the globe, more housing is needed. but these buildings themselves come with their own environmental cost. of course, building and running offices and homes contributes massively to our carbon footprint — more than 13 billion tons of c02 a year. that's nearly 40% of the world's total carbon emissions. so how about making buildings that are part of the solution, not the problem? maybe it's time to rethink renewable energy, the construction materials that we use, and what happens to them at the end of their life. later, we'll see how demolished buildings can be sorted and salvaged using what's in here. drum roll, please. all the rubbish is being tossed around and eventually, the smaller items will make it through one of these tiny holes. just wait till you see what's waiting for them down the line. but first, to swansea university's active building centre. instead of pulling its power from the grid, this place powers itself using the latest innovation in solar energy. the conventional box—shaped solar panels that we've been seeing on rooftops for years were just the beginning. now, newer, flexible cells are starting to cover roofs across the world. not that you'd necessarily notice they're solar panels. this feels just like a bit of protective flooring rolled up. but when i unroll this, take a look at that — a solar panel that is that bendable compared to the traditional—looking ones there! they are slightly less efficient but the fact that you can cover a whole roof area with them is one of their advantages. and they work very well in low light conditions, so they're ideally suited for use in the uk — in the northern hemisphere, really. part of the electricity generated here also comes from these vertical panels encased in tubing, which produce thermal and solar energy at the same time. on average, one wall could provide enough power per day to boil 38 kettles. that's a lot of tea! but what could truly revolutionise solar energy next is in the labs. i'm ready! this is a solar cell and it's printed? wow! the idea that we're looking at is making these new materials to put on all of the outsides of buildings. there are also semitransparent versions of these that you can put onto glass for the windows. it reminds me of old negatives. yeah, it's actually very similar to photographic film orfilm that you'd make a movie with. it's just got a conducting layer on it so that you can collect the solar energy, the electricity that the solar cell is making. but what does this mean for buildings? well, over in a larger clean room, this is happening. it's the same sort of kit as you would print a t—shirt with, but it's bigger! right? the sample goes under it, the ink comes on there and it's just dragged across, so it literallyjust prints straight onto the glass. this allows the structure of buildings to change, as they don't need to withstand heavy building materials, and can also be put on curved roofing. you don't put the solar cell on top of a roof, you make the roof into a solar cell. the efficiency is very likely to be in the same order initially as the flexible ones we showed you, but the cost is likely to be dramatically lower. this means that more and more buildings can become their own energy hubs by combining printed solar cells with next gen batteries. and here, you're storing the power that you've been collecting? yes. so if plug the car in, we can set it so that it will not charge the car necessarily as soon as it's plugged in. having the ability to release solar energy wherever and whenever it is needed means that here, the offices, the university and the electric vehicles can share with each other, creating a solar—powered community. in many parts of the world where there are no grid connections or the grid connection is weak, you know, rural communities can have power, say, at a school and then share that power around with the local houses, so that they can have an amenity that they can do educational things in, but they can also have power — and particularly at night time, you know, which is very important for safety. so we are seeing more more possibilities of how solar can power and empower. the next challenge, though, is how we're going to get more of these infrastructures in place. there's also been innovation taking place in the construction industry itself. jen copestake�*s been finding out more. we've come over 900 kilometres north of sweden's capital stockholm to lulea, to see a world—first project in the manufacturing of steel. ssab is one of the world's leaders in high—strength steel production, which is used in everything from construction to cars. we're just going into the blast furnace, and this is the current technology that's used to manufacture steel. for every ton of steel that's produced globally, on average, 1.85 tons of carbon dioxide is released into the atmosphere — about 8% of global emissions of carbon dioxide. this factory is actually one of the cleanest in the world, but it still produces 1.6 tons of carbon dioxide for each ton of steel produced. steel is made from iron ore — a compound of iron and oxygen. the blast furnace removes the oxygen. iron ore is put into the furnace, along with coke, a reducing agent and fuel made from coal. burning it produces high heat with little smoke, but emits high level of carbon. and this blast furnace receives two train loads every single day from northern sweden of iron ore pallets — 65 containers full. every five minutes, they are put into the blast furnace at the top — it is 85 metres above our heads. the iron ore pellets are heated 1100 degrees and then, they turn into this liquid metal, which is then manufactured into steel. this technology has not changed much in 1000 years but an ambitious goal to make fossil—free steel by 2026 has led to the development of a new plant on this site. along with europe's largest supplier of iron ore, lkab, and energy supplier vattenfall, ssab have developed hybrit — a way of removing oxygen from iron ore using hydrogen that is produced with fossil—free electricity. sweden is an ideal place for this kind of experimentation, combining access to fossil—free electricity and raw materials with a globally established steel industry. looking at the hybrit plants compared to the furnace, already, it looks completely different. it feels cleaner. is that on purpose orjust the natural by—product of what's happening? no, it's natural — it's natural, how the new process is gonna look like. yep. and i think that's — if you notice it, i think it's good. yes — it's quieter. yes, it's quieter. it's not hot! well, it's not as hot. instead of producing blast furnace hot metal, the process makes sponge iron. the reduction takes place at 900 degrees so the metal does not liquefy. we do this reduction with hydrogen in the solid phase. in the solid phase, so there is still no... still very high temperatures but not in the liquid phase for the steel, so this is what comes out. 0k. the pallets are then made into small bricks to make them easy for transport. the hybrit plant combines the reduction reactor for creating sponge iron on the higher levels with the production of hydrogen on the lower levels. well, the key difference between the conventional technology is that it uses coal, whereas here, we use hydrogen, and the hydrogen is made from fossil—free electricity instead, and that is happening right behind us in that building, where we have two units making hydrogen out of electricity and water. and this is the end product — it's the world's first piece of fossil—free steel. and this steel was delivered to volvo, who made it into an autonomous vehicle. they actually made a vehicle that was shown mid october. we need to make not only our customers but the end user understand the benefits, understand the difference with other types of steel. i think the conversations that we are having with our customers today is very important and i think — and i know — it's very frequent. to keep the process of making hydrogen cost—effective, excess will be stored in a new underground facility. so this is where they are building a future hydrogen storage site. so it's going to be 30 metres under the ground, about 100m behind me, and any excess hydrogen that's produced at the plant they can save here, so they can produce it in times when energy is plentiful, when there is a lot of solar and wind energy, and it can be used in the future to help fuel the plant. is there something that can be replicated anywhere in the world? do you need specific...? the technology can be replicated, but i think the unique thing is the partnership. because a lot of different pieces of the puzzle that need to be fitted together. sweden has got a lot of that. yes, and we have the fossil—free power. we have the iron ore — high—quality iron ore — and we have ssab, which is one of the major steel producers, so in that cooperation, i think it's not easy to duplicate. by 2026, the industrial—scale production of fossil—free steel is expected here, and the conversion of the traditional blast furnace should be completed by 2040. ssab is aiming to be fossil—free across all its sites by 2045. hello and welcome to the week in tech. it was the week elon musk sold $5 billion worth of his tesla shares. it follows a twitter poll that asked whether he should sell 10% of his stake in the electric car manufacturer. an original apple computer built by co—founders steve wozniacki and stevejobs in 1976 sold for $100,000 at auction. the rare apple i is one of only 200 made — and still works! and meta, formerly known as facebook, said it plans to eliminate advertisers�* ability to target people based on factors such as ethnicity, religion and sexual orientation. the uk's supreme court has rejected a claim that saw billions of pounds in damages from google over alleged illegal tracking of millions of iphones. the case could have potentially seen users receive compensation from the way their data was used. glasgow nightclub swgs is set to trial technology that captures heat from dancers and creates renewable energy! yes, the system, called bodyheat, could heat up the audience or cool down the venue and would save approximately 70 tons of c02 per year! and finally, let a robot give you your next covid—19 jab, as robotic start—up cobionix have created one that can autonomously administer injections without needles. instead, it uses a tiny high—pressure fluid jet to inject the vaccine directly into the tissue. maybe this will help with nerd immunity! we know that constructing buildings uses resources. but when they're demolished many precious materials also go to waste. it's a problem that recycling sites like as this one in finland are trying to solve. construction and demolition waste is usually crushed and most of it will be burned in incineration plants to energy. here we try to do the opposite, we mechanically handle material to produce raw materials that can be reused again. this is one of those places that is frighteningly industrial and frighteningly massive. what happens is the waste arrives in lorries at the far end and then the commercial and the industrial waste gets sorted along these conveyor belt and machines here and construction and demolition waste gets moved along this side here and it's all a very big deal. but to avoid just crushing and burning everything, debris has to be separated into different materials and different sizes that can be recycled individually. and that's where the fun begins. once we get rid of the small stuff, we have the medium and the large size. and that's what we feed it to the robots. no, this is not a warehouse disco, these are sorting lines where an ai brain commands robotic arms to pick out metal, wood, and stone and hurl them into their respective bins. it's fast, furious, and continuous. i have to say, these things are moving like lightning. they're not getting everything, they're missing quite a bit, but that's because they're still training these robots and calibrating the system for this type ofjunk. in waste sorting the first problem is that no—one really knows what's on the belts. if you are welding cars then obviously the next car will come on the conveyor in 5.04 seconds and there's never really anything unexpected. for these robots, they need to be smart in order to survive the surprises. wow. it's just flinging stuff around. with all sorts rolling towards them, the robots are visually track the items with sensors beneath the belt and lasers scanning shapes and sizes, helping to decide what each is made of, how much it weighs, and how much it's worth. it sees not only the wavelengths that humanoids see, they also see infrared and they also sense metals. so we basically show the robot that here's a bunch of rocks and here's a bunch of bricks, here's a bunch of high quality wood. based on the on that training, the robot then learns. but knowing what to grab is just part of the problem. there are hundreds of billions of ways how to position in the gripper on the belt. the robot needs to have, basically, a second opinion as to whether the attempt was successful or not, something that the robot learns fairly easily. today, 80 arms are working around the world, including smaller, faster ones with vacuum grippers, which are better for light items like plastics and tin cans. all in all, these robot arms are rougher and tougher than human workers and, obviously, it's much safer as well. and despite their different skills, each robot feeds back into one shared system. the more we have robot arms in the world then we have basically one family of robots that learn and then all of the arms that we have around the world get smarter. of course, there will always be some materials that can't be used again, but robots like these can help recycling plants to recover more and more and save stuff from incineration. and closing this loop means buildings can become much more sustainable — both at the start and the end of their lives. wow. now, while buildings contribute massively to emissions, it all comes down to energy use in the end. the greener the better, of course. although nick kwek is sailing into the blue. on a voyage to find future energy solutions, i've strapped on my sea legs and come here to this archipelago off the north—east coast of scotland. this is scapa flow, which, for a while now, has been a test bed for a boundless source of renewable energy — the ocean. but now it's playing host to a new prototype device which harnesses the power of waves. there it is. five years in the making, motion energy's hinged raft is finally being trialled in wild waters. we are generating power, it's working. i mean, obviously not everything is going perfect, but that's the point of the project, you know, to learn about things. and you can see the marine growth and the bird poo, but it doesn't affect the performance. you only have solar power during the day. wind power can be highly variable. whereas wave energy helps to provide another source of renewable energyjust to balance that whole supply. because you've got to have supply meeting the demand of the grid. now, the sea conditions today are obviously very calm, but when it's very wavy would see that swivel mechanism doing this and it's that which generates electricity. the blue x, which is yellow, can power around ten homes, but it's being targeted first at our oil and gas industries to help reduce their platform running costs and pollution. the by—product of powering the rigs with natural gas and diesel accounts for almost 3% of the uk's total carbon emissions. the traditional way to get power to offshore systems is with really long umbilical cables. there's actually quite a bit of embedded carbon in the cable and you're disturbing a lot of the seabed through that installation. rather than running a cable for 150 kilometres, we can provide renewable power and a communications link. the government has poured in over £3 million for the project. well, if we are to get to net zero by 2045 in scotland and 2050 in the uk, we need to use all the technology that we have available. the oil and gas sector is changing its focus from fossil fuels towards renewables. that engineering capability that's being used to extract oil now can be used to deploy wave energy, tidal energy, wind energy in the future. motion is trying to bring its device to market with help from the european marine energy centre, where it hopes to feed into the national grid. we get waves out here 18 metres high. trying to find the ways in which we are going to extract these huge quantities of energy we know are in the sea is something we've got to discover. neil took the helm 16 years back and has overseen 30 inventions being put through their paces. there was the penguin by finnish firm wello, which wobbles around to generate power. the pelamis, made up of different carriages that would twist and bend, and the shellfish design of the aquamarine 0yster that sits on the seabed and tilts to and fro. despite investment in the industry, millions have been lost at sea. the penguin literally sank. oh, wow, look at this! this which room is, surprise, surprise, filled with giant switches were any output from newfound contraptions is measured. but at the moment there are no wave energy devices connected to the grid here. it's important we're not impatient, but it's also important that we are impatient, that we get on with it. we've got to get on with this so that it's ready as soon as we can get it ready. but is all this a viable solution to our energy issues and will our planet really be better off? we're not going to run out of waves and wind and tides, so this is a sustained, in the true sense of the word, industry. i find it difficult to believe that people are still on the fence about climate change. and if they want to stay on the fence, well, good luck to you. we've got to get on with this and we've got to fully commit to it. we've got to get on with it now. do you think we will manage it? yes, we don't have a choice. we genuinely do not have a choice, because if we don't sort this out the planet will sort us out. that's it for the final of our sustainability specials, but we will be bringing you lots more on the topic. in the meantime, you can keep up with the team on social media. find is on youtube, instagram, facebook, and twitter @bbcclick. and we will be back next week. thanks for watching. bye— bye. wednesday morning will be a little bit colder compared to the last couple of mornings. and, indeed, by day, it'll feel a touch fresher, too. but overall, the next 2—3 days will remain above the average for the time of year. i want to show you the jet stream — and there is a dip in thejet stream at the moment across the uk, and you can see the blue colours — so that's the slightly colder atmosphere that's spread across the country into the early hours of wednesday. and, with the clearer skies, that means that, in many towns and cities, temperatures will be around five celsius or so, especially out towards the east and in central parts of the uk. even colder than that in aberdeen, barely above freezing. but that means a lot of bright and crisp weather in the morning, especially across central, eastern, and southern areas of the uk. not necessarily in western scotland and northern ireland, always a bit more cloud here and a chance of catching a shower. and you can see those temperatures actually not far off the average, just a fraction above. but look what happens on thursday — another change in the jet stream. now this time, the jet stream's way to the north of us, it's bulging northwards of the uk and allowing for a stream of really mild air to sweep in from the azores. so, mild south—westerlies across the uk, cloudy and damp in western and northern scotland — but where the skies clear, where the sun pops out for any lengthy period of time, temperatures will reach around 15—16, maybe even 17 celsius to the east of the highlands because of something called the foehn effect — you'll have to look that up, not enough time to explain it. but look where we are, nine celsius is the average this time of november — we are talking about 17 celsius, eight degrees above the average for the time of year. and the same pattern continues in a friday, as well — east of the highlands, possibly 17, we could get 16 also east of the pennines, and widely around 14—15 celsius. and then, a reversal in the wind direction — you can see this time, rather than from the southwest, it's coming in straight from the north. now this looks pretty cold, doesn't it? well, it won't be that cold — it will be relatively speaking, but actually, we'll be going down from 15 to around nine celsius, which, of course, is about the average for the time of year, give or take. welcome to bbc news, i'm david eades. our top stories: clashes on the border between poland and belarus as polish authorities use water cannon and teargas to push back migrants. all chaos has broken out. the polish forces have responded with water but also with gas. it is difficult to breathe. former england give shocking details of the racism he faced, saying he was constantly subjected to offensive language at yorkshire cricket club. pollution crisis in india with all schools and india in delhi staying shut until further notice with a