Photovoltaic (PV) modules produce electricity from sunlight, and are simple, effective, and durable. They can run your appliances, charge your batteries, or make energy for the utility grid.
A PV array is the energy collector – the solar “generator” and does so via the photovoltaic effect. Discovered in 1839 by French physicist Alexandre-Edmund Becquerel, the photovoltaic effect describes the way in which PV cells create electricity from the energy residing in photons of sunlight. When sunlight hits a PV cell, the cell absorbs some of the photons and the photons energy is transferred to an electron in the semiconductor material. With the energy from the photon, the electron can escape its usual position in the semiconductor atom to become part of the current in an electrical circuit.
To use the energy from the array, you may also need other components, such as inverters, charge controllers and batteries, which make up a solar-electric system. The components required are dependent on the system type designed.
Our company promotes the following types
PV – DIRECT SYSTEMS: These are the simplest of solar-electric systems, with the fewest components (basically the PV array and the load). Because they don’t have batteries and are not hooked up to the utility, they only power the loads when the sun is shining. This means that they are only appropriate for a few select applications, notably water pumping and ventilation – when the sun shines, the fan or pump runs.
OFF – GRID SYSTEMS: Although they are most common in remote locations without utility service, off-grid solar-electric systems can work anywhere. These systems operate independently from the grid to provide all of a household’s electricity. These systems require a battery bank to store the solar electricity for use during the night or cloudy weather, a charge controller to protect the battery bank from overcharge, an inverter to convert the DC PV array power to AC for use with AC household appliances, and all the required disconnects, monitoring, and associated electrical safety gear.
GRID – TIED SYSTEMS WITH BATTERY BACKUP: This type is very similar to an off-grid system in design and components, but adds the utility grid, which reduces the need for the system to provide all the energy all the time.
BATTERYLESS GRID – TIED SYSTEMS: These most common PV systems are also known as on-grid, grid-tied, utility-interactive, grid-intertied, or grid-direct. They generate solar electricity and route it to the loads and to the electric utility grid, offsetting a home’s or business’s electricity usage. System components are simply comprised of the PV array, inverter(s), and required electrical safety gear (i.e., fuses/breakers/disconnects/monitoring). Living with a grid-connected solar-electric system is no different than living with utility electricity, except that some or all of the electricity you use comes from the sun. (The drawback of these battery less systems is that they provide no outage protection—when the utility grid fails, these systems cannot operate.)
Our company has developed world-class design and construction management capabilities. As the largest buyer of many utility-scale PV power electronics, our global supply chain network has strong purchasing power and ensures the timely delivery of the modules and balance of system components to construction sites. Our proven construction management capabilities provide a significant value to plant owners, developers, and plant builders.
Hydro-electricity is fundamentally the combination of water flow and vertical drop (commonly called “head”). Vertical drop creates pressure, and the continuous flow of water in a hydro system gives us an ongoing source of pressurized liquid energy. Pressurized, flowing water is a very dense resource, and hydro-electric systems convert a very large percentage of the available energy into electricity because the resource is captive in a pipe or flume.
People have been tapping the energy in flowing water for centuries, first for mechanical power, and, in the last hundred years, for electricity. Early applications included milling, pumping, and driving machinery. Unlike wind and sun, the right hydro resource can be available 24 hours a day, 365 days a year. This allowed pioneers to run irrigation pumps and grain mills, and allows people today to make clean, renewable electricity at a reasonable cost.
Power from the natural flow of streams and small rivers can be harnessed to bring clean, reliable electricity to remote communities, providing light to study and work by and helping small businesses grow.
What are the benefits of using micro-hydro?
In remote areas, small-scale hydro schemes can bring electricity for the first time to whole communities. This provides lighting, TV and communications for homes, schools, clinics and community buildings. The electrical power generated can be enough to run machinery and home appliances, thus supporting small businesses as well as homes.
The main environmental benefit of micro-hydro power plants is to reduce greenhouse gas emissions and local pollution from fossil fuels. This includes kerosene for lighting, diesel for running machinery, and fossil fuels for generating electricity.
Since the early discussions, through design, planning, installation and commissioning, our team will guide you through the process of realizing the potential of your Micro-Hydro Power Plant project.
Wind energy is a dynamic resource – the energy available in a moving mass of air. From grain grinding by simple wind – driven machines in ancient cultures to modern electricity generating devices, the wind has been tapped to work for us.
Wind is a cubic energy resource. As the wind speed increases, the power available increases cubically. This means that it’s very important to get into higher wind speeds, and the way we do that is with taller towers. Regardless of the turbine or tower type, going higher is the tried-and-true, reliable way to increase performance in a wind generator. And the most common mistake in wind electricity is installing a turbine on a short tower.
The swept area of a wind turbine is the second most important factor (after the wind resource itself) that determines energy production. The circle “swept” by the blades is the collector area. It’s not possible to get a large amount of energy out of a small collector area. Betz’ theorem says we can only get about 60% of the energy out of the wind before we start slowing it down too much and actually decreasing performance. In the real world, well-designed machines can achieve about half of that.
Turbines can be divided by orientation, directionality, generating mode, and by other characteristics. Horizontal-axis wind turbines (HAWTs) are the most common and effective orientation. Vertical-axis wind turbines (VAWTs) may appeal to the uninitiated, but continue to disappoint as far as performance and longevity – both of the machines and the companies. Upwind (the wind hits the turbine before it hits the tower) and downwind (the wind hits the tower before it hits the turbine) designs can both be very effective.
Generating devices generally fall into one of three categories. Most home – scale turbines use permanent magnet generators (PMGs), which typically have fixed coils of copper wire and rotating groups of magnets that pass by them. Some older machines use wound-field alternators, which use a small amount of the wind energy to create electro-magnetism in the rotating part of the alternator. Induction motor/generators use conventional induction motors, but have the wind push them beyond their normal operating speed, which takes them from using electricity to making electricity.
Three basic tower types are used for residential wind-electric systems. Freestanding towers are the most expensive, but can be installed in very close quarters, and are perhaps the safest to install and maintain. Tilt-up towers allow all maintenance and repair to be done on the ground, but require a large open area for installation and use. Fixed-guyed towers include lattice and pole styles that do not tilt, and must be climbed for installation and service. These are typically the least costly, and need a moderate area for installation.
A wind-electric system is much more than just the wind generator and tower. Also required are transmission wiring, electronic controls, batteries if storage or backup is desired, an inverter for household AC or grid-interconnect, as well as metering, overcurrent protection, and other standard electrical components. All appropriate components should be chosen for compatibility and functionality; it takes a whole system to make wind electricity.