Estimation of Costs

The impact of the simplifications of the DFR system will be estimated quantitatively in the following. This will lead to a conservative assessment for a serially produced reactor based on experience from plant engineering and construction:

*For the future gas cooling option, the heat exchangers cost less (about 30/70 millions) and the turbines a bit more (250/650 million) compared to the given values in the table. Therefore the sum remains unchanged.

A closed working gas loop with a tertiary cooling system was assumed. Chosing an open air operated loop, the tertiary cooling system can be omitted, which reduces the costs by 10%.

The capital costs of the DFR are comparable to those of a coal-fired power station. They are far below the capital costs for a modern nuclear power plant, which are of the order of for example 3.3 US$ / W_e for the EPR. Scaling for the number of simultaniously built blocks as well as for the size of the reactor a further reduction in costs is achievable. Because no pressure tanks are necessary, it is technically easy to increase the power while the building costs would rise logarithmically. The technology of the reactor also allows to substitute expensive turbines in the conventional section by modern techniques for electricity generation, thus additionally reducing the costs in the further development.

Hence, the operating company does not have to balance high capital vs. low fuel costs for a nuclear power plant compared with a coal-fired power station, where the situation is the opposite, with the nuclear power plant starting to profit from the gains not before 20 to 30 years.

Assuming a service life of 50 years the annual operating costs are composed as follows:

Based on an annual average of 8,000 full-load hours, which corresponds to an operational availability of 90%, the electricity production results in 4,000 million kWh at a production cost of 0.56 ¢ / kWh. Here, the fuel costs have a share of 0.0165 ¢ / kWh, even when assuming an uranium price of 330 US$ / kg. Depending on the configuration, the capital costs sum up to 0.43 to 0.50 ¢ / kWh. Thus, the production costs add up to a total of 1.00 to 1.05 ¢ / kWh with the fuel costs contributing ~1.6%.

Already with the small 500 MW_e plant the electricity production costs are only 30% of the costs of a light water reactor or a coal-fired power station. They further decrease to 20% for the 1500 MW_e DFR. The DFR output power can be scaled up much more easily contrary to pressurized water reactors due to their size-limited pressure vessels.

Hydrogen is the base input material needed. Conventional facilities burn natural gas to produce hydrogen while the DFR can produce it directly from water. From hydrogen, hydrazine is produced in two steps. These steps and their corresponding facility costs per kilogram hydrazine are

The sum is 11-13 US¢ / kg. However, the synergistic and scaling effects reduce it to 8 US¢ / kg. That synergistic and scaling effects are so large can be seen from typical (10 million tons annual output) petroleum refineries^[4] which are far more complex than the hydrazine production facility.

Apart from facility costs, additional costs for energy is needed. The energy input for the production of 1kg hydrazine combines as follows:

Those needs can be matched by a 3,000 MW_th DFR with turbines producing 800 MW_el. The overall costs of such a DFR system would be 10% cheaper than the 1,500 MW_el DFR mentioned in the preceeding section because it needs less turbine power but has the same total thermal power, leading to energy costs of 0.5 US¢ / kWh_el and 0.22 US¢ / kWh_th. The hydrazine output of such a DFR would be about 3,000 tons per day at 90% load. The resulting energy costs for hydrazine production are 7 US¢ / kg.

Both, the energy costs and facility costs add up to 15 US¢ / kg, and, not considering synergistic effects, up to 21 US¢ / kg. For smaller plants the price could rise as high as nearly 20 US¢ / kg. A similar calculation for the new SSAS process leads to total costs of 11 US¢ / kg and 17 US¢ / kg without synergetics, respectively.

The hydrazine production costs can now be compared with conventional fuel extraction and production costs. The following table shows crude oil costs using different extraction methods as well as production costs for gas and coal liquefaction evaluated 2008^[9].

For refinery, additional cost of 6 ¢ / kg (8 $ / barrel) must be added.

The energy costs contribution is not negligible and depends on the method by which the oil is extracted. For refined oil from the Middle East it is only 2 ¢ / kg ^[10] but for the energy intense oil sand extraction in Canada (in-situ SAGD process with suceeding hydro cracking) it contributes with remarkable 7-8 ¢ / kg. Here the DFR can reduce the costs significantly by providing heat and electricity at extremely low costs.

The energy cost savings become extreme when producing synthetic fuels. With conventional methods the ammonia and hydrazine production is dominated by 70-80% energy costs and therefore can not compete even with gasoline. This changes dramatically when using the DFR. Hydrazine and ammonia can now even compete with Middle East oil. The following table shows overnight costs for some fuel production processes, both for with conventional energy supply and DFR energy supply. A fuel-producing DFR facility unites all processing steps in one unit causing lower labor and capital costs, compared to the conventional production lines.

It is stressed again that hydrazine can be used in vehicles with higher efficiency when mixed with water compared with gasoline which does not mix with water. Therefore, the hydrazine costs related to the mechanical energy (or to the distance driven by a vehicle) are a factor of 1.5-2 lower than the per-energy costs. On a per-energy basis, the hydrazine-producing DFR facility can compete with oil production costs equal to or higher than 40 US$ per barrel (including refining), so only conventional oil sources on land are cheaper. On a per-weight as well as on a per-distance basis, only oil fields suitable for primary oil recovery (e.g. Middle East) can compete with hydrazine from the DFR facility. These resources are expected to be exhausted first and soon^[9].

The economical productivity of a power plant is rated by the ERoEI. The ERoEI or ERoI is the energy returned on the energy invested (or energy return on investment). It is the quotient of the sum of exergy produced by a power plant during its service life and that exergy, in this case actual work, that is needed for its construction, operation (including procurement of fuel) and waste management. A power plant has to have an ERoEI significantly bigger than 1, otherwise the invested effort does not pay off. In the economical process a power plant is the more productive the higher the ERoEI. For a low ERoEI the effort is wasted.

In the following, the ERoEIs for different types of power plant technologies are compared.

The so-called renewable sources of energy (energy is not renewed, especially not exergy) have low ERoEIs and employ the spent exergy inefficiently, thus not sustainably. They are characterized by a very high exergy input for the construction of the plants and high maintenance with relatively short service lifes, except for hydroelectric dams. Since electricity cannot be stored, a power plant must produce the electricity on demand. The 'renewables' are incapable of that and need means to store the untimely produced exergy by conversion to other forms of storable energy. The exergy expenses for these storage facilities enter the denominator of the ERoEI thus reducing it considerably. Growing experience with environmental inclemencies, increasing maintenance expenses, and/or shortening service life are not yet considered and would further reduce the ERoEI significantly. So the values for the 'renewables' as given in the table pose upper limits.

The monetary return on investment factor is usually lower than the ERoEI because deviating market prices and different personnel expenses reduce the value albeit there is a proportionality. Empirically, the value of the ERoEI must be greater than 5 to gain profit.

So the ERoEI determines the energy generation costs. In an economic region the energy price is determined by the ERoEI of the prevailing power plant technology. If the power technology is changed the quotient of the energy prices before and after the change are equal to the inverse of the quotient of the correspondent ERoEI's. During the transition, energy generation costs of the 'new' power plants are still dominated by the 'old' power technology since the 'new' power plants are constructed with energy from the 'old' power technology. If a change from fossil power to solar power is be done the quotient of the ERoEI's is about 0.1. The energy price will be 10-fold after the change is accomplished. Meanwhile the solar energy price is considerably lower (although increasing) because of the subsidization by fossil power. Conversely, while changing to the DFR technology the DFR energy price is increased by fossil power though finally decreasing below one tenth.