Due to the non-sustainability of traditional fossil fuels, and the adverse environmental impacts incurred in obtaining these fuels and in using them for energy generation, the world is investing concerted effort and resources into increasing the use of renewable energy sources. Some of these, in particular hydropower, have been in use for many decades, while others are still maturing as solutions. The bottom line is, the overall use of renewable energy is increasing hugely, and green energy options are now well established as viable solutions.
As of 2015, an estimated 19.3% of the planet’s energy consumption was provided by renewable energy sources. This is only set to grow as the world lessens its reliance on non-sustainable forms of energy.
What Is Green Energy?
Green energy refers to energy (usually electricity, but sometimes heat) that:
Is green, meaning it:
- Is generated from fuel obtained via natural non-invasive processes
- Fossil fuels require excavation, mining and drilling to extract the fuel from the Earth, and often, the extraction sites are in remote environmentally sensitive locations; the same holds true for the transportation routes to get the fuel to where it is needed.
- Green energy, on the other hand, is readily available, is collected naturally at the location where it is used, and has no requirement for transporting the fuel (e.g. solar power stations collect sunlight at that location), thus eliminating the environmental impact of fuel transportation
- Produces zero or only a small amount of negative environmental impact (as opposed to say coal-fired electricity generators, which produce pollutants that include greenhouse gases)
Is renewable, meaning it is generated from fuel that is continuously replenished via existing natural processes, without additional human intervention to replenish it. Green energy is also often referred to as clean energy. Note: All forms of energy generation, including green energy, incur an adverse environmental impact during the manufacture, transport and construction of the power generating facility. These impacts will vary depending on the size, location and type of power generating facility.
Green Energy Types
Solar energy uses photovoltaic ( PV) cells to capture sunlight and convert it into electricity. Solar energy is the most prevalent type of renewable energy. Its cost has been falling steeply since its introduction and its adoption is growing rapidly year-on-year. In addition to its use in generating electricity, solar energy is also used to generate heat for buildings and water.
Solar energy is used across the entire spectrum of size and location possibilities, from hand-held gadgets to portable devices for homes and businesses to standalone charging units in homes, offices and city centers, to use in small-scale solar power generation for ebikes, public spaces and utility-scale electricity generation (for example, via Concentrated Solar Power). Famously, solar energy has also been used in space exploration for decades.
Wind power works by harnessing the power of wind flowing across the Earth’s surface. The wind is used to move large, highly efficient wind turbines, and this mechanical energy is converted into electricity via generators attached to the turbines. Most commonly, wind turbines are sited in groups, referred to as wind farms. Typically, the best conditions for wind farms tend to be on elevated sites, and just offshore from coastlines, due to the prevailing wind patterns.
Although wide-spread and significant, wind power is not as ever-present as solar energy as an single installation for individual homes. And of course, wind power is not applicable to hand-held devices nor can it power city center charging stations that way that solar energy can.
Hydropower, also referred to as hydroelectric power, is generated when large volumes of water held behind a dam are released through power-generating turbines housed within the dam’s structure. With a small number of local exceptions, this type of renewable energy is used almost entirely in utility-scale energy production.
Tidal and Wave Energy
The ocean’s tides constitute a huge amount of ongoing energy, and tidal energy refers to the process of installing electricity generating water turbines in coastal waters in a way that captures the tidal energy and converts it into electricity. In a similar vein, the ocean’s waves, whose energy is a result of many factors, including tidal patterns, wind and currents, represent huge stores of energy. Like tidal energy, it can be captured via water turbines and converted into electricity. Both of these are utility-scale solutions.
Geothermal energy captures heat within the Earth’s crust and converts it to electricity. There are vast quantities of this heat, arising from the planet’s molten core and natural processes within the Earth’s shifting layers of its crust. For example, the amount of underground heat available in North America is estimated to be in sufficient quantities to produce 10 times as much electricity as currently produced by coal-fired electricity generation plants. Like hydropower, this type of renewable energy is used almost entirely in utility-scale energy production.
Biomass energy refers to the process of generating electricity from natural waste, such as wood waste, sawdust and combustible agricultural wastes. This is done by burning the biomass materials to generate electricity in a similar way to burning coal in a coal electricity plant, but with far lower production of harmful greenhouse gas emissions than coal and natural gas electricity generation facilities.
Biofuels are the result of converting biomass materials into fuels such as ethanol and biodiesel. Biofuels are currently providing a modest but noteworthy share of the the world’s transportation fuels (as substitutes for petrol and diesel). However, the projections are that by 2050, biofuels could provide more than more than 25% of the global demand for these fuels.
The Future for Green Energy
Green energy continues to go from strength to strength, and is now a significant and rapidly growing solution for the world’s energy needs. As highlighted in the REN21 Renewables Annual Report 2017:
- The amount of renewable energy installed in 2016 was 9% greater than in 2015, bringing the global total to more than 2,016 Gigawatts (GW) (920 GW if hydropower is excluded).
- Of this total for 2016, solar energy accounted for 47% of the renewable power capacity installed in 2016, compared to 34% for wind power and 15.5% for hydropower.
- As of 2015, an estimated 3% of the planet’s energy consumption was provided by renewable energy sources.
In short, renewable energy is a major source of energy for the planet, it’s here to stay, and it will continue grow in importance and prominence.
Key references for this article:
- What is Green Energy? – Mother Nature Network 25 Jul 2012
- Types of Renewable Energy – Renewable Energy World
- REN21 Renewables Annual Report 2017
Win a Solar Power System
- Green Energy Alternatives: Alberto Masnovo | Shutterstock.com
- Green Energy Bulb: Denphumi | Shutterstock.com