POWER March 2017 - 38

WATER & WASTEWATER
Reclaimed Water Reduces Stress
on Freshwater Supplies
Courtesy: Veolia Water Technologies
Power generation need not be another source of strain on diminishing freshwater
resources. Well-established water reclamation technologies are enabling producers
to conserve resources-and money.
Michael Pudvay
M
eeting the needs of a planetary population
expected to surpass eight
billion people by 2025 is requiring
more output from fewer resources. In the
case of dwindling supplies of freshwater, the
strain on the natural resource from economic
and population growth, and climate change,
can be exacerbated by other demands. One
example: producing enough food for the
growing population. Agriculture requires
large quantities of water for irrigation and
now claims close to 70% of all freshwater
appropriated for human use.
Power generation is another rising demand
drawing heavily on water resources. The energy
sector is responsible for 10% of global
water withdrawals, second only to agriculture,
mainly for power plant operation as well
as for production of fossil fuels and biofuels.
As new power plants are built to accommodate
the growing population's power needs,
increasing amounts of water will be needed
for power generation and cooling. By 2040,
16% of electricity consumption in the Middle
38
East will be related to water supply, according
to the International Energy Agency.
Interwoven Resources
In addition to water's importance to power
production, energy is also vital to providing
freshwater needed to power systems that collect,
transport, distribute, and treat it. Each
resource is thus interdependent on-and
vulnerable to-the other. For the power generation
sector, constraints on water can challenge
the reliability of existing operations as
well as the physical, economic, and environmental
viability of future projects. Conversely,
the use of water for energy production can
impact freshwater resources, affecting both
their availability (the amount downstream)
and quality (their physical and chemical
properties).
In recognition of the vulnerability of water,
a resource critical to the future of power
generation, the industry is increasingly looking
to solutions that conserve water through
reclamation, recycling, and reuse.
www.powermag.com
Multiple Solutions
A relatively easy way for the industry to reduce
water consumption is to use water more
efficiently, such as by increasing the cycles in
cooling towers. Another method is identifying
nonfreshwater sources for cooling, which
accounts for most of the water usage in a
power plant. This can involve recycling and
reusing plant wastewater and/or using treated
sewage or industrial wastewater from an external
source. Power unit efficiency can also
be improved to produce more megawatts per
gallon of water used, which also adds to both
sustainability and profitability.
One solution for power plants to reduce
freshwater usage that is proving increasingly
interesting is using reclaimed water or treated
municipal wastewater. Use of sewage effluent
for cooling began in the U.S. in the 1970s,
and it is proven and safe. Today, more than 70
power sites in the U.S. are using treated, reclaimed
water-and not just in arid regions.
Highly available, sewage is a virtually
risk-free source. It has consistent quality and
POWER | March 2017
http://www.powermag.com
POWER March 2017

Table of Contents for the Digital Edition of POWER March 2017
