How is renewable energy development linked with groundwater

A map of groundwater storage trends for Earth’s 37 largest aquifers using GRACE data shows depletion and replenishment in millimeters of water per year.

Image credit: NASA/JPL-Caltech

About 71% of our Earth’s surface is covered by water, however, 97.5% of all water on Earth is saltwater, leaving barely 2.5% as freshwater. Only ~1% of the world’s freshwater is accessible for direct human uses. This is the water found in lakes, rivers, reservoirs and those underground sources that are shallow enough to be tapped at an affordable cost. From that groundwater, only 0.61% is considered freshwater (National Ground Water Association – NGWA-).

Even though we may only notice water on the Earth’s surface, there is much more freshwater stored in the ground than there is in liquid form on the surface. In fact, some of the water we see flowing in rivers comes from seepage of groundwater into river beds. Water from precipitation continually seeps into the ground to recharge aquifers, while at the same time water in the ground continually recharges rivers through seepage (United States Geological Survey -USGS-).

Current world’s population is by around 7.7 billion and it is growing by about 82 million people per year (worldometers) and it is predicted to reach 10 billion by 2050. Major aquifers are tapped on every continent, and groundwater is the primary source of drinking water for more than 1.5 billion people worldwide (Safe Drinking Water Foundation – SDWF-). Merely in the US, groundwater supplies drinking water for 51% of the total population and 99% of the rural population (Groundwater Foundation).

An estimated 20% of the world’s aquifers are being over-exploited (Gleeson et al., 2012), leading to serious consequences such as land subsidence and saltwater intrusion (USGS, 2013). The advent of modern and cheaper drilling techniques and submersible pumps has allowed irrigators to make up the shortfall in surface water or to expand irrigation in areas previously cultivated under rainfed conditions or even semiarid to the desert (Molle, F.; López-Gunn, E. and van Steenbergen, F. 2018). Groundwater has also been the preferred resource of industries seeking good quality water and reliable supply, of cities, and of under-served communities.  Groundwater contributes as much as 43% of agricultural water needs (Dalin et al., 2017) and much more in arid and semiarid regions. The magnitude of groundwater use can be illustrated by the fact that the net amount of water withdrawn from aquifers is even contributing to rising sea levels (Wada et al., 2016).

More than 5 billion people could suffer water shortages by 2050 due to climate change, increased demand and polluted supplies, according to a UN report on the state of the world’s water. Freshwater scarcity is an urgent problem indicated by the alarming rates of groundwater depletion in different parts of the world (Dalin et al., 2017; Gleeson et al., 2012).

On that way, to avoid overexploitation and aquifer depletion, groundwater’s potential contribution to human development must be based upon the local (hydrogeological and climatological) conditions that determine the available quantity, quality and the feasibility of abstraction. For example, deep aquifers with limited renewability are relatively sensitive to depletion, whereas alluvial aquifers overlain with permeable material are relatively sensitive to quality deterioration. On that way, the general lack of knowledge with respect to groundwater resources management and human development claim for a dedicated hydrogeological analysis, which will provide the basis for feasibility studies of groundwater development in regions where groundwater is underutilized in order to balance the demand without affecting the groundwater recharge (Maya Velis et al 2017).

The importance of groundwater is likely to increase in the future as its buffering capacity should help to reduce the impact of extended dry periods that may result from climate change. As well as groundwater bearing rocks, which provide a source and a sink for heat, can also contribute directly to the provision of renewable energy via geothermal technology. (The UK Low Carbon Transition Plan – National Strategy for climate and energy, chapter 3 –2009).

Energy and water are intricately connected. All sources of energy (including electricity) require water in their production processes: the extraction of raw materials, cooling in thermal processes, in cleaning processes, cultivation of crops for biofuels, and powering turbines. Energy is itself required to make water resources available for human use and consumption (including irrigation) through pumping, transportation, treatment, and desalination (United Nation – Water for Life 2015-2015).

On this way, we identify the role that groundwater can play in achieving the Government’s low carbon transition plan but also address the detrimental impacts on groundwater and dependent ecosystems. (UK Groundwater Forum Secretariat).

by

Juan Carlos Beltran Paredes

Subject Matter Expert in Conventional and Renewable Unconventional Energy Systems