101 guide into alternative energy sources

A 101 Guide into Alternative Energy Sources

Are you concerned about your carbon footprint? One simple way to reduce it is to look at your energy consumption and where are these sources of energy coming from. Do you use alternative energy sources that lessen the carbon emissions? What are the different energy sources available to you? Which alternative energy source is best for you, your household, or your business? Answers to these and other questions can be found in this post, a 101 guide into alternative energy sources, so keep on reading!

The fight against Climate Change is getting tough and tougher. That is why all actions, minor or significant count to win this race. This 101 guide into alternative energy sources will give you an initial understanding of renewable energies so that you can make those choices that count. 


Just to put the current situation in numbers, there is a 50:50 chance of average global temperature reaching 1.5 degrees Celcius above pre-industrial levels in the next five years, however, it is quite likely that this threshold will be reached by 2030 and certain by 2035. That is quite concerning when you think about it. Moreover, at the current trend, AI-generated scenarios point out that by 2050, the Earth will reach 2.0 degrees Celcius above pre-industrial levels. 

However, when we think about this, we cannot imagine what does this global temperature increase really mean for us, for the rest of the species around the world, the ecosystems and for the entire planetary environment. The main characteristic of Climate Change is that there is no single evenly “warmer Earth” as each part of the world is experiencing different degrees of increased temperatures and more frequent and intense heat waves, while other parts will experience droughts, water scarcity, extreme weather events or floods due to extreme precipitation. The strongest warming phenomenon is happening in the Arctic during its cool seasons, and in Earth’s mid-latitude regions during the warm season. As these regions get warmer, the weather frontiers for invasive species will also swift to higher latitudes increasing the risk of contagious diseases like Dengue Fever or Malaria in these regions. The loss of biodiversity is also rising at an alarming pace, which not only affects the continuation of natural ecosystems and their valuable services but also the continuation of our agriculture.  A warmer planet means the disappearance of the polar ice caps, warmer oceans, and rise of the sea levels resulting in increased coastal flooding, beach erosion, salinization of water supplies and other impacts on humans and ecological systems. The greater the oceans capture carbon, the less oxygen content, and the more acid waters negatively impacting a broad range of species, from algae to fish, and the loss of entire marine ecosystems leading to “dead zones”, which will affect the fisheries stock for our own survival. 

Humans will not be spared from the consequences of these disasters at the receiving end as well. The inland and marine loss of biodiversity, water scarcity and droughts will impact our food stock putting food security at high risk. Extreme weather events and catastrophes will destroy our cities and disrupt our status quo. The rise of temperatures will cause heat-related diseases and higher mortality rate. More people will die from vector-borne diseases as mosquitoes carrying these contagious diseases will see their latitude band increased. Finally, the economies all around the world will see major financial crisis which could lead to the action of states of emergency and even the full crash of country’s socio-economic-politic systems. 

It becomes paramount to reduce our carbon emissions to be able to mitigate the consequences of these global environmental impacts. Keeping the planet to 1.5 degrees Celcius above pre-industrial levels is vital to our own survival.  

As pointed out by the World Bank, energy produced from fossil fuels currently account for the lion’s share of emissions across all industries, sectors, business, organisations or individuals. Transitioning from fossil fuels to alternative energy is key to addressing the climate crisis. So let’s dive into the different types of energy source you can find in the 101 guide into alternative energy sources.

World CO2 emissions (metric Tns/ capita). Source: The World Bank


Alternative energy is the energy that does not come from fossil fuels, and technically thus does not contribute to climate change. However, within this umbrella we can find renewable energy sources such as the wind or sun and non-renewable energy sources that do not contribute to climate change like nuclear energy. This 101 guide into alternative energy sources will look at those ones that are renewable.

Renewable energy is understood as the energy derived from natural sources that are replenished at a higher rate than they are consumed. Renewable energy means energy from renewable non-fossil sources, namely wind, solar (solar thermal and solar photovoltaic) and geothermal energy, ambient energy, tide, wave and other ocean energy, hydropower, biomass, landfill gas, sewage treatment plant gas, and biogas.

In Europe, the directive that regulates Renewable Energies is the Renewable Energy Directive (2009/28/EC) first introduced in 2009. The Directive was revised in 2018 and was legally binding since June 2021. The existing directive sets the overarching European target for renewable energy and includes rules to ensure the uptake of renewables in the transport sector and in heating and cooling, as well as common principles and rules for renewables support schemes, the rights to produce and consume renewable energy and to establish renewable energy communities, and sustainability criteria for biomass. The directive also establishes rules to remove barriers, stimulate investments and drive cost reductions in renewable energy technologies, and empowers citizens, consumers and businesses to participate in the clean energy transformation. The directive sets a common target – currently 32% – for the amount of renewable energy in the EU’s energy consumption by 2030.The 2022 study ‘EU’s global leadership in renewables’ confirms that the EU is already in a leading position for renewables technology development and deployment but suggests that its competitive position on global renewable energy markets could be further strengthened.  Hence, in July 2021, the Commission proposed another revision to accelerate the take-up of renewables in the EU and to help reaching the 2030 energy and climate objectives. 


As described above, renewable energy sources are those that can be replenished at a higher rate than they are consumed. While renewable energies can bring energy security and resilience to a country due to its local availability and accessibility, they often involve a higher initial investment and long-term vision. Renewable energies are also intermittent and difficult to store bringing a factor of unreliability, which could put in question the investment decision in the first place. However, technology and development in renewable energy have come a long way and it’s time to debunk old myths. In fact, renewable energies are obtained from natural sources that are not exclusive to certain countries and during the operation phase, they generate electricity without contributing to global warming. These are the types of renewable energies listed in this 101 guide into alternative energy sources: 


The solar energy is the primary energy force; it warms the Earth, causes wind, weather, sustains plant and animal life, and even the formation of fossil fuels that took place 3 billion years ago. All other forms of energy are due to the Sun and its electromagnetic radiation (EMR). Technologies that harvest directly the abundant energy coming from the Sun are considered Solar Energy Technologies. There are different ways of capturing solar radiation and converting it into usable energy.Photovoltaic (PV) solar panels transform the photons contained in the UV rays of the solar radiation spectrum into electricity. While Concentrated Solar Power (CSP) uses mirrors to reflect and concentrate sunlight onto a receiver, which heats a high temperature fluid contained inside the receiver, generating thermal energy, that can be used to spin a turbine or power an engine to generate electricity.


Wind is the result of differences in temperature and pressure in different areas of the atmosphere, the rotation of the Earth, the Coriolis effect, mainly. These phenomena can be planetary, regional, and even locally produced. The local phenomena is very characteristic of mountainous regions and coastal lines due to the differential temperatures of different mases between the day and the night. 

The kinetic energy resulting from air currents, or the local flow of the wind can be harnessed by wind turbines, which rotate to generate electricity. The amount of wind power in a location is measured by the Wind Power Density (WPD). When the location is in land, it is classified as onshore wind energy, and if the location is outside the coastal line, it is classified as offshore wind energy. Offshore wind energy is more consistent and less prompt to turbulence compared to onshore wind energy.There are 2 types of wind turbines, horizontal-axis turbines or vertical-axis turbines, however, vertical-axis turbines have been found not to perform as well as the horizontal-axis ones, which are commonly most in use. 


These technologies use the kinetic energy of a water stream to produce rotatory energy that is transformed into electricity. When enough water flow passes through hydro-turbines, the mechanisms move to make electricity. 

Hydropower can be classified in large, small, and micro hydropower plants depending on the capacity to generate electricity, measured in Megawatts. Technologies can also be divided into 3 categories being run-of-river, storage, and pumped storage hydropower. Due to its capacity to store water, hydropower becomes the easiest way to store energy in large capacity. The most common structures used in the large hydropower plants are dams but diversion structures that alter the natural flow of a river or other body of water are also employed in the small hydropower or the micro hydropower plants. 


Bioenergy is a source of energy stored in the carbon bonds of complex carbon chains found in organic materials like plants during photosynthesis reactions. The wide range of organic materials used in the bioenergy umbrella is called biomass and it can be found in its solid, liquid or gas form. There are three ways to harvest the organic material to produce biomass: pressure and fusion processes to extrude solid biomass, transesterification to convert the vegetable fats and oils into liquid biofuel, or biological processes like bacterial decay that take place in controlled landfills, or sewage treatment plants to produce biogas. Unlike the solar energy or the wind energy, biomass can also be easily stored until it is needed. 

Biomass is then used to generate energy similarly to fossil fuels, thus releasing CO2 during the combustion process. Although bioenergy involves the generation of CO2 emissions, it does not contribute to global warming because it comes from the capture and storage of carbon that was already contained in the atmosphere. Unlike some forms of intermittent renewable energy, bioenergy can increase the flexibility of electricity generation and enhance the reliability of a renewable source electric grid. Hence, becoming a good candidate to substitute the residual use of fossil fuels in certain sectors such as aviation. Waste (and refuse) To Energy (WtE) is a sort of energy recovery process that uses this specific carbon biomass to harvest the energy released during treatment processes, employing new technologies that will convert them into heat, electricity or fuel (hydrocarbons). 


Power is generated capturing the heat of the Earth Crust constant temperature. Geothermal power plants draw fluids from underground reservoirs to the surface to produce steam. This steam then drives turbines that generate electricity. The technologies used in this category include dry, flash steam, binary cycle plants, or enhanced geothermal systems (EGS).

To generate power from geothermal systems, three elements are needed:

  • Heat—Abundant heat found in rocks deep underground, varying by depth, geology, and geographic location.
  • Fluid—Sufficient fluid to carry heat from the rocks to the earth’s surface.
  • Permeability—Small pathways to move fluid through the hot rocks.

Once the three requirements are met, geothermal power plants can produce electricity consistently and can run essentially 24 hours per day/7 days per week, regardless of weather conditions.


Ocean energy refers to all forms of renewable energy derived from the sea. Ocean energy technologies exploit the power of tides and waves, as well as differences in sea temperatures and salinity, to produce electricity. The primary types of ocean energy are:

  • Tidal Stream: Potential energy associated with tides can be harnessed by building barrage or other forms of construction across an estuary, while kinetic energy associated with tidal (marine) currents can be harnessed using modular systems. When enough water streams and goes through hydro-turbines, the mechanisms move to make electricity.
  • Wave Energy: Kinetic and potential energy associated with ocean waves can be harnessed using modular technologies.
  • OTEC: It is a form of energy conversion that takes advantage of the temperature gradient between the sea surface and deep water. To harvest this energy, cooler temperature water, from deeper in the ocean is brought to the shallower surface to heat it up. The exchange of heat produces thermal energy that can be harnessed using different Ocean Thermal Energy Conversion (OTEC) processes.
  • SWAC: Sea Water Air Conditioning (SWAC) systems work pumping water from the nearby sea or ocean. Depending on the water depth and the season, the pumped seawater is used to cool or heat a closed freshwater loop via a series of heat exchangers. A single system can provide heating or cooling to an urban area several kilometres wide. Hence, this technology scores high to decarbonise heating and cooling systems around the world’s coasts.
  • Salinity Gradient: At the mouth of rivers where fresh water mixes with salt water, energy associated with the salinity gradient can be harnessed using pressure-retarded reverse osmosis process and associated conversion technologies.

Its predictability makes it an ideal balancing partner for wind and solar and it has little or no environmental impact.


This 101 guide into alternative energy sources has dealt so far with those which its technology has been developing for more than 3 decades. However, in the last decade, other alternative energy sources have been making some impressive technological improvements. We are referring to hydrogen energy which is making human being think that the Net-Zero dream could really be a future reality.

Although hydrogen is the most abundant element in the universe, in this planet, hydrogen is currently produced by separating it from other elements in water and fossil fuels. While producing hydrogen requires energy, hydrogen is emission-free at the point of use. Geological hydrogen is also naturally occurring, found in underground deposits and created through fracking. However, there are no strategies to exploit this hydrogen at present.

Green Hydrogen: This form of hydrogen is sourced using renewable energy sources to power electrolysis to split water molecules into hydrogen and oxygen.

Blue hydrogen is produced mainly from natural gas, using a process called steam reforming, which brings together natural gas and heated water in the form of steam. The output is hydrogen, but carbon dioxide is also produced as a by-product. So, the definition of blue hydrogen includes the use of carbon capture and storage (CCS) to trap and store this carbon. It is classified as low carbon hydrogen.

Grey hydrogen is created from natural gas, or methane, using steam methane reformation but without capturing the greenhouse gases made in the process. Grey hydrogen is essentially the same as blue hydrogen, but without the use of carbon capture and storage. Most of today’s hydrogen use is grey.

Pink hydrogen is generated through electrolysis powered by nuclear energy. Nuclear-produced hydrogen can also be referred to as purple hydrogen or red hydrogen. The very high temperatures from nuclear reactors could also be used in other hydrogen productions by producing steam for more efficient electrolysis or fossil gas-based steam methane reforming.

Turquoise hydrogen is a new entry in the hydrogen colour charts where hydrogen is made using a process called methane pyrolysis to produce hydrogen and solid carbon. In the future, turquoise hydrogen may be valued as a low-emission hydrogen, dependent on the thermal process being powered with renewable energy and the carbon being permanently stored or used.

Fuel Cell System: A fuel cell uses the chemical energy of hydrogen or other fuels to cleanly and efficiently produce electricity. Fuel cells work like batteries, but they do not run down or need recharging. They produce electricity and heat as long as fuel is supplied. In hydrogen fuel cells, hydrogen is the fuel, which undergoes a catalyst at the anode separating the hydrogen molecules into protons and electrons, which take different paths to the cathode. If hydrogen is the fuel, the only products are electricity, water, and heat.


Ambient energy is that sort of residual energy that is naturally stored in the environment, such as the ambient air. This form of energy is still in an elemental research stage, but it is to be noted that this type of energy could still be used to power the increasing growing network of IoT devices if they could harvest and generate sufficient power from environmental conditions such as light, vibration, and heat to allow self-report, self-powering and self-sufficiency (energy harvested vs energy consumed), likewise any other living organism would do in the natural environment. 


If you are on your journey to improve your ESG performance, and looking to reduce your CO2 emissions, facing the challenge of investing in alternative energy sources for your home or business can be daunting. At Pangea Green, we hope that the 101 guide into alternative energy sources has been useful. Some of the factors that you should look at are the availability of the renewable resource in your area, the accessibility to the technology required, the ROI, and last but not least, maintenance and repair response services. 

The most obvious factor is the availability of the resource; if there is no resource to harvest there is no investment to be made. Examples of these kind of limitations could be faced trying to harvest the energy of the wind in mild wind areas, tidal energy in coastal areas with low tidal range or hydropower with no rivers. 

Further, the technology needs to be available in your area. Otherwise importing technology for your investment could require a substantially longer ROI period, which could make it almost worthless. Finally, if you decided to import the technology you might face challenges when it comes to maintain and repair the equipment. You should ensure that either the company which sold you the equipment is willing to provide these services as per the recommendations in the manufacturer’s manuals, or you obtain the necessary knowledge to be able to conduct these activities on your own. If the second is your selected option, make sure you stock some replacement pieces of those equipment that might be difficult to acquire in your area. 

Other considerations should also be taken into account such as space required to install the equipment, potential environmental and social impacts, such as impacts to biodiversity, noise disturbance, other resource consumption, or waste generation and management, just to name a few. 

If you are decided to invest in renewable energies, reading this 101 guide into alternative energy sources will have built your understanding on the different kind of renewable energies there are available, and how this technology could serve your purpose. However we recommend to conduct a deep research checking internationally recongised organisations websites, in addition to making sure you check and comply with your local laws and directives, conducting environmental assessments as per your country’s regulation and getting professional advice to assure your investment is feasible. 

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