Fuel cells and electrolysers in future energy systems - VBN

listed in table 5 are from the Danish Energy Authority [25]. The handling costs of biogas are assumed to corre‐
spond to the level of natural gas, while keeping in mind that this is also dependent on local conditions.
For the electricity market exchange analyses, long‐term electricity costs are required. The analyses are per‐
formed of the Nordic electricity exchange market, Nord Pool. Here, the long‐term electricity prices recom‐
mended by the Danish Energy Authority are used [25]. The average price is expected to be 49 €/MWh, which
is used here in combination with the hour‐by‐hour fluctuations on the Nordic electricity market in 2005. CO2
quotas are assumed to affect the prices with a constant input of 9 €/MWh; thus, the price of 40 €/MWh is
expected to fluctuate. In this analysis, each type of plant produces according to its business‐economic mar‐
ginal costs including handling costs and taxes. In the results, taxes are excluded, representing socio‐economic
costs.
The socio‐economic feasibility study does not include externalities connected to environmental effects or
health etc. The CO2 quota costs are included; however, this does not reflect the externality costs of the emis‐
sions. CO2 quota costs are currently approx. 26 €/ton. In accordance with the recommendations of the Danish
Energy Authority, a long‐term price of 23.3 €/ton is used here, although this level may prove conservative in a
future with stricter emission reduction targets.
The current Danish taxes and levies (2008) are used in a business‐economic feasibility study with current
public regulation. In this study, an interest rate of 6 per cent is applied. The aggregated levies are currently 7.6
€/GJ of natural gas and 0.086 €/KWh of electricity. Subsequently, a new public regulation scheme is recom‐
mended on the basis of the socio‐economic feasibility study.
3 Results
The results are grouped according the analyses conducted; i.e. a technical analysis of the alternatives; an
electricity market exchange analysis; a feasibility study and a series of sensitivity analyses. Subsequently,
adequate public regulation measures are proposed in order to create business‐economic conditions which
support the socio‐economic feasibility identified in the analyses.
3.1 System fuel efficiency of individual house heating alternatives
The fuel efficiency and the excess electricity production of the alternatives are described in detail for the
analyses of the BAU 2030 CHP system. Subsequently, the energy system analyses of the Non‐CHP system are
described. The heat demand for the population of 300,000 houses is supplied from boilers involving 4.5 TWh
of natural gas/biogas or 5.3 TWh of wood pellets, as illustrated in fig. 2. Such house heating does not influ‐
ence the electricity supply or the excess electricity production, which is 1.66 TWh/year.
Fig. 2, Annual natural gas, biogas or wood pellet consumption of supplying
300,000 houses with heat from individual boilers.
In fig. 3, the energy conversion with geothermal HP is illustrated. Combined with peak load electric boilers,
the HPs require 1.41 TWh of electricity to meet demand. During some hours, electricity consumption can be
met by excess electricity production. Here, the excess production is reduced by 0.36 TWh from the 1.66 TWh
in the reference energy system. During other hours, the increased electricity demand has to be produced
either by CHP or PP. When additional electricity is produced by CHP plants, more boiler heat production is
replaced in the CHP district heating systems and, consequently, the marginal extra fuel consumption is rela‐
tively low. In total, the annual extra fuel demand is 1.48 TWh, most of which is used in the condensing PP. In a
sensitivity analysis, all wind power is removed, and thus, fuel consumption is increased for all electricity con‐
sumed in HP.
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