Mission/goals and limits of the work
PSI has investigated the potential and cost of electricity generation from „new“ renewable energy sources and new nuclear technologies in Switzerland for the Swiss Federal Office of Energy (BFE).
This is part of the ongoing updates to the Energy Perspectives (Energieperspektiven), which cover the period up to 2035 as an approximate view to the year 2050.
New renewable energy carriers and nuclear energy are basically differentiated by their characteristics, their degree of market readiness, their economic competitiveness and public perceptions. But both possess at least one common aspect, they make significant contributions to climate protection policies.
The present work investigates how large the contributions could be in the next 30-40 years in the context of Swiss electricity generation. It must be expected that there will be variations in these amounts, and barriers which must be overcome, before this possibility can be realized.
The framework for the options considered for electricity generation were defined by BFE. The following renewable energy systems were investigated: small hydro, wind energy, photovoltaics, solar thermal and solar chemical generation, geothermal and wave power. For wind energy import of wind power were considered, in addition to domestic production. Solar thermal and solar chemical power, as well as wave power were based solely on their potential for power imports. The emphasis of the work however has been in the area of domestic electricity generation.
The greatest attention has been paid to the respective technologies, and their progress during the time horizon of this study.
This work does not contain any modeling of the economic potential under particular conditions, or review measures which could be used to increase the market penetration of the various technological options. However the results achieved may be used for such developments and applications.
Procedure
In the course of this project, the following work was carried out:
1. Selection of the technologies to be considered
The respective technologies were based on available knowledge and literature. Based on practical considerations, the selection was limited to technologies which were considered to be representative on the basis of cost and potential.
2. Literature studies of potentials and costs, contacts with persons and institutions possessing relevant information, collection of information and data.
The relevant literature was systematically studied. In the course of the project selected organizations and persons were contacted that possessed expertise in the corresponding areas. This
4. Analysis of technology specific attributes of a challenging or deterrent nature which could influence the achievable future potential.
This can include ecological objections, but also aspects that may influence social acceptance. The influence of a possible future internalization of external costs upon the economic competitiveness of individual energy carriers was investigated
5. Integration
The results of the individual research areas were integrated and collected into a final report. One decisive aspect is the assurance of a reasonable consistency and balance between the evaluations of the individual options, based on a review of the differences in the state of knowledge and uncertainties which are associated with this judgment.
New Renewable Energies Current situation in Switzerland
Total Swiss electric generation in the year 2003 was 65,266 GWh, of which 57.3% came from renewable resources. Based on the Swiss statistics for renewable energy, 97.4% of the renewable electricity came from hydroelectric generation, while new renewables contributed about 1.4%. For small hydro plants there are no separate statistics, as these are included in overall hydro production.
Figure 1 shows a detailed breakdown of Swiss electricity generation.
Fig. 1 Electricity generation in Switzerland in 2003.
Current policies are aimed at achieving a 10% share of total Swiss electricity generation from „new“
renewables by the year 2030. This is defined based on current electricity demand, and therefore represents a total of about 5,500 GWh/year.
Overall potential of Renewables
Renewable resources are very large in comparison with energy demand. This is however based on theoretical rather than technical grounds, and the amount of future use is chiefly based on the economic performance of the technologies which must be implemented to apply these energy resources. The maximum available resources which are available in the long term have been designated as the theoretical potential. Renewable resources gain significance for energy supply as soon as there is a demand and appropriate technologies are developed for energy transformation and use. The estimation of the technical potential is therefore based on technological and technical process criteria.
Small hydro plants
Electricity generation in small hydro power plants poses an economically and, above all, an ecologically interesting option. With the goals of a broadly diversified electricity supply as well as the promotion of renewable energy carriers, the still available potential should be as widely used as possible. The current electricity generation of about 3400 GWh/yr from hydro power plants of less than 10 MW on natural waters could be raised to about 5600 GWh/yr, with the average generation cost of most of the new capacity being about 10-25 Rp./kWh. The maximum available potential at water purification and wastewater treatment plants is far smaller, and is estimated as between 120 GWh/yr (at a cost of 5-23 Rp./kWh) and barely 50 GWh/yr (at a cost of 9-85 Rp./kWh). Most of the costs above the current market price should not pose a barrier, with appropriate marketing of the power as „Ecostrom“ (green power). Even when appropriate ecological measures must be taken to maintain the ecosystem during the renovation or new construction of a small hydro plant, the impacts are likely to be much smaller than for other energy carriers, which is a significant ecological advantage for the development of small hydro potential. In general, the ecological effects as well as the electricity prices are very strongly dependent upon the site of each small hydro plant, and should be estimated for each individual case.
The data presented above on the potential and current costs should be relatively reliable, as the technology used is mature and there are many years of experience in Switzerland with small hydro plants. This also means however, that the possibilities for reducing plant costs are in general relatively small. Lower electricity costs are primarily possible through a reduction of operating costs by means of automation.
Table 1 shows a comprehensive overview of the indicators for electricity generation by small hydro power plantsa.
Tab. 1 Characteristics and indicators for electricity generation by small hydro plants.
Physical and technical potential Transformation of energy in flowing water into electricity Physical potential No specification
Technically realistic achievable potential [GWh/a]
2004 2020 2035 2050
Natural waters
<10 MW 3’422 4’700 5’600a
6’800b 4’200c
5’600d
<1 MW 781 860 920 960 e
<300 kW 300 380 420 450 e
Water purification plants 65 120 155e 175
Wastewater plants 5 15 25 e 50
Resource Strongly location dependent
Status of the Technology Current technology is largely mature Environmental Effects See chapter 4.5
Strongly location dependent
Technology Water turbines for electricity generation Production Method Industrial manufacture
Efficiency 2005 2020 2035 2050
relatively constant, mature technology 0.70-0.85 0.72-0.87 0.74-0.89 0.75-0.90
Market readiness Mature, available
Plant life 30 years (water purification and wastewater treatment plants) 80 years (run-of-river and storage dam plants)
2020 2035 2050
Electricity cost [Rp./kWh]
(see also Tab. 4.6, Fig. 4.11 and Fig. 4.14)
2005
These values are based on rough assumptions and should serve as general indicators. For single plants the costs are strongly location specific.
Water purification plants 5-23 4.5-21 4.2-19 4-18
Wastewater plants 9-85f 8-77 7-70 6.5-65
Hign and low head power plants < 10 MW 40 kW - 2.2 MW
Picohydro plants <40kW 15-45 13-37 12-33 11-30
Pico-alpine power plants 40-100 35-85 32-78 30-75
Additional Costs No further costs
Learning curve See chapter 4.4.2, especially Fig. 4.14
Planning time Location specific; 2-4 months licensing, 1-8 months planning, 1- 2 months for permits
Typical operating cost Location specific; between 1 und 10% of the capital cost; share of the average generation costs around 10%-40%
a (Elektrowatt 1987), average generation costs of about 14-22 Rp./kWh.
b (Lorenzoni et al. 2001), realistically achievable without economic or ecological restrictions.
c Estimation by (Lorenzoni et al. 2001), realistically achievable under economic and ecological restrictions.
d This value is taken here as the practically achievable potential. The time frame for achieving this potential depends strongly on conditions.
e According to Hr. Buser, BFE Program Leader for Small Hydro, this amount represents the economically and ecologically interesting portion of the available potential (14.6.2004). According to conditions, this potential could be achieved significantly earlier or later.
f About 50% of the potential shows average generation costs of less than 20 Rp./kWh (Chenal et al. 1995) (see Chapter 4.4.1).
g Existing plants; no subdivision by capacity.
h Average values for new construction and renovation of existing plants.
Wind energy
Currently, wind turbines contribute a share of only about 0.5% of the total 950 GWh/yr from renewable energy (not including large and small hydro plants). Various studies have shown that a realistic technical potential from wind parks for Switzerland is on the order of 1150 GWh/yr by the year 2050. This is divided into 96 locations, of which most of those identified are located in the Jurabogen, as well as others in the fore-Alpine and Alpine regions. Individual turbines, which also satisfy the criteria of the Swiss wind energy concept, could produce an additional 2850 GWh/yr. To achieve the goals of Energie Schweiz of 50-100 GWh/yr for 2010 and 200 GWh/yr for 2020 would require a partial development of the potential of 316 GWh/yr at the 16 cantonal/communal and 12
„priority“ locations. An increase to about 600 GWh/yr by 2035 appears possible, and with a full development of all wind park locations the total potential of 1150 GWh/yr could be achieved by the year 2050.
Concerning generation costs, the only current, somewhat competitive wind generation prices are from the Mont Crosin Ost plant with a cost of 12 Rp./kWh, while other plants are in part significantly above the grid tariff level of 15 Rp./kWh. Although wind energy is technologically established, there is a potential for improvements as well as cost reductions because, with the exception of Mont Crosin, no large plants have been built. By the year 2020 average generation costs in the range of 12.9-14.3 Rp./kWh can be expected, by 2035 between 12.0-13.8 Rp./kWh, and by 2050 only a further minor reduction to 11.6-13.8 Rp./kWh may be expected.
In general, neither a deficiency of suitable locations nor the costs are a limiting factor to the future development of windpower in Switzerland. A much larger obstacle to further development are the regularly recurring objections of wind power opponents, based on protection of the landscape and nature. At present there are windpower projects blocked in Switzerland with a total capacity of around 20 MW. However in general the environmental consequences can be reduced to a low level by careful planning.
Regarding the future availability of imported wind power, scenarios for estimating this potential can indeed be developed. Whether and under what circumstances imports from the year 2020 on may be a possible option depends significantly upon the political conditions. A further critical factor is that current estimates depend upon the assumption that prices for wind power imports would not lie much below the cost of domestic production in Switzerland.
Table 2 gives a comprehensive overview of indicators for electricity generation from windpower plants.
Tab. 2 Characteristics and indicators for electricity generation by wind power.
Physical and technical potential Conversion of wind to electricity, typically starting with a wind speed of about 3.5 – 4 m/s
Physical potential 9.2*109 GWh/a1 (BFE/BUWAL/ARE 2004b)
Integrated potential in Switzerland Nameplate capacity 5.35 MW; Annual generation 5.4 GWh/a (End of 2003)
Technically realistic achievable potential in Switzerland
Scenario (BFE/BUWAL/ARE 2004a; BFE/BUWAL/ARE 2004b):
1150 GWh/a from wind parks (728 turbines at 96 locations) 2850 GWh/a from single installations
(Reference turbine with capacity of 1250 kW) Scenario (Horbaty 2004):
1470 GWh/a (Reference turbine with capacity of 1750 kW) to 1680 GWh/a (Reference turbine with capacity of 2000 kW)
For detailed assumptions see chapter 5.3.2.
Resource Strongly location specific; varies between ca.750 und 2000 full load hours/year; good wind conditions in the Jurabogen and above 800 m altitude
Status of technology Horizontal axis wind turbines with 2 or 3 rotor blades with current commercially available capacities of 600 kW to 3 MW (onshore) and up to 5 MW (offshore);
Rotor diameter onshore: 40 m – 95 m Tower height onshore: 40 m – 120 m Rotor diameter offshore: 80 m – 125 m Tower height offshore: 60 – 100 m Environmental effects See chapter 5.5
Strongly location dependent
Technology Horizontal axis wind turbine
Production method Industrially manufactured
Efficiency (development over time) 20%-35% (approaching constant, mature technology)
Market readiness Available
Lifetime 20 years (some 40 years)
Costs (development over time) Current CH: 12-20 Rp./kWh (Mt. Crosin 600-850 kW) 50-60 Rp./kWh (Grenchenberg 150 kW) up to max. 90 Rp./kWh (small units) Future CH2 (2020): 12.9-14.3 Rp./kWh
(2035): 12.0-13.8 Rp./kWh (2050): 11.6-13.8 Rp./kWh Current DE: Onshore: 7.8-20.2 Rp./kWh Future DE (2020): Onshore: 4.7-12.4 Rp./kWh Current Europe: Onshore:
6.2-7.8 Rp./kWh (very good location) 9.3-12.4 Rp./kWh (average location) Offshore: 7.8-18.6 Rp./kWh Import costs (2020): total 7.7-14.9 Rp./kWh
Additional costs Grid connection:
Onshore: 14% of plant cost (Europe) 20% of plant cost (CH) Offshore: 25% of plant cost (Europe) Planning costs Onshore: 2.5% of plant cost (Europe)
Offshore: 4% of plant cost (Europe) Planning time Up to 1 year (without objection) Typical operating cost Onshore: 2-5% of plant cost
Offshore: 5-7.5% of plant cost Learning curve Cost reduction potential:
by 2010: 15%
2011-2025: 10%
2026-2050: 0% (Millais & Teske 2004)
1Represents the energy of the moving air up to about 300 m above the ground across the total land surface of Switzerland.
2These costs predominantly apply to the 16 cantonal/communal and 12 „priority“ windpark locations, which represent a potential of about 316 GWh/yr. For the „other“ locations, these estimates may well be optimistic. According to (Horbaty 2004), the average generation costs in the year 2020 are around 13 Rp./kWh. This is about in the same range, if one assumes that only plants of about 2000 kW capacity would be built to develop the potential of 1.7 TWh/yr. However, the range of generation costs extends from a low of 8 Rp./kWh in the best locations to 20 Rp./kWh in the less suitable locations.
Biomass
Due to the large range of options for the use of biomass and limited project resources, the whole area of biomass could not be treated in a comprehensive way. The emphasis in this part of the work lay in the identification and presentation of the technological possibilities and trends in electricity generation from biomass. The ecologically utilizable biomass potential in Switzerland would allow a significant increase in electricity generation from biomass. On one hand there can be expected an increase in the amount of the types of biomass suitable for energy use, and on the other hand there can be expected a development in the conversion efficiency to electricity by a factor of 2 to 3, which would both significantly raise the potential for electricity generation.
Figure 2 shows the efficiency ranges for processes to produce electricity from woody biomass. The hatched areas give the range from the various published data investigated. One conclusion can be easily reached from this figure: the efficiency of the generation is a function of the size of the plant, which is shown especially significantly with the most widely introduced steam processes.
Fig. 2 Summary diagram of current and future expected electrical efficiencies with dry biomass (wood) fired generation plants.
In the present study there have been two scenarios made of market and technology development. In the so-called cogeneration scenario we assume that that biomass will be predominantly used in cogeneration plants. In this way, the plants will tend to be smaller due to the expected heat demand and the electrical conversion efficiency will be higher. The average generation costs in this scenario will be higher than in the second scenario investigated, which maximized electricity generation. In the so-called electricity-scenario development goes in the direction of larger plants. The increasing scale, and the resulting opportunities/possibilities for hybridization with fossil-fired plants (e.g. combination with a cogeneration plant using natural gas) allow this scenario to project more strongly sinking costs.
The expected future cost trends depend upon the development of costs in agriculture and silviculture (forestry), as well as upon disposal fees that can be raised for the evaluation of wastes. The cost trends for the conversion technologies depend in the largest part (minimum 50%) on developments in the use of fossil resources. In particular, the possible application of fuel cell technologies depends upon their penetration into the fields of fossil-based electricity generation and also cogeneration.
Photovoltaics
The cumulative installed PV capacity has grown worldwide with a long-term average rate of 21.6%
per year, and in Switzerland at a rate of 15.3% per year. At the end of 2003, the total installed PV capacity for all of Switzerland stood at about 21 MWp. The potential in the near future will be limited by the available roof surface. Possible PV generation on the roofs most suitable to PV installations is limited to a capacity of almost 11 GWp, which would represent electricity generation of 9.4-13.7 TWh/yr. The actual electricity generation in the last year also depends upon the speed of market penetration. To accelerate a broad market introduction, time-limited incentive financing as well as a guaranteed price at the grid based on Swiss circumstances will be necessary.
The average generation costs for PV in Switzerland currently range from about 34 to 89 Rp./kWh, depending upon technology and location. The most expensive installations are small rooftop PV in the Swiss midlands, with a cost of 68 to 89 Rp./kWh. In the Alps this cost is reduced to 48 to 63 Rp./kWh.
If large installations were built in the Alps, the lowest costs for Switzerland that could be achieved would be in the range of 34 to 44 Rp./kWh. In the Swiss midlands, the cost for such a large installation would be in the range of 48 to 62 Rp./kWh. Advances in technology mean that by the year 2020 a
small rooftop installation in the Swiss midlands would have generation costs of 44 to 51 Rp./kWh, and in the Alpine regions a cost of 28 to 37 Rp./kWh. By the year 2035 an equivalent PV system in the midlands could have a cost in the range from 32 to 42 Rp./kWh, and in the Alps the cost could then lie in the range from 23 to 30 Rp./kWh.
The potential for technological development and the resulting potential for cost reductions is far from being exhausted. Further research and development means are required, especially the development of new and cheaper semiconductors with higher efficiencies, and simpler, energy-saving and more economical manufacturing processes. The transformation of these advances into technically optimized products and system must also be advanced. Mass production of components will further reduce manufacturing costs by economies of scale.
The international trend is today partially in the direction of large, central PV power plants. In Germany several large PV plants in the range from 2 to 18 MWp are currently being planned and built.
The construction of large PV plants in the Alps can also be currently reconsidered. Alpine locations have the advantage of offering significantly higher annual insolation, and the winter share of the generation is more than double that in the midlands. The great disadvantage of large installations in Alpine locations is that massive opposition can be expected on the basis of landscape protection aspects.
Table 3 shows a summary overview of indicators for electricity generation by PV installations.
Tab. 3 Characteristics and Indicators for power generation in photovoltaic installations
Physical and technical potential
Direct conversion from solar radiation to electricity Physical potential
Total potential in Switzerland (End of 2003)
Installed capacity: 21 MWp(18 MWp grid connected, and 3 MWp off grid)
Power production: 16.7 GWh (15.2 GWh grid connected, and
1.5 GWh off grid)
Technically achievable potential
Installed capacity Power production
Roofs 46 km2 a 10.9 GWp 9.4-13.7 TWh/ab
High 0.234-0.350 1.84-2.76 6.96-9.78
Moderate 0.120-0.168 0.73-1.02 3.19-4.48
Linear 0.034-0.048 0.080-0.112 0.194-0.272
Insolation 1000-1400 kWh/m2a (Swiss midlands and alpine valleys) Status of technology Continuous further development
Environmental effects See chapter 7.5
Greenhouse gas emissions: ca. 65 g (CO2-eq./kWh) for roof installations Technology Direct conversion from solar radiation to electricity
Production methods Industrial production
2004 2020 2035 2050
Efficiency
(Depends upon cell type;
typical commercial modules)
8-16% 12-20% 16-24% e 20-28% e
Market readiness On market, available in large quantities
Lifetime 25-30 years
Costs [Rp./kWh]
(Swiss midlands)
2004 2020 2035 2050
Rooftop installations 1-10 kWp 68-89 44-51 32-42 k.A.f
Large plants >500 kWp 48-62 31-36 22-29 k.A. f
Strong dependence on interest rates (here 3-6%);
For details see Tab. 7.10 (2004), Tab. 7.11 (2020), Tab. 7.12 (2035)
For details see Tab. 7.10 (2004), Tab. 7.11 (2020), Tab. 7.12 (2035)