This article is a continuation of our series about various topics in renewable energy.A gas turbine is a type of internal combustion engine that has a rotating compressor in its upstream coupled to a turbine in its downstream. In between is a combustion chamber. In the gas stream, energy is added where fuel is mixed with air and ignited. In the high pressure combustion chamber, the temperature is increased by the combustion driven expansion of the fuel. The combustion’s by products are forced into the turbine section. From there, high volume and velocity gas flows straight through the nozzle and through the blades of the turbine, spinning the turbine that powers the compressor. In power turbines, this usually also drives the mechanical output shaft. Energy in to the turbine is transferred from the reduced temperature and pressure from the exhaust gas. Energy is then extracted in the form of compressed air or thrust, shaft power, and any combination of these. This energy is used to power aircrafts, trains, generators, ship and tanks.Gas turbines were originally developed for and used in the military and aerospace applications. Nowadays, these are used in many industrial applications. The same types of gas turbines used to power aircraft are used in power turbines for compressor, mechanical drive, generator and general applications.Currently, there is heavy spending worldwide to build gas turbine power plants in many countries, as power generation is one of the growing concerns. Environmental issues have increasingly become highlighted. Governments around the world are pressured to enforce strict regulation on the reduction of carbon emissions and the use of alternative fuels. Gas turbine generators are favored for low emissions among traditional fossil fuel powered plants.Gas turbine power plants are basically dependent on fuel and air for combustion, and ultimately for generation. The process of generation involves combustion of fuel and air in the combustion chamber.Because of the gas turbines’ flexibility, they are often deployed as peak load machines. This is where gas turbines come in handy and work effectively when consumers are utilizing maximum use of power from the grid (i.e., late summer afternoons while industry is still working and consumers are heading home to turn on the AC).Gas turbines involve low installation and maintenance cost compared to other alternate fuels. An average gas turbine generator plant of 400 megawatts with three units can be built at a cost no more than 300 million dollars. Gas turbines are very low maintenance machines resulting in low operations and maintenance cost requirements.It takes several minutes to start a gas turbine, run up to full speed at no load and synchronize to the grid. This quick start machine feature is important especially when power is immediately needed. Power generators often start with diesel fuel before switching to natural gas for continuous operation.Gas turbine technology is continuously evolving since humble beginnings. Research is in progress to produce smaller, more efficient combustions chambers, better cooling engine parts, reduced emissions and more powerful gas turbines. On the emission side, research and development is underway for combustor technology to achieve near zero emissions. In the 1990’s compliant foil bearing were introduced to gas turbines which can withstand more than hundreds of start / stop cycles and do not require a bearing oil system.Photo Credit: Alstom
This article is a continuation of our series about various topics in renewable energy.A fuel cell is an energy conversion device that produces electricity from external sources. Energy is created when two elements with opposite properties are placed in a fuel cell and react together. The energy created will continuously flow until there is nothing more to react. Fuel cells generate clean energy. The only waste product is water vapor. With today’s changing economy and increasing fossil fuel prices, many people are looking for alternatives. For these reasons, the technology on hydrogen fuel cell has developed. Fuel cell technology provides a wide array of important benefits and advantages including the following:Fuel Cells are ReliableFuel cell technologies are more reliable as compared to traditional combustion engines. Researchers say that a technology such as this has shown reliabilities that can be applied to any kind of engine. With 100% reliability, it has proven to be more appropriate for the most demanding applications.Fuel Cells Raised Quality PowerFuel cell technologies provide a high quality of DC power, perfectly compatible to any kinds of electrical applications, specifically like electronics used inside the hospitals. By using fuel cells as the distribution product in energy networks, brown outs, black outs and power fluctuations can now be lessened or better, completely avoided.Fuel Cells are CleanFuel cells technologies only produce water that comes from fueling hydrogen into the system. Regardless if it is powered by high-priced fossil fuels, polluting emissions produced less compared to other conventional technologies.Fuel Cells are Vibration FreeWithout the presence of moving parts, fuel cells are vibration free and are silent as night. Unlike traditional engine technologies that create sound / noise, fuel cells are quieter and no vibration at all even if it is made up of compressors, pumps and other parts.Fuel Cells CostAlthough fuel cells are more expensive than fossil fuels, it is predicted that in the near future, fuel cell power will be less expensive and more efficient. The cost is an enticing advantage for the future.The above are just some of the benefits of hydrogen fuel cell technologies. With this generation, a shift in usage can determine better effects than other traditional combustion engines.On the other hand, there are also several disadvantages such as the fact that fuel cells actually lose energy such that it cost more to produce energy. Other concerns include the tricky issues of finding feasible ways to produce, ship, and distribute hydrogen (used to fuel the fuel cell). And lastly, fuel cells are bulkier and bigger as compared to other energy sources.Bottom line and truth remains that using hydrogen fuel cells as an alternative fuel is in the long run, a positive effect on the environment. The only emission is water vapor, a lot environment-friendly than the toxic elements released into the air by burning fossil fuels and gasoline burning cars. The advantages outweigh the disadvantages. Hydrogen as an alternative fuel has the most promise over other alternative fuels.