The excitement over green hydrogen has grown intensely over the years across the globe. The concern is, will it live up to the hype? In the early 2000s, it was thought that hydrogen would dominate the clean automobile market.

However, the 'hydrogen highway' never materialised.

Some of the reasons being that hydrogen power needed new infrastructure.

Battery technology was already well advanced, but hydrogen was not. And, on top of that, the hydrogen process was wasteful and very inefficient as it involves turning electricity into gas, compressing it for storage and converting it back into electricity. Last year, a twostep shuffle was dismissed by Tesla car chief Elon Musk as 'staggeringly dumb', 'fool cells'.

The market will ultimately be driven by cost among the options. We are dreaming about changing Nepal's economy by exporting hydrogen.

Nepal has poor wind resources, moderate solar and hydro resources, and a high population density.

In comparison, western China, the Middle-East, Australia, North and East Africa, southwest USA, the west coast of South America and other places have low population densities, and vastly larger high quality wind and solar resources, access to ports, and can produce solar and wind electricity at two-thirds the price in Nepal.

The notion that hydrogen storage is ready to play its part to store variable solar and wind energy is contradicted by looking at what is happening in countries like Australia.

Australia already generates 25 per cent of its electricity from wind and solar and is tracking towards 50 per cent in 2025.

Australian solar and wind energy is being produced for around US$30 per MWh, which is much cheaper than Nepal's hydro or solar, because Australia has better sun, much better wind and vastly more land per person. It is physically isolated from other countries and cannot trade excess electricity with other countries. In response, Australia is investing in pumped hydro and battery storage, transmission and demand management.

There is negligible hydrogen storage or hydrogen-powered vehicles.

Hydrogen can be sustainably produced using renewable electricity to electrolyse water. However, hydrogen is difficult to store. Options include liquefaction at very low temperatures and conversion to a more tractable chemical, such as ammonia. Conversion of hydrogen energy to a useful form such as electricity or motive power is a low efficiency process.

Typically, the round-trip efficiency of electricity-hydrogen-electricity is 20-30 per cent compared with 80-90 per cent for batteries or pumped hydro. Basic physical constraints mean that hydrogen storage can never have high round trip efficiency. The cost and difficulty of transporting hydrogen is paramount and beyond the limit of what hydrogen proponents could think of now in Nepal.

Some countries are talking about renewable hydrogen.

However, there is vastly more money being invested in solar, wind, electric vehicles and batteries than into hydrogen.

The hydrogen hype train is going full speed, making an alliance in those countries, convincing them green hydrogen is the 'clean fuel' of the future, and gaining it political, financial and regulatory support. However, even today less than 0.1 percent of global hydrogen produced is from renewable electricity. Almost all hydrogen production is because hydrogen atoms are needed to make some chemicals.

At the global level, some announcements on blending hydrogen with natural gas may have been a valid reason to extend fossil-fuel power plants to operate for years even beyond when they should have been shut down. Some plans and intentions of burning hydrogen as a clean fuel are also popping up here and there, including in Nepal.

Nepal Oil Corporation seems to be supporting hydrogen fuel and says that it plans to generate green hydrogen from hydropower and store it for export, burn it to replace fossil fuels and use it for fuel cells in the transport sector. The company is grasping vainly to keep selling something that looks a bit like oil and gas.

However, the future is with electricity.

Hydrogen production in Nepal is unlikely to be significant.

Hydrogen or hydrogen-rich chemicals, such as ammonia, could be used to store and transport energy in Nepal.

However, this is unlikely to occur because the efficiency is very low compared to batteries, pumped hydro and thermal storage, which unavoidably translates to high costs.

It is difficult to see how hydrogen could compete with batteries for shortterm storage because batteries react in milliseconds to grid disturbances and have 90 per cent round trip efficiency. It is difficult to see how hydrogen could compete with pumped hydro storage for overnight and longer storage because pumped hydro storage has 80 per cent round trip efficiency and is mature and already low cost.

A sad reality that was overlooked is besides cost and difficulty in storage, burning hydrogen generates emissions that are equally harmful. A few studies on hydrogen enriched natural gas combustion shows significantly high levels of nitrogen oxide (NOX), six times that of methane. Long-term exposure to NOx increases the risk of respiratory problems and heightens the sensitivity to allergens. It also acts as a catalyst to the formation of fine particles (PM2.5) and ground level ozone, both associated with adverse health effects and climate change.

Electric vehicles are being produced at multi-million-scale per year. In contrast hydrogen-powered vehicles have a negligible market share. This means electric vehicles are likely to dominate land transport in the future, which eliminates the automotive market for hydrogen.

For example, the Tesla electric semi with a 35-ton load has an expected range of up to 800 km (similar to the width of Nepal).

Lohani is a lead professor of Renewable and Sustainable Energy Laboratory (RSEL), Department of Mechanical Engineering, Kathmandu University

A version of this article appears in the print on August 13 2021, of The Himalayan Times.