The Dark side of the Hydrogen Economy
By Nicholas Vafeas
Published October 24, 2023
At a Glance
The Core Problem: Ireland faces an urgent mandate to reduce greenhouse gas emissions by 51% by 2030, with residential heating standing as the single largest consumer of annual energy and the primary obstacle to meeting EU climate commitments.
The System Failure: While hydrogen is heavily promoted by fossil fuel interests as a convenient "green molecule" replacement for gas networks, the physics of green hydrogen electrolysis results in a massive 30% energy loss. This creates a critical system inefficiency when compared directly to electric heat pumps or underutilized geothermal and district heating networks. Furthermore, a clear cross-departmental communication breakdown has led to Ireland's Hydrogen Strategy completely ignoring concurrent geothermal policy alignments.
The Solution: Policy frameworks must reject the "model of convenience" that forces hydrogen into low-to-medium temperature residential heating. Instead, green hydrogen must be strictly ring-fenced for hard-to-decarbonize industrial and transport sectors, while residential infrastructure pivots toward proven, highly efficient electric heat pumps and geothermal district networks.
Green Hydrogen Inefficiency: The visual promise of an endless, glowing 'green-molecule' fuel source often masks the harsh reality that 1 kW of electricity is required to yield just 0.7 kW of usable hydrogen power.
Ireland’s heat energy demand, accounts for more than one third of its total annual energy consumption, with residential heat use indicated as the biggest consumer. Slow progress in decarbonising residential heat has, in the past, been identified as a primary obstacle to meeting Ireland’s commitments to the EU. Ireland’s commitment to a 51% reduction in greenhouse gas emissions by 2030, coupled with its obligations to the EU to increase heating and cooling from renewable sources, has prompted extensive consultation into renewable heat options by the Irish government.
The Department of Climate, Energy and the Environment recent National Hydrogen Strategy is the first step in recognising the potential of hydrogen as a decarbonised replacement for traditional fossil fuel, and is compatible with the goals set out in Ireland’s Climate Action Plan 2021 (CAP2021). Similar sentiments have been expressed globally, placing hydrogen at the forefront of climate talks such as the recent COP27 climate conference, and as an attractive bargaining chip for future “green” investment. But is hydrogen truly the “green-molecule” that it is often suggested to be? And how does it stack up as a solutions to Ireland’s green-energy goals and obligations?
Hydrogen is the lightest element on the periodic table and is used for manufacturing anything from fertiliser to rocket fuel and is seen by many as a convenient method to decarbonise difficult niches of the Irish economy with relatively little inconvenience. Strictly speaking, “clean” hydrogen is often categorised into “blue” and “green” hydrogen. Blue hydrogen is sourced from natural gas, where the hydrogen is separated from methane and the carbon dioxide is captured and transported underground for long-term storage. Green hydrogen, whilst less common at present, is often seen as the cleaner option and is made by splitting of water molecules through electrolysis and emitting oxygen as a by-product.
The United Kingdom’s Department for Energy Security and Net Zero Hydrogen strategy, views the blending of green and blue hydrogen as a promising option to phase out fossil fuels, despite a recent study to suggest that blue hydrogen could inadvertently be 20% worse for the climate than simply burning the original natural gas. The Irish government, however, seems to have taken a more reserved approach, seeking extensive consultation on the use of green hydrogen rather than blue. This certainly comes across as a preferable option and can be entirely emission-free if generated using renewable electricity. This is especially attractive given Ireland’s position as the 2nd highest producer of wind-generated electricity in Europe.
With increasing tensions surrounding heating in Ireland and Europe as a whole, the integration of green hydrogen seems like a “no-brainer”. Hydrogen can be transported via pipes, road, rail or ships or stored for times of increased demand. Furthermore, opportunities for the profitable exportation of excess green hydrogen, as mentioned in Ireland’s Hydrogen Strategy, offers additional attraction for the energy industry. With relatively little investment, Ireland’s gas grid could potentially be upgraded to accommodate hydrogen within the existing natural gas infrastructure. This is further encouraged by plans in the CAP2021 to build regulatory frameworks to enhance the role of green hydrogen deployment.
But as with all exciting prospects, the devil is often in the detail, and in this case the detail is inefficiency! Electrolysis, the process of splitting water molecules using electricity to produce green hydrogen, comes at a higher energy cost. On average, 1 KW of electricity is needed to make 0.7 KW of hydrogen.
For every 1 KW of hydrogen produced, we would lose 0.3 KW of wind-generated electricity that could otherwise contribute to an already strained electrical grid.
Compare this to standard heat pump technology in which 1 KW electricity produces 3 KW of heat, the benefit of heat pumps becomes blatantly clear.
Given the inefficiencies of green hydrogen production, why does green hydrogen remain such a popular topic of discussion for decarbonising heat? The simple answer is, it fits into an economic model of convenience. The gas infrastructure already exists, allowing energy utilities to continue as usual, boiler manufacturing could continue with little upheaval, and proponents of blue hydrogen, namely existing fossil fuel companies, would find support in society’s eventual submission to the convenience of a hydrogen-dominant model.
While the role of hydrogen in replacing fossil fuels is certainly recognised, particularly in sectors such as transportation and manufacturing, the evidence is becoming clearer that hydrogen has comparatively little benefit in decarbonising low-medium temperature heat. There are, however, strong alternatives that are being investigated, despite often being over-shadowed by the glamour of hydrogen. These include Ireland’s first district heating network, as well as the potential for geothermal heating systems, a Policy Statement for which was recently released. Given the relatively concurrent release of DECC’s Geothermal Statement, and its subsequent Hydrogen Strategy, which specifically excludes hydrogen for residential heating, there was an opportunity for strategic alignment. Ironically, despite both the Policy Statement and the Hydrogen Strategy stressing the importance of “engagement with the public and stakeholders across… state agencies” and “engagement and collaboration between relevant Government Departments and agencies” respectively, the Hydrogen Strategy overlooked any mention of geothermal energy. This oversight indicates an apparent breakdown in cross-communication, and highlights the need for the effective adherence to identified principles.
Recognising that the Government of Ireland’s approach to hydrogen synthesis and integration, is still in its early stages, it is important to stress that, whilst hydrogen has a potentially vital role to play in Ireland’s industrial and transportation sector, its future as a decarbonising fuel should be considered carefully.