Renewable Energy : Le Voie a Suivre



Morning class ! I hope you rested your minds during that brief break and that you are now ready for more knowledge.

 This is going to be a double lesson so I want you to prepare yourselves. There’ll be a 10 minute water break to have a short walk and get some refreshments.

 Are you ready?

 Let’s start.

 Now, as we all know, energy is the driver of economic growth. Energy comes from fuels. For a country to develop, it must be energy secure. The IEA (International Energy Agency) defines it as having a sufficient amount of energy to be able to satisfy the energy needs of its population at a reasonable price. Long term energy security means that you plan ahead to take into account economic development and also being environmental friendly. Short term energy security means that there’s enough supply to cater for sudden spikes in energy demand.

 Energy efficiency means that one can use the same amount of energy to do more or use a lesser amount of energy to achieve the same results. For example, an energy efficient jiko uses an X amount of charcoal or briquettes for 6 hours and does a lot while an energy inefficient jiko will use twice that amount for the same time period.A LED (light emitting diode) bulb lasts far longer than incandescent or compact fluorescent bulbs.

 What are non renewable fuels?

  These are fuels that cannot be naturally replenished. They are mainly fossil fuels which unfortunately make up80% of all energy used on planet Earth. But one day, they will run out.In what state will the planet be?

 So, why are fossil fuels popular?
Ø  Cheap to mine.
Ø  Well established
It is a well-developed system and there are long standing structures in place including subsidies which makes fossil fuels a cheap option.
Ø  Lucrative.
It’s really profitable. Due to the above mentioned points, fossil fuels give very good returns.The fossil fuel industry is a multibillion industry so you can see why some people are hesitant and a bit allergic to change.

 In some circles, the term l’or noir black gold  (also known as liquid gold) is used to describe oil. Basically if your country hits oil, them Mama! We made it! But we are looking to change that.
An oil rig in Turkana - cra.kenya
Fossil fuels are responsible for the current climate change. When burnt, fossil fuels emit carbon dioxide, which is a strong greenhouse gas.  Greenhouse gases cause global warming which in turn causes climate to change. That of course puts the rest of us at risk.

Renewable energy

 What are renewables? These are fuels that can be restocked naturally. They constitute 20% of all energy used in the world. They are sustainable.

 Examples of renewable energy include solar, wind,hydro(tidal, wave et al) biomass,hydrogen and nuclear energy. Note that when I say renewable, I mean that they can be naturally refreshed. Some of them though pose some degree of risk to the environment in one way or the other. We’ll get into that shortly.

 Solar energy is energy derived from the sun. It is in the form of heat and light. Solar energy has been used for centuries in photosynthesis, preservation of foodstuff and such things as drying the washing as well as other examples you find convenient but true. However, when it comes to large scale 
industrial use, it lags behind fossil fuels. It is actually one of the best sources of energy because;

v  It is feasible and will continue to be until 1 billion years from now, when the sun will become a red giant and Earth will be too hot to support life.
v  It is freely available
v  It is sustainable
v  Inexpensive after the initial costs of installation.
v  It can be off grid energy–ideal for developing countries especially in vast rural spaces which are not connected to the main grid. That is, it is ideal for far flung, isolated or difficult to reach areas.

Solar energy is either passive – for example how you position a building, orientation towards the sun, natural cooling systems.

 It can also be active – conversion of solar energy to electricity by solar panels.
Photovoltaic systems (panels and the like) which are very common convert sunlight directly into electricity.

 Concentrated solar power is using mirrors to concentrate large amounts of sun rays into a single spot, heat water to steam which in turn turns turbines to make electricity.
Solar panels are relatively easy to install and maintain. They also don’t pose a problem in terms of locomotion (I just mean movement). Panels can also be combined with rooftop gardens to make a building ecologically friendly.

 In the developed world, solar energy is so developed that there are entire solar farms dedicated to producing electricity. They are usually connected to the grid. In Africa, it is mostly off grid and small scale.

 However it may pose an environmental hazard in that reflection of heat and light by solar farms can fry birds flying overhead. A relatively new idea i have seen is installing solar panels in areas that were previously covered by lakes that dry up because of climate change. Or in deserts. However this poses a threat to desert life as these species may even go extinct due to destruction of their habitat.

 Geothermal energy is energy derived from the belly of the earth. It is mainly from two sources, natural plate tectonics and radioactive decay of elements/minerals that releases heat. It is so hot that rocks melt. This molten rock is known as magma. Magma heats water trapped in the rocks. It is this steam which being released at high pressure is used to turn the turbines that produce electricity.

 Geothermal energy has pretty much the same advantages as solar in that it is;

Ø  Freely available
Ø  There’s plenty of it
Ø  It is relatively safer compared fossil fuels environment wise.
Ø  It is cheap to develop
Ø  Can be used for electricity as well as for auxiliary purposes such as hot springs, saunas (good for relaxation and having a good good time)

 Geothermal energy is used in both heating and cooling and is usually connected to the main grid
Concerns about environmental health when it comes to geothermal energy include the fact that hydrogen sulphide gas is also released alongside the steam. Iceland and Kenya are some of the global leaders when it comes to exploitation of geothermal energy.
If you are Kenyan then you know all about Olkaria and geothermal. Read about Iceland too.

 Hydroelectricity is electricity generated from turning of turbines by water. Hydropower is the leading source of renewable energy with slightly below two thirds of all green energy. Hydropower means
a)      damming of rivers with high volume and velocity
It is popular in developing countries but also in China and India.
It has some ecological effects like destruction of surrounding vegetation (flooding) spread of waterborne diseases, salinity (no fresh flowing water) and also affects downstream vegetation because of the reduced volume. It is also a potential source of greenhouse gases because of algal growth that releases methane.

b)      A micro hydropower plant generates about 45 watts and above.
c)      Pico hydro produces just enough for a few bulbs or enough to charge your phone.
It is ideal for small communities with a relatively small population.These communities are mostly located in areas with plenty of free flowing water and mostly need electricity for household use. Micro hydro power plants are also particularly easy to install as they need just a bit of technical expertise and a lot of innovation. Personally I have seen such projects take off in areas far from the cities and not connected to the main grid.

 Its advantage is that it is off grid electricity and is cheaper, reliable and more environmentally friendly than say thermal power plants.

 Hydro electricity is however dependent on water volume so destruction of water catchment areas as well as long droughts as a result of climate change directly affects output.
d)     Tidal energy is energy derived from high tides. Tides are caused by the pull of the moon. Since the moon will orbit around the Earth for a long long time, the supply is inexhaustible. It is also sustainable.

 After the initial cost of plants to convert tidal energy to electricity, this option is actually cheap. Problem is that it could cause problems with marine life because of interference with their habitat, migratory routes etc. There is also a lack of areas with lots of high tides which also must be relatively clear (devoid of human activities and marine life)
It hasn’t been extensively developed and is still under trial.
e
)      Wave energy is harnessed from the wind waves, that is, the ability of wind to move water in waves.
It is relatively more developed than tidal energy but is also behind solar or hydro power.
Norway for example produces 99% of all its energy from hydropower.

 A good example of use of hydropower used to generate energy is in grain milling. All that is needed is a place where there is water moving with high velocity like a small waterfall or in tides. This practice has been in existence since the man was created. Ask your parents or grandparents about it.

 Wind energy is energy derived from wind that moves turbines hence generating mechanical power which is then converted to electricity. Wind contributes to about 3% of the world’s energy.
Wind power plants are generally located in windy areas with fewer obstacles and little or no human population. Offshore wind farms are becoming common in Europe because they are cheap, sustainable and also because they are not near human settlements (because of the cold and view).
wind turbines - daily mail, uk
 
Wind mills are dangerous for birds. Netherlands, Denmark and Morocco are big users of wind energy.
Now, it’s time for that break I promised. Do not take sugary drinks, I want calm people in the classroom. Water is good, it keeps you hydrated.

 I’ll be back shortly.

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