Remote communities provide a special set of economic and environmental circumstances that create particular advantages for the use of renewable energies, heat recovery systems and energy management strategies. The vast majority of remote communities are not grid connected and are served by prime diesel-electric generation a source that is highly polluting and utilizes non-renewable fossil fuels.
Power generation in remote communities requires special consideration. These communities have no back-up from the continental grid, and as such reliability is paramount. The challenge is to provide power generation solutions that are economical and environmentally sensitive. The most effective solution is achieved by combining technologies and implementing hybrid systems.
Small Hydro with Diesel-Electric Back-up
Where small hydro development is feasible, this provides a highly reliable energy source that is emissions-free and considered renewable. However reliable, in the event of a rare failure and periodic maintenance, there will be a requirement for back-up power. As far as initial investment is concerned, diesel-electric has the most attractive dollar to power available ratio. However, due to the high cost of operation, this system is better suited to short term usage.
Wind-Diesel Hybrid Systems
Much research and development has been undertaken to provide a system that generates renewable electricity when adequate winds are available and diesel-electric generation when the wind is insufficient. These hybrid systems are designed such that the transfer from source to the other does not disrupt the power output of the system. This is accomplished by integrating a synchronous condenser on the main power bus connecting the two source generators. Advanced controls anticipate changes in available wind through trending to start and stop the diesel generator accordingly. Many systems have been installed with this configuration and have proven successful, even in harsh climates, such as Alaska!
"Distributed" in this case refers to a network of generators that are remote from each other and serve a community or campus distribution system. This differs greatly from a centralized powerplant that is more common. Distributed generators are comprised of diesel-electric generators with a direct heat recovery system, providing heat to building it is attached to. Other sources of generation, such as wind turbines can be included in the "Distributed" network. A centralized control system provides the multi-site control and monitoring of each generator. The result is an integrated generation system.
Distributed generation has many benefits, especially in cold climates. The expense of a large centralized powerplant building is eliminated. In some cases, the generators can be a containerized construction; yielding lower-cost site construction and time to start-up. It also presents opportunities for independent power producers to sell to the micro-grid, perhaps saving on overall financial investment of the community or utility.
District Heating Systems
District heating systems may be as simple as a central heating plant supplying multiple buildings. They may also be incorporated into a central powerplant; using the waste heat from the diesel engines. Other system types capture heat from industrial waste and biomass incinerators.
The most common heat recovery district heating system uses the waste heat from the central powerplant diesel generators and circulates it through a glycol loop that serves building heating systems. Systems remain isolated from each other through the use of high efficient heat exchangers. This prevents multi-system failure when one system is requires maintenance. For example, if the main distribution piping is required to be drained for repairs, then the generator cooling system is isolated and diverted and building heating systems revert to their back-up boilers.
The major economic benefits are achieved through the elimination of burning fossil fuels in boilers. Heat exchangers are capable of transferring heat at an impressive 95% efficiency. Utilizing, otherwise lost heat, compared to burning oil at 50-70% efficiency has undisputed cost benefits. The community benefits further from reduced localized pollution and global injection of greenhouse gases.
Climate Change & the North
The effects of climate change are having adverse affect on the lives of northern peoples. The western longitudes of the north are experiencing warmer winters which are causing serious problems. Winter roads are essential to the re-supply of goods to the communities. The winter roads are deteriorating under melting conditions and the season is getting markedly shorter. The permafrost is a critical component in the environment and foundation on which buildings are constructed. Deterioration of permafrost is going to have untold cost implications on the building infrastructure in arctic and sub-arctic communities.
Warming of the arctic environment is also having adverse on the wildlife; an integral part of the northern peoples existence. New species have been observed which add to the delicate competition for the limited resources. Melting permafrost will also influence mobility of the wildlife. The issues are growing and the future impacts remain uncertain.
What is certain is that there are measures available to reduce the greenhouse gas emissions. Although motor vehicles and industry are the major contributors in the south, electricity generation and oil burning are the main contributors in the north. Technologies to improve efficiencies and reduce non-renewable energy sources must be implemented to ensure a prosperous future for the peoples of the north.