Conventional alternatives

Despite the fact that OTEC systems have no fuel costs and can produce useful by-products, the initial high cost of building such power plants (up to 5,000 per kilowatt) currently makes OTEC generated electricity up to five times more expensive than conventional alternatives. As such, at the present time OTEC systems are largely restricted to experimental and demonstration units. One of the major facilities for OTEC research is the Natural Energy Laboratory of Hawaii Authority at Keahole Point on the island of Hawaii. An experimental OTEC facility located there has had a maximum net power production of 100 kilowatts, at the same time producing 5 gallons per minute of desalinated water. 

Table 14.7 Microbial, biological and botanical organic materials and their typical conventional alternatives the average use rate in pesticides used in conventional farming compared to the pesticides used in organic farming...

Organic pesticide conventional alternative Trade name Typical use rate (pounds active ingredient/acre) Ratio of average conventional use rate to organic use rate... 

Organic pesticide conventional alternative Trade name LD50a cPADb,e aPADc,e PEAS EIUd EIU crop... 

Table 14.10 Mineral, petroleum and soap-base organic materials and their typical conventional alternatives toxicity comparisons (see notes)... 

Here, meq is number of milliequivalents and CEC is the cation exchange capacity, expressed in milliequivalents per 100 g of sediment. According to the Vanselow convention, alternatively, the activity is expressed as the the fraction of the sites occupied by the ion,... 

Fig. 1. A high-throughput platform of the carbohydrate-based microarrays. A high-precision robot designed to produce cDNA microarrays was utilized to spot carbohydrate antigens onto a chemically modified glass slide. The microspotting capacity of this system is approximately 20,000 spots per chip. The antibody-stained slides were then scanned for fluorescent signals with a Biochip Scanner that was developed for cDNA microarrays. The microarray results were subsequently confirmed by at least one of the conventional alternative assays.

For the evaluation of probabilities for spin-forbidden electric dipole transitions, the length form is appropriate. The velocity form can be made equivalent by adding spin-dependent terms to the momentum operator. A sum-over-states expansion is slowly convergent and ought to be avoided, if possible. Variational perturbation theory and the use of spin-orbit Cl expansions are conventional alternatives to elegant and more recent response theory approaches. 

Under all conditions, the capability to provide simultaneous heat and power provides substantial advantage for the microgrid system relative to the conventional system. The ability to effectively manage an H-APS to efficiently match both heat and power demand, including seasonal factors and unexpected events, is also key to the success of these systems. Installing technologies appropriately sized to deliver necessary heat and power as efficiently as possible will maximise benefits relative to conventional alternatives. 

This type of analysis would help indicate where opportunities exist to deliver both financial and environmental benefits relative to conventional alternatives. 

Waterborne epoxy coatings and adhesives have established the building and construction industry as their largest market. Commercial systems have been available for many years. The following characteristics propel their use over conventional alternatives ... 

Energy from biomass is hardly commercially viable for any technological option at the current price levels of competing conventional alternatives in the Netherlands. Representative price levels for the production and supply of these alternatives are presented in Table 2. Due to the cunent process of liberalisation of both the electricity and the gas markets, prices are expected to drop substantially. Regarding electricity the decrease may lie in the order of 20 - 25%, whilst the gas wholesale prices may become 10-15% lower. Therefore, utilisation of renewable electricity from biomass is stimulated by financial and fiscal incentives to achieve the Dutch COj-targets. These measures should be placed in the above-mentioned framework of the Dutch policy to achieve an improvement of 10% energy supply from renewables in 2010,... 

In most industrialised countries the investor can choose between the application of a biomass technology and a conventional alternative. The conventional alternative for the investor is normally to produce heat with a fossil oil/gas boiler and/or to buy electricity from utilities. This is specified as the standard situation in this paper. 

So, as the comparison of technology related data and the comparison of specific cost are not likely to describe competitiveness for different kinds of biomass conversion technologies, it seems to be necessary to choose the application of technologies as a basis for describing the competitive situation. The term application is used in this paper to describe a plant and its purpose, size, the fuel used, the aimual operation time, the specific labour cost and the cost for the conventional alternatives given for the investor. 

The annual cost of the conventional alternative is calculated by using specific cost data for heat generation based on fossil fuels and for electric power purchased from utilities. These data are compiled for the different applications discussed depending on power demand, consumer specification (industry, utility, private) etc. 

Cost of conventional alternatives (Table i) have been collected in spring 2000 for the situation in Austria and reflect the cost, that private and companies have to pay for producing heat with fossil oil/gas and purchasing power from the grid instead of operating a biomass application. 

The cost of the competing conventional alternative for co-combustion is a special case in this calculation. As the gasifier produces gas for a coal power station, the competing conventional alternative is not heat or power, but the coal, that is substituted. Therefore the cost for the conventional alternative is the cost for the substituted coal. 

In Table 7 results are given for the applications selected and specified before. The relation between overall cost of the biomass application and the cost of the conventional alternative gives the competitiveness factor CF as described in the chapter Approach . 

CF-values <1 indicate that the biomass application is more expensive than the conventional alternative and therefore not very competitive. The higher the CF-value is, the more conqjetitive is the application investigated. 

Based on the data mentioned in the previous section, the MILP model has been formulated. Due to the lack of space a thorough discussion of the model equation is impossible. The model has been solved applying the MILP solver SYIMPHONY [6]. For the product demand an initial 35% of the total product demand achieved in the tenth year was assumed with a linear progression. This product demand forecast was used for the conventional alternative and the stepwise capacity expansion. 

Conventional alternatives to a microreactor, such as non-catalytic tubular reactors, exhibit about 100-150 m m surface area to reactor volume, a value very similar to conventional heat exchangers. Using these reactors with porous catalysts filling the tubes can increase the surface area dramatically up to 10 nf m . Typically, the surface area of microreactors is in the range of lO to 10 nf m . This is the surface area only of the microreactor walls, which in general are non-porous. 

There are several competing concepts to applying a subsea gas compressor. The most conventional alternative would be to install a minimum facility platform with conventional topside compressors. When establishing the rehabdily target for the subsea gas compressors, this alternative would therefore be a natural basis for the comparison. 

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