Energy sources fuel cells

Currently, the higher cost for this energy system (as compared to conventional energy systems) is primarily due to the energy source (fuel cell) and the power system. Recent U.S. Department of Energy (DOE) studies have predicted that for fuel-cell energy systems to be economically viable, the cost of the power systems have to be < 400/kW while the cost of the power electronics needs to be < 40/kW. The issues of durability and life of the fuel cells are of key importance. 

Fuel cells have several important benefits over conventional electrical eneigy generation from sources such as coal, as they are more efficient at converting fuel sources to end-use energy. The fuel cell vehicle will have no harmful emissions such as nitrogen oxide (NO ), sulfur oxide (SOJ, or particulates. Fuel cells provide waste heat utilization in co-generation, units which serve to raise the overall energy efficiency (65-85%). 

Fuel cells have several important benefits over conventional electrical energy generation from sources such as coal. They are more efficient at converting fuel sources to end-use energy. The fuel cell vehicle will have no harmful emissions... 

Figure 5.3. Layout of a decentralised, building-integrated hydrogen and fuel cell system based on intermittent primary power sources (such as wind or solar energy), reversible fuel cells and local stores, including stationary and maybe vehicle-based stores, and possibly capable of interchanging hydrogen with users in other buildings through pipelines (Sorensen, 2002a).

Narayanan SR, Valdez n (2008) High-energy portable fuel cells power sources. ECS Interface 17 40-45... 

Figure 6.6 FuelCell Energy deployed units end-user markets Source Fuel Cell Energy...

Hart, D. (2000) Sustainable energy conversion fuel cells the competitive options Journal of Power Sources, 86, 23-27. 

KBs are generated from acetyl CoA in liver cell mitochondria. The three KBs are acetoacetate, acetone and 3-hydroxybutyrate. They are carried in the blood to tissues that can use them as an energy source. Liver cells are unable to utilize KBs as fuel, as liver cells lack the enzyme 3-ketoacyl CoA transferase that is necessary to regenerate acetyl CoA from the KBs. 

In summary, fuel cell development is being accelerated both by the wide variety of applications and by the search lor cleaner and more efficient utilization of primary energy and, ultimately, renewable energy. Because these forces for change are unlikely to disappear, It is quite likely that fuel cells will emerge as one of the most important and pewasive power sources for the future. 

If hydrogen is made from decarbonized fossil fuels, fuel-cycle emissions can be cut by up to 80 percent. With renewable energy sources such as biomass, solar, or wind, the fuel cycle greenhouse gas emissions are virtually eliminated. It is possible to envision a future energy system based on hydrogen and fuel cells with little or no emissions of pollutants or greenhouse gases in fuel production, distribution, or use. 

Dry cells (batteries) and fuel cells are the main chemical electricity sources. Diy cells consist of two electrodes, made of different metals, placed into a solid electrolyte. The latter facilitates an oxidation process and a flow of electrons between electrodes, directly converting chemical energy into electricity. Various metal combinations in electrodes determine different characteristics of the dry cells. For example, nickel-cadmium cells have low output but can work for several years. On the other hand, silver-zinc cells are more powerful but with a much shorter life span. Therefore, the use of a particular type of dry cell is determined by the spacecraft mission profile. Usually these are the short missions with low electricity consumption. Diy cells are simple and reliable, since they lack moving parts. Their major drawbacks are... 

Note that fuel cells do not provide a new source of energy. They are designed to use conventional, currently available fuels. Their main advantage lies in the efficiency of their operation, which creates fewer byproducts to threaten the environment. 

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