When was the last time you thought about the origin of the water that comes out of your tap? For most of us, gone are the days when we had to spend so many hours just to transport water. Now we just open the tap it's there – it's so obvious. But we still need huge amounts of energy to transport the water to our buildings. Pumps and pipes now do the job for us. And that process is very, very energy intensive. In fact, the treatment and transport of water consumes a staggering 4% of the world's energy. And its carbon emissions... rival that of the aviation industry. So here's the mind-blowing part: what if I told you that these simple water pipes have huge untapped energy potential? They have enough energy to power your house. In fact, millions of houses around the world. This is not just a pipe dream. It is already happening in places like the US state of Oregon or the Turkish city of Manisa. So how much power can we harvest from the flow? Water is the greatest moving mass on Earth, with huge energy potential. Hydropower is a cornerstone of low carbon energy generation. But dams have become bigger and more controversial. Yet the water pressure in our pipes goes mostly untapped. So how does water get to our taps in the first place? "The conventional water supply system brings the water from the source and treats it, delivers it to people in the majority of countries, comes out of your tap, then it's taken away, it's treated, then put back in the environment." This is Newsha Ajami. She and her team have examined the research on in-pipe turbine technology. "This process is very energy intensive. You need a lot of energy to move water from location to location, to treat it, to distribute it among people" Some cities are lucky, and their water comes from higher altitudes. So, gravity does most of the job, and less energy is needed to transport it. But in Berlin, London or Delhi, for example, the water supply system relies on pumps. And in some countries in the Middle East the water needs to be desalinated first. That absorbs 4 times more energy than conventional water infrastructure. We also need a strong water flow so that it doesn't take 10 mins to fill a pot. If our water doesn't come from reserves at higher altitudes, we need pumps. But to stop pipes bursting due to too much water pressure, we install devices called pressure valves. They basically remove the excess pressure. That is where all that juicy energy is wasted. And where in-pipe technology can come in. A turbine in the pipe could convert that excess pressure into electricity. This is a little water turbine. We can install this into our existing water infrastructure that we depend on every day. The water would rush through this turbine and it would make it spin like crazy. And you know what happens when a turbine spins, right? It generates good old electricity. In California 20 percent of the state's energy goes into water infrastructure: pumping it up from the ground, moving it to different locations, and making it drinkable. A huge chunk of energy could be recovered by harvesting the excess pressure. Lets' find out how this works in principle. I am setting up a little circuit to connect different gadgets to harness the electricity generated from this tiny water turbine. I can charge a battery, run a motor, turn on a light, and charge my phone with it. This is of course just a tiny, tiny water turbine. We can install bigger ones wherever there is an abundant water flow. The energy that can be created depends on the turbine as well as the amount of pressure in the pipes. "We really don't have a solid number to say this is how much energy we can generate. But the reality is – across the world, the way we have built our water systems, water is moving from location to location, and it can potentially be used to generate energy. So I think the potential is quite high." Different studies give different estimates. One report for the US Department of Energy estimates that in-pipe turbines could produce 1.41 gigawatts of electricity across the US. That's quite a conservative estimate. It would be enough to power at least one million homes in the US, or more than 10 million in India. Yes, a house in the US uses 10 times more than one in India – but that's another story. Other studies are more optimistic: Alden Research Lab from the US says up to 43 gigawatts of energy per year could be harvested in the state of Massachusetts alone. Water systems were built a long time ago. With only one thing in mind: to deliver water. So, we haven't got much to go on when we try to calculate the potential energy within pipes. Because generating energy was never part of the plan. That's one reason why the reports differ over this technology's potential. "We need to craft our institutions to be responsible for both water and energy. So far our energy-generating institutions are independent of our water supply institutions. This is Vishwanath Srikantaiah. He has been working in the water sector in India for the last 36 years. "In my city of Bangalore, 65% of the income of the water utility goes towards paying energy charges. Water should be transported 95 kilometers and 300 meters high. So energy is the most important component of the water price." If water companies created their own energy using their infrastructure, the price of water could drop. Another great piece of news is that these turbines can be retrofitted without harming the environment. "The operators love it. We are powering EV-charging stations." This is Gregg Semler. His company has been charging cars with in-pipe electricity. How cool is that? "The biggest challenges that we have is that it's new. And so, with anything that's new, people always want to understand what its impact is on their operation. But whenever I do a presentation, or whenever our team is presenting to people who are knowledgeable about water distribution, they get it immediately." Obviously, cost is another thing, and these new systems are not yet incentivized in many places. "People can recover the cost in a couple of years or in less than decades and that's what we have seen. Obviously depends on the scale of the project, as I said, the cost of electricity. But then again you need to have enough upfront capital to be able to invest in these systems and then have time to recover them. This might be tough for small businesses – but municipalities and big companies have a responsibility to step up. Countries in the Global South have a great advantage as they are currently expanding their water systems. India is the world's largest consumer of groundwater, and most of its cities don't have constant running water at the moment. But the country is planning to invest hundreds of billions of dollars to provide its huge population with pressurized water 24/7. "There are exciting and immense possibilities to do that. That's because we're going to build half of our infrastructure in the coming 20 years. India will be urbanizing very fast, our water supply networks will be expanding very fast and therefore these opportunities will lend themselves." Some cities are already on board with this technology. Take Portland Oregon, for example. They are harnessing the power of in-pipe water to light up their streets and power essential public infrastructure. And the Eastern Turkish city of Diyarbakir is already generating 2 million watts of electricity and selling it to the local grid. And it doesn't stop there: San Francisco, Manisa, Cape Town – they're all catching on to the potential of the untapped energy flowing beneath their streets. You could say that in-pipe technology is an energy hero with a low profile. It makes the most of what's already in place while reducing our reliance on fossil fuels. With zero to very low environmental impact Of course in-pipe turbines are not going to decarbonize our whole economy. But if I managed to charge my phone, light up the bathroom, turn the fan, with this little fella – imagine what we can do on a larger scale. Tell us what you think in the comments. And don't forget to subscribe. We have new videos like this one every Friday.
