fbpx
Home > Ask the Expert > Engineer, Brian Roffey

Engineer, Brian Roffey

Engineer, Brian Roffey

Q: Why are my water costs so high?

BR: In the past many Caribbean islands relied on collected rainwater, stored in cisterns, for their everyday needs. As harmonious with nature as this sounds, the reality is expensive (because building and properly maintaining a cistern for potable water adds a large capital and operational cost) and not totally reliable. Today, the region’s modern water infrastructure plays a major role in making our tropical life possible.

On many island inhabitants fresh water is produced by desalinating water from the surrounding sea, primarily using a process called reverse osmosis (RO). In a nutshell, RO uses powerful pumps to push salt water through a semi-permeable membrane, forcing fresh water out the other side. With today’s technology, 40% of the salt water is converted to clean drinking water. Although the technology is ever improving in efficiency, a large amount of energy use is unavoidable. The principal energy source for RO plants is electricity, which, in turn, is predominantly produced by burning fossil fuels. As such, our water is produced indirectly from fossil fuels, the price of which fluctuates depending on the global market and local taxation policies.

In order to explore further, I’ve performed a basic analysis to estimate the amount of diesel used to produce a gallon of tap water in the Cayman Islands. In Grand Cayman, The Consolidated Water Co. (CWCO) and Cayman’s Water Authority (WAC) are responsible for producing and delivering the water we consume, and the Caribbean Utilities Co. Ltd. (CUC) provides the energy for its production. Please take statements below with a pinch of salt, as I’ve had to make a few assumptions based on the best of my knowledge.

  • The country’s eight RO plants are capable of producing approximately 10.2 million gallons of water per day. CWCO’s plants, servicing the Seven Mile Beach and the West Bay areas, have a capacity of 3.8 million gallons per day.
  • In 2013 CWCO sold over 750 million gallons of water, through retail operations, mostly to residences and businesses in the Seven Mile Beach and the West Bay areas.
  • In 2013 CWCO stated the direct cost of producing the water sold at about US$11 million. Assuming this is primarily for energy and the price of energy is US$0.33-0.35 per kWh, energy consumed can be estimated at 30 million kWh.
  • CUC produces energy at an approximate rate of 14.6 kWh per gallon of fuel.

Looking at these figures allows us to estimate that CWCO’s plants consumed 0.04 kWh for every gallon of water produced, which equates to about 0.0027 gallons of diesel.
Considering that a gallon of Fiji bottled water consumes a gallon of fossil fuel per every gallon delivered (and that’s before it ships from the USA), the drinking water produced locally is by far the cleaner option.

So drink up, but drink local.

SOURCES:
1.    CWCO 2013 ANNUAL REPORT: http://ir.cwco.com/annuals.cfm
2.    CARIBBEAN UTILITIES COMPANY, LTD. 2013 ANNUAL REPORT: https://www.cuc-cayman.com/annual-reports
3.    PABLO CALCULATES THE TRUE COSTOF BOTTLED WATER: http://www.treehugger.com/clean-technology/pablo-calculates-the-true-cost-of-bottled-water.html
4.    http://en.wikipedia.org/wiki/Diesel_fuel


Ask a Question




Can't read the image? click here to refresh

Please provide your name.
Please provide a valid email.
Please provide a question.
Please select an expert to ask a question.
Sorry but we are currently experiencing techincal difficultes. Please try again later.
Please write correct captcha.

comments powered by Disqus

Read More

The Inner Warrior

“A warrior accepts that we can never know what will happen to us next. We can try to con...

Read More

Reinstatement Cost Assessments: Be prepared

Although Cayman is well acquainted with the threat of hurricanes, the 7.7 magnitude earthq...

Read More

From blueprint to built

So you have decided to build... whether it’s a project for rental income, renovations or...

Read More

She Shed – Your Private Escape

Men have been sloping off to their man caves to drink beer, play with power tools, watch s...

Read More

Customise your closet

When every piece of footwear, jewellery and clothing sits in its rightful place and you ca...

Read More

Dr. Carrie Manfrino – The Caribbean's Coral Reef Crusader

Dr. Carrie Manfrino cuts a diminutive figure, but in the world of coral reef conservation...

Read More

Cayman-style

As the Cayman Islands keep pace with global trends and innovations, the growing discourse...

Read More

KUAVO Cayman

Howard McLaughlin, Kuavo Cayman Broker/Owner, discusses how the current global economic cl...

Read More

Cayman Villas – Celebrating 50 years of business in the Cayman Islands

Founded by Penny Cumber, what began as a one-woman property management business run out of...

Read More