Revolution or evolution? However you define current and prospective developments in the global energy sector, surely this much is certain: the sector has begun to experience an irreversible, far-reaching transformation. Precise timeframes and the exact shape and substance of the final outcome may be up for debate, but the basic wish-list underpinning the process is clear: low/no carbon emissions; improved security, stability and availability of supplies; and a more efficient, integrated and cost-effective approach to energy provision. Harnessing hydrogen can help tick all of these boxes and radically change the way the sector goes about its business. But how exactly?
Change in Store
Here’s a fact that goes to the heart of the challenge now facing the energy sector: storing electricity at the right scale, in the right place and over the right timeframe is neither easy nor particularly cost-effective. Although substantial efforts are targeting improvements, battery technology has big practical limitations when it comes to bulk and long-term power storage. Yet these are precisely the types of storage needed in order to maximise the contribution of carbon-cutting renewable energy sources – and avoid the perversity of shutting down wind turbines on windy days and solar installations on sunny ones because supply exceeds demand and surplus power can’t be stored practically or cost-effectively.
Hydrogen is an excellent high-capacity, long-term energy storage medium that dovetails particularly well with intermittent renewables like wind and solar. Excess electricity can, via electrolysis of water, produce hydrogen that can be kept in gaseous or liquid form for indefinite periods without harming its energy content. At times of peak power demand, the stored hydrogen can then be used to generate grid electricity using combined-cycle gas turbines (CCGTs) or distributed energy supplies using fuel cells, for example; alternatively, it can be harnessed to heat homes, to fuel road and other vehicles, and in many additional applications.
Think of hydrogen as a bridge that can eradicate a big road block to optimal deployment of clean, decarbonising renewables. The EU-funded demonstration project HyBalance, for instance, is turning wind-generated electricity into hydrogen and its plant in Denmark was inaugurated this year; the Electricity Generating Authority of Thailand (EGAT), meanwhile, has announced plans to develop Asia’s first-ever wind-to-hydrogen project. Such steps may be modest, but a 2017 study by the EU’s Fuel Cells and Hydrogen Joint Undertaking boldly claimed that ‘power-to-hydrogen’ isn’t just key to tomorrow’s energy transition – it’s actually bankable today. Furthermore, its decarbonising potential applies not only to ‘green’ hydrogen produced from renewables but also to ‘blue’ hydrogen produced via decarbonised fossil fuel routes – an approach discussed in the previous piece in this series.
In the Balance
For all the importance of stored hydrogen’s potential role as a major enabler of decarbonisation, it is vital not to let this totally overshadow its parallel potential (touched on above) as an on-demand grid-balancing solution – an especially critical consideration in scenarios where renewables achieve very high levels of market penetration. Close matching of power supply with demand whatever the weather, maintaining power quality (an ever-increasing requirement of our ‘digital age’), and avoiding damaging power surges by ‘skimming off’ surplus electricity simply must be part and parcel of energy systems equipped to achieve maximum efficiency and cost-effectiveness. In all of these respects, stored hydrogen offers a solution.
Doubts remain, though. At last month’s Future Energy Summit in London, some industry figures went on record saying that high costs could limit hydrogen’s grid-balancing role to instances where cheap surplus green electricity is already available. But perhaps this relative pessimism fails to factor-in sufficiently the promise of projects such as the EU-backed, Italy-based INGRID initiative. Balancing highly variable power supplies by combining a record-breaking one-tonne ‘green’ hydrogen storage installation with cutting-edge smart grid technologies, INGRID is intent on underlining the practical scope for hydrogen to provide a crucial ‘missing link’ in energy chains worldwide.
The Strongest Link?
Where hydrogen storage is concerned, there are some intriguing options. Natural gas grid infrastructure, for example, comprises a vast and existing potential storage network that can provide a home for gaseous hydrogen as well as a tried and tested transmission and distribution mechanism. Directly injecting hydrogen into these grids is easily feasible at concentrations of around 2% – which could rise to 5% assuming modest upgrades to infrastructure. Not that this need be the ceiling of ambitions: in May, a new report from the Institution of Mechanical Engineers urged the UK government to promote use of up to 20% hydrogen in gas distribution networks by 2023. (Note: methanation of hydrogen by reacting it with carbon dioxide to produce ‘clean methane’ – in other words, synthetic natural gas or SNG – eliminates the need to upgrade existing gas infrastructure, including gas turbines.)
In such models, the resulting blend of natural gas and hydrogen could heat buildings or be used to produce electricity at CCGT power stations, for instance. If the hydrogen in this blend is ‘green’ or ‘blue’, the outcome would be the partial decarbonisation of gas supplies, as well as preservation of natural gas reserves and reduced need for imports. Worldwide, a number of ‘power-to-gas’ (P2G) demonstration projects are either operational or in development, including the Markham Energy Storage Facility in Ontario, Canada. Badged as North America’s first multi-megawatt P2G facility, this began operating in July – with stability, flexibility and reliability of grid operations all cited as key benefits of converting electricity into hydrogen.
But hydrogen’s game-changing potential goes further. Consider the new buzz-phrase now rebounding around energy circles – ‘sector coupling’. In many respects, this represents energy’s Holy Grail: the ability to connect all power- and heat-consuming sectors (industry, transport and buildings) with the power/energy-producing sector in a fully integrated energy system based on renewables, decarbonised fossil fuel power generation and nuclear power. One concept that illustrates this sort of holistic thinking is shown here – this was presented by Johannes Schaffert of GWI at IFRF’s TOTeM44 in Essen, March 2017, in a paper titled ‘Power-to-gas technologies as a toolbox for sector coupling in the future energy system’. As a readily storable, versatile energy carrier (vector), hydrogen is an ideal candidate to help link diverse parts of the energy landscape under a single ‘green’ (or possibly green-and-blue-striped!) umbrella, where every energy need is met from no/low-carbon electricity either directly or (via hydrogen) indirectly. Underpinning this new energy terrain would be hydrogen’s ability to meet the needs of many different energy markets in many different ways – a topic I’ll be focusing on in the next blogpost in this series.
Boosting the sustainability, efficiency and cost-effectiveness of the global energy system, hydrogen-enabled sector coupling could drive new synergies between energy sectors, forge new linkages between supply and demand in both centralised and distributed energy systems, and help make a truly interconnected, all-pervasive low-carbon energy system a reality. And that’s an opportunity which surely needs to be taken – and pursued – very, very seriously.