for birds are known, and we don t site wind turbines in those areas or wind farms in that space. but there can tjust be a wholesale rejection of this technology because of the threat of something that would be negative. that collaboration is the real opportunity for us to work together. so it s a partnership, really, it s you delivering the technologies that make the future possible, and us adopting them and making the right choices to protect us from this growing threat. thank you so much. we re going to move to questions now. this is the engineers: clean energy. we ve been discussing the future of solar energy, wind power and electrical storage, and i m going to ask who would like to ask a question of any of our clean energy engineers. hi, i m ajay gambier, - iworkjust around the corner at the grantham institute for climate change and l the environment at imperial college. i would like to ask, i is it a surprise to any
hi, my name is shivika from imperial college. i just want to know about the future regarding the airborne wind turbines. what do you think that in the near term there is a future for airborne because google investing in airborne wind turbine system, we ve already seen one first wind turbine system in germany. so what is the future of that technology? so, we ve had land, we ve had sea and now we re asking about air turbines. i m fascinated to hear the answer to this. for those who haven t heard about this concept the airborne based wind farms are essentially like kites or tethered aeroplanes that are released up into the very high atmospheres, essentially at a very high altitude. they circulate and move around in the sky and generate electricity through their motion. generally they re much more costly than traditional wind or solar, and there s the challenge of taking
the technology s there, but if it doesn t get employed and deployed, then it s not going to work. thank you. kristian? i think accepting what is happening on that side, | as henry mentions, is crucial. and then an aspect that. i would emphasise as well is that we have to look at wasting energy - as unacceptable. we can t waste energy in any form of action. i so when the energy is. going to be challenging to harvest at large scale, we re solving parts - of harvesting as much energy as we can in good ways, - and then we have - to use that energy as efficiently as possible. and before we open it up to questions, danielle, when it comes to the threat that climate change presents to us, who is going to do the heavy lifting? is it going to be the engineering or is it going to be the individuals? i think the biggest changes will happen at the country level. there s going to be a need for us, in terms of our public policy, to support these kind
cells on top of each other we call multi junctions, and the simplest multi junction is a tandem cell, two solar cells on top of each other. and the perovskite we tune to match perfectly silicon. it absorbs only the visible light and we let the silicon absorb all the infrared. and in doing that we actually fundamentally improve the efficiencies. if we made a perfect perovskite on silicon tandem cell, that would top out at about 45%. so we ve fundamentally lifted the ceiling. and if we went one step further to anotherjunction, triple junction, three junctions, that would top out at just above 50%. so what perovskite does is lift the ceiling for potential efficiency and gives us a new path forward to go to higher and higher efficiency. so, i mean, substantial gains in efficiency here. how close is this really to being a real technology? is this now, or this is far flung future? this is very near term.
out in the world, it d be 24% reduction in cost. and as you continue to see volume increase in these technologies you will continue to see cost reduction. thank you so much, danielle. so we are now going to go to scotland, to alastair, who has a question about nuclear energy. alastair? hello, today we ve got representatives of wind and solar, which are often portrayed as the two examples of clean energy. but there are still huge challenges with the amount of land required and energy storage required challenges which aren t faced by existing nuclear power technology, something i would argue we really need to prioritise. i wonder if you think nuclear should form a key part of the clean energy mix, and should be a large part of the discussion today, and if not, how do we ensure we invest in and choose the most effective technologies that are going to make the biggest difference to stopping climate change? i m going to give that one over to kristian here. nuclear, it s a fair point, isn