How Does Hydrogen Energy Work?

In this article, SoluForce is taking a look at one of the fuels our products help to distribute - Hydrogen. This “Future Fuel” is rapidly gaining ground as an alternative to both petroleum and natural gas, making the prospect of a low, or even zero carbon energy grid a genuine reality

When hydrogen is produced using sustainable methods, it’s a clean, green energy source with a host of useful applications. 

Let’s dive in and find out how hydrogen energy works:

Hydrogen - A Brief Introduction

Before we explore how hydrogen can be used as a form of energy, let’s take a step back and talk about the element itself:

Hydrogen is usually found in gas form. It’s the lightest element in the universe and also the most abundant. When hydrogen is exposed to oxygen it instantly reacts, generating lots of explosive power and heat. That means this lightweight gas has huge potential as a source of fuel.

The fact that hydrogen reacts so readily with oxygen might give you a few clues towards the benefits and drawbacks of this element as a widespread fuel source:

On the one hand, the only byproduct of an oxygen-hydrogen reaction is pure water (H2O) - Which effectively means hydrogen energy is zero pollution and zero carbon dioxide.

On the downside, hydrogen’s volatility means that most of the gas here on earth has already made a reaction with oxygen to form water, meaning it needs to be “extracted” or “split” before it can be used as a fuel.

How Hydrogen is Extracted

As we previously mentioned, most of the hydrogen here on earth is bound up with oxygen in the form of water. Surprisingly though, the majority of the 70 million tonnes of hydrogen sold every year is actually sourced from fossil fuels:

Brown Hydrogen

We’ve known about electrolysis - The process of using electricity to split water into hydrogen and oxygen - since 1800, but it requires a lot of power to fuel the reaction at an industrial scale.

Most of the world’s electricity is still derived from coal or natural gas, and because those fuels contain small amounts of hydrogen themselves, it’s much more efficient to extract it directly, rather than using those fuels to perform electrolysis on a water source.

The obvious downside of this approach is that although the hydrogen extracted from coal or methane is extremely clean, the fuel source is anything but: For every kilo of hydrogen produced in this fashion, 7 kilos of CO2 are released into the atmosphere.

So Hydrogen Energy Isn’t Really Renewable?

Not so fast!

Whilst it’s hard to argue the case for burning coal to create a clean fuel, it’s worth pointing out that a large, centralized coal plant represents a much better way of supplying hydrogen energy to cars than thousands of exhausts producing another layer of emissions on top of the refining of crude oil into petrol.

In addition, hydrogen energy producers are increasingly investing in “carbon capture” technology to embed or trap CO2 underground, preventing it from dissipating into the atmosphere.

As well as these advances in fossil fuel technology, we’re also increasingly turning to renewable power to produce emissions-free electricity, opening up “Green Hydrogen” as a realistic source of versatile energy.

Green Hydrogen Energy Explained

Power sources like wind turbines and hydroelectric plants produce plenty of electricity without having to burn any carbon at all. In addition, due to their proximity to large volumes of water, when hooked up to an “electrolyzer” they open up the possibility of carbon and pollution free hydrogen energy.

So all the Problems with Hydrogen Energy Problems Have Been Solved?

In theory, yes. However there are still some major obstacles to overcome:

Producing enough green hydrogen to replace coal and methane sourced derivatives is going to require vast amounts of water and electrical power. Unfortunately, places like Australia and the Middle East have plenty of potential for solar generation, but precious little in the way of excess water.

Surely it’s More Efficient to Use Renewable Energy Directly?

That’s very true. 

On the surface, it does seem odd to divert perfectly good electricity from solar or wind generation into an energy intensive activity like hydrogen production.

The answer lies with hydrogen energy’s storage potential.

Unlike solar or wind power, hydrogen gas can be stored in liquid form until it’s needed. So alongside the future development of hydrogen fuel cells and direct combustion engines, there’s a great deal of potential to use hydrogen energy as a kind of “battery” for those times when solar or wind power can’t meet surges in demand.

How Does Hydrogen Energy Work?

In short, hydrogen energy works either as a replacement for combustible fuels, or something resembling a chemical battery. Here are a few examples of how this future fuel technology could be used:

Home Heating

Much of the world uses natural gas as a method of heating homes and cooking. In the future, cities and towns could shift en-masse to hydrogen-fired boilers. This may seem outlandish, but let’s not forget that the whole of the UK converted from heating their homes with town gas (a combination of hydrogen, carbon monoxide and methane from coal) to natural gas from the North Sea. 

A nationwide program converted 40 million appliances during the 1960s and 1970s, proving that whilst there are significant challenges, hydrogen energy homes could eventually become feasible.

Hydrogen Combustion Engines

In addition to home boilers, some car manufacturers such as Toyota, continue to develop hydrogen combustion technology alongside EVs, with a view to using a very similar infrastructure to the current network of petrol stations.

The aviation industry, too, hopes that hydrogen combustion might offer an answer to the problems faced by aircraft pollution, due to the light weight and high energy potential of the gas compared to unfeasible alternatives such as (heavy) banks of batteries. 

Hydrogen Fuel Cells

One of the most obvious (and likely) mainstream uses of hydrogen will be in the form of portable (or hot-swappable) fuel cells, where hydrogen’s volatile and reactive properties aren’t used for combustion, but instead work in broadly the same way as a regular lithium or lead-acid battery. 

Whatever the final use case for green hydrogen, it will inevitably mean overcoming plenty of obstacles, not least of all logistics.