What is the energy payback for photovoltaics? Producing electricity with solar photovoltaics (PV) emits no pollution, produces no greenhouse gases, and uses no finite fossil-fuel resources. The environmental benefits of PV are great. But just as we say that it takes money to make money, it also takes energy to save energy. The term “energy […]
Hurricanes are violent storms which bring intense winds, heavy rain, storm surge, flooding, erosion, landslides and tornadoes. While it is difficult to predict the exact time, place, and force of hurricanes, residents along the Atlantic and Gulf coasts must be prepared. The season for hurricanes runs from June through November, with most hurricanes occurring mid-August […]
Ethanol is a renewable fuel made from plants. Essentially non-drinkable grain alcohol, ethanol is produced by fermenting plant sugars. It can be made from corn, sugar cane, and other starchy agricultural product. The cellulose in agricultural wastes such as waste woods and corn stalks (also know as “cellulosic ethanol”) can also be used as a […]
Here are the five elements that constitute a complete passive solar design, using a direct gain design as an example. Each performs a separate function, but all five must work together for the system to be successful. Aperture (Collector): the large glass (window) area through which sunlight enters the building. Typically, the aperture(s) should face […]
Part 15 of Buying and Using Renewable Energy at Home. One of the more challenging ways to use clean energy is in fueling our cars. Advanced transportation technologies—including fuel cells, electric motors, advanced engines, improved materials, and other technologies—aim to reduce pollution and minimize petroleum fuel use in cars, trucks, buses, fleet vehicles, and public […]
Part 12 of Buying and Using Renewable Energy at Home. Heating and cooling uses more energy and drains more energy dollars than any other system in your home. Typically, 44% of your utility bill goes for heating and cooling. What’s more, heating and cooling systems in the United States together emit more than a half-billion […]
Part 11 of Buying and Using Renewable Energy at Home. Your dealer can help you analyze your loads and size your system correctly. The dealer will install your equipment, making sure that it runs properly. Dealers will also have contacts at the local utility if you are connecting your system to the utility grid. With […]
Part 10 of Buying and Using Renewable Energy at Home. In addition to wind turbines, PV modules, or a microhydropower generator, you must purchase BOS equipment, when generating your own power. This may include battery charge controllers, batteries, inverters, wires, conduit, a grounding circuit, fuses, safety disconnects, outlets, metal structures for supporting the PV modules, […]
Part 9 of Buying and Using Renewable Energy at Home. According to many renewable energy experts, a standalone “hybrid” system that combines generation sources, such as wind and PV, offers several advantages over a single generation system. In much of the United States, wind speeds are low in the summer when the sun shines brightest […]
Part 8 of Buying and Using Renewable Energy at Home. If you are fortunate enough to have a stream running through your property, you might be able to generate hydropower. Microhydropower is a term used to describe very small hydropower systems. The definition of microhydropower varies, but is generally below 300 kilowatts. At this size, […]
Part 7 of Buying and Using Renewable Energy at Home. Photovoltaic cells produce direct current (DC) electricity. About 40 cells are joined together in enclosed, protective casings called modules. About ten of these modules are mounted in one PV panel. These flatplate PV panels can be mounted facing south, or they can be mounted on […]
Part 6 of Buying and Using Renewable Energy at Home. All wind energy systems consist of a wind turbine, a tower, wiring, and the “balance of system” (BOS) components: controllers, inverters, and/or batteries. Home wind turbines consist of a rotor, a generator mounted on a frame, and (usually) a tail. With the spinning blades, the […]
Part 5 of Buying and Using Renewable Energy at Home. At first glance, generating your own electricity using renewable fuel sources seems like the ideal way to avoid monthly utility bills. For some homeowners, self-generation is a choice that makes sense for their circumstances and fits into their values. However, self-generation involves investing your money […]
Part 4 of Buying and Using Renewable Energy at Home. The following briefly describes renewable energy technologies that might be offered in green pricing programs or competitive markets in your area. If you do not currently have the option to choose your electricity supplier, contact your utility to find out what their plans are regarding […]
Part 3 of Buying and Using Renewable Energy at Home. When describing electricity production, the terms electric power (or capacity) and electric energy (or electricity) are often used. “Power” is the ability to do work and “energy” is the actual performance of the work, or the use of that ability over a period of time. […]
Just a few years ago, we did not have the ability to choose our electric service. Currently, the electricity industry is undergoing changes that will bring choice to many consumers across the country. Already, utility customers can choose to obtain electricity from clean generation sources—also known as green power. Green power is electricity that is […]
Part 8 of Wind Power for the 21st Century. For the past two years, the wind industry has enjoyed record-breaking growth, and industry experts predict that with the extension of the PTC through 2008, the next two years will be record-breakers as well. The challenge for industry is to maintain the long-term wind energy growth […]
Part 6 of Wind Power for the 21st Century. Southwest Windpower conducted performance optimization and blade-fatigue tests at the NWTC on its new Skystream wind turbine. The 1.8-kW turbine, developed in partnership with DOE, won the Best of What’s New Award from Popular Science Magazine and was listed as a best invention for 2006 by […]
Part 5 of Wind Power for the 21st Century. One program R&D project that shows potential for demonstrating a significant increase in overall system performance is the 2.5-MW Liberty wind turbine developed by Clipper Windpower. Clipper completed its prototype in 2005 after only 3 years of R&D. The new machine’s innovative distributed-path powertrain design incorporates […]
Part 7 of Wind Power for the 21st Century. Large Wind Technologies Although research efforts for the past two decades have led to dramatic reductions in the cost of wind energy, continued incremental improvements to wind turbine performance will lower system costs even further while improving system integration and enhancing technology acceptance. The Wind Energy […]
Part 4 of Wind Power for the 21st Century. Systems Integration The natural variability of the wind resource can present challenges to grid system operators and planners with regard to managing regula-tion, load following, scheduling, line voltage, and reserves. While the current level of wind penetration in the United States and around the world has […]
Part 3 of Wind Power for the 21st Century. In support of Advanced Energy Initiative objective to expand the use of wind energy, the Wind Energy Program is increasing its efforts to overcome near-term deployment barriers to wind by enhancing public acceptance, promoting supportive public policies, engaging key stakeholders, and addressing siting and environmental issues. […]
Part 2 of Wind Power for the 21st Century. The DOE Wind Energy Program is one of 10 clean energy technology programs within the Department of Energy. It is managed by program staff at DOE Headquarters in Washington, D.C., and its Project Management Center (PMC) in Golden, Colorado, manages the financial assistance, provides program support, […]
After you have assessed the appropriateness of your site, you need to determine how much electricity your PV system must generate. This depends on how much electricity your loads require. Again, your dealer can help you with sizing a system that will meet your needs. The sidebar illustrates the steps involved in sizing a PV […]
Part 4 of Get Your Power from the Sun. People decide to buy photovoltaic systems for a variety of reasons. Some people want to help preserve the Earth’s finite fossil-fuel resources and reduce air pollution. Others want to invest in an energy-producing improvement to their property. Some people like the security of reducing the amount […]
Part 2 of Get Your Power from the Sun. Photovoltaic (PV) systems convert sunlight directly to electricity. They work any time the sun is shining, but more electricity is produced when the sunlight is more intense and strikes the photovoltaic modules directly (as when rays of sunlight are perpendicular to the photovoltaic modules). Unlike solar […]