The Water-Energy Nexus

water-energy

Over the last few years, it has become abundantly clear that water and energy are deeply intertwined and should as such be managed simultaneously for sustainable development. Great is this issue that the theme of the 2014 World Water Week was the water-energy nexus.

This particular event was intended to encourage collaboration between the water, energy and food security sectors. It goes without saying that none of these sectors can thrive without the others. Here we outline the relationships that exist between the water and energy sectors and what can be done about them.

Water is used to generate electrical energy

With approximately 49% of Kenya’s installed power capacity being derived from hydroelectric energy, it is evident that water plays a major role in this country’s energy sustainability.

It is therefore concerning that Kenya’s freshwater availability per capita is a mere 647 cubic meters per year, significantly lower than the global benchmark of 1000 cubic meters per year. As if that wasn’t enough, continuing climate change has made it even more difficult to predict future water availability trends.

Due to Kenya’s water scarcity issue, its sustainable development depends heavily on the installation of better water management systems and water conservation methods. It would also be extremely advantageous if focus were to move from hydroelectric energy to alternative energy resources; a fact that the government has quickly acknowledged.

In fact, as part of Kenya’s Vision 2030, the government is working towards drawing most of the country’s power supply from alternative energy sources such as wind and solar energy. This will ensure that hydropower accounts for only 5% of the installed power capacity.

Source:iaea.org

Source:iaea.org

Water is used in cooling

According to a report by the United States Department of Energy, water’s high specific heat (4.2 joules/gram-Celcius) and latent heat of vaporization (2260 joules/gram) are responsible for its impressive cooling qualities.

As such it is commonly used for thermoelectric cooling in a variety of power-generating plants across the United States of America. Here in Kenya, water is used in the cooling of heat exchange equipment. This water is usually later on used for other industrial purposes such as cleaning of such equipment.

Due to the role of water in manufacturing plants across Kenya, it comes as no surprise that organizations such as the Kenya Association of Manufacturers feel that this country could highly benefit from a comprehensive industrial water policy.

Water is involved in the extraction of fossil fuels

First of all, water is used in hydraulic fracturing; a process that stimulates the release of oil and gas resources.  This process usually takes a lot of water and can therefore contribute to water scarcity, especially in arid areas.

It is also interesting that a lot of water is produced during the extraction of fossil fuels. However, the extraction process has been known to pollute surface water and groundwater.

Using fossil fuels contributes to climate change

It has long been established that using fossil fuels produces CO2 emissions, the culprit behind global warming and climate change. With the global scene already experiencing effects such as rising sea levels and severe droughts, it is best not to further disrupt the water cycle.

As such, the global energy sector has begun leaning towards green energy solutions. Although these clean energy solutions do reduce the global carbon footprint, some of these resources consume substantially more water than the fossil fuel extraction process.

For instance, technologies such as biofuels and carbon capture and storage require substantially more water to sustain than conventional fossil fuel technology.

Energy is used in water treatment and distribution

Due to the increasing strictness of water quality regulations, it is not surprising that even freshwater sources seldom meet the required drinking water standards. As such, the global demand for water and wastewater treatment has increased over the years.

With water of high salinity, high organic content or high oil concentration requiring the most energy to treat, energy efficiency demands that we treat more freshwater than other nontraditional types of water.

Apart from water treatment, the use of pumps to distribute water across the country also uses up a substantial amount of energy. It is worth noting that the bigger the change of elevation experienced by the pumped water, the higher the amount of energy required to pump it.

What can be done?

Now that we are at a point in time where the global community is keenly aware of the linkages and the interdependencies that exist between the water and energy sectors, it is important that we put such knowledge to use.

As such, the government of Kenya and industries countrywide should work towards coming up with strategies that handle energy and water management as a unit and not as separate entities. Such strategies may include:

  • Apply knowledge in water quality and availability to promote the reuse of water produced during the extraction of oil and gas resources
  • Promote the continued use of nontraditional water resources such as wastewater and seawater in the production of energy. Special emphasis should be placed on the use of these resources in their original state
  • Put in place monitoring systems and management strategies that reduce the risks of energy production interfering with the quality of surface water and groundwater
  • Reduce the amount of water used in industrial cooling by increasing the energy efficiency of plants. This can be achieved by waste heat recovery and reuse of water from cooling towers

Parting Shot

Ultimately, it is evident that water efficiency and energy efficiency are greatly intertwined and codependent As such, the key to sustainable global development lies in the continuous and simultaneous monitoring of these two variables.

Further Reading

KAM – Need for water policy

Water and Energy – Understanding the connection

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