From Renewable Energy to Hydrogen and finally to electricity

Let's explore the process of transforming 1 kilowatt-hour (kWh) of renewable energy directly into hydrogen gas and then back into electrical energy. Here's an overview of the process and an estimation of the final yield or efficiency:

Conversion of Renewable Energy to Hydrogen:

To convert renewable energy (such as solar or wind power) into hydrogen gas (H2), the energy can be used for the process of electrolysis.

Electrolysis involves passing an electric current through water (H2O), splitting it into hydrogen gas (H2) and oxygen gas (O2).

The exact efficiency of electrolysis can vary, but assuming high efficiency, let's assume a conversion efficiency of 80%.

Hydrogen to Electrical Energy Conversion:

To convert hydrogen back into electrical energy, we can use a hydrogen fuel cell.

In a fuel cell, hydrogen gas (H2) is fed into the anode and combined with oxygen gas (O2) from the air at the cathode.

Through an electrochemical reaction, the hydrogen atoms release electrons, generating electrical energy, while the protons combine with oxygen to produce water (H2O) as a byproduct.

The efficiency of hydrogen fuel cells can vary, but assuming high efficiency, let's assume a conversion efficiency of 50%.

Efficiency

Calculating the Final Yield or Efficiency: Based on the assumed efficiencies mentioned above, we can calculate the final yield or efficiency of the process:

Renewable Energy to Hydrogen: Efficiency = 80% (conversion efficiency) Hydrogen Output = 80% of 1 kWh = 0.8 kWh

Hydrogen to Electrical Energy: Efficiency = 50% (conversion efficiency) Electrical Energy Output = 50% of 0.8 kWh = 0.4 kWh

Therefore, from 1 kilowatt-hour (kWh) of renewable energy, the estimated final yield or efficiency of the process, considering the assumed efficiencies, is approximately 0.4 kilowatt-hours (kWh) of electrical energy output.

It's important to note that these efficiency assumptions are approximate and can vary depending on specific technologies, operating conditions, and efficiencies achieved in practice. The actual efficiency of the conversion processes can be influenced by factors such as fuel cell design, system losses, and the purity of the hydrogen gas.

From Renewable Energy to Hydrogen and finally to electricity using Ammonia as a carrier

The process of producing ammonia from renewable energy sources and using it as a carrier for energy storage, which can be later converted back to electric energy, involves several steps. Let's break down the process:

The first steps are Renewable Energy Generation, electrolysis of water and hydrogen production which have been explained before.

The next step involves the Haber-Bosch process, which is a well-established method for synthesizing ammonia (NH3) from hydrogen (H2) and nitrogen (N2). In this process, the hydrogen is combined with nitrogen obtained from the air in the presence of a catalyst (usually iron-based) and at high pressure and temperature. The resulting ammonia gas is then cooled and liquefied for storage and transportation.

Ammonia as an Energy Carrier: Ammonia has excellent energy storage properties as it has a high energy density and can be easily transported and stored at ambient conditions. It can be used as a carrier for transporting energy from renewable sources to different locations or for long-term energy storage.

Ammonia Decomposition: When there is a need to convert the stored energy back into electricity, the liquefied ammonia is subjected to a process called ammonia decomposition. This process involves heating the ammonia to a high temperature, causing it to decompose into hydrogen and nitrogen gases.

Fuel Cell or Combustion: The decomposed hydrogen gas can be used in fuel cells to produce electricity directly, with only water as a byproduct. Alternatively, the hydrogen gas can be combusted in a turbine or internal combustion engine to generate mechanical energy, which can then be converted into electricity using a generator.

By following these steps, renewable energy can be efficiently converted into ammonia, which can serve as a carrier for energy storage and transportation. When needed, the stored energy can be released by decomposing the ammonia back into hydrogen gas, which can be used in fuel cells or combustion systems to generate electric energy. This process enables the integration of renewable energy sources with the existing energy infrastructure, providing a flexible and sustainable solution for energy storage and distribution.

Overall yield of the described process

To calculate the final efficiency or overall yield of the described process, we need to consider the conversion efficiencies at each step. Based on the previous estimations, let's assume the following efficiencies:

Electrolysis of Water Efficiency: Assuming high efficiency, let's assume an electrolysis efficiency of 80%. This means that 80% of the input energy is converted into hydrogen gas.

Haber-Bosch Process Efficiency: The Haber-Bosch process is well-established and can achieve high conversion efficiencies. Let's assume an efficiency of 90% for the conversion of hydrogen and nitrogen into ammonia.

Ammonia Decomposition Efficiency: Assuming high efficiency, let's assume that the decomposition process can achieve 100% efficiency, meaning all the input ammonia is converted back into hydrogen and nitrogen.

Fuel Cell or Combustion Efficiency: The efficiencies of fuel cells and combustion systems can vary. Let's assume a high fuel cell efficiency of 50% and a high mechanical energy output efficiency of 80%.

With these assumptions, we can calculate the overall yield or efficiency:

Renewable Energy to Hydrogen: Efficiency = Electrolysis Efficiency = 80% Hydrogen Output = 80% of 1 kilowatt-hour (kWh) = 0.8 kWh

Hydrogen to Ammonia: Efficiency = Haber-Bosch Process Efficiency = 90% Ammonia Output = 90% of 0.8 kWh = 0.72 kWh

Ammonia to Hydrogen: Efficiency = Ammonia Decomposition Efficiency = 100% Hydrogen Output = 100% of 0.72 kWh = 0.72 kWh

Hydrogen to Electric Energy: Efficiency = Fuel Cell Efficiency = 50% Electric Energy Output = 50% of 0.72 kWh = 0.36 kWh

Therefore, the final yield or efficiency of the process, considering the assumed efficiencies, is approximately 0.36 kilowatt-hours (kWh) of electric energy output from 1 kilowatt-hour (kWh) of renewable energy input.

It's important to note that these efficiency assumptions are approximate and can vary depending on the specific technologies, operating conditions, and efficiencies achieved in practice.

From Renewable Energy to Hydrogen and finally to electricity using Ethanol as a carrier

Let's explore the process of transforming 1 kilowatt-hour (kWh) of renewable energy into ethanol and then back into electrical energy. Here's an overview of the process and an estimation of the final yield or efficiency:

Conversion of Renewable Energy to Ethanol:

To convert renewable energy (such as solar or wind power) into ethanol, the energy needs to be used for the process of electrolysis to produce hydrogen gas (H2).

The hydrogen gas produced from electrolysis is then combined with carbon dioxide (CO2) through a catalytic process called hydrogenation, which converts it into ethanol (C2H5OH).

The exact efficiency of this conversion process can vary, but assuming high efficiency, let's assume a conversion efficiency of 80%.

Ethanol to Electrical Energy Conversion:

To convert ethanol back into electrical energy, we can use a process called ethanol fuel cells. Ethanol fuel cells operate similarly to hydrogen fuel cells, but with modifications to handle ethanol as the fuel source.

Ethanol is oxidized at the anode of the fuel cell, generating electrons and producing carbon dioxide and water as byproducts.

The electrons produced are then sent through an external circuit, generating electrical energy that can be utilized.

The efficiency of ethanol fuel cells can vary, but assuming high efficiency, let's assume a conversion efficiency of 50%.

Efficiency

Calculating the Final Yield or Efficiency: Based on the assumed efficiencies mentioned above, we can calculate the final yield or efficiency of the process:

Renewable Energy to Ethanol: Efficiency = 80% (conversion efficiency) Ethanol Output = 80% of 1 kWh = 0.8 kWh

Ethanol to Electrical Energy: Efficiency = 50% (conversion efficiency) Electrical Energy Output = 50% of 0.8 kWh = 0.4 kWh

Therefore, from 1 kilowatt-hour (kWh) of renewable energy, the estimated final yield or efficiency of the process, considering the assumed efficiencies, is approximately 0.4 kilowatt-hours (kWh) of electrical energy output.