Renewable innovation

Technological innovation can be chaotic and even disastrous at times, as with early attempts at flight.  In the renewable energy field there have been failures, including with some early wave energy systems.  But in general, we have learnt from them, and, for the leading technologies, wind and solar, we have now moved on to steady progress. Some new wind ideas have emerged, most obviously floating offshore systems, but the basic horizontal propellor-type technology dominates so far, with the units getting larger and taller. Nevertheless,  Darius ‘eggbeater’ type vertical axis systems are being looked at again. So too are double-unit vertical axis contra-rotating systems. However, although very varied in design, micro wind designs have generally not been favoured of late, given their lower efficiency, but some novel small wind ideas have still emerged and may yet have niche markets.  

Some new PV cell materials are emerging, beyond just crystalline and thin film systems, some with higher efficiencies, and floating PV arrays offer new design and siting options, but the basic PV concept remains the same, although some Concentrated Solar thermal designs may compete in some settings, and there is also continued interest in novel hybrid PV thermal systems. Much more speculatively, there is some interests in the old arguable very oddball high-tech idea of putting massive PV arrays in orbit in deep space, with power beamed back to earth via microwave links.

Wild, potentially very high cost, ideas like that apart, solar and wind technology development patterns seem to have mostly converged on fairly standard designs and concepts, the mature phase of innovation and market diffusion, whereas wave and tidal are still mostly in the early radical innovative phase, with new ideas still emerging. That said, some wave projects seem to be based on earlier concepts, as with the Danish Weptos duck-type wave system, the Cypriot raft-type waveline device  and a new Australian Oscillating Water Column system. However, although innovations continue to emerge, there have been no big wave energy breakthroughs as yet: in general, as I noted some while back, wave energy has proved to be harder to develop than tidal technology- it is easier to tap energy from regular undersea tidal flows than from chaotic surface wave action. 

The tidal field is certainly developing quite fast, in the UK especially, with wind turbine-like tidal current turbines doing well, including the Atlantis seabed-fixed units being tested in the Pentland Firth and Orbitals 2MW floating system off Orkney. Tidal lagoon systems are also still being considered. Their economics though is not brilliant, with, for example, a CfD of £100/MWh considered as being needed for the proposed 2.5 GW West Somerset scheme. Moreover, that is a rather speculative estimate and no tidal lagoon project has yet got funding. Instead, the 4 tidal turbine projects that won contracts in the recent 4th CfD round all had a higher strike price- £178.54/ MWh.  Still much more expensive than wind or solar, but perhaps indicating the beginning of a path to lower costs, as had happened with offshore wind and PV. Meanwhile, although there have been many studies of barrage ideas for the Severn Estuary over the years, and some continued interest, large barrages are still seen as a potentially very invasive, as well as expensive, long shot.

Biomass based energy systems continue to attract attention, although there are significant issues in relation to land use and environmental impacts. So biofuel production for vehicle use has significant limits and risks, and large scale biomass burning plants for power production using forest derived products can also be problematic- and strongly opposed. However, some see biogas production via Anaerobic digestion of wastes as a reasonable option, since it doesn’t use new-land, and there are many other ideas emerging for energy supply in the bioenergy field, including the use of algae and a wide range of green syngas and synfuel conversion options, some of them quite exotic. 

The big advantage of biomass is that it offers storable energy, able to supply power on demand, an option also offered by geothermal and hydro power. Geothermal plants, run on Combined Heat and Power mode, can be cost competitive in some locations and new plasma drilling technologies may reduce the cost of drilling deep geothermal wells. Hydro is the largest renewable source of power so far, with pump storage offering balancing options, and small run of the river projects can be useful locally. However, large hydro projects, with large reservoirs, can have significant environmental impacts and the impact of climate change on rain water supplies may make them less reliable as a power source in future. Though they could be a good site for floating PV!

While, as can be seen, for some options like hydro, breakthrough innovation is less likely, innovation in most other areas of green power supply continues. But a lot of the most crucial innovation concerns the demand side, the more efficient use of energy especially. In terms of end-use efficiency, heat pumps, large and small, are widely seen as a vital way ahead, including for urban district heating. With more use of variable renewables, there are also key system integration needs, including storage and grid management services.  Zero-carbon hydrogen gas production from wind or PV-derived power is of particular interest for grid balancing, for long duration cavern storage especially. There is also many other flexible balancing and storage options, including improved batteries of various types, pumped hydro and compressed air storage systems. Heat storage too - using sand or molten salts . My old outline of the overall system possibilities still stands up quite well. But now we are fleshing it out, with new technologies, as is reported in the annual Renew review- the next one being due out in December. 

Innovation is always hard, and there is often resistance to it. That has been the case for some renewables, notably on-shore wind in some locations, although local engagement and local ownership can help avoid resistance to change. However, with climate change now widely recognised as a major threat, attitudes are changing, aided by the rapid reduction of prices for wind and solar, now widely seen as very successful innovations, with the UK in particular doing especially well with offshore wind deployment.  China though is in the lead in most areas- hopefully adding impetus for the rest of us to keep up. Or else we may all be buying kit from them in the future!