How Sand Batteries Can Make Mongolia Energy Secure
Mongolia is one of the countries in the world with the greatest temperature variations throughout the day and across the seasons, owing to the combination of its landlocked location in the temperate zone and its extraordinary aridity. The country experiences warm to fairly hot summers and brutally cold winters due to sparse cloud cover, limited precipitation, and the lack of a significant water body's moderating effect.
These daily and yearly temperature severe differences are likely to grow further as a result of climate change and loss of plant cover, both of which exacerbate each other.
Upset climate patterns not only increase the amplitude of the daily and yearly temperature cycle, but also make it chaotic, resulting in irregular oscillations, frequent and escalating hot and cold waves, and staggered spells of precipitation.
Over 90 percent of Mongolia’s electricity is sourced from coal and air-pollution is becoming a growing concern. Because of use of simple building materials and traditional design, most Mongolian homes are inadequately insulated by modern standards. Houses without central heating are obliged to utilize raw coal for heating, which is an extremely inefficient calorific technology that leaves a large carbon footprint posing a significant health risk.
As a result of indiscriminate home and industrial coal consumption, the world's coldest capital city is threatened by debilitating pollution.
Because of the poor condition of the heat-conveying pipes, a lot of energy is wasted. Meanwhile, population increase, economic development, and urbanization are driving up the demand for civic heating.
Five thousand kilometers away, residents of Kankaanpää, a town in western Finland, enjoy year-round heating of homes, swimming pools, and baths, by means of an ingenious innovation – a seven-meter tall, four-meter wide silo of hot sand. Nicknamed the ‘sand battery’, this giant cylindrical structure situated in the Vatajankoski Power Plant, houses sand at a high temperature.
The sand is first heated to temperatures in the range of 500-1000 degrees Celsius using green electricity, i.e. electricity sourced from renewable sources such as solar or wind energy.
The heat is then retained for months by the well-insulated sand column, with little dissipation to the surroundings. When necessary, heat can be given by releasing hot air from the sand battery to heat water, which is then transported to housing and office blocks via thermal plumbing, often via the District Heating system, a lifeline during the harsh Arctic winters.
A sophisticated software package constantly monitors the entire system to coordinate charging, discharging, and distribution to improve productivity, retentivity, and utility. In the midst of Europe's recent gas crisis, inexpensive, adaptable, local solutions like the Sand Battery have become even more significant.
As climate change makes the weather more erratic and precarious, sand batteries are a game changer toward addressing both the cause and the consequence, assisting in overcoming the drawbacks of weather inconsistency while decreasing carbon footprint to prevent further climate change.
Sand has a high specific heat capacity when compared to metals, which means it can store a lot of heat for a given temperature rise. Most importantly, it is readily available in Mongolia. Furthermore, despite its temperate climate, Mongolia's prominently clear skies, flat terrain, and little vegetation provide the country with a high practical solar potential.
The country's southern region also has great potential for wind energy development. By tapping into these natural resources and storing the captured energy in a cost-effective yet trustworthy sand battery, Mongolia may easily improve energy security for its whole population.
Sand batteries are fairly scalable, adaptable to varied environments, require little to no maintenance, and can fill gaps and disruptions in energy supply. The excess of summer sunshine can be used to thermally charge the sand battery, and this stored heat can be used for home and even micro-industrial heating during the hard, dark winter months.
In Finland, high-temperature storage is used to keep as much heat as possible inside a restricted amount of sand. This high-temperature energy must be reduced in order to be used for indoor heating, which is a relatively wasteful operation.
However, in Mongolia, where sand is much easier to come by, the same amount of heat could be stored at a lower temperature (more in line with domestic requirements) by using a larger mass of sand, avoiding the need to moderate the temperature before supplying (allowing direct passage to buildings) and slowing the rate of heat loss.
Alternatively, the high-temperature heat might be delivered directly to industries that require such heating. The sand column might potentially be built underground by insulating and filling a borehole.
Even with tremendous advancements in solar and wind energy capture technology and infrastructure, energy storage and long-distance transmission remain significant hurdles. Large-scale battery technology continues to be a research hotspot, but the numerous ongoing competing research initiatives have yet to provide commercially viable and widely-adoptable solutions.
Metal-ion and polymer-based batteries are still too complex to be used economically. Grassroots solutions, such as the sand battery, can help decentralize, streamline, and simplify energy distribution, making not only energy but the entire energy-production process, more accessible and inexpensive across geography and demographics.
About the Author: Pitamber Kaushik is a writer, journalist, columnist, and independent researcher based out of Jharkhand, India. His writings have appeared in 130+ publications across 45+ countries.