Take CO2 from the Air, combine it with Hydrogen extracted from Water ( using renewable energy) and you can make various fuels like ethanol, diesel, kerosene, petrol and aviation fuel.  Fuels made like this can notionally get to Net Zero, although are more likely to generate  90% fewer emissions than the conventional hydrocarbons. Still pretty good, and another benefit is they work without needing expensive modifications to the car or plane. https://carbonengineering.com/news-updates/ce-lanzatech-jet-fuel/

Sewage sludge, which is fully of organics and nutrients, is often used for fertiliser. But sewage sludge can contain pathogens, microplastics, heavy metals, PFAS and chemicals. Pyrolysis (high heat/no oxygen) is a process often used to render biomass (sludge) safe. RMIT have developed a novel pyrolysis reactor which optimises heat/mass transfer processes. This translates directly into savings in capital and operating costs. It also delivers a 30% reduction in CO2 emissions, while shrinking the tech to make it highly mobile. Trials of the new reactor in real-world applications are underway in Victoria, Australia.

Vessels moored off-shore typically rely on diesel for fuel. For vessels like feeding barges, used in aquaculture, frequent re-fuelling also risks spills and other disruptions to their operations. But what if you could harness the energy from the waves for an endless, reliable, clean source of energy by using a submerged buoy to convert the motion into electricity energy? Over the next two year Carnegie Clean Energy will test its adapted CATO system for just these sorts of applications. If successful, decarbonising offshore aquaculture would be just the beginning.

Phase Change Materials (PCM) are substances which absorb or release heat when they go through a change in their physical state, eg. water changing from ice to liquid. You can tap this energy. PCM batteries can operate just like an electric battery, but can be 2 - 3 times cheaper. A South Australian company is developing PCM battery versatility even further by partnering the battery with heat pumps, renewable energy to power the battery processes, advanced weather and system usage forecasting, as well as energy pricing data to maximise energy efficiency and financial return. https://www.youtube.com/watch?v=OMr0wgb3r4E&t=4686s

One of the common ways to capture wave energy, is via a point-absorber which harvests energy from the up and down movement of waves. Australia's RMIT has designed a point-absorber with a novel counter-rotating dual turbine. The design can apparently deliver twice the efficiency of other currently available point-absorber wave technologies. https://www.rmit.edu.au/news/all-news/2021/aug/wave-energy-technology