Wake Up To The Hoopla Surrounding Green Hydrogen For Heating

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Governments all over the world are creating plans and packages of laws to meet their ‘net-zero’ aspirations for reducing climate change. Of course, authorities have recently been more concerned with limiting exposure to imports of fossil fuels and the hazards they entail as a result of the awful Russian conflict against Ukraine.

Game changer 

The current US administration has described hydrogen as a “game-changer” in the fight against climate change and the transition away from fossil fuels.

Such proclamations are impacting the politics of energy.

The European Commission is proposing to allow gas infrastructure owners to fund hydrogen-readiness work, and potentially use the energy bills of electricity consumers to pay for it.

In normal times, such ‘cross-subsidisation’ would never be allowed.

But the climate and energy price crises, mean we are no longer in normal times.

The perceived need for speed means that rapid action is considered more important than due process.

“Modest role”

To reach net zero, practically all fossil-fuel combustion needs to be replaced.

For buildings, heat pumps are a clear winning technology, extracting the majority of their heat output from outside air, ground or water.

The Intergovernmental Panel on Climate Change’s (IPCC) recent report explains that “scenarios assessed show a very modest role for hydrogen in buildings by 2050”.

The IPCC also highlighted the importance of heat pumps.

With gas currently providing the largest share of the world’s heating, as well as public policies being considered and designed to remove fossil fuel heating from buildings, it should come as no surprise that the gas industry has been overselling the idea of converting gas infrastructure to run on hydrogen.

And while research into and evidence of lobbying tends to be limited, there are plenty of publicly available examples, indicating the scale of the efforts.

These companies are all incumbents in the gas industry.

In the US, gas monopolies are promoting the conversion of their infrastructure to hydrogen and blending hydrogen into the gas mix, while fighting government policies to reduce gas use alongside general efforts to undermine building electrification.

There are two potential impacts of such lobbying.

Firstly, there could be direct impacts on policy, with governments offering financial and regulatory support for investments in hydrogen, in spite of evidence suggesting this may be a poor use of funds.

Pumping up the pressure

On the face of it, for countries such as the UK and the Netherlands, with well-developed and highly interconnected gas systems, it makes sense to consider the existing system and ask whether it be used in a zero-carbon world.

In the same inquiry, one UK gas network owner explained that “a hydrogen-ready boiler solution supplied by a repurposed gas network – which is already built to meet peak heat demand in winter – offers the optimum route to decarbonise heat at the scale required with the lowest levels of disruption and most value for customers”.

In some respects, hydrogen does have some extremely valuable characteristics for clean energy systems.

Secondly, like fossil gas, it can be burned to produce heat or electricity; or used in fuel cells (producing heat and electricity at once).

Yet just because you can do something, it doesn’t mean you should.

In the same way that champagne is reserved for special occasions, hydrogen is a premium product with a specific value.

Not a source of energy

A common misunderstanding is that hydrogen is itself a source of energy.

It is solely a vector or energy carrier: a means of storing and transporting energy.

Hydrogen gas does not exist in a state where it can be extracted from the environment in useful quantities, but it must be created, which is energy intensive and costly.

Blue hydrogen is controversial principally because of worries that it might be worse for the climate than simply burning methane.

These concerns stem from the fact that the production of the gas used to make it could lead to increased fugitive methane emissions, a very potent greenhouse gas, and also because capturing and storing CO2 emissions is difficult, expensive and has not been successfully achieved at scale anywhere in the world.

A belief that the whole idea of hydrogen had been captured by the fossil-fuel industry led to Chris Jackson resigning as chairman of the UK’s Hydrogen and Fuel Cell Association, saying the group’s support for blue H2 “is at best an expensive distraction, and at worst a lock-in for continued fossil-fuel use that guarantees we will fail to meet our decarbonisation goals”.

Although you won’t hear that mentioned by many industrial hydrogen proponents.

While on the face of it, a move from fossil fuel-derived hydrogen to renewably produced hydrogen might appear to be a good thing, the reality is that burning green hydrogen at scale seems even less plausible than burning blue hydrogen.

The energy content of green hydrogen comes from electricity and the production process involves significant energy efficiency losses.

Heat pumps operate with an effective efficiency of over 300%, with each unit of electricity going in, resulting in three units of useful heat.

These conversion efficiencies are a basic element of energy economics and are the nub of the green hydrogen debate.

Energy conversion basics

All energy conversion processes result in losses, meaning you get less useful energy out compared to the amount you put in.

For example, a power station burning gas may be around 60% efficient with 40% of the energy lost as heat.

Fundamentally, the hydrogen pathway for heating (all the way from electricity generation to burning it in a boiler) has much greater energy losses than the direct electric route.

Blue hydrogen was, at least before the gas price explosion, potentially cost-effective compared to the widespread use of heat pumps in various independent pieces of analysis, albeit under less stretching greenhouse gas reduction targets.

The high cost of hydrogen compared to alternatives becomes quite obvious once you understand how the energy efficiency of green hydrogen compares to electrification.

The graphic above spells this out. The first route (shown on the left) shows the transmission of the electricity to a consumer where it powers a heat pump. As heat pumps use electricity to heat a building from the environment that results in around three (or more) units of heat for every unit of electricity consumed, they have an effective 300% efficiency (known as the “coefficient of performance” or COP, which is in this case three). While some losses occur in the transportation of electricity, the overall effect is that 100 units of electricity results in about 270 units of heat reaching the consumer. This is an amazing energy uplift when you consider the value of clean electricity and that over two-thirds of the useful heat is coming from an inexhaustible renewable source.

The second route (centre) uses a simple electric space heater, powered by green electricity. There are small losses in electricity transportation, but most of the 90 kWh of electricity reaching the heater is converted into useful heat, yielding about 86 kWh.

The third route on the right shows the generation of green hydrogen which is burnt in a boiler for heating. Significant losses occur in the conversion of electricity to hydrogen. But further losses occur as energy is used to store the hydrogen and transport it to buildings and also when the hydrogen is burnt in boilers. 100 units in at the start of the process lead to 46 out in this pathway. Comparing the left-hand and right-hand routes, the heat pump route delivers about six times more heat than a green hydrogen boiler for the same amount of electricity generation.

This six times difference is the stark reality of using hydrogen for heating compared to heat pumps.

If providing the equivalent amount of heat by the green hydrogen route requires up to six times as much primary energy, it would be necessary to build up to six times as many offshore wind turbines or nuclear power stations, all with their own environmental and resource impacts. Clearly, this electricity capacity would take much longer to build, cost more and would delay decarbonisation. Hence comments from the UK’s Climate Change Committee CEO warning that switching all heating to hydrogen would be “impractical”, particularly when climate change demands rapid and immediate action.

Perhaps it is not quite that simple

Now, you might be thinking, OK that’s great in theory, but you don’t always have renewable electricity being generated when you need your heat pump running and so you will not be able to get that efficiency all of the time.

However, as pointed out by the late Sir David Mackay – the British physicist, mathematician, Regius Professor of Engineering and Chief Scientific Advisor to the UK Department of Energy and Climate Change – even running a heat pump solely on electricity generated by gas power stations would still use less gas and therefore have lower emissions than using a gas boiler.

That’s because, even though your gas power station may be only 50% efficient, your heat pump is 300% efficient and that makes the overall process more efficient than burning gas in a boiler.

It’s also important to bear in mind that heat pumps perform less well when it is colder with a performance of possibly 150% (a coefficient of performance of 1.5).

The impracticality of hydrogen is not just limited to expanding the electricity sector to infeasible levels.

Need for speed

Clearly, the climate is changing and atmospheric greenhouse gas concentrations continue to increase.

Slow progress thus far means that the world needs to decarbonise as quickly as possible.

We obviously also need to wean ourselves off increasingly expensive fossil fuels.

This idea is unlikely to ever get beyond limited trials.

A more likely scenario is that more time is wasted considering the idea of burning hydrogen for heat and more is spent funding companies to research it because politicians do not want to take the required difficult decisions.

 

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