The building blocks of decarbonisation: Power-to-X and sector coupling
7 min read
24 Aug 2021
7 min read
24 Aug 2021
Power-to-X will be one of the key solutions to accelerate the energy transition, especially when paired with sector coupling.
Just a few years ago, creating carbon-neutral, renewable fuels that capture CO₂ in the manufacturing process sounded like science fiction. Now this technology is reality.
Power-to-X – also known as P2X – captures CO₂ from the air and combines it with green hydrogen to create different carbon-neutral future fuels. When Power-to-X is paired with sector coupling, the path is paved for the decarbonisation of multiple industries.
“Sector coupling is a hot topic around the globe. In short, it means interconnecting the power producing sector with energy consuming sectors such as transport and industry – and moving all these sectors away from fossil fuels to clean electricity,” explains Antti Alahäivälä, General Manager, Business Development, at Wärtsilä Energy.
Affordable, renewable energy like wind and solar power are central drivers of sector coupling and P2X.
“The cost of producing clean energy has dropped considerably. In Finland, wind power is now undeniably the cheapest way to produce electricity. This makes P2X technology, such as Power-to-Gas, an economically viable solution for energy producers,” Alahäivälä points out.
“The development of new technologies that extend the feasibility of electrical power applications are naturally also central to energy transition plans, as decarbonisation and electrification go hand-in-hand,” Alahäivälä adds.
A pioneering project combines sector coupling and Power-to-X
Vantaa Energy – one of Finland’s largest urban energy companies – intends to be fully fossil free by 2026.
“The energy sector plays a significant role in mitigating climate change. We want to be pioneers in contributing to a speedy transition to clean energy production,” says Jukka Toivonen, Vantaa Energy’s CEO.
Vantaa Energy will be phasing out coal already in 2022, thanks to the biopower plant that it took into use in 2019, and the expansion of its innovative Waste-to-Power plant that will be finished in 2022. The next step is to replace the fossil gas currently used in its energy production with a carbon-neutral alternative. Vantaa Energy aspires to be a carbon-neutral energy company by 2030.
“To achieve this goal in a cost-effective way, we needed a top technical expert to partner with,” Toivonen says.
“Wärtsilä’s expertise in Power-to-X technology impressed us, and in spring 2020 we signed a concept development agreement for exploring the feasibility of building a plant that produces carbon-neutral synthetic methane,” explains Toivonen.
Carbon-neutral gas for heating and transport
Together, Wärtsilä and Vantaa Energy came up with a plan that demonstrates sector coupling of heat, electricity, and transportation, and provides Vantaa Energy completely new business opportunities.
“Our modelling showed that building a Power-to-Gas plant next to Vantaa Energy’s existing Waste-to-Power plant brings many synergy benefits,” Alahäivälä says.
“The infrastructure is already in place, and the new plant can utilise raw materials obtained directly from Vantaa Energy’s current operations: clean electricity from wind power, water, and carbon dioxide. The produced fossil free synthetic methane can then be utilised both in district heating and to fuel trucks carrying waste to Vantaa Energy’s Waste-to-Power plant,” Alahäivälä adds.
Vantaa Energy currently uses fossil gas in district heating during the winter.
“As you know, we can have extremely cold days during the winter, even in southern Finland. When the thermometer drops drastically, we need a lot of power, fast. Gas is the most effective source of power at times like these,” Toivonen says.
Approximately 10% of the synthetic methane produced in the new plant would be used to replace fossil gas now used in district heating – making Vantaa Energy’s production 100% fossil free. The remaining 90% of the carbon-neutral methane would be used in transportation, for example to fuel 200 trucks that collect waste for Vantaa Energy’s Waste-to-Power plant.
“The project is a prime example of sector coupling benefits. We would not only be eliminating the use of fossils in our energy production, but also reducing emissions from transportation. We are highly enthusiastic about this project. Climate change won’t wait, so neither can we,” Toivonen reminds.
The world’s largest thermal energy storage
To produce synthetic methane in a Power-to-Gas plant, renewable electricity is first used to produce green hydrogen from water via electrolysis. Then, renewable electricity is used to capture carbon dioxide, which is combined with green hydrogen to create fossil free, synthetic gas. The only “wastes” this process creates are oxygen and heat.
For Vantaa Energy, the waste heat created by the planned Power-to-Gas plant is an opportunity.
“We are in the heat business, and we have no plans of letting heat go to waste,” Toivonen confirms.
In addition to the state-of-the-art Power-to-Gas plant, Vantaa Energy plans on building a seasonal thermal energy storage facility underground to store waste heat produced in the P2G plant, as well as solar energy, geothermal energy, and recovered waste heat from real estates and industry, which is available especially during summer time.
The thermal storage will inventively use the surrounding groundwater to keep the storage water pressurised, which will allow storing the heat in water up to 140 degrees in temperature. Once finished, it will be the world’s largest thermal energy storage facility, with a capacity of about one million cubic metres and 100-gigawatt storage – the equivalent of the annual heating needs of a medium-sized Finnish city.
“The thermal energy storage is integral to achieving our goal of being fossil free by 2026. It is also essential to our Power-to-Gas plant idea. Storing the waste heat and utilising it during the winter makes the endeavour economically viable,” Toivonen says.
“And as a sidenote, we won’t let the oxygen produced in the process go to waste either. It too can be sold forward,” he adds.
Leading the path towards 100% renewable energy
One year into the project, Vantaa Energy was confident that the plan was feasible and moved on to the next step: planning toward an investment decision. Wärtsilä will also lead the pre-engineering phase of this pioneering project.
The current plan is to have the plant commissioned in 2025. Once finished, it will be the largest in Finland – and the first to produce carbon-neutral, synthetic methane on a commercial scale with a fuel capacity of 10 MW.
“Wärtsilä’s technical expertise combined with our energy production competence was a winning combination in the concept planning. We are investing a great deal in this change. We already are a trailblazer in energy transition, and we have every intention of staying on this path,” says Toivonen.
“Our collaboration is a win-win for both parties,” Alahäivälä agrees.
“The project has allowed us to further develop our Power-to-X technology and integration competences to meet future market needs. The plan we came up with together enables Vantaa Energy to move forward to fossil free energy production by 2026, which will be an extremely impressive achievement,” Alahäivälä adds.
Alahäivälä and Toivonen both affirm that the energy sector needs to accelerate the move towards decarbonisation. The time to act is now.
“At Wärtsilä, we are dedicated to lead the path towards 100% renewable energy with our strong knowledge base. Our collaboration with Vantaa Energy demonstrates our vision of working towards a renewable energy future, in which future fuels and sector coupling play a vital role,” says Alahäivälä.