Combined heat and power (CHP) is simultaneous generation of electricity and heat in a single process. CHP has high overall efficiency that is over 70% while efficiency of the conventional gas-fired power station is around 40% due to losses in distribution and transmission. The fuel sources that are used for CHP is natural gas and renewable sources such as biomass and biogas. It can help to save energy, reduce environmental impact and decrease social impact in the area.
CHP system can be employed over wide range of sizes, application, fuels and technologies. Normally, it employs a gas turbine, an engine or a stream turbine to drive an alternator to generate electricity that can use wholly or partially on site. The heat produced during power generation is recovered and it can be used for space heating and domestic hot water. CHP can be used in many places such as commercial building, residential area and industries.
Benefits of deploying CHP system in the building include the following :
Reduced energy cost
Building owners can reduce their cost energy by deploying CHP systems because compared to conventional systems, provide the following advantages
Increased energy efficiency
Reduced demand charge
Reduced peak electrical energy cost
Due to higher energy efficiency of CHP system, it consumes nearly 40% less fuel than conventional system. The reduced fuel consumption can significantly reduce energy cost. The cost of electricity to the building generally based on power demand and electricity energy usage.
CHP system reduced power demand in 2 ways
By generating some of power at site
By using thermal energy from power generation equipment instead of electricity, for operating cooling, heating and humidity control equipment.
Reduced life-cycle costs
The initial cost of CHP system for buildings is higher than purchasing all electricity power needs and using conventional chillers and boilers for cooling, humidity control and heating needs. The life-cycle cost of CHP is often lower due to energy cost saving over its useful life over 20 years.
Attractive return on investment
If the incremental installed cost of CHP system over conventional system is treated as investment and annual saving in its energy cost are treated as the return on that investment, the return can be varied attractive.
Improved power reliability
Economic losses due to power outages. Since CHP system generate power on-site or near-site. These systems improve power reliability by reducing and eliminating a building’s dependence on electrical power grid, and by providing an additional power option to the buildings. Power outages caused by losing distribution line are improbable because of CHP system located near building
The higher number of building that used CHP system, the lower demand on electricity grid will be. In areas where the grid is at or near capacity, the reduced demand provided by CHP will result in increased grid reliability.
CHP system help society and nation including :
Improved environment quality
Integrated systems for CHP for buildings improve efficiency of energy utilization as much as 85% compared to that around 35% for conventional system. Increased efficiency of energy utilization decreases the amount of fossil fuel consumed per unit of energy used and leads to 45% reduction in air emissions compared to conventional centralized power plants.
Reduced energy consumption
As discussed above, integrated systems for CHP for buildings increase efficiency of energy utilization from 51% for conventional power generation systems to as much as 85%. Therefore, the use of these systems reduces the consumption of fossil fuels, for a unit of energy required for a building, by about 40% of that used by conventional systems. In other words, conventional systems require 65% more energy than the integrated systems. This is important for prolonging the period of availability of our scarce fossil fuel resources (natural gas, oil and coal) and reducing our dependence on imported fuel and on nuclear energy.
Homeland security
Since overloading of grids is one of the primary reasons for major blackouts, CHP systems improve homeland security because the facilities that use CHP systems generate some power on-site, and thus reduce the load on the electric power grid. Since CHP systems also reduce our dependence on large-capacity central generation plants, these systems improve homeland security by reducing the impact if a large central power plant is shut down.
© University of Strathclyde 2009
