Most renewable energy ultimately comes from the sun. The earth receives as much energy from sunlight in twenty days as the planet’s entire reserves of fossil fuels contains.
- save hundreds of dollars on water heating bills
- hedge against increasing energy prices
- reduce dependence on foreign oil
- use clean, renewable energy
- reduce air pollution
There are currently three different ways to harness the sun's power:
Passive solar usage can be applied anywhere with sufficient sunshine. The concept behind passive solar is simple. It involves managing natural sunlight in such a way that it maintains a desired temperature inside a building. The remains of early Greek buildings show that their architects were experts in passive solar design. With today's technology, houses with passive solar design and efficient insulation have been proven to save as much as ninety nine per cent of energy used for space heating and cooling.
Many active solar water heaters consist of a flat plate mounted on a wall or roof, which receive solar radiation. The plate cover will be transparent, usually made of glass, to admit as much thermal energy as possible. Inside the plate is a series of tubes containing fluid (usually water, but sometimes oil) on a black background. The liquid is heated by the sun and transported by a pump to a heat exchanger in an insulated water tank.
The term photovoltaic comes from the Greek “phos” which means light and “volt”, from the scientist Allesandro Volta. In other words, photovoltaic literally means “light-electricity”. Today, photovoltaic cells can be found in watches and calculators, in addition to being used as power systems for yachts, and even large scale rural power applications.
Photovoltaic cells take advantage of the fact that light dislodges electrons from atoms when it strikes. These are used to generate a potential difference between two semi-conductor materials. Closing the circuit establishes an electric current. Photons contain various amounts of energy depending on the different wavelengths of the solar spectrum. This energy level determines what happens when photons strikes a photovoltaic cell, where they will either be absorbed, reflected or pass right through. Some of the absorbed photons generate electricity, others generate heat, and some never reach the external circuit.
Photovoltaic cells are an exciting prospect for energy generation, because:
- they produce no noise, emissions, vibration or pollution of any kind during operation.
- they have a long operating life and low maintenance costs.
- they can be integrated into building designs.
For all of the benefits of photovoltaics, there are still some problems to overcome. Currently photovoltaic cells:
- are costly and complex to manufacture.
- need a large surface area to generate power due to their low area density.
- cannot generate electricity without light
- are vulnerable to seasonal and daily variations in energy output.
How much electricity is generated with photovoltaic cells?
Around fifteen per cent of the energy of sunlight can be used to produce electricity using photovoltaic solar technology. The individual solar cell's size determines the amount of current and power it is capable of producing - at most some 0.5 Volts (V). In order to generate a significant amount of electricity, several solar cells are assembled into modules.
Certain kinds of cells, such as those made from thin films, can be made directly into modules without needing to make separate cells first. Generally constructed to give an output somewhere between twenty W and 100 W, these modules can themselves be connected together to make arrays that could potentially supply several megawatts of power.
Photovoltaic conversion, which enables the sun's rays to be converted into electricity, occurs in solar cells manufactured from silicon. Silicon is one of the most abundant materials on the planet (in the form of quartz sand) and is an environmentally friendly material. Today, the range of solar cells spans many materials and molecular architectures, in the quest to extract maximum power while keeping the costs to a minimum.
What are the different types of solar cells?
Solar cells can be made of different semiconductor materials. Each solar cell also consists of an electrical contact with the semiconductor that carries the electrons away from the solar cell and into the electrical circuit where they can, for instance, power a light bulb or charge a battery. The whole cell is then encapsulated in a transparent cover that provides environmental protection and contains an anti-reflection coating to make sure that as little light as possible is reflected away from the cells.
The different types of solar cell are:
- Crystalline silicon solar cells
- Thin film solar cells
- Non-silicon compound thin film solar cells
- Nano-crystalline solar cells
- Fullerene solar cells
Advanced CIS (Copper indium diselenide) thin-film technology could provide a real cost breakthrough for solar power. It uses only 1% of the materials used in silicon. The production process is simpler, with less chance of breakage and no need for expensive silicon. The CIS metal solutions are sprayed onto a glass sheet in layers, much the same way that coated windows are made, eliminating the need for complex wiring and assembly. CIS panels are particularly well suited for urban areas. Their smooth black appearance makes them easier to integrate into building walls and roofs. They convert more sunlight to power in shady conditions than silicon panels.
From the ancient Egyptians to today’s modern wind farms, the wind has always been a natural ally in propelling our societies forward. Today, instead of grinding grain and pumping water, we can harness the wind to generate electricity. There is enough wind blowing across North America, that if harnessed with today's technology, it could supply all of the nations electrical needs.
Future Solar Power partners with the most reliable manufacturers of small wind turbines designed for home, farm and small commercial applications.
Our in-house wind experts help choose the right application for your needs, contact one of our sales rep for more information.
The term ‘bio-fuels’ describes fuel components produced from biomass such as plants, straw or biomass waste streams. Bio-fuels can be used either 'pure' or as a blend with standard automotive fuels. There are two main bio-components for fuels: ethanol and bio-esters.