'Renewable' Energy Sources and 'Green' Energy Sources

As understanding about our impact on climate change has increased and the realisation that fossil fuels will not last forever, scientists have tried to find new ways to create infinite energy supplies that reduce the harmful effects on our environment.

Renewable energy sources offer us another way of creating power. With advanced technology, energy can now be sought from many natural sources instead of fossil fuels.

In Europe alone, renewable energy sources made up nearly nine-tenths of new power added to Europe’s grids in 2016. However, this number is much smaller in the UK (only ¼ although there are efforts to try and improve this).

The terms ‘renewable’ and ‘green’ are often used interchangeably, although actually mean something quite different.

Renewable = Renewable energy relies on natural resources and unlike fossil fuels, can be created more quickly and be used continuously without running out e.g. wind power, biofuel.

Green = Green sources are environmentally friendly e.g. solar power.

Green energy is often renewable, but not all renewable energy is good for the environment/green! Biofuel is an example of this as although relies on natural products, often release greenhouse gases. Biofuel is discussed in more detail in the specific heading below.

Renewable energy is not as new an idea as many people think. Many of the processes where first discovered (and often by accident) many years ago.

BIOMASS Biomass is the process of creating energy from materials that come from living or recently living organisms. Fire is an example of biomass energy and evidence of fire being utilized to cook food traces back to 400,000 BCE. Over the last century gasification and pyrolysis processes have helped make it easier to get energy from biomass products such as plant clippings, trash, tires, and even animal manure. Biomass can be used to make BIOFUEL.

BIOFUEL

Biofuel is a hydrocarbon either made directly from a living organism or through a chemical reaction in a laboratory using organic matter (biomass). Biofuels can be made within a matter of weeks or months, which is much faster than a fossil fuel e.g. gas, which takes millions of years to be created.

Biofuels can be solids, liquids or gases, but are often made into liquid form as this makes them easier to transport. Some examples of liquid biofuels are: biodiesel (made from vegetable and animal fats) and ethanol (made from starches of corn, fruit and wheat).

Unlike fossil fuels, biofuels are seen as renewable and should not ‘run out’. Biofuels need lots of land to grow, however, which means they are often not produced as quickly as required and have to compete with land use for growing food.

• Problems with Biofuel: Although renewable, biofuel is not really seen as ‘green’. Biofuels produce carbon dioxide, which is a greenhouse gas. Plants for biofuel also use fertiliser which produce nitrous oxide, another greenhouse gas. When producing biofuel, it is easier to make it from producing one type of biomass e.g. one type of corn. Growing a single type of corn instead of many different kinds, means lower biodiversity. The problem with this is that pests eating that type of corn will increase and may even become immune to pesticides.

These ‘less green’ biofuels are known as First Generation Biofuels and are made from items such as sugar, starch or vegetable oil. They have a greater impact on biodiversity and the food supply if used a lot. Second Generation Biofuels are greener, although not currently as widely used. Examples of these are: methanol (from inedible plant matter) biohydrogen (made from algae breaking down water). Further examples can be seen in a table on the biofuel website: http://biofuel.org.uk/types-of-biofuels.html

GEOTHERMAL POWER

The development of geothermal energy can be traced back to 1905 when a farmer drilled a well to find fresh water he could use on his land. Instead, he found hot water that would quickly turn into steam as it hit the cool air. From this discovery, the idea of placing a turbine over steam was created in an effort to generate electricity. This principle has been expanded upon a great deal over the last century, and today there are geothermal plants in existence across the globe that create clean as well as renewable energy 24/7.

HYDROKINETICS/HYDROELECTRIC POWER has one of the longest histories of any of the renewable energy sources, with its first application coming about in 200 BCE more than 2000 years ago. Water wheels and watermills were created in China, Imperial Rome, and India to power a grind to process flour, and a saw to cut stone and timber. Today it is used to generate energy from ocean and river currents without harming the natural aquatic life. This is more commonly known as hydroelectric power or ‘hydro power’.

According to the British Hydropower Association (BHA) hydropower is one of the most reliable, predicable and environmentally friendly renewable energy source technologies available. You can find out more information on their aims and views on their website: (http://www.british-hydro.org/index.html).

In the UK hydro-power can be from rivers/streams or man-made installations (such as a reservoir). There are three main ways it can be used:

• Storage schemes Using an area of stored water e.g. reservoir. A dam keeps the water enclosed to feed a generator.
• Run-of-river schemes weir Using a natural flow of water e.g. river. A weir (type of low dam) is introduced to increase the water flow and direct it towards a generator.
• Pumped storage Using two reservoirs. Electricity is used to pump water from lower basin to upper basin where power can be used when it is in high demand.

Some people have started installing their own ‘micro-hydro’ schemes on their own properties, which can provide power for a number of houses and in some cases, a small community. These can be expensive to install, but save costs in the long run as can last for decades and generate renewable energy 24 hours a day.

Feed-in Tariffs Scheme (FITs) – This came in (April 2010) as a financial incentive to those creating hydroelectric power (as long as Ofgem checks its eligibility e.g. protection of wildlife/fish in the area it is installed).

For more information you can contact the Energy Savings Trust on 0800 512 012 or check their website:

NUCLEAR ENERGY

Nuclear Fission is the splitting up of uranium atoms to produce heat. This heat is often used to produce steam which spins a turbine to generate electricity.

Nuclear Fusion is the combining of two small atoms e.g. hydrogen or helium, in order to produced heavier atoms and energy.

Although nuclear power does not emit and greenhouse gases, there is something called ‘nuclear waste’ left behind after nuclear fission, which can cause biological damage and last for hundreds of thousands of years. Well known disasters such as Chernobyl and Fukushima meant radiation was released into the environment, with severe consequences.

SOLAR ENERGY Solar power using photovoltaics has a more contemporary history that can be traced to 1887 when Heinrich Hertz recorded the photoelectric effect. He saw that when light hit substances that conducted electricity, the electrons would flow. Albert Einstein looked in the matter a bit more deeply and won the Nobel Prize in 1921 for his observations. Today researchers are attempting to make solar energy more efficient and cost effective by looking at nano-scale quantum physics applications.

WIND ENERGY also has a long history dating back to 1700 BCE when Hammurabi, the emperor of Babylonia, used wind to attempt to irrigate farmland. However, the power of wind energy was not truly realized until Heron of Alexandria, a Greek engineer, created a wind wheel so that the wind could be used to power a machine. Wind farms today are still in use to create clean/green power, and as prices continue to drop, wind energy is almost as efficient as coal.