Материал: The_Future_of_Hydrogen-IEA-2020

based fuels such as ammonia) offer ways of reducing emissions that are proven at scale. However, negligible quantities of hydrogen are currently used for this purpose today.39

Despite having the potential to eliminate emissions from high-temperature heat for industry, hydrogen remains an expensive alternative to fossil fuels in the context of a low-carbon pathway for the energy system, even when CO2 prices reach USD 100/tCO2 (Figure 49). Bioenergy tends to be more cost-competitive in this context, assuming a bioenergy price range of USD 8–12/GJ in 2030. In all regions explored in Figure 49, bioenergy is cheaper than the hydrogen-based fuels and thus shows a smaller differential relative to coal and natural gas prices.

Figure 49. Economics and future potential in the context of a USD 100/tCO2 carbon price

Notes: LOHC = liquid organic hydrogen carrier; NH3 (H2) = hydrogen transported as ammonia and then converted back to hydrogen; NH3 = ammonia transported and combusted as ammonia. High-temperature heat demand refers to non-chemical/iron and steel sector heat demand > 400°C. The regional price differentials are calculated using the cheapest source of each hydrogen-based fuel available (whether imported or domestically produced) and the domestic prices of coal and gas. More information on the assumptions is available at www.iea.org/hydrogen2019.

Source: IEA 2019. All rights reserved.

In key regions for high-temperature heat demand in 2030, low-carbon hydrogen-based fuels are likely to be a significantly more expensive alternative to fossil fuels than bioenergy

Bioenergy is set to become cost-competitive with natural gas as a source of high-temperature heat in 2030 in India, China and Japan, even at the higher end of the bioenergy price range explored (USD 12/GJ). This is due to relatively high natural gas prices in these regions in the context of a Paris-compatible pathway for the energy system (USD 3.8–10.6/MBtu). A CO2 price of around USD 200/tCO2 would be needed before the cheapest hydrogen-based fuels (at a delivered cost of USD 2.3–2.7/kgH2) become competitive with coal and natural gas.

Hydrogen does, however, offer some advantages for decarbonising elements of this diverse segment of energy demand, despite its relatively high costs and the need for it to overcome

certain practical difficulties (Box 11). For example, low-carbon hydrogen has the potential to help decarbonise the more geographically fragmented portions of industrial high-temperature heat demand where direct application of CCUS may prove impractical. Hydrogen, either via pipeline or using small-scale on-site electrolysis, could form a low-carbon energy supply to these “hard-to-reach” segments of industry. Its potential role may also grow if the supply of sustainable bioenergy is limited in the future; bioenergy is also likely to be in demand in other end-use sectors such as aviation.

Box 11. General challenges facing the use of hydrogen for heat in industry

Pure hydrogen cannot simply replace coal or natural gas in many industry sectors, owing to the diversity and specific nature of the energy conversion devices (such as kilns, furnaces, boilers, reactors) that those sectors use. In the cement industry, for example, several factors would require changes to equipment and practices, adding to the total costs of conversion:

Hydrogen has a high combustion velocity relative to carbon-containing fuels, and a nonluminous flame, which makes it difficult to monitor optically. These challenges can be partially overcome by using hydrogen/ammonia mixes, as ammonia burns at a much

lower velocity and with a visible flame, also helping to reduce (nitrogen oxide) NOx emissions (Li et al., 2014).

Hydrogen flames achieve relatively low radiation heat transfer compared to other fuels, requiring other (carbon-free) media (such as clinker dust) to be introduced into the fuel stream (Hoenig, Hoppe and Emberger, 2007).

Current burners may need to be redesigned to deal with any new media being introduced (for example, to cope with the abrasive properties of clinker dust).

Hydrogen causes corrosion and brittleness when it comes into contact with some metals, requiring new coatings and other protective measures.

Intermittent sources of hydrogen could present difficulties for high-temperature heat users operating “on-demand” processes, and potentially require costly on-site storage, although other high-temperature heat users could be remunerated for flexibility and the enabling of ancillary grid services.

Handling and storing hydrogen on site presents additional difficulties compared with traditional fuels, due to its explosive properties. While many industrial operators are experienced at handling hazardous substances, it may be safer to store hydrogen in other forms, such as ammonia (Hoenig, Hoppe and Emberger, 2007).

Sources: Hoenig, Hoppe and Emberger (2007), “Carbon capture technology – options and potentials for the cement industry”; Li et al. (2014), “Study on using hydrogen and ammonia as fuels: Combustion characteristics and NOx formation”, International Journal of Energy Research.