Updated: Jun 17, 2019
Water. We use it everyday and likely, in more ways than you know. Unfortunately, for a resource that is in many ways our most precious, we often take it for granted. As Canadians, we use around 325 L of water per day for hygiene, cooking and drinking purposes! To put that into perspective, that is equivalent in volume to around 650 water bottles.
Although 325 L/day may seem like a lot of water, you are actually using much more water without even knowing it. The use of water in the industrial production of materials we consume pushes the daily water use per Canadian citizen to 12 times the residential usage amount. With about 70% of industrial water usage going to paper and metal production, Canadians have the 3rd highest water usage per person in the world.
The cost for everyone
The enormous load this water demand puts on our community can be seen in our energy use and pollution rates. In a recent survey, water treatment requires 38% of the total energy requirements of all municipal services. It is reported that this number may be as high as 60% in some American cities.
Water treatment and processing is often overlooked because of its relatively low cost and necessity. However, due to overuse, municipalities pay an astounding $260 million dollars every year just to power their water and wastewater systems.
With only 33.4% of Ontario energy being generated by renewable sources, this burden on the energy grid is responsible for a large portion of municipally-generated dangerous pollutants. Now, more than ever, reducing our carbon footprint and energy use should be among our top priorities. If we want to create a sustainable society, we need to reduce our waste and for Ontarians, our water usage is a good place to start.
To read more about the water problem in Ontario and how we are planning to improve, check out "Every Drop Counts - Reducing the Energy and Climate Footprint of Ontario’s Water Use”, a report put out by the Environmental Commissioner of Ontario
The cost for you
Despite the lasting ecological impact of non-renewable energy, perhaps the largest cost for you is heating your water. Canadians spend around 19% of our total energy use on heating the daily 75 L of water that we use. With an average energy use of 105 GJ, that is equivalent to 4.8 tons of TNT explosives! If you are like most Canadians, this will cost you over $600 a year.
In the energy breakdown below it can be seen that water and space heating accounts for 82% of the annual energy use for an Alberta home. Being such a large part of the energy demand, together these heating applications present the largest problem with the greatest potential for energy reduction or supplementation.
This being said, hot water does not have to be a burden on households and the environment. Many technologies exist to generate hot water renewably and efficiently. When these methods are used to provide hot water for heating applications, buildings can derive most of their power from responsible sources.
Smart uses of water
queens steam heating
A prime example of waters use in efficient heating is Queens' steam heating. Queen's currently operates on a centralized steam heating plant which produces 700 million pounds of steam a year at an efficiency of 90% ! This plant produces both electricity and steam for Queen’s university and once powered both the women’s and federal penitentiary as well. Unfortunately, built in 1923, this plant is powered with bunker oil which is not the green power source of today. But having a centralized system to pass steam through miles of tunnels, this resource is used in the most responsible way possible.
hydronic floor heating
Using hot water for heating purposes is a difficult and sometimes expensive task. However, when done correctly, hydronic heating can be more efficient that traditional forced air methods. By heating the floor, a more favorable “bottom-up” heat distribution is obtained while not needing as much energy to power large blower fans. Use of this technology in conjugation with a renewable hot water source could significantly reduce the energy footprint of your house
Solar collectors are an excellent way to renewably source hot water to a building. Using solar energy to heat water directly, efficiency is optimized by reducing modes of energy transfer. Where an electric boiler can receive 15-20% of the suns power from a solar panel, collectors can capture around 70%. Sizing these systems appropriately, 60-70% of a homes hot water needs can be met renewably.
Written by Scott Sikich, Mechanical Engineering '20.