My Studies – Alison.com – Course: Renewable Energy Sources

Module 1 – Energy Use & Sustainability

Current Consumption

Oil

Oil will not be running out any time soon. Concerns we only have a few years left have been exaggerated. However it is true that oil is finite and will finish eventually.

Current Reserves – Two thirds of the worlds oil is in the Middle East & North Africa.

Oil remains a problem both in its extraction from the Earth and it’s transport, by way of coal mine accidents, fires on oil rigs and oil spillages. Likewise the combustion of oil leads to polluting the Earths atmosphere and damages our health. My doctor gave me Neurontin to help me with chronic pain in my back and my legs, he said it was neuralgic. It is not the cheapest remedy, but I had buy Neurontin online and to take it because my pains were really bad. Luckily it helped me starting from the first day, and now I take it when I my pains can’t be helped by other drugs. Not to mention climate change and the Earths warming temperature.

Nuclear Power

Nuclear makes up 7% of the worlds energy consumption. Nuclear doesn’t produce any greenhouse gasses. We have enough Uranium deposits to last possibly centuries.

Nuclear does produce radioactive waste and likewise can lead to being used in Nuclear weapons.

A solution may be on the way in future, but as of today, these remain huge problems.

Renewables

Renewable energy currently includes solar energy, bioenergy, hydroelectricity, wind and wave. These have some environmental impact but much less than fossil fuels or nuclear.

The current high cost of these renewable energy technologies is all that is holding them back from being adopted mainstream.

In order for renewable energy to really take off, vast improvements will need to be made in terms of efficiency in harnessing and storing the energy as well as installation costs.

Currently Available Energy Sources in Detail

Coal

Coal has the lowest energy density out of all the fossil fuels and it causes the most pollution. So called ‘clean coal’ uses technology to improve the burning efficiency of coal and reduce pollution.

There is enough coal in the world to sustain our energy needs for a few centuries, but it’s not cost effective and likewise causes mass pollution.

Oil

Oil has a much higher energy density than coal and is much easier to manipulate.

It does produce pollution when burnt, like carbon dioxide but not as much as coal.

We have enough reserves of oil to last us many decades.

Natural Gas

Natural gas has the highest energy density out of the three fossil fuels. It’s also considered to be the clean fossil fuel as it doesn’t produce anywhere near the same amount of pollution as coal and oil. It does still produce carbon dioxide and nitrogen oxide but again less than coal and oil.

Our gas reserves are likewise sufficient for several decades.

Nuclear

Nuclear is by far the most concentrated and energy dense source we have available to us today. The generation of nuclear produces no pollution. However it’s radioactive by-products, if not controlled properly, can severely damage the environment.

Reserves of uranium are enough to last us many decades.

Biomass

Biomass energy comes mainly in the form of burning wood and charcoal. It accounts for 10% of the worlds energy usage, mostly in the developing world.

Biomass can be considered renewable if it’s consumed at the same rate that other trees are being grown. This is because the pollution caused by burning them would be offset by the new trees taking in the carbon dioxide and producing oxygen.

Biomass can also come in the form of waste, like animal dung, sugar cane waste and rice hulls (the hard protective covering rice is grown in.)

Solar, Wind & Hydro

Solar, wind and hydro have low energy density’s in comparison to other energy sources. However, these are the cleanest energy source, producing no pollution.

Renewable energy in this form accounts for 8% of the global energy usage.

Concentrating, Storing & Transporting Energy

Concentrating Energy

Different energy sources have different strengths, from ‘dilute’ to ‘concentrated’.

Water vapour is in abundance around the Earth, however it is considered as a diluted form of energy since we would not be able to get it to spin any turbines to generate energy.

Water in it’s concentrated form however can power many turbines, such as hydro technology in high tide areas or within dams.

Energy density is the amount of energy stored by a resource, divided by the volume of space it occupies.

Some energy sources are able difficult to ‘concentrate’ and thus we consider them to have a low energy density.

Wind and solar rays from the sun are very difficult to be concentrated. We attempt to get around that by placing wind turbines and solar panels in places where natural factors enhance them. For example out in the ocean for wind turbines and in desserts for solar panels.

Fossil fuels are naturally concentrated forms of solar energy from millions of years ago.

Matter is the concentrated form of energy, which is what Nuclear uses to generate energy.

Storing Energy

In order for energy to be useful to us, it must be accessible to us, when we need it, in amounts that we can handle safely.

The problem we have is that we need light at night time and we need to heat our homes in Winter. Thus we need electricity and gas, readily available to us, in our homes.

We have two forms of energy that can be stored.

Potential Energy

Potential energy is defined as mechanical energy, stored energy, or energy caused by its position. The energy that a ball has when perched at a top of a steep hill while it is about to roll down is an example of potential energy.

Chemical Energy

Batteries, biomass, petroleum, natural gas, and coal are examples of stored chemical energy. Usually, once chemical energy is released from a substance, that substance is transformed into an entirely new substance.

Transporting Energy

Converting energy fuels into energy usually needs to be done away from our home or car. Therefore we need a way to transport that energy to us, where we need it. The ease of transporting a fuel is incredibly important to us.

Low density energy sources require a lot of effort to transport since much larger amounts are needed. Think a train full of coal.

Higher density energy sources require much less effort to be transported, however they need to be protected. The high density means that very large amounts of energy could become dangerous very quickly. Think oil tanker.

Fossil Fuels

These three things considered, fossil fuels make great forms of fuels. They are highly concentrated forms of energy, energy can be stored for long periods of time and can be transported safely with care.

Energy Supply & Demand

Currently our efficiency in which we use energy, is quite low. We only use about one third of the energy we generate. The remaining two thirds is lost as waste, usually during transport.

One of the reasons we waste a lot of energy is due to the low cost of energy. We have little incentive to improve our efficiency since it would lead to small financial benefit.

Linking Supply To Demand

Each step in the chain of supply to demand, we lose energy. Our energy is generated at it’s source and then transferred through many different means to us, the end consumer.

At each stage, we convert energy from one form to another. For example, extracting gas from the ground, carrying it through pipes to the power stations, burning the gas and using it to boil water, which produces steam to spin the turbines to produce electricity. This is a very long process converting energy many times over. Then once this electricity is produced, it needs to be carried through the national grid power lines, to our neighbourhoods, converted into lower wattage and then put into our homes for us to boil the kettle.

Supply

From a supply perspective, the way we generate our electricity is often extremely inefficient and waste’s huge amounts of resources. We could use technologies to improve the way we generate electricity in these power stations.

The efficiency of a power plant is the percentage of energy produced by the plant, based on how much energy was initially put in.

The Combined Cycle Gas Turbine (CCGT) is the best fossil fuelled power plant we have available today. It’s efficiency is still only 50%.

The UK reduced it’s CO2 emissions greatly in the 1990’s by switching from coal fuelled power plants to CCGT power plants.This was later known as ‘dash for gas’. These CCGT plants produce 40% less emissions than their coal powered counterparts.

Energy Demand

Our energy demand is just as important as our energy supply. Energy demand is affected in two major ways; technology and socially.

Improving our technology means improving the way our cars, houses, gadgets and appliances can use less energy to achieve more. An example of this are high quality, efficient washing machines with short spin cycles.

Changing our energy demands socially means improving our lives, individually and collectively in both major and minor ways. An example of changing our energy demands socially are shared office spaces, where a group of 50 people can rent one large office space, rather than each renting 50 offices.

We could live in densely populated towns with all shops, schools, businesses and entertainment locally around you, within walking distance. Likewise these towns could have regular transport services allowing 50 people to travel in one vehicle.

Alternatively you could live in a small town, with houses spread far apart, and shops, schools, businesses and entertainment, in the town centre. These towns usually have poor transport services and so the residents opt to drive, each one in their own car.

The two towns receive the same level of service, but those living in the smaller towns use significantly more energy to produce the same tasks. If 50 of them want to go to town, they all drive there, in 50 cars. In the more densely populated town with better transport, 50 of them could get what they need by walking or riding together on a bus.

Government Energy Statistics

The statistics the government use are broken down into 4 main areas;

  1. Domestic
  2. Commercial
  3. Industrial
  4. Transport

Domestic Energy

Domestic energy consists of individual houses. The main uses of energy in homes are; heating rooms, heating water, cooking, lighting and other electrical appliances.

Commercial Energy

This consists of all conventional businesses. Buildings such as offices, shops, hospitals, banks etc. The energy requirements in the commercial sector are similar to that of the Domestic sector. Air conditioning is one of the very few additions in this sector which contribute to a large amount of energy use.

Industrial Energy

The Industrial sector consists mostly of manufacturing companies. Similar to both Domestic and Commercial sector, the Industrial sector uses it’s energy to heat buildings, water and run electrical appliances. The main difference here is that the Industrial sector uses high amounts of energy to get extreme results, such as heating steel to very high temperatures. This requires a lot more energy than an oven or a TV.

Transportation Energy

This sector uses various amounts of energy to power Motor Vehicles, Rail Vehicles, Aeroplanes and Boats. These vary in their energy use from cycling (none except food) to aeroplanes requiring huge amounts of fuel.

Module 2 – Global Climate

Importance of the Sun

The Sun

The Sun is the ultimate source of energy, it is what warms up the Earth.

The Earths temperature stability is due to the fact that the energy that comes in from the Sun is equal to the amount of energy that leaves the Earth, back out into space. If this balance of energy coming in and energy leaving is disrupted and no longer equal, then the Earth will either heat up or cool down.

The energy that flows to and from the Earth is radiation, electromagnetic radiation.

The electromagnetic radiation that leaves the sun comes in a variety of different wavelengths. The wavelength spectrum consists of wavelengths that we can see and wavelengths we can’t see. We can’t see x-rays or infrared light.

When the suns solar rays hit the Earth, many of them are reflected back into space.

Albedo

Albedo is the percentage of sun that is reflected directly back into space from a surface. This sunlight radiation doesn’t get a chance to heat the Earth.

The oceans have a low albedo of about 5%, meaning only 5% of the the suns radiation is reflected off them.

Clouds and the Antarctica have a really high albedo, about 90% – meaning the majority of the suns rays that hit them are reflected back into space.

General land, continents etc, have an albedo of about 20%.

All in all, the Earth has about a 30% albedo. This means that 30% of the suns radiation is reflected immediately back into space. The remaining 70% is kept in the Earths atmosphere to heat up the planet.

No Atmosphere

If the Earth didn’t have an atmosphere, then the remaining 70% of the radiation would not be kept in the planet. It would escape back into space and the Earths temperature would drop from the current 15 degrees Celsius down to -19 degrees Celsius. Life as we know it would end.

Electromagnetic Radiation

All things emit electromagnetic radiation, regardless of size. The amount of electromagnetic radiation they produce is dependant upon their temperature. The hotter the object, the more radiation it emits. This is caused by the atoms in that object jostling about and hitting one another. This can also be known as Terrestrial radiation.

By itself, the Earths 30% albedo would cause its temperature to increase to extremely hot levels. Far hotter than we could live on.

Thankfully due to the electromagnetic radiation all objects http://www.massagemetro.com/shop/ produce on Earth while being heated by the sun, this radiation is keeps the Earths temperature cool.

The Earths electromagnetic radiation, which escapes into space, creates an equilibrium of the Suns radiation in and the Earths radiation out. This causes the Earths temperature to remain constant and balanced.

Natural Greenhouse Gasses

Natural greenhouse gasses absorb infrared radiation from the sun and trap this heat in out atmosphere. This is done through vibrations in their molecules.

The greenhouse gasses are; water vapour, carbon dioxide, methane, nitrous oxide and ozone. These have been around long before we ever did anything to the planet.

The greenhouse gasses absorb infrared wavelengths. These wavelengths are trapped in our atmosphere and heat up the atmosphere. Some of it escapes to space.

The two key greenhouse gasses, H20 and CO2 are more abundant close to ground level. They are increasingly less the higher up in the atmosphere you go. The atmosphere is thinner at the top and thicker at the bottom. The top being close to space and the bottom being close to sea level.

The infrared wavelengths are repeatedly bounced around the atmosphere and even as they bounce off the Earths surface and escape through the lower levels of atmosphere, the higher levels often bounce some back towards the Earths surface. The wavelengths are repeatedly absorbed and re-emitted throughout the atmosphere until eventually they escape through to space.

This means that it is hotter closer to sea level and the higher up you go in the atmosphere – the colder it gets. Imagine walking up a mountain, it would get colder the higher you reached.

The atmosphere is made up of 4 main levels. Starting from the troposphere to stratosphere, mesosphere, and finally the thermosphere. We live in the Troposphere along with almost all life. Likewise all weather occurs in this level, the Troposphere.

The temperature high up in the stratosphere actually begins to heat up before dropping significantly down to -100 degrees Celsius in the mesosphere.

Ozone Layer

Most of the Earths Ozone layer is in the Stratosphere (90%).

This ozone layer in the stratosphere absorbs the shorter ultraviolet wavelengths which can kill many biological molecules.

Clouds

The clouds have a role to play in our environment. They reflect a lot of sunlight. At any given time, the Earth is covered 50% by all the clouds.

55% of the Earth’s albedo (sunlight reflection) comes from clouds.

Clouds absorb and re-emit long wave radiation which works as a natural greenhouse effect. This is why it’s warmer on a cloudier night than on a clear-sky night.

Module 3 – Non-Renewable Energy Sources

Impact of Industrial Revolution

CO2 is certainly building up in the atmosphere. This is not the only gas on the increase. New records show that Methane and Nitrous Oxide are too, likewise increasing in our atmosphere.

Records of CO2 pollution have been on the up since the beginning of the 18th century, 1700’s. For the 800 years before that, CO2 levels were constant. Since the 1700’s rates of CO2 have been increasing massively. They are also increasing faster and faster. From 1970 to 2000 the CO2 levels increased the same amount they did in the previous 200 years before 1970.

We know the levels of CO2 and other gasses levels by drilling into the ice in Antartica. Because the ice is built, layer on layer, over years. The deeper we dig, the further we go back in time and when we test that ice, it gives us the atmospheric levels from the year that water froze.

Carbon Dioxide

Carbon Dioxide is produced from burning all these carbon fossil fuels. That’s not the only way it’s produced. For many years now we have been cutting down trees and burning them to create farmland for our ever growing population. This process produces a lot of carbon into the atmosphere.

Methane

Methane is a gas that often comes from mammals. It’s created from a breakdown of bacteria that thrive in oxygen-free environments, namely intestines. Much of methane comes livestock, rice fields, and natural wetlands.

Nitrous Oxide

Nitrous Oxide is produced naturally by micro organisms in soil. It is also produced by the high temperatures created during the combustion of fossil fuels, when nitrogen reacts with oxygen.

Earths Temperature

The Earths temperature can be tracked by drilling into huge ice glaciers that have been there for thousands of years. The temperature is known by tracking the oxygen in the ice.

We have seen in the last 50 years the coldest parts of the Earth have warmed up the quickest. Alaska’s mean temperature has gone up by 2.3 Celsius in the last 30 years. The Antarctic has warmed by 2.5 Celsius in the last 50 years.

Non Renewable Energy Sources

Coal is the most abundant fossil fuel in the world. Most of the worlds coal reserves exist in Asia and Eastern Europe. Current reserves should last more than 50 years. Sulfur content in coal is very high and when the coal is burned it produces high amounts of sulfur dioxide.

Crude oil is refined into gasoline, diesel and heating oil. It also provides the base material for plastics, road surfaces and chemicals. The majority of the worlds oil is in the middle east. Oil will last another 30 years. Oil burns cleaner than coal and is more efficient. Oil when burnt does produce sulfur dioxide as well as other pollutants.

Natural Gas, often found close to oil, is another form of fuel. It is built up underground. It’s a mixture of methane, ethane, butane and propane. Natural Gas usually doesn’t have sulfur in it and is thus the cleanest fuel to burn. It’s estimated we have 100 years of gas reserves left. Most of the worlds gas is in Russia and the Middle East.

When propane and butane are removed, natural gas becomes liquefied petroleum gas (LPG). Natural Gas is actually odourless but sulfur is added to it so we can smell it in case of a gas leak.

Coal

There are 3 types of coal; Lignite, Anthracite and Bituminous. Lignite the softest and weakest energy output. Anthracite is the hardest coal, 100% carbon and produces the highest energy output. Bituminous is the most common and causes the most pollutants.

Oil

Oil builds up in rock underground. Wells are drilled into the ground to extract this oil. Oil is found usually near the various tectonic plates. The first stage is to pump the oil out of the ground, this gets out 25% of the oil in the rock. The next stage is to pump hot water into the well to force the rest of the oil to the top for easy extraction. The third stage would be to pump carbon dioxide into the well, this would help extract the remains of the oil. This is known as tertiary recovery.

The last stage in recovering Oil is factional distillation. This is when the oil is boiled and then the various gasses are separated from the oil.

Oil shale and tar sands are two other types of oil. They require a lot of energy to extract, around half a barrel of normal oil is needed to extract one barrel of oil shale or tar sand oil.

Nuclear Power

Traditional power plants heat water and use the steam to turn turbines to generate electricity. Fossil fuelled power plants heat water using burning coal, oil and natural gas.

In a Nuclear power plant, the fission of uranium atoms in the reactor heat the water.

The reactor core is made up of uranium fuel. The uranium is put into fuel rods and thousands of these fuel rods make up the the reactor core. Heat is produced in the reactor when neutrons strike uranium atoms, causing them to split and heat up.

Nuclear power doesn’t produce any pollutants to the environment. However it does produce nuclear waste that can be very dangerous.

Module 4 – Petroleum & Natural Gas

Petroleum

Petroleum is an oily, flammable dark brown or greenish liquid that is found naturally beneath the surface of the earth. Petroleum is used to produce fuel oil. It’s also the main material in producing plastics, pesticides and fertilisers. It’s known as the black gold.

Petroleum is the worlds primary energy resource.

The United states consumes 7.5 billion barrels of oil per year.

The most difficult part of extracting oil is finding the oil. Once the oil has been detected, a drill is sent down into the well and oil is extracted. Once the easy oil is extracted then the second phase is to inject water and gasses into the well to increase the pressure underground and extract more oil. After the first stage (primary) and second (secondary) stage, usually about 25-35% of the oil is extracted. As long as it’s still profitable to do so, the third stage is to insert CO2 or steam into the well, which makes the oil easier to extract. This method allows for a further 10% of oil to be extracted.

The third stage, tertiary oil recovery, is only done if it’s profitable to do so. This depends on the current price of oil. If oil prices are low, companies will leave the oil underground until oil prices rise and then they’ll go into to get the oil.

The petroleum industry can be divided into upstream producers and downstream transporters. The upstream producers are the companies who find and develop the oil. The downstream transporters are the companies who deal with the transport of oil via pipelines and tankers.

Petroleum needs to be refined and before it can be used as fuel or material.

Gasoline

Gasoline or petrol is derived from petroleum. It’s the main fuel used in internal combustion engines.Gasoline is separated from petroleum using distillation.

Diesel is produced from petroleum as well and is about 18% denser than gasoline. Diesel causes more pollutants than gasoline due to the higher sulphur content. Diesel is more energy efficient than gasoline which contributes to better fuel economy.

Kerosene is a colourless highly flammable liquid. It’s used mostly in Jets as fuel and also still used for lamps and cooking in some developing countries.

Bitumen is the heaviest fraction of oil and is produced by fractional distillation of oil. It is most used as Asphalt and Tar.

Some have argued that the need for oil will rise the price of oil over time which will cause other companies to go searching for new oil fields. This will not increase the amount of oil in the ground, that oil is finite and will eventually run out.

Natural Gas

Natural Gas is one of the cleaner fossil fuels. It is also one of the most efficient fuels, only 10% of the fuel is wasted before it’s burnt.

Natural Gas is found trapped underground between rocks. 40% of the worlds gas reserves are in the middle east and 25% in Russia.

Natural Gas is a combination of methane, propane and some other gasses. The primary substance in natural gas is methane, about 90%. Methane is highly flammable, burns easily and completely and produces very little air pollution.

It is extracted by drilling, both onshore and offshore, into the ground. It usually comes out by itself due to pressure underground.

Natural gas is used in cooking, water warming and heating in homes. In businesses it’s used in manufacturing, waste management, burning, heating and drying. Within the power generation sector, natural gas is used to heat water which creates steam to spin turbines and generate electricity.

Module 5 – Coal

We still use coal as a fuel because we have so much of it. Coal was formed over millions of year from highly compressed land plants.

The plant debris are buried under large amounts of mud and sand. As the plant debris are pushed lower into the earth, pressure increases. As the depth of the plant debris increases and gets lower in the Earth, the temperature also rises down there, heating the plant debris, mud and sand up. Compaction under pressure increases the hardness of coal.

The two ways coal is mined out of the ground are surface mining and underground mining. Surface mining involves digging and using explosives to remove the rock on top of the coal and expose the coal. Underground mining is when the shafts are created to go deep underground and extract the coal. Surface mining is easier, cheaper and safer but not always possible. Surface mines usually only go 100 metres into the ground while underground mining can go a kilometre down into the ground.

Coal produces high amounts of pollutants to the atmosphere but it also damages the environment.

Surface mining creates lots of dust, noise and needs to be restored afterwards. Underground surface mining can cause land subsidence, which is a gradual settling or sudden sinking of the Earth’s surface owing to subsurface movement of earth materials. Underground mining can also seriously pollute the fresh water underground.

The UK has 0.2% of the worlds global coal reserves. The EU in total has 10% of global coal reserves. The majority of the worlds coal reserves are in the Northern Hemisphere

Due to technological advances in transport, the UK has been a net importer of coal since 1970 due to it being cheaper to buy coal elsewhere and transport it to the UK, instead of mining it out of the UK mines.