Groundwater as a Renewable Energy Source For Cities

Observation of increased groundwater temperatures in urban environments are been researched for its energy potential. Measuring groundwater temperatures in Cologne (Germany) and Winnipeg (Canada), Zhu et al. (2010) have discovered a warming trend of up to 5ºc. The temperatures have been intensified by the urban heat island effect. That is the build up and magnification of heat due to increased hard surface area and reduced transpiration by plants. Extractable geothermal energy in Cologne resulted in an amount 2.5 times the residential heating demand of the whole city.

The results reveal an incredible potential for cities, particularly mega-cities such as Shanghai and Tokyo, to supply heating demand for decades. Hsiao (2012) states that large cities in China, such as Beijing, have already been heating districts for the last 30 years by pumped heated groundwater. Development into the extraction of geothermal groundwater, by either closed or open pumping systems, will depend on future research into the environmental impacts.

The effects on recharge is not even fully understood in China (Hsiao, 2012). Therefore essential investigation into hydrological/geological process, land use and urban conditions in relation to extraction will need to be known. The research is key in the mitigation of greenhouse gas emissions in relation to growing urban centres.

References

1. Hsiao, G. (2012) Dr. Zhonghe Pang on Groundwater Recharge, Geothermal Energy, and Carbon Sequestration. http://www.picarro.com/community/blog/dr_zhonghe_pang_on_groundwater_recharge_geothermal_energy_and_carbon_sequestration

2. Zhu. K, Blum. P, Ferguson. G, Balke. K and Bayer. P. Environmental Research Letters, 5 (2010), 044002 http://dx.doi.org/10.1088/1748-9326/5/4/044002 http://iopscience.iop.org/1748-9326/5/4/044002/fulltext/