One of Europe’s leading experts in emerging low-carbon energy technologies has given Recharge an exclusive insight into some of the most promising low-carbon technology developments of the coming years.

As chairman of the European Energy Research Alliance (EERA) — an association of more than 250 public research centres and universities working on low-carbon energy research, made up of about 50,000 researchers across 30 European countries — Nils Røkke has an unmatched perspective on which under-development technologies could have a significant impact on the energy transition.

EERA plays an important role in the EU’s goal of net-zero emissions by 2050 as it oversees the European Commission’s Strategic Energy Technology Plan, which aims to accelerate the development and deployment of low-carbon technologies to help the bloc meet its goal. The plan largely consists of 17 research “Joint Programmes” that each cover a different part of the low-carbon energy sector, including wind power, PV, energy storage, hydrogen and carbon capture and storage.

In a wide-ranging interview with Recharge, Røkke discusses many of the technological breakthroughs on the horizon that could help the EU reach its climate goals.

Seven technologies stood out:

1) Modular floating wind

Floating wind arrays could be cheaper than onshore wind farms within ten years, Røkke tells Recharge.

“Innovations are going to come in floating wind systems, which is still in its infancy,” says the Norwegian. “And I think in the future that this will be cheaper than onshore wind because they can be made modular and you don't need to have tailor-made turbines for every application. You will be able to produce them in their thousands. Modularised design — and getting an efficient production chain for this — I think that’s going to be the next big thing.”

2) Broad-spectrum solar

The cost of solar energy may have by fallen by almost 90% over the past decade, according to analyst Lazard, but the efficiency of solar panels remains remarkably poor, capturing only about 20% of the energy thrown at them by the Sun. There is still plenty of room for improvement.

Panels that can capture more of the light spectrum are “going to be key”, Røkke says, giving the example of standard crystalline polysilicon panels that are better at absorbing energy from the red part of the visible light spectrum than the green part, while they cannot capture more than half of the infrared light that makes up 53% of sunlight’s energy.

“Systems which can utilize the largest spectrum of light give much higher efficiency. So I think there is really scope in that area,” he says.

This could be achieved by using different materials to silicon, such as perovskite, or by adding lenses that concentrate light or by fitting filters that can capture a wider spectrum of light.

“There’s quite significant work ongoing on this,” Røkke says.

3) New battery chemistries

Lithium-ion (Li-ion) technology has cornered the battery market, accounting for more than 90% of all utility-scale and electric-vehicle (EV) batteries, and seeing cost reductions of 85% between 2010 and 2018, according to Bloomberg NEF.

But the technology is far from ideal. It struggles to hold a full charge for longer than four hours, its storage capacity noticeably reduces over time and it is prone to burst into flames during a short circuit.

A sub-group within EERA’s Energy Storage Joint Programme is focusing on what it calls “post Li-ion batteries”, including new chemistries such as zinc-air and lithium-sulphur.

“Advanced batteries that have much higher energy densities is a big area, but there are still unsolved issues with these,” says Røkke.

“The amount of research which has gone into batteries the last 50 years is just so small compared to, say, improving piston engines. If you direct more research towards these kinds of [advanced battery] technologies, you will have minor miracles, I'm sure about that.”

4) Clean hydrogen — blue, then green

In the past two years, hydrogen has emerged as a key technology of the energy transition, as it is a versatile zero-carbon fuel able to be used for long-term energy storage, heating buildings, long-distance transport and high-temperature heat in heavy industry.

About 95% of the hydrogen used industrially today is derived from natural gas or coal, resulting in the emissions of nine to 12 tonnes of CO2 for every tonne of H2 produced.

But there are three methods of producing hydrogen without the emissions — by using renewable energy to split water molecules into H2 and oxygen inside an electrolyser; by capturing and storing the CO2 from steam methane reforming and coal gasification; and a process known as pyrolysis, where natural gas is heated in the absence of oxygen, giving a by-product of solid carbon, rather than CO2.

If clean hydrogen is to become a key part of the energy transition, it will need to be produced in huge quantities at low prices with virtually zero emissions. But electrolysis, carbon capture and storage (CCS) and pyrolysis are still expensive processes that have yet to be proven at a commercial scale.

Røkke says that “hydrogen is going to be very important for Europe”, and believes that so-called “blue hydrogen” produced with CCS will be cheaper and easier to scale up than “green hydrogen” derived via electrolysis.

He dismisses the oft-used argument that green hydrogen could be produced cheaply during times when the amount of wind and solar power on the grid exceeds demand and the wholesale price falls to zero or below.

“You could have [green] hydrogen being produced from an almost zero-cost electricity when there are particular wind conditions. But you cannot rely on that for the large volumes you need,” Røkke says. He explains that due to the high capital cost of electrolysers, the levelised cost of green hydrogen gets more expensive when the amount of time it is running is reduced.

“I also don’t subscribe to those who think we'll have shedloads of free electricity in the future. Who would develop those [low-revenue] projects?”

Røkke also points out that even though CCS technology can currently only capture up to 95% of emissions from steam methane reformation, it would still be more environmentally friendly than H2 produced from grid-connected electrolysers, due to the carbon footprint of Europe’s electricity mix (only 30% of the continent’s power currently comes from renewable energy).

Of course, it would be different if, say, an off-grid offshore wind farm delivered all its power to electrolysers.

“Blue hydrogen is cheaper than [H2 derived from] electrolysers… but I think that will change because we know the end game, it has to be hydrogen from electrolysers. But I don't think you can do the transition from where we are now — where 95% of hydrogen is produced from fossil [fuel] to 100% [from] renewables without having access to the hydrogen from natural gas with CCS. [You need to] get the hydrogen economy up and running, And that's going to be very, very important for not only Europe, but for the rest of the world to decarbonise.”

He adds that clean hydrogen should replace methane in the European gas grid, ammonia derived from clean H2 could be used to power ships, while carbon-neutral synthetic aviation fuels could also be produced from H2.

5) Carbon-negative technologies

The pyrolysis process could also be used to remove carbon dioxide from the atmosphere, not just methane, Røkke points out.

Biomass such as wood, grass or other organic material, captures CO2 as it grows. If that biomass is then used to generate heat and electricity inside pyrolysis ovens, it converts that CO2 into solid carbon — which can be scattered in soil to improve water retention or easily stored at brownfield sites such as disused coal mines.

“I first read about this about 10 years ago in an Australian newspaper and I thought the Australians had gone completely mad,” says Røkke. Now it makes sense given that we need these kind of net removal technologies.

“It's clear that we're not going to reach our [Paris Agreement] targets [globally] and we're going to need these kinds of technologies that can remove CO2 from the atmosphere.”

He agrees that direct-air capture technology, which scrubs CO2 from the air using carbon sponges or CO2-absorbing liquids, is inefficient and power-hungry, but believes that such carbon-negative technologies may be needed in the long-term — particularly as industries such as agriculture and long-distance aviation may be too hard to decarbonise by 2050.

“We don't spend enough [money on] research on this,” he tells Recharge. “It's something which we have maintained to the [European] Commission that Europe does not have a research innovation agenda for these carbon-negative technologies, which we are bound to need.”

Investment is needed now to ensure that commercial solutions are available in the coming decades, he adds.

6) Ocean biomass

While biomass can be used for renewable carbon-negative energy — as planned at the giant Drax power plant in northern England — it will always be a limited resource due to land-use constraints.

“If you look to the amount of biomass you need for the world, it’s just daunting. Looking to biomass CCS, as one example, for 10GW a year by 2050, we would need the same area as all the forests in Russia. And by the way, you need to produce food as well.“We have reports saying that we really cannot utilise nature any more than we do, [if we want] to have ecosystems that are sustainable. So that's going to be a huge constraint.

“But I see hope in one thing and that’s the ocean space, which to a great degree we haven't explored in terms of solutions to climate change and the biodiversity issue. If you have problems sourcing enough biomass for food and for energy… what can we harvest from the oceans in a sustainable way?”

Here, Røkke is mainly talking about seaweed — also known as macroalgae.

“The growth rate of these macroalgae is just amazing and can grow two and a half centimetres per day in the best season. It also takes out the CO2 from the seawater and if you're able to harvest this and to maintain the carbon and isolate it from re-entering the atmosphere or, or re-entering the ocean, you have a solution. And this is a solution that is heavily under-researched.”

Concepts for large-scale seaweed harvesting are being developed at the Norwegian research organisation Sintef, where Røkke is executive vice-president of sustainability.

“We have some concepts we are working on, how to produce seaweeds, maybe have two or three harvests during the year. There's a huge spinning machine, which has infused cords which go out to a huge wheel and then [the seaweed] is left to grow for a certain amount of time and then harvested in a mechanical manner.”

But before seaweed can be grown and harvested at a large scale, research would need to be undertaken to see how that would affect underwater ecosystems, he says.

7) 5G-based smart grids

The fifth generation of wireless mobile phone technology, known as 5G, offers super-fast broadband communication at speeds of up to 2.5GB per second, allowing remote locations to communicate vast amounts of data quickly.

This technology could enable hugely complex smart grids able connect billions of data points across huge distances — from huge wind turbines to rooftop solar panels, and from electric vehicle batteries to internet-of-things dishwashers working on a demand-response basis.

Processing all this big data, alongside artificial-intelligence-led local weather predictions, would ensure that every watt of renewable energy can be utilised as cheaply and efficiently as possible at any given moment, according to rapidly changing power prices.

“We are not making enough effort to prepare the grid for a new day tomorrow, so to speak,” says Røkke. “And how we can use the components in the grid to be active players in the quest to have net zero [emissions] all the time — how you can use your hot-water boiler at home to store energy in your system; how we can utilise the electric car… and the internet of things and big data, and how you can manage these systems.

“When we go to 5G… [we will have] full control of the electricity grid and the data grid, with the connectivity [between supply and demand] really melting together.”

Change can only be driven by policy

Yet despite all the promise of these upcoming technologies, net-zero emissions will not be reached without new regulations and laws “to guide the energy transition”, explains Røkke. These should include emissions performance standards (EPSs) and laws that set a date for phasing out certain technologies, he explains, pointing to how the car industry has reacted to regulations on sulphur dioxide and nitrogen oxide emissions.

“[Initially] people said they’re going to kill the industry, but it didn’t, and now these kinds of processes are all well-managed and controlled in terms of emissions. And we’ve seen that EPSs are not going to ruin our industry. It’s really showed that you need to have these regulations in place to make things happen.

“In Norway, we have a parliamentary agreement that all new cars sold by 2025 have to be zero-emission. That is really, really driving consumer behaviour.”

Without such rules and regulations, no-one will invest in technologies such as clean hydrogen, CCS and carbon-negative solutions, he declares.