Biofuels and aviation

Posted on May 10, 2019April 8, 2019 by admin

Using sustainable biofuels represents one of the most effective ways to reduce CO2 emissions in aviation. If the aviation sector switches to sustainable biofuels on a large scale, CO2 emissions can decrease by as much as 80%. Biofuel is therefore much more sustainable than fossil fuel, which is the current standard within the aviation sector. There are, however, still many problems in the way of a large-scale biofuel implementation within the aviation sector.

Future planning

Several years ago the leading airlines and aircraft manufacturers have signed a challenging environmentally-friendly agreement. According to this agreement, the fuel efficiency of the aircrafts must increase by not less than 1.5% by the year 2020. Moreover, the European Union is planning to drastically decrease the amount of CO2 emissions from the atmosphere, with the new laws planned for 2020. By the middle of this century, airlines must produce twice as little CO2 emissions as they did in 2011. These goals are very ambitious and big changes have to happen to make them possible. One of the possible ways to reach the desired levels of CO2 emissions by 2050 – is using the biofuels. Biofuels will significantly reduce the emissions, even if they constitute only 4% of the total amount of fuels in aviation.

The biggest drawback here is the cost of environmentally-friendly biofuels. Currently, the majority of the types of biofuel cost twice to three times as much as the conventional kerosene. Some researchers believe that as the biofuel production will grow, the prices will start decreasing. The conventional energy sources, on the other hand, will become more and more expensive. That means that biofuels may become more economically advantageous already in the near future.

Another factor limiting the usage of biofuels in aviation is that it’s impossible to use some types of biofuel at high altitudes. Biodiesel fuels tend to thicken or even crystallize under low-temperature conditions. However, for successful implementation in aviation the new types of fuel must have similar characteristics to conventional kerosene. This will allow to avoid replacing the expensive plane engines, and in some cases even whole airplanes. For this reason, most of the current biofuel-research is devoted to developing new types of fuel, as well as new production technologies.

Combining biofuel with conventional fuel

Currently almost all types of biofuel have to be combined with certain amounts of traditional fuels before they are used in aviation. The most important factor in the development of such fuel compositions is to maintain a good balance between price, amount of harmful emissions and specific consumption of the mixture. Thousands of planes, including commercial flights, have already been flying on biofuels or biofuel-based mixtures, to test the existing solutions.

Unfortunately Sustainable Aviation Fuels (SAFs) aren’t available on large scale yet, especially if you’re a consumer. If you’d still like to fly and do something back for nature, we recommend booking through FlyGRN. They’re a flight search engine that offers similar price tickets and automatically offset carbon emissions. You can also offset your flight’s emissions afterwards.

Geothermal energy

Posted on April 22, 2019February 8, 2019 by admin

A source of enormous energy is located deep inside the Earth. The Earth stores this energy as heat, therefore, we call it geothermal energy. Sometimes it is also referred to as “environmental energy”. Both the Earth’s top layer – the soil – and the layers deep inside the Earth contain this environmental energy. Environmental energy has potential for both heating and cooling purposes. The Sun warms up Earth’s top layer, the soil. A device called heat pump can further increase this temperature, so that we can use it for heating. A couple of hundreds meters deeper inside the Earth a new source of energy already becomes more noticeable – the Earth’s inner heat.

Part of that geothermal heat heats up the ground water. In most countries the ground waters can only be used for heating when they lie at a depth of several hundreds meters. In some countries, however, geothermal heat is visible even on the surface, in the form of geysers.

Geothermal energy has one big advantage over the other forms of sustainable energy, like solar and wind energy, – it does not depend on the weather conditions. This is a big reason to develop techniques enabling the usage of this energy in the future.

The energy of the Earth

The natural decay of radioactive isotopes inside the Earth continuously produces energy in the form of heat. Only 30% of this heat is the so-called primordial heat – the heat our planet has kept since its formation. The Earth itself continues to produce 70% of its internal heat. The main difficulty with using this immense heat source is that the heat flow to the surface of the Earth is very small. That happens because the rocks forming the Earth are very poor thermal conductors. Compared with good heat conductors such as the majority of the metals, thermal conductivity of the rocks is lower by a factor of 500.

Therefore, the heat flow to the surface is far too low, it constitutes only about 1% of the heat the surface receives with the sunlight. If we want to make effective use of geothermal energy, we have to penetrate very deep inside the planet. For each kilometer of depth the temperature increases by roughly 30 degrees Celsius. Heat pumps provide the means to use geothermal energy stored deep inside the Earth

Using the geothermal energy directly

Direct use of geothermal energy is only possible if heat energy is the desired energy. That means, that we do not want to use it as, for example, electricity, but we really need to heat something up. Using the geothermal energy directly can be very helpful with heating up building or providing warm tap water.

In order to get the heat from the inside of the Earth to the surface, one usually implements a system of two heat reservoirs – a cold one and a hot one. First water is directed to move along a layer of hot rocks – the rocks are heated by Earth’s internal heat. Consequently, the pumps direct this heated water up to the surface, where it enters the heating pipes system of a building. The water then releases its heat at the desired location. The water that has cooled down again after releasing its heat travels back into the ground again where it reheats. Then the whole cycle repeats.

Similarly to using the hot water, one can directly use the cold superficial water close to Earth’s surface, for cooling purposes.

Wind power

Posted on April 2, 2019February 8, 2019 by admin

Wind power is an excellent source of sustainable power. Wind energy never runs out. Moreover, it’s always a clean energy source, unlike the conventional fossil fuels, like coal or oil. The demand for fossil fuels worldwide is immense, the majority of the developed countries depend on oil and gas supplies. This dependency on fossil fuels can sometimes lead to dramatic consequences. The most recent case of such negative consequences happened in 2009 during the Russia-Ukraine conflict. As a result of this conflict some parts of Eastern Europe were cut out from the gas supplies.

Moreover, natural reserves of fossil fuels are rapidly running out. To ensure that we have enough energy to satisfy our needs, we need to learn how to efficiently use the renewable energy sources. Wind is one of such sources and wind power technologies are currently developing at an increasing pace.

Another important disadvantage of conventional energy sources is the continuous release of greenhouses gases (especially CO2) into the atmosphere. These greenhouse gases contribute to Earth’s climate change, influencing all aspects of life on the planet. Wind power does not have this disadvantage.

Wind turbines

Using wind turbines is the most common way of generating sustainable wind energy. There are two types of wind turbines:

Wind turbines rotating around a vertical axis;
Wind turbines rotating around a horizontal axis.

Due to the fact that wind turbines with a horizontal axis are much more popular, we will focus on them here. Wind turbines are often organized in the so-called wind farms. Such farms usually consist of hundreds of turbines, either on land or off-shore. A big advantage of off-shore wind farms is that they do not interfere with the day-to-day business of the society. Moreover, winds are often stronger at sea. The biggest disadvantage is that such farms require expensive long high voltage cables to transfer the electricity to land, where we need it.

Principle of operation

Any wind turbine consists of three main components – the blades, the nacelle with the generator inside, and the tower. The blades are always directed towards the wind. Modern wind turbines have the ability to change the position of the blades, so that they are always at an optimum angle. The lifting force, caused by the flow of moving air, rotates the blades of the wind turbine.

The nacelle is the part of the wind turbine on ttop of the tower. The blades are also attached to it. The nacelle combines the basic operational parts of the wind turbine, such as the shaft (the axis) and the generator. The rotating blades cause the shaft to rotate as well. Special gear wheels transfer this rotational energy of the shaft to the generator. The generator then generates the power – that’s the wind power!

A generator of a wind turbine actually works just like a big dynamo. The movement of the shaft in a magnetic field creates the electric currents. The nacelle contains another important element of a turbine – a transformer. The transformer creates a potential difference (voltage), so that the generated current can be efficiently transferred.

The heights of the towers of wind turbines can vary significantly. The exact height depends on the specific wind conditions in the region.

Solar power

Posted on March 14, 2019February 7, 2019 by admin

The Sun is a star that is approximately 150 million kilometers away from the Earth. The Sun is an inexhaustible source of energy, therefore, solar energy is sustainable energy. Our planet receives the energy of the Sun through radiation in the form of light and heat. This energy, together with the secondary forms of energy, such as wind energy, tidal energy, hydropower and biofuel, forms more than 99.9% of all renewable energy on Earth. Solar energy is not polluting, it is silent and we can use it as long as the Sun exists. Because of the recovered solar energy, mankind can keep using fossil sources of energy for longer. Moreover, the usage of solar energy does not produce any waste products. All in all, if we know how to use it correctly, solar energy is the best and greenest energy source available on Earth!

Passive solar energy

We can use solar energy with the help of technology, for example, with the help of solar panels. However, effective usage of solar energy is possible even without involving any complex technology. If we use the solar energy directly – we are talking about the passive solar energy usage. Passive solar energy can provide us with light and heat inside our houses. However, to be able to use this energy efficiently, we have to take some factors into account as early as during the design phase of the house construction.

Glass and passive solar energy

Glass is the most important element in efficient passive solar energy usage. Windows are obviously essential for letting the sunlight to come into the house. As long as it’s light outside, there is no need in using electrical light sources. Glass windows also ensure that heat can enter the house. This heat transmission works both ways: they transmit the heat from the inside to the outside, but also from the outside to the inside. The last process happens due to the transparency of the windows, allowing sunlight to come in.

To make optimum use of the sun, one has to install relatively more windows on the southern side of the house and less windows on the northern side of the house. The reason for that is very simple – there is much more sunshine on the southern side than on the northern side. Therefore, while northern and southern windows allow the same amount of heat to pass from the inside to the outside, the heat flow from the outside to the inside is greater on the southern side.

A so-called sun-room can also generate a lot of energy profit. In the closed off sun-room under direct sunlight the temperature quickly becomes higher than in the rest of the house. This warmth can be subsequently distributed throughout the whole house with the help of a ventilation system. It is important that a sun-room should necessarily be closed. In the case of a sun-room attached to a living-room, the heat loss (especially in winter) can exceed the heat gain.

Sun protection

Many large windows on the southern side of a house provide the necessary heat in the winter. But in the summer months this heat is actually not desirable. Sun protection is essential for prevention of the uncomfortable heat in the house during the summer. It is more logical to have such sun protection outside of the house, since in this case the heat actually stays outside. Sun protection can ensure that the high sun is stopped in the summer, while the low winter sun shines under the blinds and thus enters the house.

Biofuel: part 2

Posted on February 26, 2019February 7, 2019 by admin

Second and third generation of biofuels as sustainable energy sources

2nd generation of biofuels

When people talk about the second generation of biofuels they usually refer to biofuels produced from food-unrelated materials. Plants grown specifically for this purpose make up the basis for this type of fuel. Inedible parts of certain food crops can also serve as the basis.

Jatropha oil is an example of this type of fuel. Conversion of the compressed oil into biofuel. The compressed oil can be processed into biofuel in a conventional manner, however the plant is not a food crop. The seeds of the are poisonous, therefore, it does not compete with food crops. Moreover, it can grow on very dry soil.

Another new development in the field of biofuel is making bioethanol from cellulose through fermentation. A process is now available to “crack” the cellulose from vegetable sources into fermentable sugars. This process allows to use the inedible parts of vegetable plants as biofuel. Such inedible parts can include straw, crop residues, woody crops and certain fibrous crops. This process does not evoke any fuel crop competition with food crops. Leftover products from the food industry serve as raw material for biofuel production.

Another development in the field of biofuels consists in making biogas from biomass. This biogas is subsequently used in power plants, where it is converted into liquid biofuels, such as biodiesel and bioethanol. BTL is the common abbreviation of this process, it stands for Biomass to Liquid. The end product of this process provides fuel for diesel engines.

Depending on the production method, the new generation of biofuels can reduce the emissions of greenhouse gases by up to 95%, as compared to fossil fuels. Realistically, the 2nd generation of biofuels can only come into large-scale production in 5 to 10 years.

3rd generation of biofuels

The term “third generation biofuels” remains a bit ambiguous for the time-being. Mostly, people use this term to emphasize that a certain biofuel production process is more advanced than those considered “2nd generation”. Often, this means biofuel production from algae. Algae as biofuel has the great advantage of not competing with food algae. They are specially cultivated to serve as biofuel.

Currently algae cultivation for energy purposes remains rather undeveloped. The cosmetic industry is responsible for most of the algae cultivation. Algae contain many lipids and are therefore very suitable for skin creams and other type of skin care products. Other industries involved in the algae cultivation include animal food producers, as well as the producers of Omega-3 fatty acids supplements.

However, scientists are currently performing a lot of theoretical and experimental investigations to find out new ways of converting algae into biofuels. Lipids are the key elements here, as they constitute raw materials for the production of biodiesel. Algae with high concentrations of lipids are thus the most suitable for biofuel production. One hectare of green algae produces about fifteen to twenty tons of biodiesel annually.

There are several techniques of algae cultivation and the consequent biofuel production. Most of these techniques are, however, still under development. Therefore, this source of biofuel is not yet widely being used. Nevertheless, it seems to be very promising, with more and more research conducted each year.

Biofuel: part 1

Posted on February 8, 2019February 8, 2019 by admin

Biofuel as a sustainable energy source

If you burn a piece of wood in your fireplace – a certain amount of CO2 comes out of the chimney. However, the tree that you are burning was growing in a forest and was taking CO2 out of the air not so long ago. The CO2 from the chimney is in turns again used as food for future trees, that again serve as biofuel for the fireplace. This is a simple way of how a short CO2 cycle less harmful to the environment works.

The same principle applies to other biofuels, such as biodiesel from rapeseed and sunflowers or bioethanol from sugar beet, corn and sugar cane. These types of biofuel are currently very popular. Moreover, it is possible to mix them with fossil fuels for certain purposes.

Some problems associated with biofuels

Even though biofuel seems to be rather environmentally-friendly, switching to it completely poses certain problems. First of all, growing biofuel crops requires very large agricultural areas. In countries with limited agricultural land availability, biofuel crops then become competitors of food crops. This, of course, poses certain ethical problems.

Moreover, sometimes the producers need to create new agricultural lands for the purpose of growing biofuel sources. In that case the whole process becomes much less environmentally friendly. That happens because to grow the new crops, large ares of already existing vegetation need to be cut down. This, obviously, is not a very environmentally-friendly procedure.

Even more importantly, the question of biofuel sustainability is still open. Some calculations even show that burning biofuel of certain crops eventually releases more CO2 into the atmosphere than fossil fuels do.
This is particularly evident in the production of corn- and potato-ethanol. The main problems are the usage of artificial fertilizers, soil cultivation and the usage of special machinery for the whole process. Moreover, certain fertilisers have the ability to undergo chemical reactions in the soil, which result in the release of nitrous oxide. This gas has a very high greenhouse potential.

Another major disadvantage of biodiesel is that bacterial growth can take place inside of it. This is especially dangerous in diesel oil that is stored in storage tanks for long periods of time. As a result, large machines in the fuel systems can be severely damaged.

Biofuel from organic waste

In most cases deep-frying oil and some animal fats are the sources of this type of fuel. These are residual products; therefore, the main goal of their production is not related to the production of energy

Future developments

Despite of all the disadvantages listed above, we should not give up on biofuels. Improvements are still possible in most of the related technologies. Moreover, the sustainability criteria are still not entirely clear. The European Union is currently developing these criteria. Factors such as greenhouse gas emissions, food competition, energy supply, biodiversity, prosperity and the environment play a role during this development. Producers can set up a certification system based on these criteria. Such certification system will result in more transparent and environmentally friendly usage of biofuels.

Want to know more? Check this post about different types of biofuels!

Sustainable energy and alternative energy sources

Posted on February 7, 2019April 8, 2019 by admin

Currently fossil fuels satisfy the majority of mankind’s energy needs. The current fossil energy sources are, however, running out. Moreover, the way people use these fossil fuels to produce energy has a bad influence on the environment.

The fossil fuels acting as the main sources of energy for our society are rapidly disappearing. The shortage of these conventional sources of energy leads us to the conclusion that something in our energy production process has to change. That is why people have been working on developing alternative, environmentally friendly and cheaper energy sources already for a while.

Sustainable energy sources

There are various sustainable energy sources. Among the most popular ones are solar energy, water energy and wind energy. A bit less popular, but rapidly developing sources include biofuel and geothermal heat energy. Researchers are currently investigating all these sources of energy, as well as the ways to increase their efficiency. On our website you can find multiple blogs describing the advantages and disadvantages of all these sources of energy. This post will give a short summary of all the sustainable energy sources, while the upcoming posts will focus on each energy source in more detail.

Solar power

Solar energy is the energy our planet receives from the Sun in the form of radiation. We perceive solar energy as light and heat. This energy ensures the possibility of life on Earth and largely controls the weather and climate of our planet. Solar power is a technological area aiming at using the radiation from the Sun as a source of of energy that the humanity can use for its practical needs. Obviously, Solar energy is a renewable energy source. Another advantage is that no harmful by-products are released during the active phase of solar energy use.

Water power

Water power, or hydropower is the power of running water streams or falling water. Nowadays, hydroelectric plants converrt almost all hydropower into electricity. In the past humans also used the generated mechanical energy immediately, for example to pump water with a water mill.

Wind power

Wind power specializes on transforming the kinetic energy of the moving air to the electrical, mechanical or heat energy for industrial use. Some examples of mechanisms collecting the kinetic energy of the wind include wind turbines, windmills and sails. A wind turbine transforms wind energy into electrical energy. A windmill transforms wind energy into mechanical energy. And a sail has various implementations in transport industry. Obviously, wind energy is a renewable energy source. For that reason wind power technologies are currently rapidly developing.

Biofuel

Biofuel is produced from plant or animal raw material, from the waste products of various organisms and from the organic industrial waste. Many experts consider biofuels as potential replacements for fossil fuels. Theoretically, biofuels are carbon neutral. Ideally, the amount of CO2 produced when burning the biofuel is compensated the amount of CO2 absorbed by the plants during their life-cycle. Practically, however, several other important factors play a role in whether or not a certain biofuel is carbon-neutral. This source of energy is also a renewable source.

Want to have renewable energy at home? Check out this page for the UK and this comparison engine for the Dutch market.

Find out if the world’s energy needs can be completely satisfied only by sustainable energy sources!

Related problems

Future planning

Combining biofuel with conventional fuel

The energy of the Earth

Using the geothermal energy directly

Wind turbines

Principle of operation

Passive solar energy

Glass and passive solar energy

Sun protection

Second and third generation of biofuels as sustainable energy sources

2nd generation of biofuels

3rd generation of biofuels

Biofuel as a sustainable energy source

Some problems associated with biofuels

Biofuel from organic waste

Future developments

Sustainable energy sources

Solar power

Water power

Wind power

Biofuel