Abstract:
The invention relates to methods and facility systems ( 100 ) for providing storable and transportable carbon-based energy carriers ( 108 ) by application of carbon dioxide ( 101 ) as a carbon supplier and by application of electric energy (E 1 , E 2 ). The facility system ( 100 ) comprises a plant ( 300, 301; 400 ) for providing a first portion of energy in the form of direct current energy (E 1 ) from renewable energy sources. In addition, a power supplies facility ( 501 ) is provided for tying the facility system ( 100 ) to a mixed network ( 500 ), wherein the power supplies facility ( 501 ) produces a second portion of energy in the form of direct current energy (E 2 ) from an alternating current voltage of the mixed network ( 500 ). A device ( 102, 105 ) is adapted to provide hydrogen ( 103 ), wherein a part of the energy requirement of this device ( 102, 105 ) is covered by said first portion of energy and another part is covered by said second portion of energy. A carbon dioxide supply serves for introducing carbon dioxide ( 101 ) and a reaction area ( 106 ) is provided for producing a hydrocarbon, preferably methanol ( 108 ).

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     The present application claims the priorities of Patent Cooperation Treaty Application No. PCT/EP2009/060472, filed on Aug. 13, 2009; European Patent Application No. 09154271.2, filed Mar. 4, 2009; and Patent Cooperation Treaty Application No. PCT/EP2008/067895, filed Dec. 18, 2008; all of which are incorporated herein by reference in their entirety for all purposes. 
     FIELD OF THE INVENTION 
     The present application concerns methods and facility systems for providing storable and transportable carbon-based energy carriers by application of carbon dioxide as a carbon supplier and by application of electric energy. 
     BACKGROUND OF THE INVENTION 
     Carbon dioxide CO 2  (often called carbonic acid gas) is a chemical compound composed of carbon and oxygen. Carbonic acid gas is a color- and odorless gas. It is a natural component of the air, with a low concentration, and is produced by in animals during the cell respiration, but also during the combustion of carbon-containing substances under sufficient presence of oxygen. Since the advent of the industrialization, the CO 2  proportion in the atmosphere has risen markedly. A main cause for this are the CO 2  emissions caused by human beings—the so-called antroprogenic CO 2  emissions. The carbonic acid gas in the atmosphere absorbs a portion of the heat radiation. This property renders carbonic acid gas to be a one of the so-called Green House Gases (GHG) and is one of the co-originators of the global greenhouse effect. For these and also for other reasons, research and development is performed at present in the most different directions to find a way to reduce the antroprogenic CO 2  emissions. In particular, in relation with the generation of energy which is often carried out by the combustion of fossil energy carriers such as coal, oil or gas, but also by other combustion processes, for example waste incineration, there is a great demand for CO 2  reduction. Per year, more than twenty billion tons of CO 2  are released into the atmosphere by such processes. 
     Among others, the principle of climate neutrality is aimed at by pursuing approaches in which efforts are made to compensate the generation of energy accompanied by CO 2  emissions by using alternative energies. This approach is represented in  FIG. 1  in a very schematic manner. Emitters of greenhouse gases (GHG), such as industrial enterprises (e.g. manufacturers of automobiles)  1  or power plant operators  2 , invest in or operate, e.g. wind farms  3  at other locations in the framework of compensation projects to generate energy there without GHG emissions. Purely on the basis of calculations, it is thus possible to achieve climate compensation. Numerous companies try to buy a “climatically neutral” profile in this way. 
     Wind and solar power plants which convert the renewable energies into electric energy have an unsteady delivery of power, which hampers the operation of a facility according to the requirements of an electrically mixed network and gives rise to facility and operation costs for additional reserve and frequency regulation facilities. Accordingly, the costs of power generation from wind or solar power plants are thereby raised significantly compared to conventional power. 
     It is seen as a problem that at present almost all regenerative electric energy that is produced is supplied to the public AC voltage mixed network, the frequency of which is allowed to vary only within very narrow boundaries (e.g., +/−0.4%). This can only be achieved when the generation of electric current in the network is virtually always equal to the consumption. The necessity that wind and solar power plants must always hold available the sufficient reserve and frequency regulation capacities leads to an increase in the costs of power generation with these facilities. Wind and solar power plants within the electrical mixed network thus result in further “hidden” costs and problems. 
     Already at the present stage of completion of wind power plants in many countries, the electric power supply network may create serious problems, if, e.g., as a result of wind scarcity or strong winds, wind power fails at a large scale, in particular if this failure occurs suddenly or unexpectedly. In any case however, reserve and frequency regulation capacities are necessary, which are adapted to the installed wind and solar output. 
     It follows from the above that solar and wind power plants which supply (current) into an electrical mixed network can hardly replace the installed outputs of other power plants in the mixed network. This leads to a situation that solar and wind power may be valuated approximately only with the saved fuel cost of the other heat power plants present in the network. 
     SUMMARY OF THE INVENTION 
     Now it is seen as an object to provide a method that is capable to generate storable hydrocarbon-based energy carriers, for example as fuels or combustibles. The provision of these energy carriers should be accomplished with an additional emission of CO 2  that is as low as possible, and the application of these energy carriers should contribute to a reduction of the CO 2  emission. 
     According to the invention, a method and a facility system (device) for providing storable and transportable energy carriers are provided. 
     According to a first embodiment of the invention, carbonic acid gas is utilized as a carbon supplier. Preferably, the carbonic acid gas is extracted from a combustion process or from an oxidation process of carbon by means of CO 2  precipitation. Electric direct current (DC) energy is provided. This DC energy is generated largely by means of renewable energies, and it is utilized to perform an electrolysis so as to generate hydrogen as an intermediate product. The carbonic acid gas is then brought to a reaction with the hydrogen so as to transform these products to methanol or to another hydrocarbon. 
     In another preferred embodiment, a transformation takes place in a reduction process from a silicon-dioxide-containing starting material to silicon, whereby the energy for this reduction process is provided to a large extent from renewable energies. A portion of the reaction products of this reduction process is then used in the process for generating methanol, wherein in this methanol generating process, a synthesis gas of carbonic acid gas and hydrogen is used. The conversion from a silicon-dioxide-containing starting material to silicon can be performed as an additional method step. 
     According to the invention, a facility system operation is prepared which is as constant and long-term as possible, and this is achieved by the addition to the supply of regenerative power of a conventional (e.g., fossil) supply of power from a mixed network. Preferably, according to the invention, the conventional power supply is tied in during the low-load period of the electrical mixed network. This means that, e.g., a wind and/or solar power plant and the plant according to the invention are tied mutually with the existing electrical mixed network in a way that is economically and ecologically optimized as far as possible, such that
         the total yield of the reaction products becomes as large (maximal) as possible;   and/or the CO 2  emission becomes as low (minimal) as possible;   and/or a capacity utilization of the facility is achieved that is as constant and long-term as possible;   and/or the product specific costs of investment and operation of the regenerative power plant and of the plant of the present invention become as low (minimal) as possible.       

     According to the invention, the electric energy from wind and/or solar power plants is not supplied to a mixed network, but is converted directly to storable and transportable energy forms (preferably hydrocarbons, such as e.g. methanol). That is, the renewable energies are converted into storable and transportable energy forms in a chemical way. 
     It is a further advantage of the conversion to storable and transportable energy forms that the energy conversion efficiency is raised, because in photovoltaic plants, no alternating current (AC) converters for generating an alternating voltage are required and transport over a large distance of the electric energy through long high voltage lines is generally not required. 
     The generation costs of the renewable electric energy from solar and wind power plants will be relatively high for a conceivable time. This results in a direct usage of such electric energy for chemical processes, as proposed herein, the chemical products are more expensive than the conventionally fabricated products—fabricated generally using fossils. This holds in particular, when the real environmental damages caused, e.g., by a fossil power plant, are not internalized, i.e., taken into account in the total balance. 
     In order to avoid this disadvantage, in the plant according to the invention, creates a combination of regenerative and a conventional power supply which is as economically and ecologically optimized as possible in networking with an available electrical mixed network. The plant concept therefore conceives in a preferred embodiment to use regenerative electric energy according to its production and electric energy from an electrical mixed network primarily in the low-load periods thereof for chemical reactions and thus to also store it. In periods of electrical peak power demands in the electrical mixed network, the regenerative energy can be supplied also to the mixed network—to achieve higher proceeds. This supply is optional. 
     Instead of supplying the regenerative electric energy from wind and/or solar power plants which evolves unsteadily to an electrical mixed network and of balancing and regulating their variations and failures by means of other power plants or storage facilities, the electric energy from wind or solar power plants is preferably used to operate a chemical plant of the present invention so as to generate storable and transportable energy forms. In the case that where a plant of the present invention is tied to a mixed network in order to extract a portion of the electric energy from the mixed network, a presently available excess energy portion can be extracted from the mixed network by means of an intelligent facility regulation or control, while the remaining required energy portion is taken from the solar and/or wind power plant associated with the plant. Thereby, an intelligent reversal of the existing principle is achieved, in which the variations of the regenerative power from wind and/or solar power plants must be buffered tying in conventional power plants and/or storage facilities. For operating a plant of the present invention, it is therefore not necessary to hold available any regulation and power reserves in the electrical mixed network. This principle leads to significant reduction of costs and enables a user to take into account additional technical and economical parameters in the control of the plant. 
     In addition, the regulation and control of the power supply of the plant becomes significantly simpler and more reliable, since the decision taking authority thereon rests in the range of responsibilities of the operator of the plant. In a conventional mixed network, which takes electric current from renewable energy facilities and conventional plants, numerous partners are involved, and this makes the tying in of the facilities with respect to the regulation and control technology and the decision making very complex, which also lead to supply failures in the recent past. 
     The production of the storable and transportable energy forms can be shut-down or even interrupted at any time. This happens preferably in cases when a peak energy demand exists in the electrical mixed network. The “chemical part” of the of the present invention can be shut-down or switched off relatively easily and quickly. Also here, the decision taking authority rests in the range of responsibilities of the operator of the plant of the present invention. 
     The energy form which is provided by the chemical plant of the present invention can serve as an additional energy buffer. Thus, methanol can be stored, for example, in order to provide additional electric power to the electrical mixed network during peak power demands. Methanol can be combusted on request, for example, in heat power plants, or electric energy can be generated therewith in fuel cells (e.g., direct-methanol fuel cells, called MFC). 
     The present invention is also based on the generation of hydrogen with the aid of electric energy largely taken from wind and/or solar power plants in combination with the direct conversion of the hydrogen to a hydrocarbon. Hydrogen is thus not stored or highly condensed or cooled and transported over large distances, but serves as an intermediate product that is converted at the site of its generation. According to the invention, substance-converting (chemical) processes, notably the intermediate provision of hydrogen and the conversion of the hydrogen together with carbonic acid gas to a hydrocarbon (e.g., methanol) follow an energy-converting process, in which solar energy or wind energy is converted into electric energy. 
     Taking into account standards in energy technology, facility technology and economics, together with the demand for a preserving use of all material, energetical and ecological resources, a new solution in energy technology is provided according to the invention. 
     Further advantageous embodiments can be taken from the description, the Figures and the dependent claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       In the drawings, different aspects of the invention are represented schematically, wherein: 
         FIG. 1 : shows a scheme representing the principle of climate neutrality by the investment in or the operation of compensation projects; 
         FIG. 2 : shows the basic steps of a first method to create a chemical plant of the present invention; 
         FIG. 3 : shows the basic steps of a second method of creating a chemical plant according to the invention; 
         FIG. 4 : shows the basic steps of a further method of creating a chemical plant according to the invention; 
         FIG. 5 : shows the steps of a further partial method according to the invention; and 
         FIG. 6 : shows a scheme illustrating the steps of a further partial method according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The method according to the invention is based on a new concept, which by using available starting materials provides so-called reaction products that are either directly usable as an energy carrier or that are indirectly usable as energy carriers, i.e. after performing additional intermediate steps. 
     The term energy carrier is used herein to designate compounds, which may either be used directly as a fuel or combustion material (such as, e.g., methanol  108 ) and also compounds (such as, e.g., silicon  603 ), which have an energy content or an elevated energy level and which can be converted in further steps with delivery of energy (refer to energy E 3  in  FIG. 6 ) and/or with delivery of a further energy carrier (such as, e.g., hydrogen  103 ). 
     The transportability of the energy carrier is herein characterized by the chemical reaction potential. 
     In the case of hydrocarbons (such as methanol  108 ) being used as an energy carrier, specific framework conditions should be respected during its storage and transport, which conditions are similar to the conditions for the handling of fossil fuels. In this respect, the existing infrastructure can be used without problems. Specific adaptations may be required only as far as the compounds are concerned. 
     In the case of silicon  603  being used as an energy carrier, specific framework conditions should be respected during its storage and transport so as to avoid initiating an undesired or uncontrolled reaction (oxidation) of the silicon. The silicon  603  should be stored and transported preferably in a dry state. In addition, the silicon  603  should not be heated because otherwise the probability of a reaction with water vapor from the ambient air or with oxygen rises. Investigations have shown that up to approximately 300° C., silicon has very little tendency to react with water or oxygen. The storage and transport of the silicon  603  together with a water getter (i.e., a compound that is hydrophillic/attracting water) and/or an oxygen getter (i.e., a compound that is attracting oxygen) is ideal. 
     The term silicon-dioxide-containing starting material  601  is used herein to designate compounds which contain a large proportion of silicon dioxide (SiO 2 ). Sand and shale (SiO2+[CO 3 ] 2 ) are particularly suitable. Sand is a naturally occurring non-consolidated sedimentary rock and occurs everywhere on the surface of the Earth in large concentrations. A majority of the occurances of sand consist of quartz (silicon dioxide, SiO 2 ). 
     According to a first embodiment of the invention, carbonic acid gas  101  is used as a carbon supplier, as indicated schematically in  FIG. 2 . The carbonic acid gas  101  is preferably extracted from a combustion process  201  (symbolized by a fire in  FIG. 3 ) or from an oxidation process through CO 2  precipitation (e.g., a Silicon-Fire flue gas cleaning facility  203 ). Furthermore, electric DC power E 1  is provided. The DC power E 1  is produced regeneratively (e.g., by one of the facilities  300  or  400  in  FIG. 4 ). The DC energy E 1  is used to carry out an electrolysis so as to generate hydrogen  103  as an intermediate product. The electrolysis facility, which carries out such electrolysis, is characterized in  FIG. 2  by the reference numeral  105 . The carbonic acid gas  101  is then brought to reaction with the hydrogen  103  (e.g., by a synthesis of methanol) so as to convert the (intermediate) products  101 ,  103  to methanol  108  or to another hydrocarbon. The reaction can be carried out in a reaction containment  106 , and the extraction of the methanol is characterized in  FIG. 2  by the reference numeral  107 . 
     In the following, further basic details of this method and the corresponding plant  100  are described. 
     A water electrolysis with an application of DC current E 1  is suitable in order to be able to generate hydrogen  103  as an intermediate product. The required hydrogen  103  is produced in an electrolysis facility  105  by the electrolysis of water H 2 O:
 
H 2 O−286.02 kJ=H 2 +0.5O 2   (Reaction 1)
 
     The required (electric) energy E 1  for this reaction amounting to 286.02 kJ mol corresponds to 143,000 kJ per kg H 2 . 
     The synthesis of the methanol  108  (CH 3 OH) proceeds in the Silicon-Fire plant  100  after the exothermal reaction between carbonic acid gas  101  (CO 2 ) and hydrogen  103  (H 2 ) as follows:
 
CO 2 +3H 2 ═CH 3 OH+H 2 O−49.6 kJ(gaseous methanol)  (Reaction 2)
 
     The generated reaction heat energy W 1  amounting to 49.6 kJ/mol=1,550 kJ per kg methanol=0.43 kWh per kg methanol, is extracted from the corresponding synthesis reactor  106 . Typical synthesis conditions in the synthesis reactor  106  are approximately 50 bar and approx. 270° C., so that the reaction heat energy W 1  can also be used for, e.g., a nearby seawater desalination facility or a heating plant. 
     Preferably, the synthesis of methanol is performed by application of catalysts in order to keep the reaction temperature and pressure as well as the reaction duration low and in order to ensure that high-value (pure) methanol  108  is generated as the reaction product. 
     In another preferred embodiment of the invention, a synthesis of methanol according to an electrolysis method propagated by Prof. George A. Olah is carried out. Details thereon can be taken, for example, from the book “Beyond Oil and Gas: The Methanol Economy”, George A. Olah et al., Wiley-VCH, 1998, ISBN 0-471-14877-6, chapter 11, page 196. Further details can also be taken from the US patent application US 2009/0014336 A1. Prof. George A. Olah describes the synthesis of methanol by the electrolysis of CO 2  and H 2  as follows:
 
CO 2 +2H 2 O−682.01 kJ=CH 3 OH+1.5O 2   (Reaction 3)
 
     In this reaction, CO and H 2  are generated in an intermediate step in a ratio of about 1:2. The CO and H 2  that is generated at a cathode, can be converted to methanol using a copper- or nickel-based catalyst. The synthesis path according to reaction 3 is related to a theoretical addition of 682.01 kJ=0.189 kWh of electric energy per mol of methanol  108  produced. 
     In the case that the plant of the present invention is located in the vicinity of a CO 2  source, it is possible to refrain from a liquefaction for the transport of CO 2 . Otherwise, it is relatively easy according to the state of the art, to liquefy the CO 2  and to bring it to a plant of the present invention  100 . In case of a renunciation of the liquefaction, and where necessary for storage and transport over large distances, the CO 2  is available in a conceivably cost-neutral way by accounting for CO 2  avoidance credits. Also in the case of a transport, the costs for the “buying” of the CO 2  are relatively low. 
     In  FIG. 3 , further steps of a first method according to the invention, respectively a part of a Silicon-Fire plant  200  are shown. The carbonic acid gas  101  is, as already mentioned, preferably extracted from a combustion process  201  (here characterized by a fire) or from an oxidation process by means of CO 2  precipitation, e.g., with a Silicon-Fire flue gas treatment facility  203 . The Silicon-Fire flue gas treatment facility  203  can be constructed, for example, according to the principle of the cleaning of flue gas, wherein the CO 2  is “washed out” from the flue gas  202  using a cleaning solution. A flue gas cleaning which uses NaOH as a cleaning solution and in which the NaOH is recycled, is particularly suitable for a flue gas cleaning. Details thereon can be taken, for example, from the parallel application EP 1 958 683 filed on 7 Aug. 2007. However, other principles of CO 2  precipitation or production can also be used. 
     The Silicon Fire flue gas cleaning facility  203  allows extracting CO 2  (herein called a resource) from the flue gas  202 . This CO 2  is then supplied directly or indirectly to the Silicon-Fire plant  100  which then generates/synthesizes a hydrocarbon (preferably methanol  108 ) under application of the CO 2  as a carbon supplier and under application of electric power. 
       FIG. 4  shows, in a schematic block diagram, the most important modules/components for the method steps of a Silicon-Fire plant  100 . This plant  100  is designed such that a method for providing storable and transportable energy carriers  108  can be carried out. The corresponding method is based on the following basic steps. 
     Carbonic acid gas  101  is provided as a carbon supplier, as already described. The required electric DC power E 1  is produced using renewable energy technology and is supplied for use to the Silicon-Fire plant  100 . Solar heat plants  300  and photovoltaic plants  400  which are based on solar modules are particularly suitable as renewable energy technology. It is also possible to arrange a combination of these types of plants  300  and  400  since the demand per area in relation to the electric power from the solar thermal plant  300  is less than that from a photovoltaic plant  400 . 
     According to the invention, an electrolysis  105  is carried out under application of the electric DC energy E 1  so as to produce hydrogen  103  or hydrogen ions as an intermediate product. The electrolysis  105  can be carried out according to the following three different approaches:
         either a direct water electrolysis according to Reaction 1 as represented in  FIG. 4  is performed, or   silicon is produced from a silicon-dioxide-containing composition in an electrolytic way, where the silicon then reacts with water  102  to produce hydrogen  103  and silicon dioxide in a subsequent (downstream) hydrolysis reaction, or   methanol  108  is directly produced (refer to Reaction 3) in an electrolytic way, wherein intermediate hydrogen such as hydrogen ions are generated, which react, however, directly with the other ions or reaction partners to form methanol  108 .       

     In the methods which do not produce methanol  108  directly in an electrolytic way, hydrogen  103  and carbonic acid gas  101  are brought together in the plant  100  so as to convert these in a reaction  106  to methanol  108  or to another hydrocarbon. The methanol  108  may then be extracted from the plant  100 , as represented by the arrow  107 . 
     In  FIG. 4 , a particularly preferred plant  100  is represented, which is constructed such that the initially mentioned disadvantages are reduced or compensated. For this reason, an economically and ecologically optimal combination of regenerative electric power supply (by the plants  300  and/or  400 ) and conventional power supply, here represented as a part of a mixed network  500 , are realized using the Silicon-Fire plant according to the invention. In a preferred embodiment, the Silicon-Fire plant  100  therefore enables the regenerative electric energy E 1  to be used for chemical reactions (here the electrolysis reaction  105 ) and thus to store it. A further portion of the required energy is taken from the mixed network  500 . This portion is converted into DC energy E 2 . To this end, an according converter  501  comes into operation, as indicated in schematic form in  FIG. 4 . The corresponding facility parts or components are herein referred to as the energy supply plant  501 . 
     The energy supply of the plant  100  is controlled and regulated by means of an intelligent facility control device  110 . In principle, the respective excess energy portion E 2  that is presently available is taken from the mixed network  500 , while the other energy portion (here E 1 ) is taken as largely as possible from a solar power plant  300  and/or  400  (or from a wind farm) associated with the plant. Accordingly, an intelligent reversal of the hitherto used principles is realized, in which the energy variations of renewable energy facilities  300 ,  400  are buffered by tying in and out (switching on and switching off) conventional facilities. For operating a Silicon-Fire plant  100 , it is therefore not required to hold available additional power and frequency regulation capacities for the regenerative power plants in the mixed network  500 . This principle allows the operator of a Silicon-Fire plant  100  to take into account additional technical and economical parameters in the control of the plant  100 . These parameters concern so-called input parameters I 1 , I 2 , etc., which are tied in by the control device  110  when taking decisions. Some of these parameters can be predefined within the control device  110  in a parameter storage  111 . Others of the parameters can be supplied from the outside. Here, for example, information on price and/or availability from the operator of the mixed network  500  may be input. 
     In the facility control device  110 , so-called software-based decision processes are implemented. A processor of the control device  110  executes a control software and takes decisions by accounting for parameters. These decisions are transformed into switch or control instructions, which cause the control/regulation of energy and mass fluxes, for example, through the control or signal lines  112 ,  113 ,  114 . 
     Considered from the perspective of the mixed network, the Silicon-Fire plant  100  concerns a consumer, which can be switched-on and off quickly and which can be used relatively flexible. If, for example, a sudden additional demand of electric energy occurs in the mixed network, then the control device  110  can shut down or switch off completely the portion E 2 . In this case, from that moment on, either accordingly less hydrogen  103  is produced whence energy E 1  is available, or the electrolysis is temporarily stopped completely. 
     In  FIG. 4  it is indicated by means of dashed arrows  112  which begin at the control device  110  that the control device  110  regulates the energy fluxes E 1  and E 2 . The arrows  112  represent control or signal lines. Also other possible control or signal lines  113 ,  114  are represented. For example, the control or signal line  113  regulates the amount of CO 2  that is available for the reaction  106 . If, for example, less hydrogen  103  is produced because no energy E 2  is available, then also less CO 2  must be supplied. The optional control or signal line  114  can, for example, regulate the amount of H 2 . Such a regulation makes sense, for example, in cases where there is a hydrogen buffer storage, from which hydrogen  103  can be drawn, even where there is less hydrogen or no hydrogen at all is produced momentarily by the electrolysis  105 . 
     Investigations have shown that it is particularly economical and advantageous in an environmental sense if the Silicon-Fire plant  100  extracts between 15% and 50% of the electric energy requirement from solar energy and the remaining energy requirement from the mixed network  500  (i.e., mainly fossil). It is particularly preferable to cover between 30% and 40% of the electric energy requirement from solar energy and the remaining 70% to 60% from the mixed network  500  (i.e., mainly fossil). The intelligent facility control device  110  is set or programmed according to these specifications. 
     An embodiment of the plant  100 , which provides for the extraction of cheap electric energy from the mixed network  500  in low-load periods, is particularly preferred. 
     According to a preferred embodiment of the invention, the facility control device  110  is set or programmed such that the networking between regenerative electric energy sources  300  and/or  400  and the electrical mixed network  500  is optimized such that the total costs of electric energy becomes minimal for maximum usage of the regenerative electric energy sources  300  and/or  400 . 
     According to a preferred embodiment of the invention, the facility control device  110  is set or programmed such that the networking between regenerative electric energy sources  300  and/or  400  and the electrical mixed network  500  is optimized such that the total costs of the carbonic acid gas product  108  becomes minimal for a maximum usage of the regenerative electric energy sources  300  and/or  400  and by taking into account the total costs of the electric power and the periods of capacity utilization by operation of the whole plant  100  and its facility parts. 
     According to a preferred embodiment of the invention, the facility control device  110  is set or programmed such that the networking between the regenerative electric energy sources  300  and/or  400  and the electrical mixed network  500  is optimized such that revenues are gained by temporarily supplying (emerging from) the regenerative energy sources  300  and/or  400  to the electrical mixed network  500  during its peak periods and that thereby the total costs of the electric power for the method according to the invention or the total costs of the carbonic acid gas product  108  are reduced or lowered as far as possible. 
     In periods of a peak electric power demand of the electrical mixed network  500 , the regenerative energy E 1  can also be supplied to the mixed network—to obtain higher revenues. 
     The aspects of these preferred embodiments can easily and without problems be combined by a corresponding design of the control device  110 . 
     In the following, further basic aspects of a method according to the invention for providing storable and transportable energy carriers are shown. In this method, silicon  603  as a first storable and transportable energy carrier and methanol  108  as a second storable and transportable energy carrier are provided. The method comprises at least the following steps. 
     By a transformation, a silicon-dioxide-containing starting material  601  is converted to elementary silicon  603  by means of a reduction process  602 , as shown in  FIG. 5 . The elementary silicon  603  is herein called silicon for reasons of simplicity. The required electrical (primary) energy E 1  for this reduction process  602  is provided according to the invention from a regenerative energy source  300 . In a subsequent/downstream step, at least a portion of the silicon  603  can be utilized in a process for generating methanol. In this process, for example, a synthesis gas composed of carbonic acid gas  101  and hydrogen  103  comes into use in the process of generating methanol. The silicon  603  can also be extracted from the process as an energy carrier. The silicon  603  can, for example, be stored or transported away. 
     The transformation  602  is preferably an electrochemical electrolytical transformation (with participation of an electrical current E 1 ), as schematically indicated in  FIG. 5 . 
     In the electrochemical transformation  602  according to  FIG. 5 , the (primary) energy E 1  for the transformation is provided in the form of electric current which is generated from sunlight. For the electrochemical transformation  602 , a solar plant  300  is utilized, as indicated schematically in  FIG. 5 . 
     The electrochemical transformation  602  can, for example, be carried out by employing silicon dioxide as an electrode. A metal is employed as the second electrode. Calcium chloride (CaCl 2 ) is, for example, used as an electrolyte. This electrochemical transformation process  602  functions particularly well with an electrode made of porous silicon dioxide, which may, for example, be sintered from silicon dioxide. Details concerning this method can be taken from the following publications:
     Nature Materials, June 2003; 2(6): 397-401, Nohira T., Yasuda K., Ito Y., Publisher: Nature Pub. Group.   “New silicon production method with no carbon reductant”, George Zheng Chen; D. J. Fray, T. W. Farthing, Tom W. (2000).   “Direct electrochemical reduction of titanium dioxide to titanium in molten calcium chloride”, George Zheng Chen, D. J. Fray, T. W. Farthing, Nature 407 (6802): 361-364, doi: 10.1038/35030069.   “Effects of electrolysis potential on reduction of solid silicon dioxide in molten CaCl 2 ,” YASUDA Kouji, NOHIRA Toshiyuki, ITO Yasuhiko; The Journal of Physics and Chemistry of Solids, ISSN 0022-3697, International IUPAC Conference on High Temperature Materials Chemistry No. 11, Tokyo, Japan (19 May 2003), 2005, vol. 66, no. 2-4 (491 p.);   U.S. Pat. No. 6,540,902 B1;   WO 2006/092615 A1.   

     Preferably, a reduction process  602  is performed at a temperature of approximately 1900 K (=1630° C.) so as to reduce the silicon dioxide  601  to silicon  603 . In an electrochemical transformation  602 , however, considerably lower temperatures (preferably less than 500° C.) are required. 
     In relation with  FIG. 6 , it is described how silicon  603  can be utilized as an energy carrier. The reduced silicon  603  is an energy-rich compound. This silicon has the tendency to oxidize with water in fluid or vapor form back again to silicon dioxide  604  (reverse reaction), as indicated schematically in  FIG. 6 . In the so-called hydrolysis  605  of the silicon  603 , energy E 3  (e.g., heat energy) is liberated because this concerns an exothermal reaction. In addition to the silicon dioxide  604 , hydrogen  103  is formed, which can be utilized, for example, as an energy carrier for the generation of methanol  108 . Preferably, the hydrolysis  605  takes place at elevated temperatures. Temperatures are preferred which are clearly above 100° C. In the temperature range between 100° C. and 300° C., a conversion in usable quantities is achieved in cases when the silicon  603  is brought in contact and mixed in a very finely grained or powdery consistency with water vapor  102 . Since otherwise the silicon  603  has only a very low tendency to react with water up to approximately 300° C., the hydrolysis  605  is preferably performed in the temperature range between 300° C. and 600° C. 
     The hydrolysis can also be performed with aqueous hydroxide and alkali carbonate-solutions, for which preferably temperatures between 60° C. and 160° C. are used. 
     According to the invention, in a method according to  FIG. 6 , the silicon  603  is introduced into a reaction area and mixed with water  102  in liquid or vapor form. In addition, according to the invention, care is taken that the silicon  603  has a minimum (threshold) temperature. Either the silicon  603  is heated for this purpose (e.g., using heating means or by heat-generating or heat-releasing additives) or the silicon  603  is already at a corresponding temperature level when it is introduced. 
     Under these framework conditions, hydrogen  103  is then liberated in the reaction area as a gas. The hydrogen  103  is extracted from the reaction area. 
     In the following, a quantitative example for a method according to  FIG. 6  or according to  FIG. 5  in combination with  FIG. 6  is presented: 
     1 mol (=60.1 g) SiO 2  forms 1 mol (=28 g) Si. 
     1 mol (=28 g) Si in turn forms 1 mol (=451 g) H 2 . This means that 2.15 kg SiO 2  form 1 kg Si and froms this 1 kg Si in turn, 1.6 m 3  H2 are formed. 
     The generation of methanol can be carried out according to one of the methods known and used at large-scale. A method is preferred in which a catalyst (e.g., a CuO—ZnO—Cr 2 O 3  or a Cu—Zn—Al 2 O 3  catalyst) is used. 
     The invention has the advantage that in the reduction of the silicon dioxide and in the reduction of the water  102 , no CO 2  is liberated as long as only energy E 1  which originates from a plant  300  and/or  400  is utilized in these reactions. The required energy is therefore provided at least in part from renewable energy resources, preferably from the plants  300  and/or  400 . 
     In the hydrolysis  605 , the elementary silicon  603  is utilized preferably in a powder form or in a granular or grainy form. 
     According to the invention, CO 2    101  serves as a starting material and as a carbon supplier for the synthesis of methanol in the reactor  106 . Preferably, the following serve as a CO 2  source: steam reforming facilities, natural gas-CO 2 -separation facilities, cement plants, bio-ethanol plants, seawater desalination facilities, power plants and other facilities or combustion processors which emit large quantities of CO 2 . 
     The invention avoids the considerable economical disadvantages of known approaches, when—as in the case of the Silicon-Fire plant  100 —the electric solar and/or wind energy, which is produced unsteadily, is directly converted to chemical reactions and is stored in a chemically bound form, without the additional capacities for reserve power and/or frequency regulation in the mixed network. 
     In the case that photovoltaic current is generated by means of a photovoltaic plant  400 , there is a further advantage in that the DC current E 1 , which is primarily produced from the solar cells of the photovoltaic plant  400 , can be utilized directly in the chemical process (electrolysis  105 ), without having to be converted using converters to an alternating (AC) current for the voltage transformation. 
     LIST OF REFERENCE NUMERALS 
     
       
         
               
               
             
           
               
                   
               
             
             
               
                 car Industry/automotive Engineering 
                  1 
               
               
                 operator of Power Plant 
                  2 
               
               
                 wind farm 
                  3 
               
               
                 Silicon-Fire plant 
                 100 
               
               
                 carbon dioxide 
                 101 
               
               
                 water 
                 102 
               
               
                 hydrogen 
                 103 
               
               
                 providing carbon dioxide 
                 104 
               
               
                 carrying out an electrolysis 
                 105 
               
               
                 bringing together the hydrogen (H 2 ) and the carbon 
                 106 
               
               
                 dioxide/synthesis reactor 
               
               
                 delivering/providing methanol 
                 107 
               
               
                 transportable energy carrier 
                 108 
               
               
                 (facility) control device 
                 110 
               
               
                 parameter storage 
                 111 
               
               
                 control or signal lines 
                 112, 113, 114 
               
               
                 Silicon-Fire partial facility 
                 200 
               
               
                 combustion process 
                 201 
               
               
                 flue gas comprising CO 2   
                 202 
               
               
                 Silicon-Fire flue gas cleaning facility 
                 203 
               
               
                 clean gas 
                 204 
               
               
                 flue free of CO 2   
                 205 
               
               
                 extraction of CO 2   
                 206 
               
               
                 solar thermal energy facility 
                 300 
               
               
                 conversion of heat to direct current 
                 301 
               
               
                 solar plant (photovoltaic plant) 
                 400 
               
               
                 mixed network 
                 500 
               
               
                 conversion of alternating voltage to direct current 
                 501 
               
               
                 (energy supply facility) 
               
               
                 silicon-dioxide-containing starting material 
                 601 
               
               
                 silicon 
                 603 
               
               
                 reduction process 
                 602 
               
               
                 silicon dioxide as a reverse reaction product 
                 604 
               
               
                 hydrolysis 
                 605 
               
               
                 direct current (DC) energy 
                 E1 
               
               
                 additional electric power 
                 E2 
               
               
                 energy 
                 E3 
               
               
                 input parameters 
                 I1, I2, etc. 
               
               
                 primary energy 
                 P1, P2 
               
               
                 reaction (product) heat from the synthesis of methanol 
                 W1