Simultaneous establishment of gas and electricity distribution networks to meet power demands of off-grid regions imposes high costs on the country, a report by Persian daily Forsat-e-Emruz suggests.
While heating and cooling needs of consumers could be addressed by means of electricity generation at a much lower cost, it is unnecessary to satisfy consumers' demand through a variety of energy carriers.
However, the issue of gas and electricity distribution should not be considered invariably as distribution costs vary depending on the recipients' distance from the central network, Saeed Mohazzab Torabi, head of the Energy Consumption Management Association, stated.
Establishment of electricity networks for rural areas is not economically viable, according to Torabi. Even if a gas network is established, it will be more advantageous to convert gas into electricity via a centralized system. Centralized generation, the electric power production by central station power plants, provides bulk power. Most of them use large fossil-fired gas turbines, and coal-fired boilers to produce steam. In some cases large hydro-power is also used.
Small-scale distributed power plants are an appropriate option in remote areas owing to their fuel efficiency of more than 65-70 percent, compared with that of normal power plants, not exceeding 40 percent on average.
Gas Option
Contrary to Torabi insisting on field studies and regional solutions to tackle energy distribution issues in different regions, Arash Najafi, head of Iran Energy Consummation Optimization Association, asserts gas distribution would be more advantageous than establishing an electricity distribution network.
"In spite of the fact that supplying gas is an onerous task, it results in more efficiency," Najafi told Forsat-e-Emruz. It is possible to generate power through small-scale distributed power plants using the electricity branch stretched out to the village as well as utilizing the hot steam generated via power plants to supply heat for households.
On whether solar panels are suitable to respond to power demand in remote areas, Najafi said efficiency of solar panels, currently at 12-13 percent in Iran, ought to be enhanced to 20 percent to realize this goal. Another downside is the cost. It is rarely cost-effective to power a home entirely with solar energy. Moreover, solar power cannot be considered a viable option due to the wide variance of solar exposure by location.
Combined solar power plants can be employed in the southern regions; nonetheless, gas supply and construction of small-scale distributed power plants remain a more viable alternative in the northern regions, Najafi noted. Referring to negative impacts of electricity distribution lines on environment, Najafi said not only do power lines impede vegetation growth, but also their electric flux jeopardizes the surrounding environment. "We have to consider environmentally-friendly alternatives."
As community awareness of environmental impact caused by large conventional power plants is growing, a greater interest in distributed-generation (DG) technologies based on renewable energy sources and cogeneration is emerging.
Cogeneration and Trigeneration
Through utilizing CHP (combined heat and power plants) and CCHP (combined cooling, heating and power plants), heating efficiency of gas can increase up to 95 percent. CHP or cogeneration is the use of a heat engine or power station to generate electricity and useful heat at the same time. CCHP or trigeneration refers to the simultaneous generation of electricity and useful heating and cooling from the combustion of either a fuel or a solar heat collector.
Since CHP and CCHP are more efficient, less fuel is required to produce a given energy output than with separate heat and power. Higher efficiency translates into lower operating costs, reduced emissions of all pollutants, increased both reliability and power quality, as well as reduced grid congestion and avoided distribution losses.
Construction of neither gas nor power distribution networks is economical, Ali-Akbar Soheili, former deputy head of Electricity Syndicate, said, suggesting compressed natural gas (CNG) or small-scale distributed power plants as viable alternatives for power supply in remote areas.
In spite of power shortages in summer, surplus electricity is generated during the cold seasons in Iran, Soheili noted, adding that the surplus power could be better utilized by fair means. "The energy ministry is, and should be, capable of balancing power output."
