Environmental Engineering Reference
In-Depth Information
Costs for a photovoltaic system with return on capital
For the example of the photovoltaic system ( A 0
=
6500, A 10
=
1500, ir =
0.06, q = 1.06, n = 25, E a
= 800 kWh el ) of the section above, the
calculations now become:
Discounted payments: c 0 =
6500 +
1500 · 1.06 -10 =
7338
Annuity factor: a = (1.06 - 1)/(1 - 1.06 -25 ) = 0.0782
Required repayments p.a.: B =
7338 · 0.0782 =
574
Electricity generation costs: c E =
574 / 800 kWh el =
0.72/kWh el
When generating 2000 kWh of electricity per year in regions with very high
annual solar irradiation, the electricity generation cost decreases to
0.29/kWh el . However, the electricity generation cost including a return on
capital is much higher than the cost without return on capital, as the above
example illustrates (
0.72/kWh el compared with
0.40/kWh el ).
Costs for a wind power plant with return on capital
Adapting the example of the 1500 kW wind power plant ( A 0
=
1,800,000;
50,000; q = 1.08; n = 20; E a = 3.5 · 10 6 kWh el ) to an interest rate of ir =
8 per cent yields:
A i =
c 0 =
1,800,000 +
50,000 · 9.82 =
2,291,000
a = 0.1019
c E =
2,291,000 · 0.1019 / 3.5·10 6 kWh el =
0.067/kWh el
A high number of privately financed wind power projects have been built in
the past few years in Germany. Many projects have been realized with 30 per
cent equity capital. The remainder of the investment has come from bank loans
with relatively low interest rates in the range of 5 per cent. Project risks such
as incorrect yield calculations or changes in the wind resources are borne by
the equity investor. Therefore, higher interest rates are assumed here.
Costs for a solar thermal system with return on capital
For the cost calculations of solar thermal systems, the numeric values of the
calculations without return on capital are again used. With an interest rate of
6 per cent and an operating period of 15 or 20 years the annuity factor
becomes 0.1030 or 0.0872, respectively. Table 6.6 shows the heat generation
costs for different investment costs, operating periods and annual substituted
amounts of energy. Most solar heat production costs can only compete with
electrical water heating systems. To compete with gas or oil heating systems
they usually need public subsidies at present. In regions with high solar
irradiations and low labour and investment costs, solar energy systems can
also compete with fossil-fired heating systems.
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