Mail & Guardian

Hydrogen economy vital part of sustainabl­e energy future

- Dr Henrietta Langmi

Access to clean, affordable, adequate and reliable energy is essential for economic growth, which significan­tly contribute­s to poverty reduction, societal wellbeing and prosperity. We should build our future on sustainabl­e energy sources that will continue to supply future generation­s’ needs.

I believe that the hydrogen economy, a system that uses hydrogen to transmit energy from primary fuel sources to users, is a vital part of a sustainabl­e energy future. Hydrogen is clean and has a high mass energy density. It is the most abundant element in the universe and can be produced from a variety of sources. Hydrogen can supply energy for use in buildings and transporta­tion, and can also contribute to decarbonis­ing many industrial sectors.

Hydrogen offers an important link between physical and chemical energy. As part of a sustainabl­e energy future, physical energy from renewable resources, such as radiation from the sun and kinetic energy from wind and waves, can be converted into electricit­y and used directly for various applicatio­ns. The sun doesn’t shine 24 hours a day, and the wind doesn’t blow every day everywhere, so excess energy needs to be stored until it is needed. Electricit­y can be stored as chemical energy in hydrogen, which is generated using a device called an electrolys­er. The chemical energy in hydrogen is later converted back to electricit­y in an efficient manner using a fuel cell device, generating only water as a by-product. Hydrogen storage, therefore, enables the shifting of renewables­based electricit­y between periods of excess and shortage. Apart from power generation for the grid, hydrogen can provide a solution for the electrific­ation of remote communitie­s where grid connection is uneconomic­al.

As part of a sustainabl­e energy future — besides power generation for use in buildings — hydrogen can be used in other commercial markets, e.g. as a clean transporta­tion fuel. Vehicles powered by hydrogen combine hydrogen and oxygen in a fuel cell device to generate electricit­y, unlike convention­al vehicles powered by petrol or diesel. These hydrogen-powered fuel cell electric vehicles are quiet, efficient and clean, emitting only water vapour. In addition, when compared to battery-powered electric vehicles, they provide a longer range between each refuelling, and a shorter refuelling time. Furthermor­e, unlike biofuels, the use of hydrogen as a transport fuel eliminates land-use impact such as decreased access to food and deforestat­ion. Major car manufactur­ers including Toyota, Hyundai and Honda have already launched their first mass-produced hydrogen-powered fuel cell passenger vehicles. The Toyota Mirai (Mirai is Japanese for “future”), for example, is already sold commercial­ly today in several parts of the world.

Hydrogen from clean energy sources can be used to enrich other fuel sources or converted to valuable chemicals used for energy or non-energy related applicatio­ns, contributi­ng to the decarbonis­ation of the economy. For instance, in Germany, there are power-togas plants that convert surplus electricit­y into hydrogen. The hydrogen is then injected into natural gas networks in small concentrat­ions, facilitati­ng the integratio­n of renewables. Furthermor­e, hydrogen can be used as a feedstock for producing synthetic natural gas by combining hydrogen with carbon dioxide from waste sources. This renewable natural gas can substitute convention­al natural gas for use in various applicatio­ns. The first industrysc­ale renewable synthetic natural gas plant was built by ETOGAS for Audi AG in Germany.

Hydrogen is already widely used today as an industrial feedstock, for example, in the production of ammonia and synthetic fuels, in the refining of crude oil, and in the food and chemical industries. For a sustainabl­e energy future, the use of hydrogen from clean energy sources will contribute towards decarbonis­ing several industrial sectors.

I believe that the hydrogen economy has the potential to play a pivotal role in future sustainabl­e energy systems. Hydrogen is an essential integrator that can solve the intermitte­ncy problem associated with renewable energy, creating electricit­y for the grid and for remote, off-grid communitie­s. It can also be used as transporta­tion fuel in fuel-cell-powered electric vehicles. Given its versatilit­y, hydrogen from clean energy sources can be used as feedstock in many industrial processes to make valuable products. Hydrogen can contribute in many ways across the economy and offers great promise to be at the core of the energy revolution towards a more sustainabl­e energy future.

 ??  ?? Dr Henrietta Langmi manages the Hydrogen South Africa Infrastruc­ture Centre of Competence at the CSIR, an entity of the department of science and technology. Photo supplied
Dr Henrietta Langmi manages the Hydrogen South Africa Infrastruc­ture Centre of Competence at the CSIR, an entity of the department of science and technology. Photo supplied

Newspapers in English

Newspapers from South Africa