Solar panels (PV)
Generate cheap, green electricity from sunlight
Solar panel electricity systems, or solar photovoltaics (PV), capture the sun’s energy using photovoltaic cells which don’t need direct sunlight to work. They generate some electricity cloudy days. The cells convert sunlight into electricity to run household appliances and lighting.
The benefits of solar electricity include:
• You can your electricity bills since sunlight is free; you pay only for the initial installation your electricity costs.
• You can sell electricity back to the grid if your system is producing more electricity than you need; or when you can’t use it, you can sell the surplus back to the grid.
• You can cut your carbon footprint since solar electricity is green, renewable energy and does not release any harmful carbon dioxide or other pollutants. A typical home solar PV system could save over a ton of carbon dioxide per year –more than 30 tonnes over its lifetime.
How do solar panels (PV) cells work?
PV cells consist of layers of semi-conducting material, usually silicon. These cells create an electric field across the layers when sunlight strikes them. More electricity is produced under brighter sunlight. Groups of cells are mounted together in panels or modules which can be installed on your roof.
The power of a PV cell is measured in kilowatts peak (kWp). This is the rate at which it generates energy at peak performance in full direct sunlight during the summer. PV cells come in a variety of shapes and sizes. Most PV systems are made up of panels that fit on top of an existing roof.
Solar tiles and slates
Solar tiles are also available to replace ordinary roof tiles. A system made up of solar tiles will typically cost around twice as much as an equivalent panel system, although you save the money intended for roof tiles or slates. Being more costly, solar tile systems are usually only considered where panels are not appropriate for aesthetic or planning reasons.
Use running water to generate electricity, whether it is a small stream or a larger river.
Small or micro hydroelectricity systems, also called hydropower systems or simply hydro systems, can produce enough electricity for running lighting fixtures and electrical appliances in an average home.
How do hydropower systems work?
Streams and rivers have potential energy because of height. As water flows down, hydropower systems convert this potential energy into kinetic energy in a turbine, which drives a generator to produce electricity. The greater the height and the more water flowing through the turbine, the more electricity can be produced.
Efficiency in the conversion of energy into electrical power determines the amount of electricity a system actually generates. The design and the quality of equipment and structures used count a lot in maximizing the efficiency.
The benefits of hydro systems include:
1. Cheap heating and hot water
A hydro system may generate more electricity than you need for lighting your home and powering your electrical appliances – so you can use the excess to heat your home and your hot water, too.
2. Savings on your electricity bills
A hydro system can generate 24 hours a day, often generating all the electricity you need and more.
3. A cheaper option for off-grid homes
Installing a hydro system can be expensive, but in many cases it is less than the cost of getting a connection to the National Grid if you don’t already have one.
4. Cut your carbon footprint
Hydroelectricity is green, renewable energy and does not release any harmful carbon dioxide or other pollutants.
Will hydropower work for me?
Hydropower is very site-specific. Most homes will not have access to a suitable resource even if they have a water course running nearby. Assessing a hydro site properly is a job for a professional. If you think you might have a suitable site, the next step is to contact a certificated installer, who will inspect your site for you.
To be suitable for electricity generation, a river needs to have a combination of
• flow – the volume of water flowing down the river per second, and
• head – a difference in height over a reasonably short distance
You could have either lots of flow and not much head (such as a river flowing over a weir) or lots of head and not much flow (such as a mountain stream).
The minimum flow during dry, summer months determines the viability of the system. Hence, it is not enough to be impressed by a river when it is swelled.
If you have sufficient hydro resource in or near your community, a community energy project might be preferable than a single-home hydro system.