Summary
Highlights
More than 50% of the world's population lives in urban areas, a figure projected to rise to nearly 70% by 2050. This growth places immense demand on resources like water, food, and energy, posing significant challenges in a world grappling with climate change. Revolutionizing energy supply systems for a global transition to green energy is crucial, and cities are taking a leading role due to the limited time left to save the planet.
Lancaster, California, with 175,000 residents, embarked on a journey in 2009 to become the first carbon-neutral community in the US. This transformation involved a technological overhaul and a shift in mentality, streamlining permit processes for solar installations from six months to 45 minutes. Mayor Rex Parris began by installing photovoltaic panels on municipal buildings, generating significant savings that were reinvested into expanding solar to private residences and new constructions. This led to an alternative energy network, using excess electricity to produce hydrogen for public transport, attracting new green companies, and reducing unemployment from 17% to 6% by 2023. Lancaster became a highly profitable, self-sufficient green energy powerhouse, proving that alternative energy is hugely profitable.
In Wunsiedel, Germany, Marco Krasser transformed the regional energy supply by focusing on renewable energies and sustainable raw materials. The town developed a circular system linking its timber industry with the local energy system, reusing energy multiple times and harnessing excess energy from wood waste and waste heat. Surplus solar and wind energy are used to press forestry waste into wood pellets, which can generate heat or electricity. This cascaded system integrates solar, wind, battery storage, and combined heat and power, creating local circular energy economies scalable to satisfy electricity and heat demands, including for mobility.
Copenhagen's Nordhavn district serves as the 'EnergyLab' project, a living laboratory for innovative and efficient energy cycles. The project tests real-life solutions and business models for sector coupling, aiming to utilize available energy smartly. Buildings are well-insulated, retaining heat and saving money, especially during peak hours. Commercial businesses contribute waste heat to the district heating system, optimizing energy use by converting surplus electricity from renewables into heat. This ingenious cycle ensures energy is used multiple times, benefiting the entire neighborhood and demonstrating how modern circular economies save energy and increase efficiency.
Oslo, Norway, aims to achieve zero CO2 emissions by 2030, presenting it as an opportunity rather than a restriction. New public buildings are constructed with solar panels, producing more energy than consumed, which can be shared with nearby structures. Oslo is a leader in e-mobility and has made significant progress in carbon-neutral construction, focusing on reducing consumption, waste, and promoting reuse and recycling. Hege Schøyen Dillner, a board member of a large construction company, successfully pushed for alignment with the Paris Agreement goals, emphasizing the need for circular construction practices and building with less for longer. Sonja Horn's real estate company reuses elements from old buildings in new constructions, with pilot projects attracting startups and tenants due to their sustainable concepts. The 'Powerhouse' in Trondheim, an office building with 3,000 square meters of solar panels, produces double the electricity it consumes, supplying a local micro-grid and supporting zero-emission construction sites.
Norway, rich in hydropower and with a large oil and gas sector, is confident in its transition to a carbon-neutral economy, seeing more opportunities than risks. The expertise from the petroleum industry is being leveraged for new areas like floating wind and hydrogen-powered ships. The North Sea is becoming a crucial area for large green power grids and reliable energy. The longest subsea link, connecting Norway's hydroelectric power to England's offshore wind, exemplifies this. Blyth, a former mining town, is experiencing an economic upswing from this energy transition, attracting investments and creating local jobs. The North Sea grid, under construction since 2020, aims for energy security through direct coast-to-coast lines and will feature energy islands off Denmark’s coast capable of powering millions of households.
Hydrogen holds immense potential as a storage medium for green electricity. At Siemens Energy, a simulator demonstrates its role in meeting industrial energy demands. Hydrogen, produced through electrolysis using renewable electricity, can be easily integrated into existing economic cycles. Siemens Energy's modular electrolyzer systems can scale from small industrial sites to gigawatt-scale production. Hydrogen is key for energy efficiency, electrification, and decarbonization where electrification is insufficient. It can also be refined with CO2 into e-fuels, offering a sustainable alternative to fossil fuels for heavy industry. Professor Bernd Rech at the Helmholtz Centre researches energy conversion and storage, emphasizing the potential of converting sunlight into electricity and then using electrolysis to split water into hydrogen and oxygen to create synthetic fuels by binding hydrogen with atmospheric CO2.
Sonya Calnan's research at the Helmholtz Centre, in collaboration with the University of Cape Town, aims to produce cleaner cooking fuels from solar energy and hydrogen for areas without electricity. This sustainable alternative replaces wood and fossil fuels, saving time and improving quality of life. In Singapore, Professor Madhavi Srinivasan at Nanyang Technological University focuses on recycling lithium-ion batteries and e-waste. She devises methods to extract valuable elements like lithium, nickel, cobalt, and manganese using orange peels or bacterial cultures, achieving 99% recovery. Her research aims to create a closed-loop system, minimizing the need for new materials, and has resulted in numerous patents and recognitions.
Tejs Vegge at the Technical University of Denmark organizes research into green technologies, creating a database of promising results and sharing recommendations globally. He stresses the need to reinvent material discovery for the green transition, integrating all parts of the production cycle. Professor Harry Atwater at Caltech researches solar energy conversion, including artificial photosynthesis, which mimics nature's process of converting sunlight, water, and CO2 into fuels. Researchers are developing 'artificial leaves' using semiconductor structures to turn water into hydrogen and oxygen with high efficiency (currently 19.3%). If scalable, this could make hydrogen cheaper than any other fuel. The Technical University of Ilmenau works with III-V semiconductors to create highly performant, low-cost artificial leaves, emphasizing the significance of semiconductors as the basis for advanced technologies.
While not every part of these new energy systems is fully ready, the key to a sustainable future lies in rolling out these innovations to communities and industries faster. Learning in silos is no longer an option due to the urgency of the climate crisis. The aspiration for a circular system propels global efforts to make prosperity more sustainable. Researchers have made significant technological advancements, but successfully transforming our energy supply depends on integrating these solutions into large sectors of society before it's too late.