the following parts, the evolution of the electrical mix
- Evolution of the Irish electrical mix: in this part I talk about changes in the Irish energy production since 1990 and explain them
- Comparison to French electrical mix: Ireland and France have made diffenrent choices to face their electricity demands. This result in two very different electrical mixes. But, in spite of differences between this two countries, they taking similar decisions about the renewable energies

Introduction

Today important changes are carried out by European governements in their energy consumption. For several reasons, the part of the renewable energies is growing in their energy mix. One domain is particuarly affected: the electrical mix. Indeed, it is in this domain that the renewable energies are appealed to take the most important part (compared to transport and heating) in the incoming years. These renewable sources are numerous, each of them having its own advantages and, as a result being more adapted to some countries than to others. Nevertheless, in spite of the fast growing proportion of renewable energies in the electrical mix, the main part is still produced by fossil fuels, coal especially. These fuels, strong CO₂ emitters, have no choice but to decrease because of finite stocks which are estimated to last less than 150 years in the better case. This will benefit to renewable energies, if the states have the will to invest in them, the description of Ireland and France strategies will give an illustration of choices made to develop renewable sources of electricity.

The different sources of energy

Fossil energies

Coal

The Coal power plants are the most widespread in the world. They are located, mainly, in the country owning important coal ressource as China and USA (see on the right).

Coal power plants reprensenting the biggest part of the world electricity production, about 40% (Natural gas arriving in second with almost 20%). This massive use of coal to produce electricity is due to important coal beds in many countries. Compared to other fossile energies, the world stocks of coal should last longer:

- Coal: 120 years of stock
- Gas: 60 years
- Oil: 40 years

However, Coal is the most polluting way to produce electricity: it produce about twice as much CO₂ as Natural Gas for the same amount of electricity (see figures in the Natural Gas part). Coal power plants also emite particulates, carbon monoxyde, mercury much more than natural gas or oil power plants.

right: biggest coal producers in 2008 [1]

Oil

The use of oil in electricity generation has decreased over the past decades. the diagrams below show that oil was the second source of electricity (25%) in 1973 but in 2007, less than 6% of the electricity production was due to oil power plants.

above: the 1973 and 2007 fuel shares of electricity generation [1]

It is important to notice that during this period the elctricity genreration has more than tripled (5,200 TWh in 1971 and 17,400 in 2004) so, in absolute value, the electricity production based on oil has just slightly decreased wherease the other sources have increase. This stagnation is partly explainable by the cost of this way to produce electricity. The two graph below are very explicit:

- in the first one (from 1981 to 1996), we can see how the oil crisis (due to Iranian revolution and then the war between Iran and Iraq) impacted the price of oil (and gas) generated electricity
- in the second (1995 to 2008), we can see that in the last decade, oil has become the most expensive (among fossile fuels) way to produce energy. This is due to the "3rd oil peak" which was at its climax in 2008. In 2009 the cost of oil (and gas) as decrease consequently.
- in both we can see that oil and, to a lesser extent, gas are more expensive than coal to produce the same amount of electricity

above: the price of an electric kWh depending on the fuel during the 81-96 period [2]

right: the price of an electric kWh depending on the fuel during the 65-2008 period [3]

In addition to the important and volatile cost of oil, burning it is more poluting than gas for a same production of electricity (see the Natural Gas part below for figures). All these drawbacks might explain why oil is now responsible of a tiny part of the world electricity production.

Natural Gas

Natural gas has been used by man for centuries, however it is during the XIXth century that its industrial exploitation started. In 1859, Edwin Drake, dug the well considered as the first one [4]. The gas was first used as a source of light, it is only at the end of the XIXth century that it started to be converted into electricity.

right: composition of Natural gas [5]

Natural Gas is composed of several hydrocarbon gases, the main one being methane, the table on the right shows the detail of its composition:

Natural Gas is often presented as the cleanest existing fossile fuel, the burning equation of methane only produce water and carbon dioxyde:

CH₄+ 2.O₂ -> CO₂+ 2.HO₂+ 891 KJ

In reality the combution of natural gas produce also more poluting or dangerous element such as carbon monoxide or Nitrogen oxide. But, the comparison between the different fossil fuels tends to be in favor of Natural gas. The table below details the emissions of the main fossil fuels:

above: emission of fossil fuels linked to the production of 1 Btu of electricity [6]. A Btu means British thermal unit, a billion Btu is equal to 293 MWh.

In the domain of electricity production, natural gas become more and more used compared to other fossil fuels. This is partly du to its relative few emissions but another reason is the high efficiency of combined Cycle Turbines. Indeed, some of these tubrbines reach 60% efficiency instead of 40% for the simple cycle turbines [7]. These new type of turbines allows natural gas power plant to be more efficient than Coal or Oil power plant which efficiency lies around 50%.

Nuclear energies

Fission

The first use of the nuclear energy was military, the first reactor has been built in order to produce materials used for A-bomb (enriched uranium for instance). After Worl War II, researches to produce electricity thanks to nuclear energy started and leaded, in 1951, to the first nuclear power plant in the USA. Until now the only way to produce energy through nuclear reaction is fission which is discussed in this part.

Because of the relative newness of the technologies used, the performances of the nuclear powerplant have quickly evolved. Thus the capacity factor has evolved signicantly during the XXth century. The following diagram shows the evolution of the capacity factor of US nuclear powerplants. It is important to that this high capacity factors are partly due to the fact that nuclear power cannot adjust quickly to the demand, so nuclear power plants produce energy permanently. While, for instance, fossils fuels plant can be used only during consumption peaks.

below: the evolution of US nuclear powerplants capacity factor [8]

Compared to fossil fuels, the price of Uranium (the main fuel of nuclear plant) has been signicantly decrease around 1980 (as production increased) and has remained quite stable until recently (its price has been multiplied by more than 10 between 2000 and 2007 [9]). Indeed, as a finite resource, Uranium faces the same problem as fossil fuels: finite world stock and an increasing demand. The difference, between these sources is that the cost of nuclear electricity relies less on the cost of its fuel than electricity from fossil fuels.

Fusion

Prototype of fusion power plants have already been built but are unable for the moment to produce significative amount of electricity.

Renewable energies

Hydroelectricity

Hydroelectricity might be one of the oldest way to produce electricty without using fossil fuels. The water energy has been used by human for hundred years, however its utilisation to produce electricity has started at the end of the XIX century. Among the different ways to produce electricity the most part come from dam. Due to its massive use (see the next pragraph) for decades the hydroelectricity technology are now mature, thus the efficiency of hydropower stations reaches 95% for large installations [10].

In 2010 hydropower represent 16% of the global electricity production whereas the other source of renewable energy reach 3%. However the growth rate of hydropower energy capacity is very low (3% in 2010) compared to the other renewable energy sources (over 70% in 2010 for solar PV for instance) [11]. The main reason of the slow rate of increasing is that the hydro power potential is exploited almost fully in Europe and in North America. One of the main advantage of this energy source is that it is storable (when the gate of a dam are closed) and can be used very quickly during consumption peaks.

However, hydroelectricity has also drawbacks the most obvious are caused by the impoudement which can dramatically change (some would say destroy) the environnement, for instance:

- due to the Three Gorges Dam, 1.2 million of people have been relocated
- the belo Monte dam, under construction in Brazil, will flood 668km² (including 400 of forest) which, in comparison, is more than five time the surperficy of Dublin

In addition is has been shown recently that dam produce important quantity of methane (which have an higher warming impact than carbon dioxide). An estimation is speaking about of an equivalent of 7.5 billion tonnes of carbon dioxide emitted each year which can be compare of the 6 billion tonnes issued from fossil fuel burning by the US in 2005.

Wind

Wind power has been widely used for centuries, however the generation of wind electricity on a large scale is recent. Indeed fossil fuels were found more competitive to produce electricity at low costs and on large scales. Researches on producing electricity thanks to wind as been led since the end of the XIXth, one of the main starting points was the work done by the Danish Poul La Cour who designed in 1890 the first industrial wind turbines [12].

right: Denmark wind electricity production [13]

The interest for wind produced electricity significantly increased in the 70's due to tthe two first oil crisis (73 and 79). Denmark has been a pioneer in this domain, the graph on the right shows tthe increasing capacities of wind power and the proportion of wind power in the electricity supply (Denmak has one of the highest proportion of wind electricity). Today, wind is the second renewable electricity source behind hydropower (see diagram in te biomass part).

Wind energy is a renewable energy and does not emit CO₂ when producing electricity. However wind turbines are accused to kill birds and to disturb residents living close to wind farm. This phenomenon seems, according to studies, not being relevant. Concerning bird kills studies showed that wind turbines do no kill more bird than other human building and that the impact of wind turbines over birds population is low [14]. In addition, wind turbines do not pollute instead of fossil fuel power plants, this pollution also leads to wildlife casualties which do not occure with wind turbines. The disturbance generated by wind farm is still debated, wind turbines are supposed to cause headache and insmonia. Some testimonies seems to invalidate these suppositions by comparing the noise of wind turbines to the noise resulting of a road in the worst case [15].

Solar

below: Solar world installed power [16]

To produce electricity from sun radiations there are, today, two main ways:

- Photovoltaic (PV). Based on the phtovoltaic effect discovered in 1839 by Becquerel, PV waited more than a century before starting to be commercialised when Bell Labs designed the first PV cells. At the beginning, PV cells were mainly used in the space industry: in 1958 PV array were used to empower the satellite US Vanguard I and in 1966 the Orbiting Astronomical Observatory was lauched by the NASA with an array of 1 kW. The use of PV to produce electrcity "on earth" started in the 90's when Germany and Japan launched important subsidy programs in favor of solar PV. Today world solar PV installed capacity is increasing rappidly (see the graph on the right) and is now the fourth renewable source of electricity.
- Concentrated solar power (CSP). CSP consists in concentrating solar heat, thanks to mirrors, in order to warm a fluid. This fluid then boils water wich feeds a steam turbines (as, for instance, in fossil fuel plants or in nuclear plants). This way of producing electricity is not as developed as solar PV, the global power installed is slightly superior to 1 GW, in addition the decreasing cost of solar PV makes CSP less competitive.

Because of the relative novelty of the technologies used, solar PV remains an expensive way to produce electricity. However, the growing market of solar PV and the technological progress should lead, in the future, to a decreasing price of the kWh (as shown below).

below: the estimated price of solar produced kWh [17]

Biomass

Biomass, in the energy field, reffers to organic material (mainly vegetal) which can be converted in energy. Human has used biomass since he mastered fire. Biomass is the most used renewable energy in the world mainly for heating and cooking. However in term of electricity generation, biomass comes after hydropower and wind (as shown on diagram below). Indeed, the use of biomass in power production has been developed recently; for instance the EU solid biomass electricity production has been multiplied by three between 2001 and 2009. Today biomass cofiring (burning biomass with another fuel, tipically coal) can reach an efficiency of 45% which is comparable to pure fossil fuel power plants [18].

below: Renewable power capacities [19]

Evolution of the Irish energy mix

Recent evolution

right: electricity geneation by fuel [21] and Irish fuel mix [22]

Overview

The Irish electricity production has increased from 14 TWh in 1990 to 24 TWh in 2008 (see the diagram on the right). During this period, important changes have occured in the fuel mix and in the avrage efficiency of Irish power plants. Concerning efficiency the most evident illustration is that the input energy of fuel for electricity generation has remained stable since 2001 whereas the production has increased over the same period.

About the fuel mix itself:

- The use of coal and peat (an Irish specificity, while Ireland is the second productor in the world) has been stable over this period, whith a slight decrease for coal sarted in 2005. In 2008, the energy produced by coal was equivalent to 1,046 kToe and 566 for peat
- Oil has played an important role at the end of the 90's and at the begining of the 00's (over 600 kToe were used per year during this period with a peak of 1,039 in 2000). But has decreased since then and is back, in 2008, to its production level of 1990 (respectively 351 kToe and 341)
- Natural gas, has during this period, doubled in proportion, 27.3% in 1990, is participation in the electrical mix reached, in 2008, 54.7% and representing a production of 2,811 kToe
- Renewable Energies are, for the moment, playing a little role in the production. However this source is the one which progression has been the most important, the production has been multiplied by more than 5 since 1990 (from 60 kToe to 329)

Details and consequences of these evolutions

The massive use of natural gas (the less CO₂ emitting of fossil fuels), the increasing effeciency of natural gas power plants and the rise of renewable energies in the mix have had a benefic effect on the CO₂ emitted per kWh. As shown in the graph below:

below: global Irish electrical efficiency and CO₂ emissions [23]

One of the main way to produce electricity from biomass is to burn it. This, of course, produces CO₂ but biomass is considered as a renewable energy and CO₂ neutral. Indeed, contrary to coal, gas and oil, vegetables which are burned can be replaced fastly and easily:

fastly because plants grow in several month (crops for instance) to several years (trees) instead of millions of year for oil generation
- easily because man can decide to plant trees to counter the CO₂ emission of a biomass power plant and to recreate ressources. This is impossible for fossil fuels

So, if there is no over exploitation of biomass ressources, the burn of it is a part of a neutral carbon cycle (as shown below):

trees and crops grow, thanks to phosynthesis, capture CO₂ and reject O₂
biomass is burned in a power plant creating electricity. This consums O₂ and reject CO₂

below: Carbon cycle [20]

The main advantage of biomass as a source of electricity, is that it is cheap. It requests few investments (between $50 and $250/kW) and the electricity cost is, depending sources, between 2 and 11 cents per kWh.

- the emission of CO₂ decrease slightly until 1999, while the efficiency of the electricity suply is constant. The decrease might probably be dued to the increasing proportion of natural gas in the electricity mix (the energy due to renewable sources, hydropower only, is almost constant during this period)
- Since 2000, the decrease has been very strong. This is linked with the increasing efficiency but also with an evolution of the electricity mix. Indeed when the efficiency increase, less fuel is needed for the same amount of electricity produced. So, if the mix stays unchanged we should have 0.647 CO₂ gramme per kWh produced (see calculation below). Instead of 0.647 the CO₂ gramme per kWh in 2008 is 581, this gap is due to a change in the mix.

The renewable energies role in the electric mix is called to increase. It is important to note that renewable energies sources have existed in Ireland for years as shown in the graphic above. The first renewable source where dam like the one of Ardnacrusha built in 1924. However, the electricity produced from hydro is now stable.The main evolution has been the increasing power produced by wind tubines. The first wind farms was connected to the network in 1992, fifteen years later, in 2007, 67 wind farms were connected and at the begining of 2010 [24], 1350 MW were installed (see below)

below: installed capacity per renewable sources in Ireland [25]

Perspectives

Renewable energies will play an important role in the futur Irish electrical mix. Indeed, on a larger scale European Union has fixed the goal that 20% of the energy come from renewable source in 2020. In this plan, Ireland has to reach a proportion of 16%. This has to be shared between electricity, transport and heat. The goal are very different depending on the domain: while transport and heat must reeach 10% and 12% of renewable sources proportion, it peaks at 40% for electricity [26].

The major part of this production will rely on wind farms which are planned to produce 37% of the electricity by 2020. This will put Ireland at the top of Europe in term of proportion of electricity produced from wind (Denmark, the historical pioneer targets 30%). One of the main aspect of this evolution is the development of off shore wind farms for two reasons:

- Off shore wind farms are very recent in Ireland, the first one, in Arklow, has been connected at the end of 2003 [27]. As a result there is still very few of them, so the potential is, for, the moment, still to be exploited
- Wind is much faster off shore than on shore [28]. Knowing that the power output of a wind turbine is proportional to cubed wind speed (see formula below), the amount of energy produced would be much more important than with on shore wind farms. The Arklow wind farm by being the first off shore and the biggest Irish farm in term of installed power at the time of its connection (and still the second one in september 2011) is the perfect illustration of the potential of off shore wind farms

The remaining 3% will be splitted between ocean power (wave and tidal), biomass and solar PV.

Comparison to the French electrical mix

Specificity of the French electrical mix

The importance of nuclear power

The French electrical mix was, at the begining of the 70's quite standard:

- the hydro-electrical potential was well exploited
- the additional electricity need was produced with fossil fuels powerplants

The response to the increasing demand in electricty has been first answered by developing the electricity generation based on fossil fuels (until 1977-1978). However, since the end of the 70's, the electricity produced from nuclear fission has taken an increasing part in the mix and from the mid 80's nuclear has become the main source of French electricity.

The massive use of Nuclear fission in the mix, which is the specificity of the french mix, can be explained by different reasons:

- the first one, chronologicaly speaking, was to respond to the two oil crisis in the 70's. As we can see on the diagram below the nuclear electricity has started to increase significantly during the second part of the 70's. During the same period the part of fossil fuels stagnated (1976-1980) and decreased (1980-1986). The advantage, at this time, of nuclear power was that the price of Uranium decreased significantly.
- More recently another advantage has been taken into account, the fact that nuclear power emit almost no CO₂. So in order to fight against global warming, the nuclear option is excelent. This can be an explaination of the very low proportion of electricity produced from renewable source (excluding hydro)
- the last reason is that nuclear produce the base of French electricity (ie nuclear powerplants are working permanently and at almost the same rate) whereas hydro use is "base and peak" (ie hydro produces few electricity during the night and more in the day) and fossils fuels are used during peak

However, producing electricity from nuclear has also drawbacks:

- France do not produce Uranium, it has stopped in 2001, and, as a result, depends entirely from importations
- Uranium world stocks are finite and the production begins to be unable to follow the demand which cause an increase of the uranium price

below: French electrical mix from 1970 to 2009 (prevision from 2010 to 2019) [29]. Blue: hydro; dark blue: fossil fuels; pink: nuclear power; purple: wind; green: other renewable

Renewable energies in France

France has to reach a proportion of 27% of electricity produced from renewable energies by 2020 [30]. To reach this goal, wind power might be the key energy. Indeed, today, the most part of electricity produced from renewable source come from hydropower, however the potential of this source is exploited at 90% (and represented in 2009, 12% of the electricity production [31]). Solar power has a great potential but the technologies are not sufficiently mature and, in France solar is for the moment anecdotic (0.1% of the renewable electricity production [31]). Biomass is also an important source but is actually stagnating.

Wind power in France has a great potential, France is considered as having the second biggest wind resources in Europe (after UK) and plans to reach 6 GW of installed wind power in 2020. However France was, in 2009, only the third European country in terms of wind power installed (behind Spain and Germany, almost equal to Italy [32]). The main part of this potential lays off shore and close to the sea (see below), if it was fully exploited it would reached 160 TWh, that is 45% of the nuclear production (in 2007). However the installed power increase rapidly (+40% between 2007 and 2009 [31], wind power is also the renewable source which as the most progressed in ten years) and numerous new farms are planned (for instance, at the begining of 2011 an invitation to tender has been made for 3 GW of off shore wind farms built by 2015 [33]).

below: the wind mean power in Europe and France [34]

Comparing Ireland and France

The major difference between France and Ireland is the stance on nuclear power. In France, nuclear power is more that the main electricity source, it is a important part of the country economy (it employs hundred thousands of people), it is considered as national success and the debate was almost impossible before the Fukushima disaster (even since this event, the governement stands on its ground). In Ireland, there is no electricity generated from nuclear simply because it is banned by the law.

This choices confront the two countries to different problems:

- Ireland sources more than 90% of its electricity fuels from fossil fuels that it does not product. This high dependency is, by the way, a source of debate about wether or not Ireland should cancel the ban on nuclear [35]
- France has to deal with its life ending nuclear plants, with the dangers and costs that it implies and with the growing impopularity of this source of energy among the population

However, beyond this difference, the two country are facing the same current challenge that renewable energies represent. A connection can be done between the situation at the end of the 70's and the current one. Indeed, both are periods in which the electricity mix is incited to change dramatically. The reason are different, even if, in both case, an oil crisis occures, today the main one is reducing the CO₂ emissions. However, on this point, the two coutries differ in the CO₂ emitted for a kWh of electricity produced:

- In Ireland a little less that 0.6 kg/kWh is emitted in 2008
- In France it is 0.09 in 2009
- In Europe the mean is 0.46 in 2009

But, in spite of this difference, both Ireland and France are increasing rapidly their electricity production based on renewable source. And both are relying mainly, on medium term, on wind turbines. This technology having the advantage to be mature enough (compared to solare PV) and to have an important and unexploited potential (compared to hydro) in both countries.

Conclusion

France and Ireland are two illustration of the European will to shift from fossil fuels to renewable energies, as the "new EU Renewable Energy Directive", by setting goals to each country of the Union, proves it. This directive as been made to increase the part of renewable energies in the enrgy mix to 20% by 2020, electricity production being the field where the evolution are the most important. To reach this goal, the wind energy is playing a crucial role, indeed, in most of the countries, this source will be the first renewable source by 2020. Ireland and France are planning to increase massively their production because of the important resource they have, but on a more general scale, wind energy benefit from two advantages which it is the only one to combines: mature technologies and a strong potential. This is explaining the importance of this source, however it is not the only source of energy: solar PV will be more and more used in the upcoming years and will probably be, in less than ten years, in the same situation as wind energy is today. The other sources, expecially ocean power (tidal, current and wave), will also increase but the role played might not be significative before ten or fifteen years.