Welcome to module five in our course, Our Sustainable Future. Thus far, we've been talking about climate change, fossil fuels, greenhouse gasses, and the need to shift to zero-carbon energy sources. And we need to do this quickly if we're going to meet our 2030 objectives of a 50% decrease in greenhouse gasses and our 2050 goal of net zero emissions. In this series of lessons, we're going to talk about how to do just that. As one of our biggest challenges in climate change is with greenhouse gasses associated with generating electricity. We're going to focus our attention on renewable energy or more specifically generating electricity from renewable energy sources. We'll begin with the technology that's been around for quite a long time. Hydroelectric power. We'll then dive a bit deeper into the worlds of wind power and solar energy, how they work, why we need them, and how the economics of wind and solar have changed so dramatically the last few decades. As we discussed in the last module, in order to ramp up our power generation from renewable energy sources, we need to deal with the variability of those sources and that is where energy storage comes in. So, we'll talk about what is going on in that space too. What is also exciting is while the economics of renewable energy and energy storage are becoming increasingly attractive. Scientists around the world are exploring new innovative technologies that are both more efficient and more cost effective. We don't know if these will actually become mainstream, such as wind or solar, but you never know, therefore, I will introduce them. So you have a sense of what's going on with advances in zero-carbon energy technologies. Finally, with all the talk about installing more renewable energy as a solution to global warming and subsequent climate change. How are we actually doing? We'll wrap up this module with a look at how the use of renewables has grown and how it is now making real inroads into our power generation infrastructure. As you might have heard me say a few times now, this next decade will be one of the most disruptive, innovative and exciting decades in history. And by the end of this module you'll start to understand why. It's a very upbeat way to begin wrapping up the course, especially as the first part of the course was full of dire warnings and calls for action. Now we get to talk about what is really going on and how we can start taking part in the solution. Are you ready? Let's get started. Let's face it, water is probably the most important and precious natural resource we have. We needed to replenish the water in our bodies to irrigate the plants we like to eat and to keep ourselves and everything around us clean. Of course, this not only applies to us to every other living thing on the planet. Water is so important that humans have built massive structures to build, store and move water around for thousands of years. The Pont du Gard the limestone aqueduct that you see here was built by the romans in the first century in the south of France as a way of bringing water from some 30 miles away to the town of Nimes. Water, and especially flowing water has a tremendous amount of energy associated with it. And as such, it became a primary power source for many industrial applications. The photo here is of an old Grain Mill used to make flour. The water wheel rotates by the flow of the water from the nearby river. The wheel is connected through a series of gears to large grinding stones, which converts the grain into the flour. Applications such as this existed for centuries prior to more modern electrically powered mills. In fact, the turning water wheel could be connected to a whole series of belts and police and became the power source in the early days of the Industrial Revolution for all sorts of industrial applications. Such as the textile mills that converted cotton wool or flax fiber into cloth for people's clothes. But it wasn't until the late 1800s that water was used to generate electricity. This requires several important inventions, such as the generator that we've talked about so many times in the past. Yet, because water wheels have been around for centuries, all that needed was the ability to link the rotating wheel to the generator. In 1882, the first commercial hydro power or hydroelectricity plant was constructed in the United States and operated along the Fox River in Appleton Wisconsin. It didn't produce a whole lot of power, just 12.5 kW, but it was a start. 50 years later, around 1933, the United States started construction on the Grand Coulee Dam just outside of Spokane Washington along the Columbia River. It was part of President Roosevelt's plan to help power and irrigate the pacific Northwest and provided thousands of jobs for the people that worked there. After its completion in 1942, the power plant was the largest in the United States and still is today at 6.8 gigawatts of electricity. About as much as seven large coal or nuclear power plants. So why do we include hydropower in our discussion of renewable energy? The main reason is, that if you have flowing water, you can generate electricity and you can do that without any emissions whatsoever. Assuming that our rivers will be around for a long time into the future, then we should have an inexhaustible supply of clean energy from hydropower. Therefore, we consider it a renewable energy technology. So how does flowing water end up generating electricity in the first place? What you see here is a schematic of a hydropower or hydroelectricity plant. Most of the time it starts with a large dam across a flowing river creating a deep reservoir on one side of the dam. Inside the dam itself are a series of passageways that allow water to flow through. The passageways have gates to control the amount of water flow. The water flows through the dam and passes, well, you guessed it, a turban, causing it to rotate. The rotating turbine, turns a generator which produces electricity, and the electricity is then transmitted through the grid to homes and businesses. When you think about it, the process is nearly the same process as in a coal, natural gas, or nuclear power plant. It's all about getting a turbine to rotate somehow and thereby getting the generator to turn, creating the electricity that we all needing. Only now, we don't have to burn anything to generate steam. We just let the energy and water flowing downhill to do all the work for us. Now to be complete, there's another hydropower technology out there called pumped hydro. To me that is more of an energy storage type of technology. So we'll cover that in a few lessons. Hydro electricity has been around for nearly 150 years now. So how important is it relative to meeting our overall electricity needs? The plot here represents data collected by the US Energy Information Administration or EIA. Don't confuse the EIA with the IEA, the International Energy Agency as I often do. Anyway, the graph shows the amount of electricity produced by the United States, Canada and China between 1980 and 2019. The amount of electricity is in those crazy units again, terawatt hours or a trillion watt hours. But don't worry about that right now, let's just look at the trends. To the United States, the blue line, you can see that the amount of electricity produced has bounced around a bit. But overall hasn't really gone up or down much since 1980. While hydropower might have been a significant part of our total energy production, say 40% back around 1940, it's only about 7% of our total output today. And as we'll discuss, we're not building much additional capacity these days. Canada, the gray line, has been adding to its hydropower capacity in a fairly uniform way over the last 40 years or so. And while Canada produces just a bit more electricity from hydro compared to the United States, it is a much larger percentage of its total energy production at nearly 59%. Now part of that is because Canada's population is about one tenth that of the United States. So we would expect its electricity needs to be much lower. But Canada also has some of the most perfect locations for a large scale hydro plant. And it's been taking advantage of those for quite a long time and is continuing to add capacity even today. China, in contrast to both Canada and the US shows a rather remarkable trend when it comes to hydropower. Starting at a pretty low point in the production curve back in 1980, it has steadily been adding capacity up until about the year 2000. At this point, China's economy started to really take off and so did its need for more electricity. As such, it started building many hydroelectric plants and some really big ones too as we'll see. As a result, China is now getting about 17% of its electricity needs from hydropower and has an installed base nearly four times that of the United States. You might have heard about this project, the Three Gorges Dam located on the Yangtze River in China. The project took nearly 20 years to build and at the end when they opened up the gates, it became the world's largest hydro electric power station capable of producing 22 gigawatts of power. To put that in perspective, that is about the same amount of power as you would get coming from 22 large scale nuclear or coal fired power plants. The project is also one of the largest physically coming in at more than a mile long from one end to the other. The reservoir created by the dam is nearly 300 feet deep, the length of an American football field. And how much did it all cost? That's a good question. As we really don't know the final figures, but estimates range from the equivalent of about 25 billion US dollars to nearly 80 billion US dollars. The result though is incredibly impressive from an engineering perspective. And clearly demonstrates that China is a leader in hydropower technology. As the Three Gorges Dam project is pretty much state of the art, let's take a look at the advantages and disadvantages of such a massive undertaking. Now, for sure, the project doesn't represent all hydro plants today, but let's just say that it's representative of most of them. For one, the criteria necessary to build a plant are pretty straightforward. You need flowing water and a place to build a dam. As most states and countries have locations that meet these requirements hydropower can be an excellent source of electricity. And it's a domestic source of electricity, meaning you're not subject to international markets. Hydro plants are extremely efficient. Remember when we said a typical coal or natural gas plant was in the mid 30% range. Hydro plants are more than 90% efficient, partly because there is no heat necessary. So most of the energy in the flowing water goes directly into turning the turban. And speaking of fuels, the fuel for a hydro electric plant is essentially flowing water, which for the most part is nearly free. As such, hydropower is a low cost source of electricity, often much less expensive than power coming from any other source of electricity. Some recent reports indicate that electricity from hydropower costs in the range of $0.5 per kilowatt hour or five cents a kilowatt hour, much less than fossil fuels. Now, that isn't what we pay for electricity, but that's what it takes to produce and if it's cheaper to produce, then it's also less expensive for us to buy, not a bad deal. Of course, since the fuel is just flowing water and all that does is rotated turban, there are no emissions from a hydro plant. That means no greenhouse gasses and certainly no toxic air pollutants such as particulates or nitrogen oxides. And once you've created a large freshwater reservoir, it can become a spot for tourism. This is certainly the case with places such as Lake Powell in the United States and many other locations. Perhaps most importantly, hydropower is considered a source of zero carbon renewable energy. As long as there is flowing water, there is the potential for hydro electricity generation. And the flowing water comes from natural processes sometimes referred to as indirect solar energy. The sun heats the water in streams, lakes and oceans, causing it to evaporate. The air can become saturated with water and when it cools it rains, filling up the rivers once again, leading to flowing water. As long as this cycle continues, hydropower is possible. Well, you might be thinking with all those advantages, why aren't we building a lot more hydropower plants? To be sure, we've known about hydro power for more than 100 years. As such, industrialized nations such as the United States, the European Union, Australia and Japan have already put hydropower plants where they have the most potential. So there just aren't that many locations left to cite a large industrial scale power plant, at least in many countries. But that's not the case in Asia or in developing countries however. As we've seen so far, China is building more hydro capacity than anyone. And many other countries have several active projects underway, notably Turkey and India. One of the major disadvantages of generating electricity with hydropower has to do with the dam itself. In most projects you take a river and create a large reservoir, of course, if there are people that live along or near the river, then they need to be moved. In the case of China's three Gorges Dam, more than a million people needed to be relocated as their homes, communities and businesses ended up at the bottom of the reservoir once the dam was constructed. Another problem with the dam is how it negatively impacts of flowing rivers ecosystems. For example, salmon populations in the pacific northwest have seen a dramatic decline because their seasonal migrations for spawning have been so disrupted. It's estimated that the numbers of salmon have dropped from pre dam levels of near 16 million fish to only 300,000 today. And if your economy depends on salmon, then economically you're in trouble. And then there are all the other wildlife that either lived in or near the river, wondering what happened to their habitat having their river turned into a large lake. That includes other fish, birds, animals such as beavers and otters, and of course plants, all the living things that thrive in a river, but not so much in a reservoir. Sedimentation is another big problem rivers and flowing water often carry small particles of soil, sand and rock once it hits the dam. And all those particles settle to the bottom of the reservoir, creating a mucky sediment layer. Now you need to dredge the reservoir to ensure that the plant operates properly. But it also means a concentration of chemicals that used to be widely dispersed in a flowing river. And if those chemicals are contaminants in some form now, you have a more serious health problem to deal with. Many dam structures were built decades ago, we call thee Grand Cooley Dam in Washington was completed in the early 1940s, more than 80 years ago. What does that mean? Well, these dams hold up quite a lot of water and any structural problem can lead to catastrophic failure of the dam itself. But devastation to all those living downstream to prevent this dams, like everything else, need periodic maintenance to ensure structural integrity. And this can be very expensive to do as a result of the ecological costs, displacement of communities and the negative impacts on the local economy. The United States and many of the industrialist nations are in fact decommissioning more hydropower projects than they are building new ones. That is one of the reasons hydropower has held fairly constant these past few decades. So while hydropower is a major part of our renewable energy strategy, it won't be much bigger in the future than it is today. At least here in the United States. Let's summarize our discussion with a few main takeaways. Electricity generated from hydropower has been going on for about 150 years. The technology is mature, highly efficient and very cost-effective. Hydroelectricity is clean, free of greenhouse gasses or toxic air pollutants and is renewable as long as there is flowing water, there is the potential for power generation. However, there are many ecological and social disadvantages and these negatives need to be weighed against all the benefits. Within industrialized nations there are few locations suitable for many more large industrial scale hydropower plants. Most of the growth will be in Asia Latin, America and Africa. So in the end, hydropower is a renewable energy source that can help meet our greenhouse gas objectives, but we can't build a lot more of it. So we'll need additional technologies to get to net zero emissions. So if hydropower is just one part of the solution to meeting our near term and long term emissions targets, what else is out there. One of the exciting growth areas in renewable energy is wind power. We've all seen those slowly turning wind turbines situated on farms, hillsides and perhaps out in the water. They are mesmerizing to watch for sure. They have become one of the least expensive ways to produce electricity. In our next lesson, we're going to explore wind power. How it works and how it is key to achieving our 2030 and 2050 emission goals. We're also going to dive into wind power economics, for instance, how did it get so inexpensive relative to more mature technology such as coal or nuclear. So our next lesson will be a detailed view of the wind power industry where it is today and its growth over the next ten years or so. There's a lot more to come. Thanks once again for joining me on this journey towards a more sustainable future. I'll see you next time.