The focus of renewable energy initiatives tends to center around greenhouse gas (GHG) emissions. While these are the industry’s most notable environmental impact, other factors deserve attention, too. The amount of water our electricity uses should also play a role in the nation’s future energy planning.
The power sector accounts for roughly 10% of all freshwater withdrawals worldwide. While the water footprint of renewable energy tends to be lower than that of fossil fuels, not every source of electricity is equally efficient in this regard. As the transition to renewables grows, organizations must consider these effects.
How Much Water Does Our Electricity Use?
Informed water strategies start with recognizing how much water each form of electricity uses. Once this consumption is clear, it’s easier to know which processes to prioritize and which to modify to preserve global freshwater availability.
Fossil Fuels
In addition to producing the most GHG emissions, fossil fuels are also the most water-intensive forms of power. Coal mining and combustion account for 57% of energy-related water consumption, and crude oil represents another 34%. Much of their usage stems from the cooling necessary during the operational use of these fuels.
Coal, petroleum and natural gas all produce a significant amount of heat when converted to electricity or used for direct power. Consequently, they require a substantial amount of water to keep equipment cool, a process that is often wasteful because it contaminates water streams. Even GHG-mitigating steps like carbon capture and sequestration fail to improve such waste as they require their own cooling.
Solar and Wind
The water footprint of most renewables is far lower, but still a non-zero amount. Both solar and wind – the dominant forms of green electricity today – use minimal, if any, water during energy production. Much, if not all, of their consumption comes from the manufacturing of infrastructure like solar panels and turbines. Because these sources are non-thermal, they often do not require cooling.
As for solar and wind’s precise water footprint, estimates vary. However, experts believe switching to such forms of power could reduce cooling-related water consumption by 98% annually. Improvements that large would require an emphasis on solar photovoltaics over thermal solar, as the latter requires additional cooling.
Hydrogen Fuel Cells
Hydrogen is another power source worth considering. While fuel cells may not provide grid-scale electricity, many organizations have touted them as a potential backup system, and the transportation sector may use them to power vehicles.
Like wind and solar, hydrogen provides emissions-free energy – at least in the case of green hydrogen – but unlike them, it consumes water during fuel production. Because hydrogen does not appear on its own in nature, facilities must extract it from water. Consequently, it takes between 20 and 30 liters of water to produce one kilogram of hydrogen. That’s less than what fossil fuels require, but still not ideal.
Hydropower
It’s difficult to talk about water and energy without mentioning hydropower. While hydroelectricity does not consume any water during production, as it merely uses the motion of water, not the resource itself, it can affect its quality.
Dams and reservoirs can change water chemistry and temperatures, potentially introducing new pollutants through erosion. As a result, they may lead to some loss of freshwater, although organizations may be able to reclaim it through filtering and purification processes. It’s also worth noting that hydropower can also work in saltwater environments to reduce the impact on freshwater availability.
Balancing the Water Footprint of Renewable Energy
The energy industry must pay attention to its water consumption if it wants the green power transition to be truly sustainable. Such a future is attainable if organizations follow a few key steps.
Emphasize Water-Friendly Energy Sources
The first and most impactful part of balancing renewable energy’s water footprint is focusing on its most water-efficient forms. While hydrogen and biofuels have roles to play in minimizing GHG emissions, businesses should prioritize solar and wind energy, as they use minimal water.
Wind is slightly more water-efficient than solar, but the difference is not significant enough to put one above the other. Rather, it’s best to focus on which can provide the highest clean electricity capacity in a given area. Wind’s slight edge in water consumption doesn’t make it the optimal choice if solar farms could replace a larger portion of the region’s fossil fuels.
Implement Water Management Plans
Next, facilities of all types must create a water management plan to minimize and reclaim any wastewater they do produce. Such strategies are mandatory in some states, but businesses should pursue them even when the law does not require them to.
Water management plans vary between instances, but all should include an analysis of on-site water usage, measures to reduce it and secondary workflows to purify and reuse any wastewater. Water-intensive energy sources like hydrogen production and plant cooling must go to greater lengths than most in this regard to yield the largest improvements.
Promote Green Transportation
As utility companies switch to cleaner sources of energy, they should also promote the adoption of electric vehicles (EVs). While EVs require a renewable-powered grid to be truly sustainable, they use less water than gas and diesel cars. Even though vehicles use little to no water while driving, producing petroleum fuels is a water-intensive process.
Both battery-electric and hydrogen vehicles are useful in this regard. Each technology can still consume water in its supply chain, but the resulting withdrawals are far lower than what gas and diesel production would entail.
Address Mining’s Water Consumption
Any efforts to minimize renewable energy’s water footprint are incomplete without addressing mining practices. While renewables use much less water than fossil fuels, they typically rely on technologies using mined rare earth minerals or – in the case of nuclear power – uranium. Untreated mine waste contaminates 40% of the headwaters in some regions, so something must change in this area.
Automated mining equipment can help by boosting precision. Water recovery and purification are also necessary to offset the contamination mining would otherwise produce. In the long term, researching alternative ways of building renewable technologies to use fewer mined materials will yield even greater results.
Renewable Energy’s Water Footprint Demands Attention
It’s easy to overlook how much water our electricity uses, but it’s important not to. Failure to account for water consumption could mean rising energy demands contribute to environmental and health issues beyond GHG emissions.
The switch to renewables will reduce electricity’s water footprint, but greater attention is necessary to minimize it further. As organizations implement these steps, the world can move toward more comprehensive environmental initiatives.
Emily Newton is the Editor-in-Chief of Revolutionized, an online magazine discussing the latest industry innovations and trends.
- Emily Newtonhttps://energiesmedia.com/author/emily-newton/
- Emily Newtonhttps://energiesmedia.com/author/emily-newton/
- Emily Newtonhttps://energiesmedia.com/author/emily-newton/
- Emily Newtonhttps://energiesmedia.com/author/emily-newton/
- Emily Newtonhttps://energiesmedia.com/author/emily-newton/
- Emily Newtonhttps://energiesmedia.com/author/emily-newton/
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