6 A PPLICATIONS OF SOLID OXIDE FUEL CELLS FUTURE ENERGY SYSTEMS
6.3 C OST OF ELECTRICITY GENERATION AND EFFECTS ON ELECTRICITY TRADE
hydrogen Central and Local FC‐CHP systems, the excess electricity can now be utilised. The natural gas Micro FC‐CHP application increases the excess electricity production marginally in energy systems with wind power. Although heat storages are used, these are less flexible than central and local FC‐CHP plants. This is due to the fact that the units are prioritised to increase the total efficiency, but are sometimes forced to produce electricity at times when the demand is already met by wind power and the production of power plants and other CHP plants has already been reduced to a minimum. This is also the case in the hydrogen Micro FC‐CHP system in the traditional and the 100 per cent renewable energy systems.
Here, electrolysers reduce excess electricity production, but this is increased again during some hours due to the electricity produced by Micro FC‐CHP.
‐4.00
‐3.00
‐2.00
‐1.00 0.00 1.00 2.00 3.00 4.00
Central FC‐CHP Local FC‐CHP Micro FC‐CHP Central FC‐CHP Local FC‐CHP Micro FC‐CHP
Natural gas Electrolyser hydrogen
TWh/year
Marginal changes in excess electricity
Electric heating system Electric heating system + 24,5 TWh wind Traditional system Traditional system + 24,5 TWh wind CHP system
CHP system + 24,5 TWh wind
Integrated system 100 per cent renewable energy system
Fig. 13, Marginal changes in excess electricity production of the six applications analysed in the eight different energy systems.
Large Central FC‐CHPs cannot compete with coal‐based CHP, but they have long‐term costs similar to those of CCGT and have lower costs than biomass‐based CHP, especially if the long‐term cost goals are met.
Small Local FC‐CHPs are able to compete with small SCGT, also in case that only the cost goals for 2015 are met. The better efficiencies of FCs can compensate for the high costs of replacing stacks in Local FC‐CHP, represented by the high fixed O&M. Two different price levels of Micro FC‐CHP have been included, assuming that, in the long term, it is possible to scale the Local FC‐CHP; but the efficiencies do not increase due to larger auxiliary power requirements in small‐scale generation. In all the fuel and CO2 quota price scenarios, the Micro FC‐CHPs are unable to compete with the other technologies. Some may argue that the main purpose of Micro FC‐CHP technologies is to produce heat, and that this element should be taken into account. This, however, is the also the case for some of the other fu‐
ture CHP technologies listed.
One mayor problem for the FC‐CHPs is the fuel prices, because natural gas is more expen‐
sive than coal. This is, however, also the case of gas turbines. If the electrolysers were able to operate solely on wind power, the long‐term costs of hydrogen would be approx. 15
€/GJ, not taking into account the costs of the electrolysers. Such prices cannot compete with the fuel costs used in FC‐CHP included here.
Future technologies Inv. costs Life‐
time Fixed O&M
Var.
O&M
Efficiency Total €/MWh incl. CO2 quotas Low fuel High fuel
M€/MW (%) €/MWh el. th. Low CO2 High CO2
Wind On‐shore 1.07 20 3.0 12 ‐ ‐ 38 38
Wind Off‐shore 1.87 25 2.8 15 ‐ ‐ 44 44
Large Coal CHP (2030) 1.20 30 1.3 1.8 55.0 38.0 46 80
Large Biomass CHP (2030) 1.30 30 1.9 2.7 48.5 41.5 137 160
Ngas CCGT (>100MW) 0.55 30 2.3 1.5 61.5 29.5 62 116
Ngas CCGT (>10 MW) 0.70 25 1.4 2.8 52.0 39.0 74 138
Ngas SCGT (40‐125) 0.49 25 1.5 2.5 46.0 46.0 79 151
Ngas SCGT (5‐40) 0.70 25 1.1 3.3 41.5 50.5 130 209
Ngas Large FC‐CHP ‘15 0.80 30 6 ‐ 66 24 68 118
Ngas Large FC‐CHP ‘30 0.40 30 6 ‐ 66 24 58 108
Ngas Small FC‐CHP ‘15 0.80 20 10 ‐ 56 34 116 175
Ngas Small FC‐CHP ‘30 0.40 20 6 ‐ 56 34 97 156
Ngas Micro FC‐CHP ‘15 1.87 20 6 ‐ 45 45 254 328
Ngas Micro FC‐CHP ‘30 0.80 20 10 ‐ 45 45 231 305
Table 3, Long‐term electricity prices of future technologies. For the FC‐CHP technologies, the prices are based on potential future costs and efficiencies for 2015 and 2030. The low fuel prices represent costs equivalent to 62 $/bbl oil and the high fuel costs represent costs equivalent to 172 $/bbl oil. The low CO2 quota costs represent 23.3 €/ton, and in the high cost scenario, this level is doubled. Low fuel‐high CO2, high fuel‐low CO2 and the base fuel costs, representing costs equivalent to 120 $/bbl, have been left out. For coal CHP and gas turbines, potential future efficiencies are listed; however, the costs of these are approx. current costs [49;65]. Electricity prices are based on a 3 per cent interest rate.
The combinations of seven different future energy systems, four different applications, six different fuel and CO2 quota prices, and three different electricity price levels result in more than 650 energy system analyses in the market exchange analyses. The electricity market exchange analyses are presented in detail for the Local FC‐CHP in the CHP system with 24 TWh of wind power. Subsequently, the aggregated results of the analyses are presented for all energy systems and all applications.
In Fig. 14, the electricity trade effects of the reference CHP system with 24 TWh of wind power are illustrated, in combination with Local FC‐CHP in this energy system. In the normal year, the Local FC‐CHPs are able to marginally increase net earnings by reducing import and increasing export due to a more efficient fuel conversion. In the wet year, electricity prices are rather low and net earnings are mainly connected to imports. The Local FC‐CHPs reduce import and, when electricity prices are rather low, this results in decreased net earnings, even though the Local FC‐CHPs are very efficient. In the dry year, the Local FC‐CHPs are able to increase net earnings based on larger earnings from more efficient electricity exports. When applying the assumptions on the frequency of the different electricity, fuel and CO2 quota cost levels described above, the electricity market analyses of Local FC‐CHP show that the net earnings are unchanged.
0 100 200 300 400 500 600
CHP system + 24,5 TWh wind, Revenue of electricity trade in a normal year, M€/year
0 100 200 300 400 500 600
CHP system + 24,5 TWh wind, Revenue of electricity trade in a wet year, M€/year
0 100 200 300 400 500 600 700 800 900 1,000
62$/bbl 120$/bbl 178$/bbl 62$/bbl 120$/bbl 178$/bbl
23.3€/ton CO2 46.6 €/ton CO2
CHP system + 24,5 TWh wind, Revenue of electricity trade in a dry year, M€/year
Ref. Net earnings Ref. Import Ref. Export
Ngas Local FC‐CHP, Net earnings Ngas Local FC‐CHP, Import Ngas Local FC‐CHP, Export
Fig. 14, Electricity market exchange analyses of the reference CHP system with 24 TWh of wind power and Local FC‐CHP added to this system. The results are illustrated for three electricity and three fuel prices and two CO2 quota costs.
In Fig. 15, the total average revenue of electricity trade of the reference energy systems is shown. The total net revenue of electricity trade in the references is between 110 and 170 M€/year. In the four electricity and traditional systems, the main earnings on trade are connected to imports, due to rather high production costs. This is also the case of the CHP system; while in the CHP system with 24 TWh of wind power as well as in the integrated system, the earnings on trade are reduced, due to lower system flexibility with a high pene‐
tration of CHP and fluctuating renewable energy.
In Fig. 15, the net average revenue of the four applications added in the reference energy systems is also illustrated. In all energy systems, the production of electricity in FC‐CHP, replacing the production of heat in boilers, generates rather low marginal production costs.
Still for the natural gas Central, Local and Micro FC‐CHP applications, the changes in reve‐
nue are rather low in most systems. The large import in wet years and high fuel costs ham‐
per the ability of the FC‐CHP to increase earnings on trade. In the reference systems, im‐
ports would reduce power plant production and thus enable more fuel savings than when replacing FC‐CHP, because the replaced FC‐CHP production leads to a higher boiler produc‐
when fuel prices are high, especially on the Nordic electricity market where prices are often low due to the Norwegian hydro power production.
In normal years, the profits of trade increase significantly in the CHP energy system with 24 TWh of wind; hence, FC‐CHP has good abilities to compete with the gas turbine CHPs in this system, which use the heat storages. In normal years, smaller profits can also be generated for FC‐CHPs in the CHP energy system.
In dry years, FC‐CHPs generate profits in most systems; especially in the CHP systems in which they compete with gas turbines. In the dry year, however, the Local FC‐CHP performs better than the Central FC‐CHP in the CHP energy system with wind power. This is due to the larger heat storages of the local systems.
For the hydrogen Micro FC‐CHP, electrolysers are able to profit from fluctuations in the traditional energy system with wind power. This system is rather inflexible compared to the CHP system with wind and the integrated energy system, in which CHP plants already ad‐
just prices and hence hydrogen Micro FC‐CHPs are able to increase profits. In the integrated system, the net earnings on international trade decrease marginally, as the other compo‐
nents in the system are, among others, flexible demands and heat pumps.
0 20 40 60 80 100 120 140 160 180 200
References , Total average revenue of electricity trade, M€/year
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Ngas Central FC‐CHP , Net average revenue of electricity trade, M€/year
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Ngas Local FC‐CHP , Net average revenue of electricity trade, M€/year
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Ngas Micro FC‐CHP , Net average revenue of electricity trade, M€/year
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H2 Micro FC‐CHP , Net average revenue of electricity trade, M€/year
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Ngas Local FC‐CHP , Total marginal socio‐economic revenue, M€/year
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Ngas Micro FC‐CHP , Total marginal socio‐economic revenue, M€/year
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H2 Micro FC‐CHP , Total marginal socio‐economic revenue, M€/year 0
2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000
References , Total socio‐economic costs, M€/year
Electric heating system Electric heating system + 24,5 TWh wind Traditional system Traditional system + 24,5 TWh wind CHP system CHP system + 24,5 TWh wind
Integrated system
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Ngas Central FC‐CHP , Total marginal socio‐economic revenue, M€/year
Fig. 15, Total average revenue of electricity trade and total socio‐economic feasibility of the reference energy systems and net change in revenue of the four applications. Please note that the scales vary.