In this lesson, we're going to address generating energy from the wind, one of the big two intermittent renewable energy sources, along with solar, that are growing into important components of a more diverse energy future. Long-distance sea travel, even across the oceans, could be accomplished harnessing only the wind until steamships came onto the scene in the 1800s. On land, windmills date back to the Middle Ages. Wind energy was captured by rotating blades and the mechanical energy was used primarily to mill grain. The first windmill to generate electricity was built in the late 1800s. Today, wind energy is captured by wind turbines, which convert the kinetic energy of the wind to rotational energy. This process drives a generator, which produces electricity. Although wind turbines come in a variety of shapes and sizes, the aerodynamic three-blade design is the most common. While the blades are generally made of lightweight composite material, each wind turbine uses thousands of kilograms of cement and steel in the foundation and a variety of other minerals and metals in construction of the generator and hook up to the electrical grid. We'll talk about these materials in our discussion of supply chains later in the course. Wind turbine technology is evolving rapidly, producing larger installations and lighter, more efficient blade materials. Most wind developments are onshore, but offshore developments offer many advantages, like steadier, more reliable winds, optimal spacing of turbines without concerns about land use, and the ability to build larger, more powerful turbines. New offshore wind turbines are almost as tall as the Eiffel Tower, each capable of generating up to five megawatts of electrical power when conditions are optimal. Depending on how steadily the wind blows, each turbine could power up to 1,000 homes per year. There are limits, however. German physicist Albert Betz showed that even the most efficient wind turbine can extract no more than 59.3 percent of the kinetic energy embodied in the wind. Wind farm designers must also space turbines appropriately so that they do not interfere with one another and reduce overall power output. Wind energy is used exclusively to generate electricity in today's world. It's a relatively minor source of energy overall, as our Sankey diagram shows. In fact, wind supply is about 2.2 percent of humanity's total energy supply. A Sankey diagram from 300 years ago would have shown wind energy as a significant element of transportation, as sailing ships were the main movers of passengers and cargo overseas. While we still have sailing vessels today, they don't produce enough transportation energy to make it onto the chart. Like other industries where a resource is extracted to create the final product, wind energy can be harnessed only where the wind resource is sufficiently abundant to make it worthwhile. In this map, the yellows and reds show where wind speeds are relatively high and consistently available. These areas have a good wind energy resource base and are suited for wind energy development. The North Sea and Central North America have excellent wind resources and many wind power projects have been developed to serve nearby population centers. High resource areas in Central Asia, Western North Africa, and the Horn of Africa are close to large populations, but infrastructure has not yet been adequately developed. Other high wind resource areas, as in Southern South America and Greenland, are far from population centers and would be difficult and expensive to tie into large power grids. This International Energy Agency graph shows that new wind power capacity has been added at a tremendous rate over the past 30 years. The amount of installed wind capacity is growing globally at an average of 23 percent each year. Many countries trying to reduce energy-related emissions are highly motivated to bring on new wind power and much of the growth has been focused in high wind resource areas, such as the North Sea and adjacent Europe, Central Interior North America, and China. There are questions as to how long this growth rate can be sustained, as we'll discuss shortly. Here's another way of looking at the explosive growth of wind power generation in recent years. Most new wind power is being brought to market in high-income OECD or Organization for Economic Cooperation and Development countries and in China. Wind resources in Africa and most of Asia remain to be harvested at a large scale. For perspective, let's remember that while wind power is growing rapidly as a percentage of existing capacity, it's still quite small compared to power generation using gas and coal. This chart from the IEA shows wind generating almost 1,500 terawatt-hours of electricity in 2019. But they estimate that coal-fired generation will produce 10,350 terawatt-hours in 2021, about seven times as much. Let's look at the positive attributes of wind as a source of energy. The most immediate positive feature is that once the facilities have been built, greenhouse gas emissions are small. We see here that even on a full life cycle basis, counting emissions associated with construction, that emissions associated with wind are very small. Just above the zero line. As we've seen already, wind resources are abundant in many parts of the world. Places like Europe benefit from strong and steady winds offshore and onshore. Also, after the facilities have been built, operating expenses are relatively low compared to fossil fuel generation plants, where we have to constantly purchase fuel to keep them running. That said, a review of wind operations for offshore and onshore wind in Europe, by the Renewable Energy Foundation covering the years 2002 to 2020 shows operating costs escalating with age of the facility as many turbines experienced failures in relatively short time periods. As well, recent large wind farms built in deeper water show much higher operating costs than many of the older shallow-water installations. Let's look at negative attributes or challenges in using wind energy for electrical generation. A key issue is intermittency. As we have mentioned before, wind turbines generate energy only when the wind is blowing. Depending on where you are, the wind can blow almost constantly or it can be highly variable. This graph shows wind energy output for a month in late winter of 2022 at the Windrise wind farm, a large or 200-megawatt facility in windy Southwestern Alberta, one of Canada's prime wind generation areas. There were windy days and calm days, as we can see by the highly variable amount of power generated. For more than four days in early March, the wind generated almost no electricity. From March 16th through to the 22nd, the facility generated power and more than 50 percent of its nameplate capacity, and occasionally over 75 percent or 150 megawatts. Lots of power for the Southern Alberta electrical grid, but highly variable and hard to predict. We'll explore the implications of this intermittent supply when we talk about energy storage later in the course. Wind turbines are built primarily where the wind resource is best. There are a number of projects in the Northeastern US, near the population centers of the Eastern seaboard, but many more wind projects through the Central United States are long way from the biggest cities. There's almost no wind power in the high-consuming, densely populated states of Florida and California, as their relatively poor wind resources can't support economic projects. Each wind turbine requires a lot of steel and concrete to build, plus strategic materials like copper, nickel, manganese, chromium, and zinc. In fact, wind power requires more strategic materials per megawatt of energy produced than any other major power source. All of these materials must be produced in far greater quantities in the future if we are to build the number of turbines envisioned in rapid energy transition scenarios. We'll talk more about critical metals and supply chains in a future lesson. Many early turbines are reaching the end of their operating lives and disposing of them has become an issue in some places, with images of huge blade fragments piling up in landfills. The glass or fiber composite materials are very difficult to recycle, and the issue will become more pressing as wind generation continues to build. As one would expect, however, innovative lines and entrepreneurial spirits are creating schemes to repurpose the blades. Not only in recycling the materials themselves, but in using large pieces of the blades to build playgrounds or create bicycle shelters. Every major new project seems to attract objections and protests from affected stakeholders to people who just don't like that particular project or technology. While we're used to seeing this happen for oil and gas infrastructure, it's also true for wind farm developments. In fact, turbine noise and potential psychological effects of being close to wind turbines are considered during regulatory reviews for wind farm citing. It's important to remember that just because a project is deemed to be environmentally beneficial doesn't mean it will be seen as beneficial by everyone, particularly those who live next door. There are many conflicting reports about how many birds and bats are killed by flying into wind turbines, but there's no doubt the number is large. One innovative approach to addressing this problem is to paint one of the blades black which seems to make the turbine more easily seen and avoided. Let's complete our lesson on wind energy by taking a look at how wind farms get built. I'd like to introduce Carl Feniak, a Senior Development Engineer at TransAlta Corp. TransAlta is a major electricity provider based in Alberta and operating internationally. They are a leader in diverse, conventional, and alternative energy supply. Carl is going to talk about how a new commercial wind farm is built. Carl, over to you. Thanks, Brad. Building a wind farm involves teams of highly trained, experienced professionals in different fields, including engineering, biology, construction, stakeholder relations and communications, and project management. Civil engineers design turbine pads, foundations, and roads for hauling turbine blades and other wind farm components. Mechanical and electrical engineers design the wind farm, including the number and type of turbines, where they are best located to optimize wind resources and the design of the electrical collection system and substation that will gather up the electricity and move it onto the transmission grid. Construction professionals build roads, erect turbines, and install the underground collector lines. Technicians complete all aspects of wind turbine assembly, including drive train assembly, connection of major equipment after they are lifted into place, installing operations and monitoring equipment, and commissioning each turbine once complete. Some companies self-perform project construction, but most will contract out the construction work to dedicated engineering procurement and construction companies commonly referred to as EPCs. Developers must determine the best places to harness the wind. They review wind resource maps to determine the areas where the wind blows steadily and often with low turbulence. Rough terrain and objects like large buildings and forests increase turbulence and negatively influence the way the wind flows across the blades. Once the regional analysis is complete and a promising location is identified, meteorological towers are erected to collect more detailed site-specific data such as wind speeds and patterns. For some areas, monitoring devices such as bat towers are also installed to gather data on wildlife activity. Data collection and monitoring can continue for several years until there is sufficient information to determine whether sites are suitable for generating wind power. Access to land is the next critical issue. Land costs and the willingness of landowners to participate in a wind farm project will determine how much land can be acquired. Lease agreements between developers and landowners include payments for renting the land and can also cover option payments to reserve the right of construction before the project proceeds. In some cases, leases includes royalties, which are payments to landowners based on a portion of the revenue earned from selling electricity. Lease agreement terms are designed to match the operating life of a wind farm which is often 30-40 years. Construction and operation of wind farms have impacts on the environment and must be understood and mitigated. Permitting processes at all levels of government are designed to ensure impacts are identified and mitigated. Impacts include animals and plants, water bodies, land-use impacts to industrial, agricultural, residential, and recreational activities, flight pass and landing strips as modern turbines can reach over 200 meters high, and telecommunication systems. Studies assess noise as well as shadow flicker, which is the shadow cast by turbines on residences or other buildings as they spin. Developers must submit decommissioning and remediation plans that explain how the wind farm infrastructure will be removed and cleaned up at the end of its useful life. Assessing impacts on people who live and work near wind farms is critical to the regulatory process. Developers share information about the proposed project such as the wind farm footprint, the number and size of the turbines, and preliminary studies relating to wildlife impacts, shadow flicker, and noise. They may host community meetings or one-on-one meetings with stakeholders to communicate this information. Stakeholder feedback on projects should be thoroughly documented, and the developer should work with stakeholders to address questions and concerns. Permitting and regulatory processes typically take between one and two years and often include monitoring and mitigation obligations during construction and operations. Maintaining trusting, transparent relationships with stakeholders is critical to the success of a project. Designing a wind farm layout is an iterative process, beginning with desktop renderings, followed by site surveys to pinpoint the locations of pipelines, and other existing infrastructure. Setbacks or clearances from existing roads and infrastructure are key considerations for laying out a project and are often prescribed by regulation. Developers must survey the wind farm site and plot the locations of individual turbines, collect airline routes, and roads or other infrastructure. Wind farm construction can take up to 16 months depending on the number of turbines, that terrain where the wind farm is located, the available workforce, and the weather. In some temperate climates, construction can be completed in a single year, beginning in the spring and ending in the late fall. In colder climates such as in Alberta, construction typically starts in the fall, giving construction crews the chance to get a head start on earth works before frost comes, with turbine assembly starting the next spring. Much preparation work is required before turbine components can be hauled into the site. Roads must be graded and the turning radii increased at intersections so that large wind turbine components can be hauled in. Sometimes crews have to literally cut the tops off hills, so lengthy loads like turbine blades, with the latest blades reaching over 80 meters long, don't scrape the ground. Turbine sites called pads are built next, which entails grading an area over 40 meters in diameter, as well as building access roads. Excavation for a typical turbine foundation can be as large as four meters deep and 23 meters in diameter. Foundation design depends on subsurface conditions, constructing a large concrete raft underground, or anchoring to bedrock if available. Other civil work includes digging trenches for collector lines, grading areas for the substation, on-site building, and temporary equipment lay down areas. Once foundations are excavated, crews install rebar and forms which are filled with concrete. Turbines are secured with hundreds of anchor bolts. The foundation is able to support the turbine in a variety of weather conditions. Most notably, sustained high or gusting winds which transmit a lot of force to the foundation. Quality control is critical and extensive tests are performed to ensure that the composition and placement of all material is correct. The next step is erecting the turbines. Wind turbine towers arrive at site in segments along with individual turbine blades, drive train components, and then a cell, a large rectangular box that sits atop the turbine tower and houses a gearbox and the turbine's generator. Cranes lift tower segments, then a cell and blades. Careful coordination between crane operators and crews ensures each component is properly aligned. Construction crews watch wind forecasts and schedule work to avoid high wind delays. Once each turbine is erected, technicians connect the internal workings. Within the tower, the turbine blades connect to a low-speed shaft, which transmits power to a gearbox, which in turn connects to a generator. AC power from the generator is sent down the turbine through the switch gear and along the collector lines until it hits the substation. Technicians connect these collectors through breakers and disconnect switches, ultimately leading all the power into a high voltage transformer, which is the last major piece of equipment in the wind farm facility that the power will go through. Distance to the transmission system is an important consideration for new projects. As every kilometer of new transmission line required can add $500,000 to $1 million to the project cost. Once permitted, the wind farm is connected to the grid through a ring of breakers from the high-voltage transformer output. Finally, system performance must be verified before turning it on and connecting it to the grid. Commissioning is a final check, using a structured set of tests to confirm turbines are working, lines are connected properly, breakers and switches are functioning, and transformers are operated as expected. For a wind farm that takes 14-16 months to build, over two months maybe necessary for commissioning. Once the operator is satisfied that the farm and the transmission line are operating as expected, a successful commercial operations date can be announced and closed and other project begins. Temporary workspaces are restored, construction materials and equipment are cleared out, and disturbed areas are restored as closely as possible to their original form. Carl, thanks for that fascinating journey through wind farm construction. It's amazing how much planning and how many skills and materials have to come together to create wind energy. Next lesson, we're going to talk about solar energy.
