Environmental Studies Lecture Notes - Case Study Example

ES 79 Lecture In this first lecture, the introduced us to the and went over the course objectives which is to look at the things like electrical production that is seriously affecting our environment and oil prices are impacting our economy. After pointing out why its important to study this, he showed us what some of California's energy sources are, separating them in terms of renewable and nonrenewable sources. Then he went over the course objectives which include understanding the course terminology, life-cycle costs of alternative energy, technology and applications on a commercial basis, photovoltaic power systems, applications of wind power, types of fuel cells, and opportunities for buying green power. Next he went over the homework assignments and the reading assignments. As we finally got started with the class itself, he started a discussion what renewable sources of energy are. Essentially it's an energy source that renews itself without effort; they can be used over and over again. These kinds of sources can include solar, wind, biomass, hydrogen, geothermal energy, hydroelectric energy, and ocean energy. This class is focused more on production more than previous classes in the program because it's more cost-effective to conserve energy before you try to produce it. Each of these sources of energy have some positive and potentially negative elements that might come into play. Some of the first vocabulary he went over was solar constant, which is the amount of energy that goes by the earth. Insolation talks about how much solar radiation hits the ground and there are three different kinds - direct, diffuse, and reflected. One sun is another term that will come up often and refers to the amount of sun an area gets in a day. Azimuth and altitude angle. Altitude is the height of the sun in the sky. Azimuth angle is the angle from the south. This has an effect on where and what orientation we build solar panels to achieve maximum power source. The optimum is to go south, west is better than east, and consider areas of shade. The angle of the solar panels should be equal to the latitude, but can be adjusted in consideration of the uses of the project (summer, winter, other environmental conditions like fog). Although some utilities will pay you for excess power you produce, but they aren't obligated to do so by law. Basics of PV cells is that it is a semi-conductor electron pump that creates about .5 volts of DC power per cell, a number of cells are collected to create a module and a collection of modules is an array. Types of PVs are stand alones (sometimes with batteries) or Grid intertie (tied into the grid and the meter goes backwards), and they're made of crystalline silicon (multicrystalline is the most popular right now), thin film, and concentrators or tracking devices to add greater efficiency. Building integrated PV means a low efficiency PV system that works with the building to provide additional comfort and collect power at the same time. After going over a normal set-up and some examples, we discussed the need for battery backup systems - 3-5 days of backup is typical and should provide power for the essential systems such as refrigerator, etc. There's a lot of estimating about installing a system - you have to estimate the load and the production, the available sunlight, and the reliability of the system. Have to know the difference between kW (unit of power) and kWh (energy). Factors that affect output include temperature, dirt, wiring losses, and AC to DC conversion. Then we discussed how to calculate energy. We ended the lecture with an introduction to solar thermal - heating hot water, space heating, or pool heating - and replaces the need for natural gas. Again, conservation takes precedence over efficiency. Systems are better than they used to be in the 70s. Types of thermal systems are batch heaters (collection and storage are together) and flat plate collectors (collection and storage are separate). Lecture 2 After reviewing what we talked about last time, we went into more details about the field trip that the class was scheduled to take and the details of the project that they were visiting. During the second part of the class, we moved into discussing wind power - where it can be used, how it competes with other sources of energy and what kinds of codes and community acceptance exist. Wind is about 1.5% of the energy produced in California. Fits definition of renewable energy, same net metering laws apply as for PV. It has a history of sorts so we understand it fairly well, pollution free, major source of power before 1900 (windmills), small scale is less than 100 kW, larger scale is greater than 100 kW through wind farms. Even better is wind doesn't mean you can't use that land any more. However, wind can be unpredictable and you need to consider geography, buildings and trees, ground effects, environmental effects such as bird mortality rate. Regarding bird mortality rates, there are a number of various greater contributors to bird mortality than wind turbines. Need about 12 mph average wind speed to create energy and an understanding of how wind is created - differences in air temperature. More turbulent air is more difficult to collect air power which is why a higher elevation is better. Wind has a cubic relationship with production, but it can quickly overload the system with high wind speeds and you need a means of dealing with that. Next we discussed the turbine components and the different designs that are available. There's the rotor, a drag design that gives high torque and lower speed, lift design which gives lower torque and higher speed, and transmission into AC or DC. There are also vertical axis rotors which offer the advantage of being easier to mount because they're closer to the ground and catch more of the wind, but they get more of the wind disturbance. Another form is the Darrieus rotor which is the egg-beater style rotor. Sizes are micro at 3-5 foot diameter producing approximately 300 kWh/yr (fraction of residential use), mini is 5-9 foot diameter (1500 kWh/yr), and household at 10-23 foot diameter (12,000 kWh/yr) which produces more than the typical household would need. Grouping renewable energy sources is already happening. For the last part of class, we went into a discussion of hydropower and the question of whether it is a renewable source. This source doesn't automatically renew itself unless you're very careful about how you use it in balance with the rainfall. However, it's non-polluting, it is a large part of California's electrical production (14.5%), and it is possible to build your own small scale power plant in areas where there isn't much sun or wind. We went through a few different diagrams of types of hydropower designs - impoundment or pump storage. We also briefly discussed fuel cells as a technology that hasn't been fully developed yet. The most common type of stationary cells is the proton exchange membrane (PEM) with about 60% efficient fuel to power conversion. Hydrogen is the fuel source for the fuel cell, the catch is where to get the hydrogen. The benefits is that there is reduced pollution in greenhouse gases and the by-product is water, higher efficiency than gas or diesel, can use the waste heat to improve overall efficiency, and it has low maintenance because there are few moving parts to break. The downside is that there is a current lack of hydrogen infrastructure, the production of hydrogen is not environmentally friendly, and the cost is $4000-$5000 kW. Hydrogen is obtained through external reforming, internal reforming, or electrolysis. Class ended with some discussion of more examples of buildings that are effectively using renewable energy sources and technologies. Lecture 3 Like last time, we spent the first part of the class reviewing the material we discussed in our previous class. For this class, there was a guest speaker, Heath Galloway, who works on installing PV systems. He provided some information about his own background, and then talked with the students in the classroom at the time about different ways to increase efficiency in solar power generation. He also talked about some of the problems of efficiency in working with different types of cells, saying that he preferred multicrystalline or monocrystaline cells better, depending on the specific environment where the installation is placed. Hawaii, for example, had greater issues of pitting, molding, and misting because of the humid environment there. Something that surprised me in this discussion was that he has to guarantee their systems for five years, but said that they also have some systems that they guarantee for ten years. He showed us www.iesolar.com which is his company website and has several examples of the types of arrays they install. Another thing he discussed was the difficulty of how and where to install the array for greatest effect, which is not always based on the textbook answer. He said as long as your array can produce at least as much as you said it would, your customers will never complain if you produce more than you say you'll produce. Finally, he walked through the process of doing a home installation and how they decided what the best system to install would be. He also pointed out that selling these systems is not as much about the environmental impact as it is now about personal economy. Again, the question of efficiency came up as a question of conservation first, generation of power second. He finished his discussion with some tips on what different roles that are available in the industry and some chances for students to volunteer to work with his company and get experience about what installation is like. After the break, we talked about integrating the energy components as a part of the aesthetic design process as a means of overcoming some of the objections to solar PV panels and looked at some examples. Requirements for these projects include the building having good solar access, innovative design helps, building needs to be already energy efficient, energy can be used on site, and it helps to have community, client and designer support. This approach takes a lot more area, but it is part of the building which enables you to incorporate the costs with the actual building costs. Then we moved on to biomass, geothermal, and ocean power. Biomass is plant matter, animal waste, tree trimmings, agricultural residue, construction waste, and other similar types of sources. Burning wood is essentially biomass energy. Thus, it is renewable energy because it does grow and is naturally produced on its own, so it does fit with the class definition, but it requires transportation and you have to consider the pollution issues associated with this. It's the second largest renewable behind hydro and usually used in association with coal plants. Geothermal energy is harnessing the heat from the earth to either create electricity or to use the heat itself. It can be a renewable source of heat if it is used carefully. One problem with this form of energy is that the geysers also bring up a number of additional minerals that can cause problems. Ocean energy includes tidal power, tidal fence and tidal turbines, wave power, and ocean thermals. There has been a lot of interest but not a lot of practice. Part of the problem is that the ocean is an incredibly corrosive environment and there are a lot of environmental issues regarding using the ocean right off shore where most of the animals live and people use it for recreation. Remember the wave power concept as the hot dog concept looked at by Portugal. The last thing discussed in the class is the concept of green power credits which is essentially voting for green energy by paying for green power on your electric bill. This doesn't mean your energy is actually green power, but that you are making a statement that you will support green energy. There are some referee organizations that work to ensure you're actually getting what you're paying for. The class ended with each of the students discussing their green energy projects that they've been working on. Read More