How does renewable energy impact water use?

How does renewable energy impact water use? 

The power production sector is one of the highest water users in Europe, with water mostly used in cooling. We need to reduce the amount of water used in energy systems to avoid water stress and its link to energy security. Overconsumption of water in the energy industry could lead to water reduction for the industry, potentially leading to power shortages. However, some renewable technologies can potentially reduce the amount of water required by the power generation sector. We take a look at some of the key contenders.  

How solar power affects water consumption 

Photovoltaic (PV) systems use less water to generate energy than their fossil fuel equivalents. However, the industry as a whole still requires water. For example, water use in photovoltaics starts with the production of the panels, which requires water for manufacturing.  

Concentrated solar power (CSP) and its cooling needs 

Concentrated solar plants utilise mirrors to concentrate the solar energy, which converts the water into steam. This then turns turbines, which generate energy. The water then cools and can be used to start the process again. The process is very water-intensive - up to 3,500 litres of water can be used per megawatt hour of energy produced.  

Dy-cooling and hybrid cooling technologies for CSP in arid regions 

However, there are other techniques we can use in CSP to cool the steam, and one method is called hybrid cooling. Evaporation losses can be reduced by up to 95%, reducing the net or levelled cost of energy across CSP.  

Wind energy’s water footprint 

Wind energy is considered a low-water consumer, making it a good alternative to traditional plants for low-water-consumption energy solutions.  

Wind turbines and their negligible water usage 

Wind turbines themselves do not require water to generate energy. Unlike traditional plants, they do not consume water during generation or require water cooling at any point during the process. They can actually increase water generation in the sense that they can become a key part of desalination, which treats brackish water to make it a useful water source. However, this requires energy to process the water. Wind energy could be a good solution in this instance - without causing an increase in water consumption to generate the energy for the desalination process.  

Advantages in dry and drought-prone areas 

The benefit of installing wind turbines is that they allow energy to be generated without the water-intensive cooling required by other types of energy generation. Wind energy can, therefore, be a good solution for dry and drought-prone regions requiring energy.  

The role of hydropower in the water-energy nexus 

Hydropower can act as a battery storage device and a renewable energy source. We examine this dual-purpose renewable source and how it uses water.  

How hydroelectricity uses and returns water 

Hydropower utilises a series of dams to generate energy and is currently one of the largest generators of renewable energy—globally, hydropower accounts for more than 50% of all renewable energy generated. However, due to the rate of evaporation from reservoirs, it can contribute to water scarcity, which can be significant.  

Evaporation and environmental impacts of reservoirs 

While effective, hydropower is not an effective solution for every region. Hydropower requires a lot of space for water storage, making it an inappropriate solution for regions with a lot of agricultural activity or little available land, but a great solution for countries with a lot of spare land, such as America.  

Hydropower’s dual role in water management and energy storage 

One of the most widely used energy storage solutions is hydropower. Running water is pumped into a secure reservoir to act as a backup source when a hydropower plant isn’t reaching full production levels, for example, during droughts or low rainfall. The boundaries of water storage for dams are changed during low generation periods, and when these occur, the water is released from the reservoir, generating electricity.  

Bioenergy and geothermal: Hidden water challenges 

Water needs for crop irrigation in bioenergy 

Bioenergy utilises crops, or biomass, for energy generation, which is water-intensive. It can also compete directly with agriculture for water irrigation, which can threaten food and water security. Therefore, it may not be a suitable solution in regions where bioenergy would be competing with agricultural production for water resources.  

Cooling and steam processes in geothermal systems 

When geothermal reactions take place, they involve pumping hot water from deep underground via a well using high pressure. The water then reaches the surface, pressure drops and steam is emitted, which turns a turbine, generating energy. When the steam cools in a tower, it then returns to water, pumped back down into the earth where the process is repeated. While some processes - such as drilling - do require water to operate and evaporation can cause water scarcity, there are ways to mitigate the amount of water used in geothermal energy generation. The process can utilise brackish water, often not utilised in water consumption.  

Balancing renewable benefits with local water limits 

While renewable energy is preferable to fossil fuels in terms of carbon emissions, it’s also important that renewable potential is balanced with the requirements of other industries and considerations, including agriculture, biodiversity, and ecological concerns, which also require land and water to thrive.  

Comparing water use across energy sources 

While traditional plants are considered to use high amounts of water, fossil fuels are not the only culprits behind the uplift in water consumption in the energy sector. Renewables' water intensity vs. fossil fuels should also be considered. Some types of renewable energy, such as CSP, can use up to three times more water than a conventional gas-fired power plant. From a nuclear perspective, power plants need large amounts of water for cooling, making them a high-consumer of water. 

Policy and planning for water-smart energy 

As attention turns from the increased roll-out of global renewable energy generation to the renewable water consumption issue, water impacts must be integrated into renewable energy policy. Research and development in this area is also key. As mentioned before, using dry-cooling or hybrid systems to cool plants is among the current innovations to improve efficiency and sustainability in renewable power. In the case of CSP, fans are used to cool the plants instead of using water to cool plant operations. While this reduces the amount of water used, it slightly reduces the amount of energy generated by solar power.  

Balancing clean energy with smart water use is critical. Sustainable tech and policy must reduce water intensity while expanding renewable energy systems.