In this lesson, we're going to talk about hydroelectricity, electrical power generated by falling water. It's the first of the renewable energy sources we're examining. The first use of water to provide mechanical energy was in China during the Han Dynasty, 2,200 years ago. Trip hammers powered by a vertically set water wheel were used to pound grain, break ore, and to make paper. However, the most rapid advances were made during the Industrial Revolution in England, where in 1771, Richard Arkwright set up a mill to spin cotton and so set up one of the world's first factory systems. Soon after, turbines powered by water were developed, culminating in 1849, when British American engineer James Francis developed the first modern water turbine. His Francis turbine remains the most widely used water turbine in the world today. Modern hydroelectricity generation works in much the same fashion. The energy of falling water turns blades and a turbine. But instead of applying that mechanical energy directly, as in a water wheel, it creates electricity in a generator. Hydroelectric generation has a rich history. Some major facilities such as Hoover Dam in the Western United States are almost 100 years old. As modern turbines can manage much more energy than a primitive water wheel, huge volumes of water can be stored behind dams to produce large and relatively constant amounts of electricity from month to month and year to year. On the Peace River in Northeastern British Columbia, the 183 meter high WAC Bennett dam has created Williston lake, which has an area of 1,773 square kilometers. The GM Shrum generating station below the dam has a capacity of 2,790 megawatts or 2.79 gigawatts. This electricity powers the local area and has since southward over major regional transmission lines to power communities in Southern BC and the adjacent Northwestern United States. All told, this is enough electricity for about 750,000 average homes. Canada has several other hydro facilities with similar capacity, but these are dwarfed by massive installations like the Three Gorges Dam in China, which boasts the capacity of 22.5 gigawatts, about eight times larger than WAC Bennett. There are about 70 hydroelectric generating facilities around the world with capacity similar to WAC Bennett. About 1/3 of these huge hydro facilities are in China. All of the largest hydro generation projects under construction globally are in low to middle-income countries, although several of these are on hold for economic and political reasons. Let's talk about one of the big new projects, the Grand Ethiopian Renaissance Dam on the Nile river. My colleague, Dr. Alula Damte, a professional structural geologist, has been involved with this project in his native Ethiopia for several years. You'll be amazed by the scope and complexity of this project. The Nile River is a huge transboundary water resource spanning 11 countries in Eastern Africa, as noted on this list of repairing countries, which means those on the banks of the river. The Grand Ethiopian Renaissance Dam or GERD is being built on the Abay or Blue Nile River in Ethiopia. When complete, will be Africa's largest hydroelectric dam by generation capacity and seventh largest dam in the world. Construction began in 2011. As of July 2021, the dam was 81 percent complete. It has entered the crucial last phase of construction, which includes filling the reservoir, which began in 2020. Construction is expected to be completed in 2023 and will cost approximately five billion US dollars. The GERD is a roller compacted concrete gravity dam. When the reservoir behind the dam is full, it will cover an area of 1,874 squared kilometers and it will contain 74 billion cubic meters of water, more than 1/7 the volume of Lake Erie in North American Great Lakes. The main dam is 155 meters or 509 feet high, and 1,780 meters, or just more than a mile long. A saddle dam, as you can see in the picture, was required to raise the water level to the expected height of 640 meters above sea level. It is 50 meters high and 5,200 meters more than three miles long. Their generation station will have a capacity to generate up to 5,400 megawatts of or 15,692 gigawatt hours of electricity per year, enough to meet the needs of 1.4 million average Canadian household, or approximately 30 million individuals in Sub-Saharan Africa. The offtake power line and substations have been fully built and tied to the main power station some 618 kilometers from the dam. The Blue Nile originates from the highlands of Ethiopia and contribute 57 percent of the total annual flow of the Nile river. Flow is extremely variable with 83 percent of the average annual flow occur in just four months of the monsoon season, that is from July through October. The two contrasting images on the charts show the Blue Nile falls during the dry season and the rainy season. There is so much water over the falls in the rainy season that the locals call it thesisat, meaning smoke from a fire. In addition to electricity generation, the dam is expected to provide predictable average annual flow downstream in Sudan and Southern Egypt. Historically, Cairo, Gaza, and Alexandria on the Nile Delta in Northern Egypt flooded annually during monsoon season in the Ethiopian Highlands. Thanks to the Aswan High dam built upstream in Egypt in the late 1960s, the Nile Delta no longer floods. Further upstream in Khartoum, Sudan, where the Blue Nile and White Nile meet, seasonal floods are still frequent occurrences, affecting hundreds of thousands of people every year. Construction of the GERD in Ethiopia, is expected to mitigate some of the flooding in Sudan. After several failed military campaigns control the headwaters of the Nile, in 1902, Britain secured an agreement with the Ethiopian emperor, to consult them on any Blue Nile water project that arrest the flow of the river. This word, arrest, became a point of contention between Egypt and Ethiopia in later years. In 1929, Egypt negotiated the Nile Waters Agreement with the East African British colonists to establish Egypt's right to 48 billion cubic meters of water flow. All crisis in waters, and veto power over any upriver water management projects. The Independent Ethiopian Monarch of the day was not consulted. In 1959, the Nile waters agreement between Egypt and Sudan was completed, allocated all Nile waters between Egypt 75 percent, and Sudan 25 percent. The Emperor of Ethiopia was offended by Egypt exclusion of Ethiopia in the Nile Waters Agreement, and in plans to build the Aswan Dam. As a result, he negotiated the 1959 divorce of the Ethiopian Orthodox Church, from the Orthodox Church in Alexandria, ending 1600 years of institutional marriage. In the 1990s, Egypt built the Toshka Canal. One of the world's most expensive, and ambitious irrigation projects to use additional water from the Nile. Ethiopia protested by saying, while Egypt is taking the Nile water to transform the Sahara desert into something green, we in Ethiopia, who are the source of 85 percent of that water, are denied the possibility of using it to feed ourselves. Ethiopia began plans for the Grand Renaissance Dam. In 2010, six upstream countries signed Cooperative Framework Agreement seeking more Nile water shares. Egypt and Sudan rejected the agreement, because it challenged that historic water rights. In 2015, the leaders of Egypt, Ethiopia, and Sudan, signed the Declaration of Principle to end a long-running dispute over the sharing of Nile water. The agreement was supposed to form the basis for a comprehensive agreement on the filling and operation of the dam, but allow the construction of the dam to proceed. As of November 2021, the three countries have failed to reach agreement, and the dispute has reached the UN Security Council. Dam construction continues based on the Declaration of Principle. Filling up the reservoir is seen by Ethiopia as part of the construction process, but Egypt contends it's evaluation of the agreement. Political disagreements have impeded construction of the GERD since it started in 2011, when Egypt voiced opposition to any upstream project by claiming historical rights to the river. The rhetoric reached a level where the Egyptian President proclaimed, no one can take a drop of water from Egypt. If it happens, there will be inconceivable instability in the region that no one could imagine. Ethiopia's position on the GERD is that it's a non-water consuming hydroelectric project launch to bring electricity to more than 60 million people or 55 percent of the population that are not connected to the grid. Despite the GERD's, renewable energy status, and it's hugely positive social impact, especially on women. Ethiopia was unable to secure funding from sources such as the World Bank, and EU infrastructure loan, or from Western private financial institutions, due to the sensitive geopolitical nature of the project related to the Nile Waters Sharing Agreement. The project is entirely funded from domestic and diaspora sources. Tensions remain high as the project progresses, but an initial 700 megawatts of power began being generated from the two turbines in early 2022. The story of the GERD demonstrate the challenges and long timeframe, to get major project, even renewable energy projects built in many parts of the world. Now, let's return to the main part of the hydroelectricity lesson. Our sankey diagram shows that like nuclear, and most other renewables, hydro provides energy only in the form of electricity. According to the International Energy Agency, it's applied 15.8 percent of the world's electricity in 2018. Well, hydroelectricity produces the most energy of any renewable resource, it's contribution to the world's overall energy supply is significantly smaller than oil, gas, coal, nuclear, or biomass. Electrical grids in some countries boast a very large renewables component and in every case, this is based primarily on massive hydroelectric resources which have been developed largely over the last 50 years. However, even when most electricity is generated with hydro-power, oil is still a major contributor to overall energy supply when transportation, heating and cooling, and industry are considered. This is true even in Iceland, where geothermal is hugely important as well. Well, hydroelectricity is the largest renewable energy source in the world today, its rate of growth over the past 30 years has been slow relative to solar, wind, and liquid bio-fuels. Even though substantial new capacity has been added, the established hydro-power base is so large, that new projects don't move the needle much in terms of percentage growth. As well, many of the readily available large hydroelectric sites have been developed already, particularly in higher-income nations. Later in this lesson, we'll hear about exciting new developments in smaller hydro projects that promised to bring hydroelectricity to smaller communities and more remote areas with far less environmental impact than major hydro installations. In Canada, the Site C hydro project on the Peace River downstream from WAC Bennett, is projected to have a capacity of 1.1 gigawatts. But completion is being delayed by geotechnical, cost, and project management issues. Similarly, the 0.8 gigawatt Muskrat Falls project in the Eastern Canadian province of Newfoundland and Labrador has been hindered by cost overruns and project management issues. Together with the challenges we saw around construction of the Grand Renaissance Dam in Ethiopia, it's clear that addition of new capacity and large hydro projects is restricted by many different practical considerations. Let's look at the positive attributes of hydroelectricity as a source of energy. A really important feature of hydroelectricity is that it provides electricity reliably around the clock and throughout the year. This constant energy supply is called baseload and is critically important to energy providers in maintaining sufficient supply to customers regardless of their needs. Hydroelectricity is also dispatchable to some extent, meaning supplies can be ramped up and down within certain limits on short notice to meet variable energy demand. During routine operation, hydroelectric generation releases very low levels of greenhouse gases or pollution. We see on this chart that lifetime GHG emissions per unit of power produced are among the lowest for any energy source. However, large hydro facilities are built with huge volumes of cement, steel, and other materials, each with their own emissions and environmental footprint. As well, in the early stages of a hydro project, decaying vegetation in the reservoir can create substantial GHG emissions. Hydro reservoirs can be used for energy storage by pumping water up into a reservoir when power is cheap and abundant, then releasing it to create hydroelectricity when required. We'll talk about pumped storage further along in the course. What about the negative attributes of hydroelectricity? Large hydro projects can take years to locate, plan, permit, finance, build, test, and put on stream. The Site C project in Northeastern British Columbia was initially proposed more than 10 years ago. Provincial approval for construction was granted in 2014 and construction started in 2015. First-generation is tentatively planned for 2024, with project completion scheduled for 2025. Capital costs are daunting as well. Site C is now estimated to cost $16 billion. The WAC Bennett Hydro Dam has flooded a long stretch of the upper Peace River Valley, creating Williston Lake, which stands out even on a regional map of the entire province. Seventeen hundred and seventy three square kilometers of land along the river valley has been drowned creating new marine ecosystems while destroying large tracks of forest and river valley habitats. Normally reliable hydropower generation may be reduced by low water levels as a result of drought or conflicting water issues. Here, the Upper Kananaskis Lake's hydro reservoir West of Calgary, Alberta, is held at abnormally low levels in anticipation of possible late spring flooding, reducing hydroelectric throughput in the spring, and reducing water reserves later in the summer and fall. In 2021, hydropower generation was reduced in many areas, including the Western United States, Brazil, and New Zealand, because of drought conditions and reduced water levels. As is the case for any extractive resource industry, hydroelectricity can be produced economically only where the resource exists. In British Columbia, for example, we see huge hydro generation sites concentrated on the Peace River in Northeastern BC and along the Columbia River in South Eastern BC. The primary demand center in British Columbia is in the far Southwest, in the City of Vancouver and the surrounding lower mainland. A lot of hydroelectricity has to be transmitted 500-1,200 kilometers from generation to delivery point. But hydroelectricity is not all about big remote generation projects. Smaller hydro project can be built along the course of a flowing river called run-of-river hydro. They divert part of the stream flow to a generating station, then return the water to the river a short distance downstream as we see in this photo. Higher volumes of water and steeper stream gradients give you more output, but the electricity produced is much smaller than from a large hydroelectric dam, typically 5-15 megawatts instead of 1,000 megawatts or greater. Run-of-river hydro produces fewer environmental impacts than big hydro as there is no large reservoir that submerges big land areas. However, power output is more variable as well as less is produced during low-flow periods, such as late summer or during a drought. Run-of-river hydro projects are most successful in high gradient streams in mountainous areas, and hence are popular in places like British Columbia. All of the small blue dots on this map of BC's electricity sources are run-of-river hydro stations. Run-of-river is ideal for generating electricity in remote, sparsely populated areas where it's often difficult to build other low emissions energy sources. In British Columbia, some run-of-river projects have been developed in partnership with local First Nations communities. That's our review of hydroelectricity. Next, we'll move on to a rapidly growing and very important form of renewable energy, wind power.
