A renewable electricity systemfor mainland Spain and itseconomic feasibility.

100%Renewables

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www.greenpeace.es

Greenpeace MadridSan Bernardo, 107. 28015 Madrid Tel.: 91 444 14 00 - Fax: 91 447 15 98 informacion@greenpeace.es

Greenpeace BarcelonaOrtigosa, 5 - 2º1º. 08003 Barcelona Tel.: 93 310 13 00 - Fax: 93 310 51 18

Summary document, drafted by José Luis GarcíaOrtega and Alicia Cantero, from the report entitled“100% Renewables: A renewable electricity systemfor mainland Spain and its economic feasibility”.

Design and layout: Espacio de ideas

This report has been produced thanksto the economic contributions of the membersof Greenpeace.

Greenpeace is a politically and economically independent organization which does not receivesubsidies from companies, or government, orpolitical parties. Join at www.greenpeace.es

Printed on 100% post-consumer recycled paper and totally chlorine free.

April 2007

CONTENTS

1. Presentation 5

2. Methodology 6

Temporal analysis 6

Analysis of the electricity generation system 7

3. Basic concepts 7

4. Can a system based solely on renewables meet all our electricity needs? 8

4.1. Generation by technologies 8

4.2. Examples of generation mix 10

100% renewable mix. Aim: technological diversity 11

100% renewable mix. Aim: economic optimisation 14

100% renewable mix. Aim: to make the most of demand management 17

100% renewable mix. Aim: to meet all energy demand (not just electricity) 19

4.3. Meeting demand: conclusions 22

5. Paradigm changes needed for implementing a renewable system 23

6. How many renewable stations would be needed and how should they be used, at minimum cost? 24

Need for installed capacity (analysis of a solar multiple) 24

Analysis of capacity storage 25

Analysis of the electricity generating system 25

Analysis of cost of non supplied energy (CNSE) 26

7. Final conclusion 27

8. Greenpeace proposals 28

5

PRESENTATION

The report of the United Nations group ofexperts on climate change (IPCC) confirms thathuman beings are causing a rapid global warmingwithout precedent, the consequences of whichmay be very prejudicial to life if average tempera-tures reach more than 2°C above the level theystood at in the pre-industrial era. The likelihood ofavoiding exceeding the two degree limit dependsmainly on our slowing down and stabilising thegreenhouse gas levels in the atmosphere, forwhich a drastic reduction in emissions is requi-red. Given emissions are mainly due to ourcurrent energy system, based on the burning offossil fuels, 'an energy revolution' is neededwhich would enable us, on the demand side, toput an end to our current squandering of energyby savings and efficiency, and on the generationside, to replace dirty energy sources by otherswhose use is sustainable, which are none otherthan the renewables.

The problem is that, those who make the key deci-sions, besides tackling the political and economicinterests of the supporters of the 'old energymodel', are faced with a fundamental doubt: theydon't believe it is possible to change it. Even inSpain, which has come to the forefront as worldleader in the development of the renewables suchas wind power, support for these clean energysources is constantly being questioned. This iscreating growing tension as the penetration of therenewables in the electricity system ceases to bemerely token, and even more so according tosome, such as in the case of wind power, whenthey reach what some consider to be their 'techni-cal limit '. Having reached this point, two very dif-ferent conceptions of the role that the renewablesmay and ought to play meet head-on: a comple-mentary role as yet another element in the

system, or a leading role capable of displacingconventional forms of generation. The model andthe degree of support for one or other energysource will depend in the long run on what thehorizon is which is being sought.

The aim of the survey “100% renewables" is toquantify and technically evaluate the feasibility of

a scenario based on renewable energy sources

for the electricity generating system in main-

land Spain.

In this document we present a summary of themain conclusions of the report relating to the tem-poral analysis and the grid, which together withthe conclusions of the cost analysis (see docu-ment 100% RENEWABLES: COST COMPARI-SONS) show that there are many possible confi-

gurations, with different combinations of

electricity generating systems based on rene-

wable sources, to satisfy the predicted

demand in 2050. We also show in this documentexamples of combinations of renewable technolo-gies ('generation mix') depending on the differentrequirements, which enable us to understand themain technical, economic and geographical featu-res of these mixes.

The greatest contribution of this survey resides insetting out, for the first time, the technical andeconomic feasibility of the 100% renewable gene-ration systems and to have opened up the way tofinding some answers. Although there are manyanalyses to be developed before these systemscan be introduced, we have progressed enough tobe able to see clearly that renewable energy is via-ble, and now it is the job of other organisationsand entities to take it up and make it a reality. Afterthis study there are no longer any excuses for notcarrying on urgently with the progress made inthis direction.

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6

METHODOLOGY

Once capacity, generation and cost ceilings have beenanalysed, the rest of the survey has adopted themethodology described below.

Temporal analysis

The most important analysis is that of renewablegeneration capacity and its temporal link todemand, that is, it is not enough to know howmuch can be produced, but how to deliver it to con-sumers, when and where required. Bearing in mindcosts and production and demand time variation, itis a case of determining what combinations ofrenewable generation technologies may be emplo-yed to satisfy demand completely. Given that manyoptions arise, it must be determined which of themwill be the best, both in terms of installed capacityand ways of utilising it (dispatch). In the case of100% renewable systems, this analysis cannot beundertaken separately.

■ In order to do so, first of all and by way of compa-rison, the scenario of a stand-alone system tocover the electricity needs of a single family hou-sehold has been analyzed. This is fairly easilydone nowadays, despite which it is even techni-cally easier and economically less expensive tomeet the electricity demands with renewabletechnologies for the whole of mainland Spainthan for a single family household. The compari-son with the household scenario shows that put-ting forward the 100% renewable option is not as‘unattainable’ as is often thought, and that wealready have cases (standalone systems) whichno one doubts are possible and which are actuallymuch more complex.

■ Subsequently an analysis of temporal genera-

tion capacity has been carried out on each of thetechnologies, studying how generation varies foreach technology over the year and the effect ofinstalling different renewable energies (spatialspread and technological diversity) in differentgeographical areas.

■ Outlined below is a detailed temporal analysis

of the matching of generation capacity to elec-

tricity demand.

Starting from the current situation, hydroelectricpower and onshore wind power dominate therenewables. Renewable technologies have beenintroduced by order of merit in their performancein the 2050 cost structure, irrespective of storagecapacity and without requiring them to adapt theiroutput to demand (merely dissipating excessenergy and only using biomass stations for opera-tions at point of consumption). In this way differentmixes with different levels of meeting demand

are analysed.

Then we have looked at how the models presen-

ted are affected on introducing energy storage

capacity. In order to do this it has been assumedthat the electricity system operates with no otherregulation than the dissipation of excess energyand not using biomass when there is surplusgeneration from other energy sources. It has alsobeen assumed that the storage system has a costof 10 €/kWh (in 2050) and an overall charge-dis-charge output of 70%.

7

Analysis of the electricitygenerating system

Finally, an analysis of 100% renewable generatingsystems has been tackled using the normal toolsfor 'conventional' analysis of the grid.

■ The first of these analyses has been carried outusing “generation expansion models”, in order todetermine an optimal combination for technolo-gies to be installed.

■ Once a generation mix is available, the next step inconventional grid analysis comprises determiningwhich technologies of those installed is most

suitable for use at a given time to satisfy

demand. To this end a “grid generation opera-tion” has been employed. The effects of econo-mic investment have been incorporated into it inorder to determine which stations to install (gene-ration expansion) and which to use (optimal dis-patch); two problems which, for generationsystems based on renewables, must be solvedsimultaneously.

■ The final step taken has involved optimising eco-

nomically the mixes obtained, first by incorpora-ting the thermosolar hybridization effect, that is,using thermoelectric stations which can operateeven when there is no solar radiation, using bio-mass as fuel, and then considering cost values forenergy which has not been supplied, between 2and 10,000 c€/kWhe.

BASIC CONCEPTS

In the first place it is advisable to introduce somekey concepts for this analysis:

■ Solar multiple (SM): ratio between nominal ins-talled capacity and maximum demand capacity.That is, how much power or capacity a systemhas installed in relation to the maximum electri-city demand, that is, how many stations have tobe “spare” in order to resort to them when othersare not available. For example, a mix with SM = 2will have as many stations installed in order tohave capacity equivalent to double the maximumcapacity which could be required at any moment.

■ Capacity factor (CF): ratio between usefulenergy generated and the maximum that couldbe generated operating at normal power for awhole year. That is, it gives us an idea of theextent to which we use installed capacity in apower station or in our whole system, in otherwords, how much of the installed capacity isbeing utilized. For example, a power station withCF = 60% means that this power station has pro-duced 60% of the maximum energy which wouldbe generated if the power station could be keptin operation at nominal capacity for the wholeperiod under consideration.

■ Solar fraction (SF): fraction of the demand metby the renewable generation system. That is,how much energy renewables generate compa-red to overall demand. For example, SF = 100%mean that the whole demand is covered by rene-wable energies.

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This is, without a doubt, the main issue whenanalysing the technical feasibility of a systembased 100% on renewable energy, to check if it ispossible to generate all the electricity required atall times. The study analyses in the first place thetemporal generation capacity for each techno-

logy, and then it carries out a detailed analysis ofhow the generation capacity of a system based onrenewables matches electricity demands throug-hout the year.

The object of this analysis is to be able to evaluatehow much energy can be used from what it is pos-sible to generate with installed capacity (regulationperformance), and to check how it depends on thespread of the technologies which are installed (mix)and the means of operating them (dispatch).

4.1. Generation by technologies

The analysis of how generation for each techno-logy varies over the year, includes the effect ofspatial spread, that is the effect of adding up gene-ration of one single technology spread across allthe provinces. The result is conservative, giventhat having considered each province representedby a single temporal series, we are not taking intoaccount the effect of geographical spread withineach province. Even so, spatial spread gives rise tomuch a more even generation, since at each sitegeneration is available at different times. It is thesame effect that occurs when electricity demand,which on the mainland scale, is fairly even, with anannual minimal demand which is 42.96% of themaximum. The results for each technology aregiven below:

Offshore wind power is the dominant resource inwinter-autumn, with reduced generation capacity inthe middle months of the year:

Electricity capacity generated over the year for the temporalseries obtained by averaging all the offshore mainland sites,as a relative value to the nominal installed capacity.

Onshore wind power follows a similar pattern tooffshore wind power:

Electricity capacity generated over the year for thetemporal series obtained by averaging all Onshore windpower, as a relative value to the nominal installedcapacity.

CAN A SYSTEM BASED SOLELY ON RENEWABLES MEET ALL OURELECTRICITY NEEDS?

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Total 23 sites

Onshore wind power: total 47 sites

Hour

Days: 22 sites

Time (h)

9

Thermosolar power is the dominant resource inspring-summer:

Electricity capacity generated over the year for thetemporal series obtained by averaging all thermosolar,as a relative value to the nominal installed capacity.

Photovoltaic power with azimuthal monitoring isalso dominant in spring-summer, but with greaterseasonal regularity than thermosolar power:

Electricity capacity generated over the year for thetemporal series obtained by averaging all azimuthal PV, asa relative value to the nominal installed capacity.

Photovoltaic power installed on buildings is domi-nant in autumn-spring (the following combination oforientations for the installation of photovoltaicmodules has been taken: for every four modules onroofs, 2 southward, 2 south-eastward, 2 south-westward, 1 eastward and 1 westward):

Mainland series for integrated photovoltaic energyobtained on grouping all the provincial photovoltaic seriesas a result of averaging the different orientations with thelist shown (4 roof + 2S + 2SE + 2SW + 1E + 1W ).

Wave technology provides the following profile:

Hourly capacity series dimensioned with the averageannual capacity of the mainland series resulting fromaveraging the 22 provincial sites.

Thermosolar: total 47 sites

Time (h)

FV azimuthal PV: total 47 sites

Time (h)

47 mainland sites. Total capacity PV on buildings

Time (h)

4.14.1. GENERATION BY TECHNOLOGIES

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4.24.1

Hydroelectric power shows considerably less varia-bility compared to the rest, because of the storageand concentration effect of hydrological basins andreservoirs. In a renewable system, because of theirstorage capacity, operation of hydroelectric stationswould be different from current practice.

Hourly series for hydroelectric capacity under an ordinaryand special regime for the mainland obtained bymodulating potential generation assumed for the year 2050(IIT, 2005) with the average historic producible in the year2003. These hydroelectric capacity series do not assumeany regulation of the electricity system with technology.

As far as biomass and geothermal stations are con-cerned, they are capable of operating at constantoutput throughout the whole year, besides provi-ding the possibility of adjusting their outputs toregulate the system, depending on production fromvariable generation stations, such that if operatedproperly they can provide regulation capacity andguarantee output.

4.2. Examples of generation mix

In order to analyse generation-demand temporalmatching we have developed the least favourabletechnical scenario in order to demonstrate thateven in this case it is possible to meet the energydemand. That is, different combinations of renewa-ble technologies or technological mixes have beensought which respond to the needs of an energydemand which, as currently occurs, does not incor-porate demand management1.

Generally speaking, any renewable mix is charac-terized by spatial spread and technological diver-sity. Furthermore, it must be borne in mind thatthe majority of these renewable technologies havegreat regulatory capacity, that is, they can adjusttheir ouput to demand at any time, and do so morequickly than conventional technologies, when itcomes to reducing delivered power below poweravailability (which depend on the sun, the wind,etc.) at any moment in time.

RO hydroelectric with historic producible modulation

RE hydroelectric with historic producible modulation

Time (h)

Time (h)

[1] Demand management is the term for the series of measures whose aimis to modify the way in which energy is consumed, whether by saving aparticular amount of energy or displacing its consumption to a different time.It includes regulation measures, incentives, consumer information, pricetags, etc.

4.2. EXAMPLES OF GENERATION MIX

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However, many of the renewable technologies areunable to regulate power above available output atany given moment in time, that is, if at a particularmoment the wind in an wind turbine allows 500kW to be delivered, the machine cannot provideany more.

This situation, in a generation system in whichextensive use is not made of demand manage-ment, obliges us to have available a ‘standby capa-city’ (stations which are not generating or whichare on standby to generate at any time when apower shortfall occurs) greater than that of con-ventional generation systems, whose function isto maintain electricity generation even when theavailable resource decreases.

There are several means of achieving this standbycapacity in 100% renewable mixes: increasing ins-talled capacity, using storage capacity and regula-tion from technologies such as reservoir hydroe-lectricity (including pumping), biomass, geothermaland thermosolar, or better still hybridization usingbiomass (gassified) from thermosolar stations, thatis, stations which can use either solar energy orbiomass as a fuel source2.

Of the countless combinations of renewable tech-nologies to meet electricity demand which can beput together, here we are going to show someillustrative examples seeking different objectives:technological diversity, the lower generation costs,combination with demand management. We alsodemonstrate another mix which, besides meetingoverall electricity demand, achieves coverage of allenergy demand.

100% renewable mix.

Aim: technological diversity

In the first place we give an example of a mix capa-ble of completely satisfying electricity demand in2050 using renewable energies (SF = 100 %),whose main feature is technological diversity, thatis, it makes use of a wide range of technologiesbased on renewable sources, and manages to com-pletely meet demand thanks to a small storagecapacity.

The mix in this example would have an installedcapacity of 112,680 MW, with the following tech-nology spread:

Installed capacity by technology.

4.2

[2] We have adopted a sizing criteria for renewable mixes consisting of therequirement that they have a standby capacity of at least 15% abovemaximum deficit output, and with energy available having a regulationcapacity of at least 25% above annual energy deficit.

Thermosolar

Onshore wind power

Hydroelectric

Offshore wind

Wave power

Biomass

PV on buildings

Mini-hydroPV tracking

Geothermal

Capacity (GW) — Renewable — Demand — Dissipated — Shortfall

Time = 8.760,00 [hr]

Capa

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(GW

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Capa

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(GW

)

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The following table summarizes the main features of this mix.

Main characteristics of the mix.

Installed capacity 112,68 GWpAvailable energy 396,48 TWh/aSolar Multiple (SM) 2,5Accumulation capacity 1,5 TWhMeeting demand (SF) 100 %Energy shortfall in relation to annual demand 0 %Energy to be dissipated in relation to annual demand 34,4 %Available generation in relation to annual demand 141,6 %Energy contributed by biomass 3,9 TWh/aMaximum deficit capacity 0 GWMaximum dissipated capacity 60,9 GWAnnual electricity cost (LEC) with no hydro investment 4,51 c€/kWhSolar-biomass hybridization NoMini-hydro operation BaseFraction used of the onshore wind power capacity ceiling 4 %Fraction used of the thermosolar capacity ceiling 1,387 %Land occupation 2,47 %

In the following graph we can see how over theyear available output is generated to meet demand

at all times, as well as those times when surpluscapacity would be dissipated.

4.2. EXAMPLES OF GENERATION MIX

4.2

Annual hourly development of available capacity, demand, dissipation and shortfall for a mix with SM = 2,5 with a storagecapacity of 1.5 TWh. SF = 100%.

Thermosolar

Onshorewind power

Offshorewind power

Wave power

Biomass

Geothermal

PV tracking

PV tracking

The map shows us the geographical spread byautonomous communities for installed capacity.The provinces with lowest generation costs have

been chosen for the respective technologies.Water technologies are not shown because theyuse already existing sites.

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4.2. EXAMPLES OF GENERATION MIX

4.2

Technological diversity.

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100% renewable mix.

Aim: economic optimization

In this scenario we show a mix in which the econo-mic optimum is sought, that is the minimum costfor the electricity generated, maintaining the condi-tion of completely meeting electricity demand in2050 with renewable energies (SF = 100 %), nottaking into consideration any kind of demand mana-gement.

To determine optimum dispatch, that is, how gene-ration is spread over the various stations installed inorder to minimize running costs, aspects have beenintroduce such as taking into consideration the sto-rage capacity of hydroelectric reservoirs and optimi-zation of their management, including thermosolarhybridization and the optimization of its manage-ment, including hydroelectric pumping (with its sto-rage and power regulation capacity) and optimizingoperation of each technology throughout the yearaccording to its variable costs and availability.

For minimum cost analysis, investment and lifecycle costs have been optimized, using a specialmodel which, by calculating some 500,000 equa-tions, simultaneously resolves the problem ofwhich power stations to build and which to operateat any moment in time throughout the year.

The mix in this example would have an installedcapacity of 79,600 MW, with the following techno-logy spread:

Installed capacity by technology.

Electricity configuration and generation of a mix, optimizedin a life cycle incorporating thermosolar hybridization tototally meet demand (SF = 100%). SM = 2.20; LEC = 2.47c€/kWhe.

Flatland Wind Power

Thermosolar

Biomass at thermosolar power stations

Regulated Water

Mini-hydro

Existing Water Pumping

Flowing Water

New Water Pumping

4.2. EXAMPLES OF GENERATION MIX

4.2

Onshore wind power

Solar-biomass hybridization

Regulated hydro

Existing hydroelectric pumping

Flowing hydro

Mini-hydro

New hydroelectric pumping

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Electricity generation at thermosolar power sta-tions, all of them hybrid with biomass, is brokendown between that which would be achieved usingsolar energy and that which, at the same stations,would be achieved with biomass.

The following table summarizes the main featuresof this mix.

4.2. EXAMPLES OF GENERATION MIX

4.2

Main characteristics of the mix.

Installed capacity 79,6 GWpAvailable energy 291,8 TWh/aSolar Multiple (SM) 2,2Meeting demand (SF) 100 %Annual electricity cost (LEC) with no hydro investment 2,47 c€/kWhMaximum electricity cost 9.883 c€/kWhDuration of maximum electricity cost 1 HourSolar-biomass hybridization YesMini-hydro operation BaseFraction used of the onshore wind power capacity ceiling 3,8 %Fraction used of the thermosolar capacity ceiling 0,7 %Fraction used of the thermosolar-biomass hybridization capacity ceiling 39,2 %Land occupation 2,4 %

Thermosolar withbiomass hybridization

Wind power

The map shows us the geographical spread by auto-nomous communities of installed capacity. The pro-vinces with lowest generation costs have been cho-

sen for the respective technologies. Water technolo-gies are not shown because they use already exis-ting sites.

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4.2. EXAMPLES OF GENERATION MIX

4.2

Economic optimization.

Flatland onshore wind power

Thermosolar + residual biomass hybridization

Regulated and flowing hydro

Hydro pumpingMini-hydro

100% renewable mix.

Aim: to make the most of demand management

In this scenario we seek to reduce even further thecost of electricity, in order to achieve the minimumpossible cost, studying the effect of managingpeaks by means of demand management withoutrelinquishing the use of renewable energy sourcesonly. To do se we have assumed a non-suppliedenergy cost (NSEC) of 500 c€/kWhe, such that atthose times when the of electricity generationexceeds this value (owing to the additional inves-tment required), recourse is had to demand mana-gement to avoid this consumption occurring at thattime (displacing it to times with surplus generationcapacity).

In the following graphs we see the main characteris-tics of this mix, the spread by technologies of insta-lled capacity (88,400 MW) and of energy generated,the spread throughout the year of non suppliedcapacity (substituted by demand management) andthe cost of electricity throughout the year.

Installed capacity by technology.

Electricity configuration and generation of a mix optimizedfor NSEC = 500 c€/kWhe. SM = 2.29; SF = 99.993%; LEC = 2.42c€/kWhe.

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4.2. EXAMPLES OF GENERATION MIX

4.2

Flatland Wind Power

Thermosolar

Regulated Water

Biomass at thermosolar power stations

Existing Water Pumping

New Water Pumping

Mini-hydro

Flowing Water

Annual hourly development of non-supplied capacity for amix optimized for CENS = 500 c€/kWhe. SM = 2,29; SF = 99,993%; LEC = 2,42 c€/kWhe.

Annual hourly development of the marginal electricity costfor a mix optimized for CENS = 500 c€/kWhe. SM = 2,29; SF = 99,993%; LEC = 2,42 c€/kWhe.

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4.2. EXAMPLES OF GENERATION MIX

4.2

Main characteristics of the mix.

Installed capacity 88,4 GWpAvailable energy 303,9 TWh/aSolar Multiple (SM) 2,29Meeting demand (SF) 99,993 %Annual electricity cost (LEC) with no hydro investment 2,42 c€/kWhMaximum electricity cost (CENS) 500 c€/kWhHours in the year in which the production of electricity is less than demand 7Solar-biomass hybridization YesMini-hydro operation According to costsFraction used of total mainland onshore wind power capacity ceiling 5,2 %Fraction used of total mainland thermosolar capacity ceiling 0,5 %Type of biomass used ResidualFraction used of mainland residual biomass generation ceiling 44 %Fraction used of total mainland biomass generation ceiling 21,1 %Land occupation 3 %

This example is very conservative, and only leaves0.007% of the total energy requirement ungenera-ted at the time required (consumption displace-ment), but in fact it would be economically morefavourable to act on demand instead of generatingelectricity in all those cases in which, being techni-cally possible, it is cheaper to manage demand forelectricity (saving it or displacing it to other timeswhen there is a surplus of generation capacity) thanto generate it. These would be the scenarios inwhich the cost of kWh managed would be less thanthat of kWh generated (in other words, for muchlower NSEC values).

In this scenario, using NSEC = 500, a particular sce-nario is shown, but now from NSEC = 8 c€/kWhe

practically 100 % SF is achieved, that is, the gene-ration system continues to cope with the vastmajority of demand even enabling demand mana-gement measures to come into play from low costlevels.

100% renewable mix.

Aim: to meet all energy demand

(not just electricity)

Finally, we are going to show an example of how itwould be possible using renewables to meet notjust all the electricity demand, but also all energydemands for mainland Spain in 2050.

Let us remember that for the whole study weassume a total final energy demand in 2050 of1,525 TWh/year, of which 280 TWh/year would beelectricity demand. Therefore, if besides the electri-city demand we were to meet, using electricity, therest of the energy demands, additional electricitydemand would be 1,525 - 280 = 1,245 TWh/year.To assess the amount of electricity that would haveto be generated to meet all these final demands,we assume that 60% of these other demandswould be spread over the demand for heat/cold inbuildings, industrial and other sectors and 40% inthe transport sector (this, in turn, spread 75% overvehicles using electricity and 25% using hydrogen),and we assume the following performances: 90%for electricity conversion into useful heat, 70%vehicles using electricity and 25% for vehiclesusing hydrogen. Therefore, to meet a final energydemand of 1,245 TWh/year, it would be necessaryto supply 1,862 TWh/year. This involves an additio-nal electricity demand of 1,862 TWh/year by 2050,to be added to the 280 TWh/year original electricitydemand, resulting in a total electricity demand of2,142 TWh/year.

We shall see next, in the case of this example, howthe 851 GW of installed capacity would be spreadby technology , the 2,390 GWh of electricity whichwould be generated (to meet the 2,142 TWh ofdemand), the potential development in relation tothe total available and the 14.9% of the countrythat would be occupied.

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4.2. EXAMPLES OF GENERATION MIX

4.2

Total capacity = 851 GWp

Thermosolar

Onshore wind power

PV azimuthal

PV on buildings

Offshore wind powerhydroelectric

Total biomass

Wave power

Mini-hydro (P<10 MW)Geothermal

Hydroelectric (P>10 MW)

Potential generation = 2.390 TW.h/a

Total biomassThermosolar

Onshore wind power

PV azimuthal

PV on buildings

Hydroelectric (P>10 MW)

Wave power

GeothermalMini-hydro (P<10 MW)Offshore wind power

hydroelectric

Percentage output and generation capacity distribution of the different technologies considered in mix with 851 GWp nominal installed capacity.

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Composition, generation capacity and land occupation of a mix with 851 GWp nominal installed capacity.

Capacity (GWp) Generation (TW.h/year) Capacity development (%) Land occupation (%)Hydroelectric (P >10 MW) 16,6 30,7 100 -Mini-hydro (P < 10 MW) 2,2 6,9 100 -Onshore wind power 137,3 342,8 15 8,50Offshore wind power 33,0 66,8 20 -PV on buildings 123,6 142,3 25 -PV azimuthal 106,3 207,3 15 1,32Total biomass 11,0 69,1 - 3,05

Residual biomass and biogas 8,25 50,9 100 -Energy crops 1,61 10,6 30 1,90Short rotation forestry crops 1,16 7,6 20 1,15Scrubland 0,0 0,0 0 0,00

Thermosolar 410,8 1.484,6 15 1,99Wave power 8,4 29,6 10 -Geothermal 1,49 9,8 50 0,00Total renewables 850,7 2.389,7 - 14,9

4.2. EXAMPLES OF GENERATION MIX

4.2

We shall also see how electricity generationwould vary in comparison to original electricitydemand.

Annual hourly generation capacity development togetherwith that of mainland demand, for a mix with 851 GWpnominal installed capacity.

We see that, compared with an original annual elec-tricity demand of 280 TWh, a total of 2,390 TWhwould be available. The small capacity deficitthroughout the year amounts to 0.1 TWh, whichcould be entirely met by demand management, orby energy storage systems or by the 110 TWh avai-lable at power stations which could regulate itsgeneration. Once all the original electricity demandis met, 2,048 TWh is surplus enabling this mix tomeet effortlessly the 1,862 TWh additional electri-city demand. Even at the most critical moment inthe year there would be sufficient reserves to meetthe demand, as we can see from the graph:

Contribution of the different technologies of a mix with 851GWp meeting demand at t = 7.584 h (12th November at 0hrs), the maximum capacity shortfall.

However, this example has not been optimized asthe previous ones that we have seen, but this doesnot mean that all this renewable capacity is requi-red to meet overall demand, but that it shows oneof the possible ways of doing it. Neither does itmean that the best way of meeting total demand isby generating electricity in every case, but that100% renewable electricity generation can beachieved.

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Demand Available

Eshortfall

Eregulation

Edissipation

Eavailable

Time (h)

Regular contributions a t = 7.584 h(12th November at 0 h)Demand = 34,6 GWTotal regular capacity = 23,5 GWShortfall = 11,1 GWStandby reserve without thermosolar = 20,7 GWStandby reserve with thermosolar = 431,5 GW

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4.2. EXAMPLES OF GENERATION MIX

4.2

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4.3. Meeting demand: conclusions

As we have seen, multiple combinations of rene-wable generation system can be implemented tocompletely meet electricity demand throughout theyear, and even total energy demand, taking intoaccount that:

■ An important feature of the renewable genera-tion mix is technological diversity, thanks towhich available energy resources become veryregular over time. Albeit there exists sufficientrenewable potential to easily bring together a mixwhich meets demand, even at those criticalmoments (heating peaks), by employing a fewtechnologies, by providing greater technologi-

cal diversity to the generation mix enables us

to reduce the total capacity to be installed

and increase supply security. These aims arealso achievable by using the regulation capabilityof technologies such as hydroelectricity, biomassand geothermal.

■ Besides, everything possible would have to bedone to boost the takeoff of thermosolar tech-

nology, because of its unique advantages: highpotential, capacity availability for demand peaks(in hybridization with biomass), daily energy stora-ge capacity, the generation of economic activity inSpain, Spanish industrial leadership, use in keyregions of the world and the contribution to sus-tainable development.

■ Due to the fact that a mix which meets 100% ofelectricity demand and guarantees security ofsupply using renewable energies involves theneed to dissipate a large amount of energy, itwould be advisable to integrate the total

energy system to meet all or part of the rest of

energy demands, via the surplus electricity

from the renewable electricity system.

4.3 MEETING DEMAND: CONCLUSIONS

4.3

The report put forward different “paradigm chan-ges” needed to break some barriers currently pre-venting us even from contemplating a completelyrenewable system:

■ Renewable technologies as the main element

of the electricity system

· For renewable technologies to go from beingperipheral to the electricity system to being con-sidered as the main elements, they will have togo from being operated “in maximum capacitymode” (provided the power station is available, ithas to pump the electricity it generates into thegrid) to doing so in “regulatory mode” (thepower stations must operate as electricitydemand requires it).

■ The role to be played by electricity and

demand management

· To avoid dissipating a large amount of renewa-ble generation capacity, this energy could beused for other energy demands, such as lowtemperature heat demands or for vehicles. Thiswould provide a huge “distributed storagecapacity” (stored heat in buildings, hot watertanks and heating, vehicle batteries...), veryuseful for demand management. In this waythe conversion to sustainability in the buildingand transport sectors could be accelerated,together with the use of other renewable non-electric options.

· Demand management should seek to displaceconsumption to central times in the day (theopposite to the current situation), which is whenthere is most generation in solar power stations.

· An integrated renewable system would enableus, by using renewables, to meet, in addition toelectricity demand, a large part (even 100%) ofthe energy demand of the building and transportsectors, more economically than by dealing withthe two things separately (by utilizing somerenewable technologies solely for electricitygeneration and other renewable technologiessoley for non-electricity demands). This couldlead the way to achieving the channelling ofthese other sectors towards sustainability in theshort time available, albeit this would not be theonly way of doing it and, of course, during thetransitional stage other non-electrical renewableoptions would have to be relied upon to meetthe demand of these sectors.

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PARADIGM CHANGES NEEDED FOR IMPLEMENTING FOR ARENEWABLE SYSTEM

5

Having seen that it is possible to completely meetdemand by means of renewable energies, and thatthere are multiple combinations to achieve it, wepresent below the main results and conclusionsfor each of the stages of the study aimed at res-ponding to the issues of how much renewablecapacity would be required and what would be theoperating mode of generators, in order to meetdemand with renewables at minimum cost. Firstly,we present the conclusions relating to capacityneeded to be installed: analysis of the solar multi-ple and an analysis of the storage capacity. Finally,we present conclusions relating, in addition to acombination of technologies to be installed, to theway of operating the generator park to obtain mini-mum cost: grid analysis and non-supplied energycost analysis.

Need for installed capacity (analysis of a solar multiple)

We can adjust the capacity needed to be installedto completely meet demand with renewables, bea-ring in mind that:

■ Geographical spread and technological diversity inthe mainland system allows greater coverage tobe achieved with renewables (SF) and a lowercosts (LEC3) for each level of installed capacity(SM) in relation to what is achieved in a singlefamily stand-alone system, such that what in themainland system is achieved with a generatorpark of SM = 2, requires a stand-alone system toemploy SM > 30.

■ As installed renewable capacity increases, thatpart of demand not covered by renewables beco-mes more critical in terms of capacity than ofenergy, that is, the problem is not in having suffi-cient energy but rather being able to supply it atthe very moment when demand is high. The mostsuitable solution would be to cover these deficitswith good demand management, or in its absen-ce to use power stations which can regulate theirgeneration, such as thermosolar installations withbiomass or hydroelectric and geothermal powerstations, or with small storage capacity.

■ In a system with a high percentage of renewa-bles, the most suitable use of biomass would

be in the hybridization of thermosolar power

stations.

■ From SM = 2,5 capacity which will not be usedthroughout the year is of the order of requiredelectricity capacity, which would force a hugequantity of energy not to be used. This assumesthat, at these SM values, the cost of electricitysupplied is greater than what it would be if, usingthe same generation mix, the surplus electricitywere used, and this difference grows as the SMincreases. Therefore, mixes with an SM above

2.5 would be more suitable within a frame-

work of integrated energy systems, in which

the huge surplus generation capacity in rela-

tion to electricity demand can be set aside to

meet other energy demands.

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HOW MANY RENEWABLE STATIONS WOULD BE NEEDED AND HOWSHOULD THEY BE USED, AT MINIMUM COST?

[3] LEC: Levelized cost of electricity (see document entitled 100%RENEWABLES: COST COMPARISON)

6

■ We can see the cost of regulating by using a

specific generator park to meet demand as thedifference between the electricity cost in that mixand the minimum that would obtain if all the elec-tricity generated were used. For example, the costdifference is just 0,53 c€/kWh in a SM = 2 mix ,but it rises to 29.13 c€/kWh in a SM = 15 mix.

Analysis of storage capacity

Very little energy storage capacity is required, oreven none at all, for managing the system properly,bearing in mind that:

■ For storage capacity to be able to meet the entiredemand, the total generation system performan-ce must allow there to be more surplus energyavailable (dissipation) than what is required (defi-cit) in total over the year. The greater the balan-

ce throughout the year between dissipation

and deficit, the less storage will be needed.

■ From SM = 2,5, it is less cost effective to meet

demand using storage capacity than conti-

nuing to increase installed capacity. But it willbe even cheaper to use the available capacity atthe thermosolar plants in hybridization with bio-mass, and cheaper still to manage the few deficitpeaks using demand management.

■ To meet 100% of demand with an SM mix above2.5 the low storage capacities required are

available with proper management of hydroe-

lectric resources and existing pumping.

■ The optimum economic value of storage capa-

city (0.15 TWh) corresponds to a 4 hour range

compared to average electricity demand.

Analysis of the electricity generatingsystem

Analysis of the optimum combination of genera-tion technologies to be installed and which of themis advisable to use at any particular time to meetdemand, allows electricity generation cost to beoptimized in a completely renewable system ,taking into account that:

■ The mixes obtained by including life cycle cost

(as a result of optimizing the of the problem ofmatching which power stations to install andwhich to operate) have considerable technologi-

cal diversity, not being dominated by any sin-

gle technology.

■ Hydroelectric pumping is used with much gre-ater capacity factors to those currently emplo-yed, albeit it does not require huge installedcapacity.

■ Proper development planning of the renewablegeneration mix can point in quite a different direc-tion to the one the current market situation wouldtake us in. Lack of this planning would lead us tomaking far from optimum investments, and conse-quently higher life cycle electricity costs, thisbeing conditioned by the investments made. The-refore, to achieve an economically optimum

100% renewable mix, proper planning is requi-

red, otherwise the most economical renewablesat the time will be fully developed and dirty energywill not be completely displaced.

25

■ Optimized mixes make extensive use of hybridi-

zation with biomass at thermosolar power sta-

tions, which then have continuously availablegeneration, playing the same role that conventio-nal thermoelectric stations do.

■ The marginal electricity cost, for optimizedmixes using solar-biomass hybridization, is keptpegged for practically the whole year below 2.4

c€/kWhe. There is only around one hour per yearin which the marginal cost shoots up to much hig-her values.

■ When dealing with a generation mix employing amajor contribution from renewable technologies,the existing limitations of conventional tools forgrid analysis have been shown. Major technical

and scientific development is required to

adapt the analytical tools to the new situa-

tion, which should be tackled as a matter of hig-hest priority.

■ The ability to manage a 100% renewable gene-

ration mix properly, even using the current

transmission grid, does not seem to represent

a significant technological barrier. Qualitatively,the results obtained in relation to generation capa-city management, available potential and its homo-geneous spread across the peninsula, lead us tobelieve that a 100% renewable system could beoperated, although it would probably require majoradjustments both to the grid and to the currentoperating scheme. The electricity transmission gridis a means not an end, and it should be adapted tothe requirements of a renewable generationsystem.

Analysis of cost of non supplied energy(CNSE)

We can further improve electricity generation costsin a renewable system thanks to demand manage-ment, taking into account that:

■ From the economic standpoint, the most appro-

priate solution would be the combination of a

renewable mix optimized for a reasonable

amount of the cost of non-supplied electricity

(NSEC), plus suitable demand management4.

■ So as not to oversize a technology irreversibly, itmust be taken into account that the structure of

the optimum generation mix varies signifi-

cantly according to the NSEC.

■ By increasing the value of the NSEC does not

have to increase the installed capacity and

land occupation, since for mixes with high solarfraction values, thermosolar technology substitu-tes wind power, reducing the need for installedcapacity.

■ A huge hydroelectric pumping capacity is not

required to meet the decouplings between

generation capacity and demand (a maximumof 2.69 GW pumping, with NSEC = 8 c€/kWhe,would suffice, compared to 15 GW which couldbe installed with existing reservoir capacity).

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[4] For example, an optimized mix for NSEC = 5 c€/kWhe has a LEC =2,24 c€/kWhe (and in the absence of demand management would provideSF = 92%), while the optimized mix to meet demand completely (SF =100 %) has a LEC = 2,48 c /kWhe (although there is one hour per year inwhich it would reach a marginal maximum cost of 9,.883 c€/kWhe).

■ The optimization resulting from the calculationsundertaken is relative, since it is based on techno-logical and cost projections, and over such a longterm period reality could be very different. Besides,the specific results in respect of determining “opti-mum” mixes would be different depending on thedegree of utilization of demand management.What is important is that it has been shown thattools can be developed for analyzing and opti-

mizing mainland electricity generation mixes

based on renewables and on very favourable

associated cost (below 2.5 c€/kWhe).

■ Hybridization with biomass of thermosolar

power stations provides appreciable supply

security and reduces the generation system

cost. However, given the relative scarcity of bio-mass in our country, we must be careful not to useit more intensively than is advisable.

■ Although the 'optimum' mixes do not requiremore than a few technologies, it is advisable to

employ greater technological diversity, even

though this involves greater costs, to achievebetter spatial spread of generation capacity and toobtain an improvement on hypothetical transmis-sion congestion. For example, it would be desira-ble to have sufficient capacity close to the areasof greatest demand.

■ Demand management would be the most

economical and suitable way of meeting the

rare peaks in capacity arising throughout the

year. However, what matters is the relationshipbetween demand and generation capacity at anygiven time, demand management schemescould be very different to those employedcurrently, since in a renewable mix it could bemore appropriate to displace demand to centralhours of the day, despte this being when theabsolute demand peak occurs, given that solargeneration capacity could make these times into“valleys” in relative terms.

FINAL CONCLUSION

After the detailed analysis of mainland electricitygeneration systems based on renewables, fromthe point of view of temporal generation-demandcoupling, costs and investment and use optimiza-tion, it is concluded that:

■ Consideration of a generation system based

100% on renewable energies is feasible, bothfor meeting electricity demand and for totalenergy demand.

■ The total costs of the electricity generated are

perfectly adoptable and very favourable in rela-tion to a tendentious scenario.

■ There are sufficient tools to guarantee

demand is met over the complete useful life ofthe generation system.

7

27

GREENPEACE PROPOSALS

To prevent dangerous climate change an energyrevolution is required to change the way in whichwe generate and use energy. This report shows thatSpain can reach a 100% renewable horizon for herelectricity generation, and it is even possible to con-sider such an ambitious target for meeting all herenergy needs. “100% Renewables” is economi-cally and technically feasible, and provides the onlyserious option for changing the energy model withone which enables humanity to survive climatechange without causing or aggravating otherserious environmental and social problems. Spaincan and must assume leadership of this energyrevolution. What is needed is the political will to doit. The least we can demand of a responsible Stateis that it analyses seriously and in detail the 100%renewable option and includes it in its energy plan-ning targets. For this reason, Greenpeace asks theSpanish Government:

■ To set mid and long term binding energy plan-

ning targets, specifically the following ones:

· Energy efficiency: a 20% reduction in primaryenergy demand on current levels by 2020.

· A 30% contribution of renewables to primaryenergy by 2020, rising to 80% by 2050.

· A 50% contribution of renewables to electri-

city generation by 2020 rising to 100% by2050.

· An 80% contribution of renewables to buildingconditioning by 2050.

■ Adopt CO2 emission reduction targets to contri-bute to a 30% emission reduction in the EU on1990 levels by 2020 and 80% by 2050.

■ To strengthen the premium system, by a Rene-

wable Energies Law, to ensure compliance withtargets and definite and stable returns on inves-tment, which must be more attractive than inves-tment in dirty energy.

■ Bring to an end market distortions which harmrenewable energies. Put an end to all the subsi-dies, direct and indirect on fossil fuels and nuclearenergy, to internalize all external social and envi-ronmental costs, ensuring that final energy pricesreflect all costs according to the source of energyused. To contaminate must be made costly.

■ To reform the electricity market, removingbarriers to renewables by:

· Administrative processes and simplified, coordi-nated and standard authorizations for the wholecountry for renewable projects.

· Priority access to the grid guaranteeing renewa-ble generators, removing any access tariff dis-crimination.

· Grid modification and extension costs spreadacross all consumers.

· Complete separation of activities betweengeneration and distribution companies, not per-mitting them to belong to a single companygroup.

8

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· The right of all consumers to choose the energysource they use, establishing an official electri-city labelling system and a guarantee of originfor all electricity, which ensures that all electri-city marketing companies are required to stateon their bills, in a standard format, the energysource employed and the environmental impact.

■ To adapt electricity and gas pipeline grid design,

as well as the tools and regulations for theirmanagement, to facilitate the implementation of a100% renewable system.

■ To use demand management to achieve a 100%renewable system at the lowest possible cost.

■ To put a stop to squandering energy, imposingcompulsory efficiency levels for energy con-sumption on all electrical household appliances,buildings and vehicles.

■ To continue research initiated by Greenpeace toanalyze the technical feasibility of a 100% rene-wable electricity system, providing the economyresource needed to develop tools to enable theanalysis to be undertaken.

29

Greenpeace commissioned a team from the Technology Research Institute of thePontifical University of Comillas, headed by Dr. Xavier García Casals, to conduct atechnical study whose aim was to determine whether renewables are sufficient tomeet society's energy demand. This is a key issue for knowing whether we needto develop other energy sources to make good the putative limitations of renewa-bles, or on the contrary to verify that it is possible to avoid dangerous climate chan-ge by a complete substitution of fossil fuels by renewable energies.

In November 2005, the findings of the first part of the project were submitted enti-tled “Renewables 2050. A report on the potential of renewable energies in

mainland Spain” in which it was concluded that electricity generation capacityfrom renewable sources was equivalent to more than 56 times the electricitydemand of mainland Spain projected for 2050, and more than 10 times total finalenergy demand. It was thus demonstrated that by using renewables it is possibleto have energy in more than sufficient quantities, but it failed to show whether itwould be economically and technically feasible to operate the electricity systemsolely from renewables to satisfy projected demand.

In 2007 the report “100% RENEWABLES. A renewable electricity system for

mainland Spain and its economic feasibility” offers the results of the secondstage of the study, in which the feasibility of a scenario based on renewable ener-gies for electricity generation on the mainland are quantified and assessed from atechnical standpoint. The analyses show technical and economic feasibility of

a system based 100 % on renewables.

ENERGY REVOLUTION PROJECT