Renewable energy comes from sources that nature is constantly replenishing.
Non-renewable energy are from sources that will eventually run out. Renewable energy, also referred to as "clean" or "green" energy, generates almost no waste or polluting emissions.
THE MAJOR NATURAL SOURCES OF RENEWABLE ENERGY ARE
origin of the water cycle, tides, wind and plant growth
which gives off heat and should be the same length as sun
Hydroelectricity uses the power of water (rivers and other watercourses) to make electricity in hydroelectric power stations fed by dams or flowing water.
Hydroelectric power is generated by the force of moving water, i.e. the hydraulic energy of currents or waterfalls (rivers, lakes and seas). In a hydroelectric plant, the force of the water activates the turbines which in turn drive the alternators. As they turn, the alternators transform the mechanical energy into electrical energy as the electrons move quickly back and forth.
- A renewable and limitless primary energy source (water current)
- Consumes neither water nor fossil fuels and produces no CO₂ emissions, polluting discharges or waste
TWO MAIN CATEGORIES OF HYDROELECTRIC PLANTS
- Flowing water: the force of the current drives the turbines continuously. This type of plant allows the actual river water to pass through.
- Reservoir: water is stored in an artificial lake generally confined by a dam. When electricity is needed, the valves are opened and the water flows through the turbines. This method makes it possible to match electricity production to consumer demand.
Helios has mainly run-of-river power stations providing many advantages, such as:
- Constant and reliable production (except in case of drought)
- Safe source of energy (no risk of water spill or flooding, because little water is held in the reservoir)
- Source of locally consumable energy that can supply isolated sites in rural areas
- Helps limit network losses by being located close to consumers and avoiding transportation over long distances
- Local jobs created during construction and operation of the plant along with revenues to municipalities
- Low environmental impact: plant operations cause no water-level fluctuation and very little change in the hydraulic regime (allows the actual flow of water in the river to pass through), which represents minimal impact on aquatic flora and fauna.
Wind turbines use a generator to transform the force of the wind into electricity.
Although still relatively new in most countries in Africa, wind energy has been gaining popularity in the region in the last decade. The kinetic energy of moving air is converted into electricity by wind turbines installed in locations where the weather is most favorable.
Wind turbines can be used individually or grouped into wind farms.
- Clean (and renewable)
- Requires no fuel and produces no pollutants or greenhouse gases
- Part of the energy transition plan and the fight against climate change
- New sources of income, employment and partnerships for host communities
HOW A WIND TURBINE WORKS
- The wind flows across the turbine blade surfaces.
- This creates a pressure difference between the top and bottom surfaces of the blades, which generates the thrust to turn them.
- The kinetic energy resulting from this wind is transformed into mechanical energy, then transmitted to a generator located in the nacelle of the wind turbine.
- The current then travels through underground cables to the substation, where it is converted to a higher voltage for the transmission or distribution grid and then to the consume.
Photovoltaic cells, mainly composed of silicon, capture sunlight and transform it into electricity.
Solar thermal energy uses the sun's radiation to heat a fluid (liquid or gas). Energy is received and held by the fluid for direct (e.g. heating) or indirect use. This technology is based on the principles of thermal absorption and conduction.
- Clean (and renewable)
- Emits no greenhouse gases
- The raw material, the Sun, although more than 150 million km away, is free, unlimited (on a human time scale) and available everywhere in the world
- Silent and has very little impact on the surrounding ecosystems
HOW DOES A SOLAR INSTALLATION WORK?
- Three stages are involved for a photovoltaic installation to recover the energy transmitted by the Sun, transform it into electricity and then distribute it to the customers connected to the grid:
- Solar panels convert light directly into a continuous electric current.
- The inverter then transforms this electricity into an alternating current compatible with the network.
- The transformer increases the voltage of the electricity so that the energy can be introduced into the transmission or distribution network, then to customers.
Storage allows some of the electricity generated to be stored and saved for future use.
Helios is taking its first steps in this sector: It considers that storage is a complementary option to fostering the widespread use of renewable energy and accelerating the energy transition.
- Ensures balance between the electricity generated and consumed on the networks and, in particular, mitigates the variability of renewable energy production. Fosters the penetration of renewable energies, and at the same time ensures the stability of the power grid.
- Keeps the surplus energy generated at certain times (e.g. on an extremely sunny day) for reuse in the evening.
- Provides the energy needed when there are consumption peaks or supply system failures.
- Improves the reliability and flexibility of the power grid, thereby limiting expenditure on new infrastructure, such as stations and lines.
LITHIUM-ION BATTERIES are among the most commonly used technologies today for storing energy. Their high energy density is an asset compared with other technologies, as they encourage utility-scale deployment while reducing the amount of space needed. A reliable and recognized technology, lithium-ion batteries are already used in millions of electric and plug-in hybrid vehicles as well as in our main electronic devices.
Pumped-storage hydropower (PSH) is a type of hydroelectric energy storage. It is a configuration of two water reservoirs at different elevations that can generate power (discharge) as water moves down through a turbine; this draws power as it pumps water (recharge) to the upper reservoir.
PSH capabilities can be characterized as open loop—where there is an ongoing hydrologic connection to a natural body of water—or closed loop, where the reservoirs are not connected to an outside body of water.