Summary Dena Grid Study II

7/28/2019 Summary Dena Grid Study II

1/26

dena Grid Study II Integration of Renewable Energy Sources

in the German Power Supply System from 2015 2020

with an Outlook to 2025

Summary of the main results by the project steering group

Amprion GmbH, BARD Engineering GmbH, Federal Ministry for the Environment, Natu-

re conservation and Nuclear Safety (BMU), Federal Ministry of Economics and Technology

(BMWi), Bundesverband der Energie- und Wasserwirtschaft e.V. (BDEW), EnBW Trans-

portnetze AG, E.ON Netz GmbH, EWE Netz GmbH, Siemens AG, Stiftung Offshore

Windenergie/Offshore Forum Windenergie GbR, TenneT TSO GmbH, Forum Netztech-

nik/Netzbetrieb im VDE (FNN), Bundesverband WindEnergie e.V. (BWE), Verband Deut-

scher Maschinen- und Anlagenbauer e.V. Fachverband Power Systems (VDMA Power Sys-

tems), VGB PowerTech e.V., Zentralverband Elektrotechnik- und Elektronikindustrie e.V.

(ZVEI), 50Hertz Transmission GmbH


2/26

dena Grid Study II Summary of the main results by the project steering group.

Page 2 of 26

1 Background

The key decisions on the future energy policy for fundamental restructuring of the power supply systems

in Germany and Europe have been made. The challenge which faces us is to implement a successful cli-

mate protection strategy with a guaranteed and economical supply as part of deregulated energy markets

in Europe. The energy policy goals for a faster expansion of renewable energy in the German power sup-

ply, in particular the continued expansion of wind energy, are closely related to this.

These objectives can only be reached by optimising the integration of renewable electricity generation

with the conventional power plants in the context of international power trading within Europe. The inte-gration of fluctuating electricity generation from wind energy as well as photovoltaics makes additional

demands on the design and operation of the electricity transmission grids, and requires adjustments in

other power generation systems as well as increased flexibility of the overall system.

As early as spring 2005, the study Energiewirtschaftliche Planung fr die Netzintegration von Windener-

gie in Deutschland (Planning of the Grid Integration of Wind Energy in Germany Onshore and Offshore

up to the Year 2020, dena Grid study I), written by a consortium of experts commissioned by a wide range

of interested parties under the direction of the Germany Energy Agency (dena GmbH), was published. The

dena Grid Study I investigated the extension needed in electricity transmission grids to reach the target of

generating 20% of all energy from renewable sources by 2015. As a result, power line-specific grid en-

hancement measures and an extension requirement of 850 km of new routes by 2015 in the German

transmission grid were established. The routes required in accordance with the dena Grid Study I were

incorporated in the Power Grid Expansion Act (EnLAG 2009) as priority projects.

In conjunction with the continuation of the European climate protection goals, the German government

decided in 2007 to increase the proportion of renewable energy in the power supply by 2020 to 25% 30%.

The September 2010 German Government Energy Concept confirms the objective of continuing to in-

crease the percentage of renewable energy in all areas of power supply significantly, and sets a target

margin of 35% by 2020 for the percentage of renewable energy in the supply of electricity.

2 dena Grid Study II: framework and objectives

The objective of the dena Grid Study II is to investigate suitable system solutions for the German power

supply system (up to 2020 with an outlook to 2025), to fully integrate 39% renewable energy in the power

supply into the German power grid while guaranteeing the security of supply and taking the effects of the

liberalised European energy market into account.

The dena Grid Study II assumes that the grid enhancement and expansion measures determined in the

dena Grid Study I have been implemented1.

1 Of the grid expansion measures totalling 850 km determined in the dena Grid Study I, approximately 90 km had been implemented

by the completion of the dena Grid Study II.


3/26


Page 3 of 26

A viewpoint which focuses on the relatively distant future, and which is very broad and system oriented

was chosen to strategically prepare for energy policy and energy economy decisions with a medium to

long-term reach, and to appropriately classify innovative technical solutions. The dena Grid Study II goes

far above and beyond merely establishing grid extension requirements. Both demand-side measures for

shifting loads and new storage technologies suitable for optimising the overall system were investigated.

The dena Grid Study II is divided into three main sections which are closely linked to one another:

Generation of time series for electricity feeding from wind energy and photovoltaics

Requirements and options for the extension of the transmission grids (380 kV extra high voltage level)

Complete integration of electricity generation from wind energy and other renewable energy

sources taking the increase in flexibility on the supply and demand sides in the electricity system into

account

The dena Grid Study II was drawn up and financed intersectorally with substantial involvement of the

German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (Bundesministe-

rium fr Umwelt, Reaktorsicherheit und Naturschutz, BMU) and the Federal Ministry of Economics and

Technology (Bundesministerium fr Wirtschaft und Technologie, BMWi)2. Representatives of the Federal

Network Agency (BNetzA) and representatives of the Federal States3 nominated by the conference of Min-

isters for Economics also took part in the meetings of the project steering group.

The study was drawn up by a consortium of authors under the direction of the Institute of Energy Econom-

ics (Energiewirtschaftliches Institut, ewi) at the University of Cologne in collaboration with the German

Wind Energy Institute (Deutsches Windenergie-Institut GmbH, DEWI), Fraunhofer Institute for Wind

Energy and Energy System Technology (Fraunhofer Institut fr Windenergie und Energiesystemtechnik,

IWES), 50Hertz Transmission GmbH, Amprion GmbH, EnBW Transportnetze AG and TenneT TSO GmbH.

Prof. Ulrich Wagner (German Aerospace Centre [Deutsches Institut fr Luft - und Raumfahrttechnik, DLR])

and Prof. Armin Schnettler (High Voltage Technology Institute [Institut fr Hochspannungstechnik] at

RWTH Aachen) were appointed as expert external auditors by the project steering group.

dena initiated the entire study project, directed the project steering group, and was responsible for project

management.

2The following voting members were represented in the project steering group as sponsors of the dena Grid Study II:

Amprion GmbH, BARD Engineering GmbH, Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU),

Federal Ministry of Economics and Technology (BMWi), Bundesverband der Energie- und Wasserwirt schaft e.V. (BDEW), Bundesver-

band WindEnergie e.V. (BWE), EnBW Transportnetz AG, E.ON Netz GmbH, EWE Netz GmbH, Siemens AG, Stiftung Offshore

Windenergie/Offshore Forum Windenergie GbR, TenneT TSO GmbH, Forum Netztechnik/Netzbetrieb im VDE (FNN), Verband

Deutscher Maschinen- und Anlagenbauer e.V. Fachverband Power Systems (VDMA Power Systems), VGB PowerTech e.V., Zentralver-

band Elektrotechnik- und Elektronikindustrie e.V. (ZVEI), 50Hertz Transmission GmbH3 The representatives of the Federal States have taken part in the meetings of the project steering group since October 2009.
http://dict.leo.org/ende?lp=ende&p=Ci4HO3kMAA&search=intersectoral&trestr=0x8004http://dict.leo.org/ende?lp=ende&p=Ci4HO3kMAA&search=intersectoral&trestr=0x8004


4/26


Page 4 of 26

The dena Grid Study II was accompanied by a continuous dialogue of the project steering group with the

consortium of authors to develop a solution borne by all parties involved.

Using in-depth scientific methods, the dena Grid Study II investigates the following areas:

Review of the scenarios of the dena Grid Study I for the expansion of on and offshore wind energy, and

for the expansion development of other renewable energy sources

Development of expansion scenarios for electricity generation from renewable energy sources until

2020 (with an outlook to 2025)

Modelling of the development of the power plant fleet until 2020

Methods of transporting the wind energy output from the North and Baltic Seas to the load centres

Continued development of the connection design for offshore wind farms

Identification of non-transmittable capacity, determination of the necessary extension of the trans-

mission grids and comparison of available technical alternatives for grid extension

Testing the potential of flexible line management (FLM) and high temperature conductors (TAL) to

increase and optimise the transmission capacity of existing overhead lines in the extra high voltage

grid

Investigation of options for increasing flexibility in the integration of renewable energy sources such

as use of storage facilities or the potential of demand-side management

Analysis of the requirements for renewable energy generation plants regarding security of supply

e.g. islanding and black start capabilities


5/26


Page 5 of 26

System Security in theTransmission Grid

100% Integration of

Renewable Energy

European

Electricity MarketMarket-Driven Operation

of Power Plants

39 % RenewableEnergy Sources

until 2020

Alternative Solutionsand Grid Extension

Requirements

Environmental Impact

Public Acceptance

Availability &

Economic Efficiency

Power Storage

Demand Side

Management

Increasing Flexibility

Voltage Support &

Short-Circuit Power

System Services

Islanding &

System Restoration

Flexible Line

Management

High Temperature

Conductors

Innovative

Transmission Technologies

Figure 1: dena Grid Study II schematic of subject area

For processing the tasks above, the following central assumptions were made for 2020 in the study:

Planned grid 2015 incl. grid enhancement and grid extension measures per dena Grid Study I andtaking the Power Grid Expansion Act (EnLAG) 2009 into account

Phase-out of nuclear energy (per Nuclear Energy Phase-Out Act [Atomausstiegsgesetz 2000])4

Complete integration of renewable energy sources in accordance with the Renewable Energy Sources

Act (Erneuerbare-Energien-Gesetz, EEG 2009)

25% combined heat and power generation in electricity generation by 2020

4 See section 10.


6/26


Page 6 of 26

Market-driven use of power plant and storage facilities (in conjunction with cost-optimised opera-

tion) and development of the fleet of power plants and storage facilities in the model calculation used

according to purely economic aspects

Limitation of the European electricity market solely via the capacity of the cross border transmission

lines

Also, the dena Grid Study II makes assumptions, which appear as follows compared with the objectives of

the Energy Concept dated 28/09/2010:

Development ofthe electricitydemand

Percentage of RES ingross electricity con-sumption

NPP capacities

Assumptions of denaGrid Study II

by 2020: -8% 2020:39% 2020: 6.7 GW

Objectives of EnergyConcept 2010

by 2020: -10%by 2050: -25%

2020: 35%2030: 50%2050: 80%

2020: 17.4 20.4 GW2030: 9.0 12.1 GW2040: 0 GW2

Table 1: Comparison of key assumptions of dena Grid Study II and the Energy Concept 2010

3 Electricity feed-in from renewable energy sources for 2020

The review of the scenarios of the dena Grid Study I for 2007 overall revealed that they largely correspond

to the actual developments in onshore wind energy use, whereby there are some regional deviations. In

accordance with the current developments and forecasts, modified expansion scenarios for wind energy

use in 2015 and 2020 were drawn up for the dena Grid Study II, and a well-founded outlook to 2025 was

developed. For 2020, 37 GW of installed capacity onshore and 14 GW of installed capacity offshore are as-

sumed. It is assumed that the majority of the offshore wind power capacity, 12 GW, will be built in the

North Sea.

The scenario modified for the dena Grid Study II differs from that assumed for dena Grid Study I by includ-

ing 30% more onshore wind energy and a five year delay in the expansion of offshore wind energy. The

5 RES: renewable energy sources6 NPP: nuclear power plant

7dena Grid Study II is based on the nuclear power phase-out deadline legally valid at the time.

8Values per studyEnergieszenarien fr ein Energiekonzept der Bundesregierung (Energy Scenarios for an Energy Concept of the Ger-

man Federal Government). Scenarios: II A and II B (12 year phase -out delay, various retrofitting costs for nuclear po wer plants.)


7/26


Page 7 of 26

installed capacity from other renewable energy sources is twice that in dena Grid Study I at approx. 25 GW

by 2020.

In the dena Grid Study II, the future electricity generation from renewable energy, in conjunction with the

assumption of the generation capacity stated in the following table is forecast for 2020.

Renewable energygeneration systems

Installed capacities

2015 2020

Onshore wind energy 34,100 MW 37,000 MW

Offshore wind energy 7,000 MW 14,000 MW

Biomass 5,300 MW 6,200 MW

Photovoltaics9 13,000 MW 17,900 MW

Geothermal energy 100 MW 280 MW

Table 2: Installed renewable energy generation capacities in 2015 and 2020 a ccording to the dena Grid Study II

As part of the study, detailed quarter-hourly time series of the wind feed-in were developed. For this pur-pose, historic weather model data was supplemented with real measured wind speeds and used in accor-

dance with the wind power capacity installed for 2020. The calculation of the electricity feed-in from wind

energy use takes all important influences into account: the expected future power curves of wind tur-

bines, shading effects, electric losses and failure rates. Among other things, the results confirm the expec-

tation that high annual full-capacity hours are to be expected for offshore wind turbines. For 2020, 4,200

full-load hours per annum are expected for offshore wind turbines. For onshore wind turbines, full-load

hours amounting to 2,200 per annum are forecast for 2020. The further expansion of wind energy in Ger-

many will reduce relative regional fluctuations and a higher availability of the Germany-wide electricity

feed-in from wind energy will be reached.

Detailed feed time series at 15 minute intervals and in detail for each Federal State were also developed

and used for photovoltaics on the basis of weather model data. Feed data was assumed for other renewable

energy sources, e.g. a constant feed for hydroelectric power and biomass.

9 The expansion forecast of installed generation capacities from photovoltaics assumed in dena Grid Study II is based on the BM U

guideline scenario for 2008. In light of the rapid development of expansion of photovoltaic systems, this system capacity will already

have been reached by 2011. Current estimates assume a possible expansion of photovoltaic capacity to approx. 50,000 MW by 2020.


8/26


Page 8 of 26

4 Modelling the power plant fleet

In conjunction with the model-based analysis of the electricity market as part of the investigation in the

dena Grid Study II, existing electricity market models for calculating the power plant fleet and use thereof

were refined to take the economic demand-side management potential, the additional storage capacity

requirement and contributions of wind turbines to the balancing energy market into account.

Based on the energy economy input data agreed in the project steering group (e.g. assumptions on the

development of primary energy prices, prices of power plant capacities, etc.), the existing power plants

and the power plants under construction in 2008, the conventional capacity installed in 2020 was dete r-mined when modelling the power plant fleet.

The resulting installed generation capacity in Germany in 2020, taking the assumptions on the expansion

of power generation from renewable energy in conjunction with the modelling of the power plant fleet

into account, is shown in the following figure.

Figure 2: Development of the power plant fleet in Germany in accordance with dena Grid Study II10

5 Technical grid integration of offshore wind energy

The economic and technical analysis of the available technologies for grid connection of offshore wind

farms reveals that the connection of the planned offshore wind farms in the North Sea is best implemented

10The appendix provides details of the installed capacities of the power plants as a table.

Installed Capacity

0,0

20,0

40,0

60,0

80,0

100,0

120,0

140,0

160,0

180,0

Installed Capacity 2005 Installed Capacity 2020

GW

Storage

Natural GasHard CoalLigniteNuclearOther (incl. waste)BiomassPhotovoltaics

ind Offshoreind Onshore

Hydroelectric Power


9/26


Page 9 of 26

via self-commutated VSC-HVDC technology and via cluster connections. Cluster connections reduce the

grid connection costs and also minimise the environmental interventions.

For offshore wind farms on the Baltic Sea with lower capacity and closer to the shore, individual connec-

tions based on AC cables may be the most suitable solution.

Multi-terminal solutions allow multiple converters to be connected to a direct current circuit, thus creat-

ing more than two connections to an AC grid.

In conjunction with multi-terminal solutions for connecting multiple HDVC lines, the following options

are also conceivable:

Continuation of the grid connection on land to the load centres, possibly with connection of addi-

tional generation capacity

Establishment of cross-border lines between Germany and Northern European countries, with simul-

taneous grid connection of offshore wind farms. On the Baltic Sea, offshore wind farm connections as

expansions of the interconnectors towards Denmark and Scandinavia are conceivable. On the North

Sea, the option of building a North Sea grid in the years to come is currently being investigated for the

countries with North Sea coasts.

Use of synergies in the grid connection of distributed offshore wind farm clusters via linking and

grouping the HDVC grid connections up to the formation of an offshore grid

For the versions investigated in the dena Grid Study II, undersea cables with a total length of 1,550 km will

be required to connect the offshore wind farms until 2020, which will incur annual costs of EUR 340 mil-

lion.11

6 Electricity transmission grids: dependency of the transmission capacity of the operat-

ing equipment on ambient temperatures and technologies

The dena Grid Study II takes technical options for increasing the transmission capacity of overhead line

technologies into account, both via the use of flexible line management (FLM) and the use of high-

temperature conductors (TAL). For the central investigations on integration of the feed into the extra high

voltage grid in 2020 based on the assumed generation scenario, FLM and TAL scenarios were calculated in

the dena Grid Study II.

The current-carrying capacity of overhead lines is restricted by their conductor temperature and the asso-

ciated sagging. As the standard weather conditions assumed for the design (35 C ambient temperature,

0.6 m/s wind speed) is only reached seldom during the year, there are significant capacity reserves at times.

11

The economic evaluation includes the costs for grid connection (investment costs) where applicable the costs for reactive powercompensation, operating and grid loss costs. The costs specified are annuities. The investment costs are converted to years b ased on

the typical use periods specified in the Electricity Grid Tariff Act (StromNEV).


10/26


Page 10 of 26

In FLM, the operating temperature of the conductors is monitored to allow the conductors to be loaded to

a higher degree in corresponding weather conditions (e.g. in strong winds or at low outdoor tempera-

tures). In particular in periods of high wind power feed-in, i.e. when there is high transmission demand,

FLM can increase the current-carrying capacity of overhead lines near coasts by up to 50%, by approx. 30%

in Northern Germany and approx. 15% in Southern Germany. At a medium wind power feed, this potential

drops by 10% respectively throughout Germany. The incorporation of the effects of FLM in grid planning is

not yet state-of-the-art, neither in Germany (initial pilot tests) nor internationally. In grid operation plan-

ning and in grid operation, a highly simplified FLM in the shape of seasonally-dependent current-carrying

capacities is already used in individual cases throughout Europe. To date, online weather data is only usedin individual cases in grid operation in Germany and in Europe.

Conductors made of high-temperature resistant aluminium (TAL) are designed for operating tempera-

tures of 150 C and over, which means that load capacities 50% higher than the standard conductors cur-

rently used with a limit operating temperature of 80 C are possible. These conductors are known as high

temperature conductors and are state-of-the-art, although the corresponding standardisation is still lack-

ing. Further studies are required to test whether the increased current-carrying capacity taking all frame-

work conditions into account can be fully used, as the increase of the permitted current alone cannot be

equated with an increase in the transmission capacity.

As neither the comprehensive use of FLM or TAL is considered economically viable, it is expected thatlarge-scale combinations of these two options will not lead to better values than the basic scenario. How-

ever, it is possible in individual cases that combining FLM and TAL can contribute to covering the addi-

tional wind-based transmission demand when planning specific lines taking the meteorological condi-

tions and the current state-of-the-art into consideration.

7 Effects on the transmission grid: non-transmittable power and grid extension re-

quirements

A central objective of the dena Grid Study II is to determine the need for adaptation in the German trans-

mission grid as a result of the expected development for the expansion of renewable energies (in particu-

lar wind power use) between 2015 and 2020 (with an outlook to 2025), in conjunction with the require-

ments of European power trade and a market-driven optimal operation of the conventional power plant

fleet. For this purpose, strategic integration solutions will be developed to guarantee the current high level

of security of supply in Germany in the future, in compliance with the European and national regulations.

For investigations into the effects on the transmission grid, a simplified power flow calculation using the

PTDF methodology was applied in the dena Grid Study II. The process via PTDF (Power Transfer Distribu-

tion Factors) has the objective of determining power flows quasi analytically rather than iteratively. The

PTD factor represents the ratio between the respective actually occurring electricity or power flow and the

energy flow of the power exchange between two nodes A and B within the transmission system.


11/26


Page 11 of 26

With the forecast load situation for 2020 and on the basis of the transmission grid assumed to be imple-

mented in Germany by 2015, the generation scenario used as a basis for dena Grid Study II (including de-

mand side management) shows that there is significant non-transmittable power at 70% of all borders be-

tween neighbouring regions. In some cases, this reaches totals of 2 GW to 4 GW.

Based on the generation data and typical load cur ves determined, a market simulation was drawn up and

linked with the power flow calculation in accordance with the PTDF process. For the power flow calcula-

tion in the dena Grid Study II, a regional model was used for the German transmission grid, which divides

Germany into 18 regions. For this, the feed-in capacity from the offshore areas was assigned to the

neighbouring regions in accordance with the prescribed connection points. The power flow calculation in

the 2015 transmission grid with the 2020 load situation leads to a derivation of the resulting transmission

demand between the German regions and the neighbouring foreign countries including designation of

non-transmittable power.

In conjunction with the identification of non-transmittable power in the transmission grid, various inte-

gration solutions were studied taking options for increased flexibility via the use of storage facilities into

consideration. The dena Grid Study II investigated three key variants for integration of the identified non-

transmittable power:

Integration via grid extension (version 000)

50% storage of non-transmittable power in the bottleneck region (version 050)

100% storage of non-transmittable power in the bottleneck region (version 100)

In addition to these three variants, the dena Grid Study II also investigates the use o ptions of flexible line

management (FLM) and high-temperature conductors (TAL) in the extra high voltage transmission grid.

Taking these assumptions into account for the current-carrying capacity of overhead lines, the following

variants were distinguished to identify non-transmittable power:

Basic grid with standard transmission capacity (BAS)

Flexible line management (FLM)

High temperature conductors (TAL)

The three key variants, integration via grid extension (version 000), 50% storage of non-transmittable

power (version 050) and 100% storage of non-transmittable power (version 100), were linked with the vari-

ants for the assumptions of the overhead line carrying capacity. In total, the dena Grid Study II investi-

gated nine variants for the integration of the generation scenario assumed for 2020 into the German

transmission grid, taking the assumptions for overhead line carrying capacity and increased flexibility via

storage use at a total system level into account. The nine variants studied provide approaches for optimisa-

tion of the overall system.


12/26


Page 12 of 26

Figure 3: Regional borders with non-transmittable power

On the basis of the non-transmittable power calculated, additional required grid capacities between

neighbouring regions were calculated for the versions described above. The overall minimum grid exten-

sion requirements were optimised for the different versions investigated at an overall system level.

The 2020 basic scenario without the addition of storage facilities (BAS 000) means that additional

routes totalling 3,600 km in length are required. The costs for this solution approach amount to

EUR 0,946 billion per annum.12

Due to the fact that the higher current-carrying capacity of the equipment is temporary, 3,500 km of

new extra high voltage routes must still be built, even with the flexible line management investiga-

tion version (FLM 000). The addition of transmission capacity via FLM reduces the total volume of new

transmission routes to be installed by 100 km. The costs of this solution approach are EUR 0.985 billion

per annum. In addition, this variant also results in the need to modify existing overhead lines over a

route length of 3,100 km if FLM is used.

In the high temperature conductors variant (TAL 000), taking the use of TAL conductors into account,

an additional grid construction requirement of new routes totalling 1,700 km is calculated, with a si-

multaneous need to convert 5,700 km of existing routes to high temperature conductors. When con-

verting existing lines to TAL, higher conductor costs, mast modifications and temporary structures

are required during conversion, which means that the costs of conversion are approximately the

12In addition to the costs for grid expansion (investment costs), the economic evaluation of the versions investigated, including the

other sensitivity versions, also includes the reactive power compensation costs, the operating and grid loss costs and the connectioncosts for offshore wind farms. The costs specified are annuities. The investment costs are converted to years based on the typical use

periods specified in the Electricity Grid Tariff Act (StromNEV).


13/26


Page 13 of 26

same as those for building a new conventional line. In total, the costs for this solution approach

amount to EUR 1.617 billion per annum. The significantly higher costs than the basic version (BAS 000)

are also incurred due to the higher grid losses (transmission losses) due to the use of high temperature

conductors.

Variant Need for construction ofadditional routes in transmission

grid

Route length to bemodified

Costs13

BAS 000 3,600 km 0 km EUR 0.946 billion pa

FLM 000 3,500 km 3,100 km EUR 0.985 billion pa

TAL 000 1,700 km 5,700 km EUR 1.617 billion pa

Table 3: Overview of the need for additional grid infrastructure and grid modification for the three scenarios investigated,

without taking additional storage into account

Suitable electricity transmission options

In order to integrate the non-transmittable power into the extra high voltage grid and to realise the asso-

ciated grid extension requirements, a variety of technological alternatives available were investigated.The dena Grid Study II analysed the suitability and development potential of the various technologies for

transmission of high electric power on shore and for connection of offshore wind turbines.

The following electricity transmission technologies were considered:

Conventional 380 kV AC overhead lines

800 kV AC overhead lines

Underground 380 kV AC cables

High voltage direct current transmission (HVDC) based on overhead lines

Underground HVDC cables

Gas-insulated lines (GIL)

For transmission tasks on shore, a method for evaluation and structured comparison of the various trans-

mission technologies in terms of available technical properties, economical effectiveness, environmental

effects and system reaction / system compatibility was developed and applied to four abstract point-to-

point transmission tasks, which had no reference to specific projects. The following abstract transmission

tasks were investigated:

Transmission capacity: 1,000 MW Distance: 100 km

13 Includes connection of offshore wind farms, tr ansmission losses and reactive power compensation.


14/26


Page 14 of 26




The technologies with overhead lines proved to be the more suitable solutions for all transmission tasks

investigated as examples. For lower transmission capacities (1,000 MW) and shorter distances (100 km), the

conventional 380 kV AC overhead lines provided the best results. In the three other sample tasks, multiple

transmission technologies often proved virtually equal. At line lengths of 400 km or at even higher powers,

the advantages of high-voltage direct current transmission (HVDC) come to bear.

The sample evaluations of the transmission technologies available presented in dena Grid Study II are not

suitable for generalisation. The method provided should instead be viewed as an instrument for evalua-

tion. For plans of specific lines in the transmission grid, the conditions of the respective project must be

analysed with the evaluation criteria to determine the most suitable transmission technology for the indi-

vidual case.

Sensitivity analysis expansion of pumped storage capacities

Pumped storage power plants can make a contribution for integration of renewable energy into the en-ergy system. In particular, they contribute to the provision of peak load capacity and they increase the

flexibility of the electricity system. Pumped storage power plants are characterised by a high system qual-

ity with regard to their contribution to the security of supply.

In a sensitivity analysis, the dena Grid Study II investigated the effects of increased capacity from pumped

storage power plants in Southern Germany, Austria and Switzerland with regard to grid integration of the

non-transmittable power calculated. For Germany, a 1,700 MW higher pumped storage power plant ca-

pacity by 2020 is assumed for this view.

As a result, a necessary grid extension of approx. 4,200 km of additional line length for the integration of

the non-transmittable power was calculated. The costs for this approach amount to EUR 1.017 billion perannum.

Sensitivity analysis for integration of the non-transmittable power using various transmission

technologies

In addition to the nine variants investigated for integration of the non-transmittable power calculated at

the regional borders as discussed above, the future grid extension requirements are investigated in further

sensitivity analysis variants, which are based on alternative transmission technologies.

In one variant (VSC 1), a meshed DC overlay grid was investigated, which was built with self-

commutated VSC HVDC technology using underground cables. This solution results in a construction


15/26


Page 15 of 26

requirement of 3,400 km of new routes, and with costs of EUR 1.994 billion per year, is significantly

more expensive than the basic scenario and the TAL scenario.

If the DC lines are not structured as a meshed grid, but as individual point-to-point connections, the

costs increase to EUR 2.715 billion per annum. 3,400 km of new routes would also have to be built.

That is the result of an additional calculation variant with VSC HVDC technology (VSC 2).

As part of this sensitivity analysis, the option to realise the required grid extension via underground

cabling was reviewed. The implementation of a direct current grid based on overhead lines would

also be possible. This implementation variant was not investigated in the sensitivity analysis. A further variant investigated a hybrid solution, in which a remote transmission section (overlay line)

with high capacity (4,400 MW) of 824 km runs from Schleswig-Holstein to Baden-Wuerttemberg to

transport the main transmission power from north to south. For the remaining transmission tasks, an

additional 3,100 km of overhead line routes are required. The costs are EUR 1.297 billion per annum.

.

Billion /yearRoutesin km

7000

6000

5000

4000

3000

2000

1000

5

4

3

2

1

Basic FLM TAL Hybrid VSC-HG GIL

New underground cable routes

Modification of overhead line routes (i.e. structural changes to existing routes)

New overhead line routes

Costs per year (annualised capital and operating costs)

6

MeshNetwork

(VSC1)

Individual connections

(VSC2)

Figure 4: Grid extension determined and a nnual costs for the variants investigated

Effects of the costs of the extension of the transmission grid on the transmission tariffs

The comparison of the optimisation measures regarding operation14 shows that in the basic scenario

(BAS 000), the transmission tariffs for domestic customers would increase from 5.8 ct/kWh to 6 ct/kWh,

14This comparison does not incorporate the effects on the transmission tariff for the variants considered in the sensitivity analysis(e.g. hybrid, VSC 1, VSC 2).


16/26


Page 16 of 26

and in the most expensive case calculated (TAL 100 scenario15), the tariffs would be 6.3 ct/kWh. This does

not include costs for additional expansion measures in the distribution grid if necessary.

The investigation shows that in order to reach the target (integration of renewable energy, optimisation of

the power plant fleet, European power trade), a significant optimisation of the integrated grid and the

construction of new extra high voltage lines are required.

The grid extension required stated in the dena Grid Study II using the regional model, must be detailed

using additional grid-planning investigations in order to create the fundamentals required for rapid im-

plementation.The dena Grid Study II shows the technical and economic potential of FLM, TAL and various alternative

transmission technologies for AC overhead lines. For future grid extension plans, all options available

should be compared with one another in order to find the technically and ec onomically optimal solution

for the individual case, taking the existing framework conditions into account.

8 Options for increased flexibility in the electricity system

With the expansion of renewable energy, an increasing number of options are required to react flexibly to

fluctuating generation in the power supply system, and to use suitable measures to increase flexibilitywhile optimising the system. In this context, the dena Grid Study II investigates the following options for

greater flexibility:

Market-driven use of storage facilities to reduce the load of the grid

Potential and market integration thereof by demand-side management (DSM)

Effect of future improved forecast quality of wind energy feeding

Provision of balancing energy by wind turbines

Technical potential of provision of balancing energy via biomass plants

The study investigates which storage technologies are available, the extent of DSM potential in Germany,

and their ability to contribute to reducing grid bottlenecks. In addition to this, the provision of balancing

energy via wind turbines and biomass plants and the effect of a better forecast quality of wind power feed-

ins are also considered.

All above-mentioned flexibility options with the exception of the technical potential for provision of

balancing energy from biomass plants are assumed for the investigations on grid integration of the non-

transmittable power identified in conjunction with the determination of the grid extension requirement

(cf. section 7).

15

TAL 100: Investigation version in which the grid expansion requirement using high temperature conductor cables (TAL) and theprovision of 100% storage capacity fo r the identified non-transmittable power in the bottleneck region is determined. This investiga-

tion version is not presented in detail in this summary of results.


17/26


Page 17 of 26

Use of large-scale electricity storage facilities to integrate non-transmittable power

Electricity storage facilities support the integration of renewable energy by absorbing generation capacity

which cannot be integrated, helping to smooth residual loads and providing balancing energy flexibly.

Accordingly, the importance of storage facilities in integrating renewable energy will increase further in

future. The dena Grid Study II investigates whether storage facilities are also suitable for reducing the need

to extend the grid.

Derived from the main scenarios for grid integration of the non-transmittable power identified (BAS 000,FLM 000 and TAL 000), variants were investigated to consider the grid integration effect of additional stor-

age facilities freely operating on the market. These additional variants assume storage facilities north of

the main line of the determined grid bottlenecks. In the respective investigations of the dena Grid Study II,

the storage facilities are specified such that either half (storage scenario 050) or all (storage scenario 100) of

the non-transmittable power can be absorbed.

As a result, taking the assumed investigation framework into account, storage facilities operated accord-

ing to the existing market regulations made only a minor contribution to the grid integration of the non-

transmittable power identified. Electricity storage facilities as additional energy sources or energy sinks

on the electricity market in conjunction with a market-based operation shift the generation characteris-

tics of conventional power plants. This leads to changed flows of electricity in the grid, which again results

in non-transmittable power occurring at the regional borders. As the electricity market and the grid op-

eration are economically separate, the economically optimal behaviour of storage facilities on the electric-

ity market do not necessarily result in behaviour which relieves grid bottlenecks.

The simulation of the development of the power plant fleet also shows that construction of additional

compressed air and hydrogen storage facilities will not occur as driven by the market by 2020 due to eco-

nomic aspects and the existing market regulations, in spite of the increasing volatility of generation and

the associated electricity price fluctuations. Even with an additional consideration of free storage of gen-

eration capacity which could otherwise not be integrated, these storage facilities proved uneconomical as

a result of the investigations of the dena Grid Study II.

Increased flexibility by utilising demand-side management potential

Management of the demand for electricity via load shedding and load shifting is known as demand-side

management (load management). The dena Grid Study II investigates the fundamentally available poten-

tial for demand-side management (DSM) in Germany until 2020, taking into account the parameters basic

data (e.g. electricity consumption by power and work), technical properties, cost data and assumptions for

energy policy subsidies. The usability of the technical DSM potential in the various consumption sectors

depends in particular on the investment costs required to utilise it and to make it available. The DSM po-

tential investigated in dena Grid Study II is divided into technical potential which can be utilised under the

current existing market regulations, and potential which can only be utilised with significantly changed


18/26


Page 18 of 26

framework conditions on the energy market by 2020. The study states the amount of technical DSM poten-

tial for the various consumption sectors.

In order to model the power plant fleet, the dena Grid Study took into account in the underlying market

model the economic DSM potential in the industry by 2020 (e.g. chlor-alkali electrolysis, aluminium elec-

trolysis, electric steel production, processes in the cement industry and wood pulp production), and a few

applications in domestic environments (night storage heaters, circulation pumps and water heating). The

results of the analysis of other technical DSM potential in private households and in the trade and services

sector are presented in the appendix to the dena Grid Study II, but not taken into account in the grid con-

siderations.

Overall, approx. 60% of the demand for positive balancing energy and approx. 2% of the negative bala nc-

ing energy in 2020 will be covered by DSM according to the dena Grid Study II power plant model. The

actual usage of balancing energy amounts to less than 0.1% of the gross German electricity demand due to

the high energy price. The contribution of DSM to load smoothing via this DSM potential incorporated

reduces the demand to provide peak load, e.g. by gas power stations in the model calculation by approx.

800 MW. The macroeconomic costs of electricity generation are therefore reduced by EUR 481 million by

2020 (200716).

Improvement of the forecast quality of wind energy feeding

The wind energy forecast quality can be improved by approx. 45% by 2020. The improvements are based

on the use of high resolution weather models, the development of existing models and the use of new

models, as well as wind farm-specific selection of the most suitable model.

This results in the following balancing energy which must be provided in 2020, and is roughly equal to the

current demand:

Positive secondary and minute reserve: 4,200 MW

Negative secondary and minute reserve: 3,300 MW

This result of dena Grid Study II with regard to the forecast of the balancing energy required is considera-

bly lower than the balancing energy required for 2020 predicted in dena Grid Study I in 2005.

Provision of balancing energy via wind turbines and biogas plants

On the basis of the tendering processes used to date, wind turbines can only participate in the balancing

energy market to a very limited extent. Wind turbines (their operators) can currently participate in the

daily tendering for tertiary control. Participation in the primary and secondary balancing energy market is

16The value specified is the actual value in 2007, i.e. the cost savings of the individual years were discounted to the year 2007 andsummarised for better comparability within the study.


19/26


Page 19 of 26

currently impossible as provision of power from wind turbines cannot be guaranteed for a month due to

the imprecise nature of wind forecasts in this period.

Wind turbines can provide positive balancing energy if they are operated at partial capacity initially.

However this option is only cost-efficient in very few situations, where a combination of high wind energy

feed, low load and a high load gradient prevail in the electricity system. Negative balancing energy can be

provided to a great extent in 2020, by ramping down wind turbines according to the load.

The dena Grid Study II also investigates the options of providing balancing energy via biomass plants.

Biomass plants have in principle the ability to realise high power ramps, and are therefore generally suit-able for providing balancing energy on the energy market. However, the ability to provide balancing en-

ergy differs for the various biomass plants present in the energy system (biomass combined heat and

power plants (biomass CHP) with gas spark ignition engines, biomass CHPs with dual fuel engines, bi o-

mass CHPs with gas turbines, biomass steam power plants etc.).

According to the currently applicable requirements for participation in the primary balancing energy

market, which dictate that each plant provide a bandwidth of +/- 2 MW, the installed biomass plants can-

not participate in this segment of the balancing energy market. All biomass plants in partial load opera-

tion and some CHPs in cold/warm start operation can participate in the secondary balancing market with

a correspondingly regulated pool of biomass power stations. Provision of minutes reserve power can be

implemented with a correspondingly regulated pool of plants by all biomass plants in partial load opera-

tion and by all CHPs in cold start.

9 Contribution of renewable energy to system security

In addition to the implementability of the necessary transmission tasks, the dena Grid Study II also investi-

gates the extent to which renewable energy, in particular wind turbines can contribute to voltage support,

short circuit capacity, islanding capability and to system restoration after a black out. The analyses in the

study show that generating systems for renewable energy can help support the grid to a certain extent.

The amount of short circuit and reactive power fed into the transmission grid will decrease due to the ex-

pansion of renewable energy. However, with generation systems based on renewable energy, the frequent

integration in subordinate voltage levels means that a significant amount of short circuit and reactive

power can currently not be provided for the transmission grid.

Short circuit power can be provided via the connection with the integrated grids of neighbouring coun-

tries and their still largely conventional feed. In further investigations, the need for additional compensa-

tion facilities connected directly to the transmission grid must be determined to guarantee sufficient short

circuit capacity in future.

The decreased availability of reactive power as a result of the displacement of conventional generation at a

high feed rate of renewable energy and simultaneous the increased demand via increasing load on the


20/26


Page 20 of 26

transmission lines must be made up for via additional reactive power compensation facilities in the trans-

mission grid.

The generation systems must also be sufficiently resistant to changes in voltage and frequency as a contri-

bution to system security. Modern wind turbines connected newly to the grid have mechanisms which

allow them to continue operation through major voltage drops in accordance with current grid connec-

tion regulations, and there are even further technically tested options for local voltage support via wind

turbines. As part of future development of powerful generation systems for renewable energy, the already

available mechanisms should be used or replaced with more grid compatible concepts.

With decreasing availability of conventional power plants, renewable energy sources must be prepared to

contribute to system restoration in the long term.

Renewable energy generation plants can contribute appropriately to frequency control and have the re-

quirements for stable frequency control for isolated systems disconnected from the integrated grid and

during system restoration. For this, decentralised control mechanisms via the individual systems are nec-

essary, and on the other hand, central controllability of wind farm clusters, for example, are necessary to

allow the feed to be adjusted specifically for the requirements in case of endangered system states, or as

part of system restoration. As a result of the lack of rotating masses, the operation of isolated systems ex-

clusively consisting of generation systems fed via converters is impossible with current technology.

Black start capability, and thus system restoration based on renewable energy generation systems is possi-

ble in principle, if additional cost-intensive auxiliary energy is provided for this.

10 Consideration of the effects of postponing the phase-out of nuclear power plants on

the results of the dena Grid Study II

The dena Grid Study II assumed the phase-out of nuclear energy which was valid in 2008. Based on this, the

conventional power plants required in addition to the use of renewable energy sources were modelled,

whereby decisions for the construction of new conventional power plants were derived according to

economy criteria. After the decision of the German Parliament to delay the phase-out of nuclear power

plants by 8 to 14 years, the power plant fleet will differ from that assumed in the dena Grid Study II. As a

result of the delayed phase-out of the nuclear power plants, fewer new lignite-fired power stations will be

required than are modelled in the present study which also affects the required grid infrastructure. It must

be taken into consideration that grid extension is largely determined via the transport tasks for wind-

generated electricity from east to west and north to south. After the end of the study period of the dena

Grid Study II, i.e. 2020/2025, the two scenarios for the power plant fleet (with and without delayed phase-

out) converge.

Shortly before the final completion of the dena Grid Study II, the consortium of authors commissioned (see

section 2) was asked by the project steering group to review the results of the dena Grid Study II based on


21/26


Page 21 of 26

the delayed phase-out of nuclear power stations decided by the German Parliament on 28/10/2010. The

following section reflects the main statements of this review.

The dena Grid Study II investigations are based on the assumption that electricity generation from renew-

able energy remains the priority until 2020. Therefore, delaying the phase-out does not affect the future

expansion of renewable energy sources.

In the phase-out scenario used by the dena Grid Study II, nuclear power plants (NPP) with an output of

6.7 GW are still in operation in 2020 (1/3 of the current NPP output). The delayed phase-out increases this

value to 13.3 GW.The investigations for the regions with the greatest transport demand showed that no fundamental

changes to the grid extension requirement stated in the study were to be expected there for the target

time of the study in 2020. The delayed changes in the power plant fleet could result in regional changes in

the extent and sequence of grid extension requirements during the transition phase from now to 2020.

After the planned delayed NPP phase-out, the delayed phase-out scenario for NPP and the phase-out sce-

nario assumed in dena Grid Study II converge.

11 Outlook and recommendations

With its broad approach for system optimisation, the dena Grid Study II represents a new methodical a p-

proach for determining the extension requirement for the integrated grid in Germany. The study takes

into consideration the various transmission technologies currently available (HVDC technologies, high

temperature conductors, etc.), grid management measures (temperature monitoring for overhead lines)

and the increase of storage capacities plus demand-side management for load shifting. The focus of the

dena Grid Study II extends far above and beyond that of previous approaches, in particular in its incorpora-

tion of options for greater flexibility on the demand side in the context of the grid planning investigations,

and shows the way for the future challenge of overall optimisation of the energy supply system.

The dena Grid Study II optimises the full integration of electricity generation from renewable energy

sources into the German extra high voltage grid, combined with an economically optimised fleet of con-

ventional power plants, and taking the European power trade into account.

In future, the increased European cooperation at a political and market economic level will play an

even more important role, and in particular also affect the national expansion goals of the individual

countries, as the current activities of the European commission in the energy sector illustrate. The state-

ments on the grid extension required in particular at a European level show that the extension and mod-

ernisation of the grid infrastructure play an important role in energy policy. The necessity of further ex-

pansion of the integrated economic cooperation in Europe and the necessity to create common frame-

work conditions for a common European electricity market are closely related with these objectives of the

European energy policy.


22/26


Page 22 of 26

In the dena Grid Study II, an expansion of renewable energy sources in the power supply to 39 % by

2020/2025 was investigated. The proportion of renewable energy sources assumed in this study is there-

fore only a stopping post on the further expansion path of renewable energy generation. The Federal Gov-

ernment already plans to provide 50% of electricity from renewable sources by 2030, which also means

that the grid infrastructure required must be adapted accordingly. In particular, increased use of energy

storage capacity in Southern Germany, the Alpine countries and possibly in Scandinavia means that the

grid infrastructure must be expanded.

Thus, the dena Grid Study II provides a solid determination of the grid extension requirement on the basis

of a broad system analysis, which can be used as a basis for further detailed grid planning investigations

for stating specific route plans, in principle also taking the decision of the Federal Government to delay the

phase-out of the nuclear power plants into account. The current long implementation periods of up to 10

years for infrastructure measures reveal that there is an increasing discrepancy between the expansion of

renewable energy technologies and that of the necessary grid infrastructure. Therefore, the grid expan-

sion scenarios presented in the dena Grid Study II urgently require backing with measures to permit rapid

implementation. Only then can the German Federal Governments chosen path to an age of renewable

energy be maintained.

Recommendations

Taking the main results of the dena Grid Study II into account, which reveal a need for significant grid ex-

tension based on the assumed generation scenarios in conjunction with a cost-optimised operation of the

conventional power plants and the requirements of European power trade, the following recommenda-

tions are stated with emphasised priority:

Grid planning studies including load flow and dynamic analysis, with a suitable underlying scenario

framework for determining line-specific grid expansion measures in conjunction with the specifica-

tions of the third EU internal market package for the electricity sector.

Acceleration of the approval procedures for grid expansion measures, including testing the further

development of the legal framework and increased staffing levels for the bodies in question (approval

authorities, grid operators etc.).

Taking suitable measures to increase the public acceptance for the required grid extension, which is

implemented in close cooperation of all parties involved (political decision-makers, grid operators,

suppliers, approval authorities, the public etc.).

Examination of the use of alternative transmission technologies, optimisation measures in operation

and review of optimisations with regard to technical grid connection of offshore wind turbines (cf.

section 5) as part of future grid planning. The options for speeding up the grid extension measures,

e.g. taking public acceptance into account, should also be incorporated.


23/26


Page 23 of 26

With regard to the investigations of the operating equipment transmission capacity, alternative transmis-

sion technologies and the identification of non-transmittable power in dena Grid Study II, important find-

ings and the need for further testing, study and research were revealed. The following actions should be

taken in particular:

Further investigation to determine suitable framework conditions and technical concepts for opti-

mised use of energy storage in the power supply systems with a high percentage of renewable energy.

Pilot projects for the use of selected technologies (e.g. overhead lines with AC/DC hybrid operation).

Pilot applications with high temperature conductors which are not state-of-the-art yet (e.g. ACCC andACCR high temperature conductors), but which have a high potential for development.

For further development of grid connection concepts for offshore wind turbines in conjunction with

the plans to install a European offshore grid, the further development of technical concepts for multi-

terminal solutions and the standardisation of direct current technologies at a European level are rec-

ommended.

Against the background of the initiated transformation of the power supply system to a system with a very

high percentage of renewable energy (cf. Energy Concept of the German Federal Government 2010), the

system integration of electricity generation from fluctuating energy sources (wind, sun) becomes partic u-

larly important. In developing the fleet of conventional power plants, attention must be paid to ensure

that the future requirements, e.g. compensation of resulting fluctuations and provision of guaranteed

power plant capacity, can be fulfilled at a low cost and at an economic optimum. Therefore, this transfor-

mation process means that the power supply system must be optimised overall, taking both the genera-

tion and the demand side into account. The required overall optimisation must involve a more flexible

electricity system in total.

The changes in the power supply system must also be incorporated in the framework conditions, which

determine the shape of the energy markets in Germany and Europe. In this context, the necessary modifi-

cations of the framework conditions for overall technical and economic optimisation must be reviewedand developed as rapidly as possible. This involves both increasing the flexibility on the demand side via

corresponding tariff systems (in conjunction with the use of smart metering and load management) and

the required adaptation of the electricity grids at the transmission and distribution level, as well as the

creation of incentive systems as close as possible to the market for establishing and using energy storage

facilities, in particular with regard to a grid relieving effect.


24/26


Page 24 of 26

12 Appendix

Expansion scenarios for renewable energy in the power supply

Renewable energygeneration systems

Installed capacities in 2020

dena Grid Study II German Federal Government Re-newable Energy Action Plan 2010

Onshore wind energy 37,000 MW 36,000 MW

Offshore wind energy 14,000 MW 10,000 MW


Photovoltaics 17,900 MW 52,000 MW


Table 4: Comparison of the a ssumptions on the development of renewable energy in the power supply

Assumed investment costs for power plants

[/kW] Hard coal-firedpower stations

Lignite-firedpower stations

Gas and steamplants

Gas turbines

By 2014 1,400 1,600 800 400

After 2015 1,260 1,440 800 400

Table 5: Investment costs for building new power plants, net without construction interests and financing costs, without CCS

in accordance with dena Grid Study II

Fuel and CO2 prices

Prices as real values

2007

2010 2015 2020

Crude oil [$/bbl] 80 90 101.5

Gas [ct/kWhth] 2.96 3.38 3.90

Hard coal

[/t coal equivalent]

114 105 110

Lignite [/MWhth] 1.4 1.4 1.4

CO2prices [/t] 29.4 34.29 37.3

Table 6: Fuel and CO2 prices per dena Grid Study II


25/26


Page 25 of 26

Development of the power plants per dena Grid Study II

Installed generation capacity

Current situation 2005 Modelling of the

power plant fleet in 2020

Storage PP 6,700 MW 8,400 MW

Natural gas PP 26,600 MW 18,000 MW

Hard coal PP 27,200 MW 20,400 MW

Lignite PP 20,400 MW 24,300 MW

Nuclear PP 20,400 MW 6,700 MW

Other (incl. waste) 3,100 MW 3,500 MW


Photovoltaics 1,000 MW 17,900 MW

Offshore wind 0 MW 14,000 MW

Onshore wind 18,400 MW 37,000 MW


Hydroelectric power 5,400 MW 5,800 MW

Table 7: Development of the installed power plant (PP) capacity per dena Grid Study II

Grid extension requirement for the variants of the basic scenario

Investigated variant for integration

of the non-transmittable poweridentified

Need for construction of

additional routes in transmis-sion grid

Routes to be modified

Basic scenario (BAS 000)

Integration via grid extension3,600 km 0 km

50% storage variant (BAS 050)

Construction of new storage facilities for 50% of

the non-transmittable power upstream of grid

bottlenecks

3,400 km 0 km


26/26


100% storage variant (BAS 100)

Construction of new storage facilities for 100% of

the non-transmittable power upstream of grid

bottlenecks

3,600 km 0 km

Table 8: Grid extension requirement for the three variants of the basic scenario with 380 kV AC l ines

Costs of grid extension

Grid extension scenarioAnnual costs

as annuity

BAS 000 (Basic scenario, construction of addi-

tional 380 kV AC OHL17) EUR 0.946 billion pa

FLM 000 (use of flexible line management,

construction of additional 380 kV AC OHL)EUR 0.985 billion pa

TAL 000 (use of high temperature conductors,

construction of additional 380 kV AC OHL)EUR 1.617 billion pa

PSW sensitivity analysis EUR 1.017 billion pa

VSC1 sensitivity analysis EUR 1.994 billion pa

VSC2 sensitivity analysis EUR 2.715 billion pa

HYB sensitivity analysis EUR 1.297 billion pa

GIL sensitivity analysis 18EUR 4.924 billion pa

Table 9: Overview of the costs of the various grid extension scenarios per dena Grid Study II

17 380 kV AC OHL: 380 kV AC overhead line.18 Grid expansion on the basis of underground gas insulated lines.

Documents

Summary Dena Grid Study II