Hybrid Energy Systems: Delivering Reliable Heat and Power in Remote LocationsThursday, November 22, 2018 - 11:20 to 11:39 Theatre 2
Remote reliable energy provision (heat and power) is extremely costly, and in northern Canada, with the exception of a few communities, the default technology is diesel fuel. Climate conditions and the long period of little or no sun generally eliminate wind, solar, tidal, biomass and hydro as reliable sources of renewable energy. Yet, at certain times of the year, some of these can contribute to energy systems, providing that other sources can sustain supplies for extended periods (winter months) when renewable sources are weak or absent. We consider that a combination of deep geothermal heat sources combined with a shallow ground-source heat pump storage facility can serve as the year-round reliable energy source, and other sources can be used when available. Different sources available seasonally lead to the concept of an integrated Hybrid Energy System (HES), a more complex analogy of the hybrid electric vehicle that balances the use of stored (battery) energy and actively generated (gasoline-sourced) energy.
We will show a series of options involving various energy sources, and we will factor in the additional component of energy storage of various types (mechanical, thermal, chemical). Energy storage increases HES flexibility: e.g. waste heat from one technology (compression of air for mechanical storage of energy) can be stored using another technology (a heat georepository), or used (a greenhouse or habitat) to displace other sources (deep geothermal heat). These options all reduce overall dependence on a single source (e.g. diesel engines), reduce the amount of energy needed overall, and overcome issues such as fragile fuel supply lines. Although the extreme cold of the north is viewed as a severe penalty, which it certainly is, it also allows for potential value input. Two examples: Organic Rankine Cycle engines can operate more efficiently when the ambient temperature is extremely cold; and, the extended summer sun availability at high latitudes means that collecting heat from the sun (far more efficient than photovoltaic energy) could help in creating a heat repository on a seasonal basis.
Finally, we note that some systems are more effective if hybridization is viable. In the north, ground-source heat pumps continue cooling the ground as the years go by, reducing the effectiveness of such systems. However, deep geothermal heat or local waste heat can replenish the ground temperature, sustaining the seasonal efficiency of the heat pump system.