to a category1 hurricane. president trump has cancelled next week's planned trip to north korea by his secretary of state. in tweets, mr trump complained that not enough progress had been made in dismantling pyongyang's nuclear programme. he blamed china for the stalled process, suggesting a link with current trade tensions. pope francis is due to arrive in ireland for the first papal visit there in four decades. the centrepiece of the visit will be a mass on sunday in front of 500,000 people. a series of scandals has damaged the reputation of the catholic church in recent years. after a week when donald trump saw his legal woes mount, even the

mention of impeachment has fired up the sides. democrats think getting young voters will be key to winning back the white house. mr trump has his own young supporters who are deeply devoted. chris buckler reports. it's up to you, your generation. in the presidential ballroom of the president's own washington hotel is a gathering of the trump teams. crowd chants: usa, usa! hundreds of republican high school students in the capital for a banquet meal and a week of conservative politics, and many here share donald trump's view of the world. i don't think trump's a republican. i think you can make a whole party based on what trump believes. he's conservative in some areas but he's also not conservative in some areas. you see yourself as a trump party rather than the republican party? yes, 100%. oh, that never gets old. little seems to shake the belief of the president's most devoted supporters, but donald trump junior knows his father is a divisive figure,

and recent days have only widened the gap between those who love him and those who loathe him. hate and bs is not a political platform. that is all the other side has these days. but between the booing and jeering for political opponents... and the many chants against the so—called fake news media, president trump seems to have encouraged some hate himself. i think he'sjust changing everything up. hate has always been there and he's just stirring up all of politics and people don't like that he's changing things. but that means stirring up hate? he's being 100% honest, which isn't always what we get from our presidents or the news or anything, and regardless of what they do no one is going to like a person 100%, so hate will be built no matter what. there is growing pressure for both republicans and democrats to get their voters out in november's congressional elections, and that's partly because the president has been forced to address the possibility of impeachment. it's 7pm in the evening

and there's a line of people in order to get into this church, and it stretches right down the street, and they're here to talk notjust about gun control but also politics in america. is there anybody here that maybe you're not registered to vote... congress would vote on impeachment proceedings, making the next elections crucial, and for democrats the youth vote really could matter. i think it's really disappointing and really heartbreaking to see a united states president who just has such disregard for the youth of our country. this event in georgia was one of dozens of stops on a nationwide tour by students from parkland in florida. they became famous in the worst circumstances, when 17 people from their school were shot dead. but despite months of campaigning, president trump has avoided the gun law reforms they want. it's about human lives and saving human lives and no matter what party you're from you should support that, so we need to keep as many

people together as we can and not be more divisive. but on guns, politics and president trump, america is split. would there be anybody who supports president trump here? all: no. and the last week may only have deepened this country's divides. chris buckler, bbc news, washington. later, mark kermode and jane hill will have the film review, but now on bbc news, it's time for click. florida, america's sunshine state, and home to the us‘s

first sustainable town. this is babcock ranch. powered, befittingly, almost entirely by that big burning ball in the sky. it's 33 degrees. the humidity is, i believe, about i,000,000%. and i've come to a solar field, so you don't have to. 343,000 solar panels span some 440 acres, providing 75 megawatts of electricity. and that's enough to power 15,000 homes. one of the big problems with solar energy has always been when the clouds come over or especially when it gets dark, the whole thing effectively goes dead. and we haven't really had a way of storing solar energy until very recently. but over there, ten buildings full of batteries. so it's a start. a pretty good one too.

babcock has the largest combined solar and storage facility in the us. the batteries can store 40 megawatt hours of electricity, which is enough to keep around 2000 average us homes alight forfour hours. of course, lithium batteries are just one way of storing energy to use later. and we've seen other methods before. there's electric mountain in wales, which holds water at a top reservoir until power is needed, it then releases it back down to the lake below. switzerland's air cave fills itself with compressed air and then blows it out to turn turbines. well, now, over in california, kate russell is on track to see a new solution. since the oil crisis of the 1970s, california has invested heavily into wind and solar power, with the latest state legislation calling for 50% renewable energy by 2030, and all new homes must have

solar within two years. the state is way ahead of its target, so much so that they've had to start paying neighbouring states to take some of the energy from them. as we've heard before, the problem is storage. the grid was built to handle fossil fuel generated power and storage solutions like hydroelectric dams are in short supply. batteries too are very bad for the environment, turning unused renewable energy into not such a green solution. california—based company aries have come up with one alternative. aries was really an attempt to think of a way to use the inexhaustible, always reliable power of gravity. right? we know gravity is going to be there for us. we don't have to worry about shortages or any of that. so how do we use gravity to store and then discharge power when we need it?

one of the most efficient ways to move mass known to man, which people have spent billions of dollars to perfect, are railroads. right? 150 years of experience, incredibly efficient, steel wheels on steel rails are one of the most efficient ways to move mass. dubbed the gravity train, energy is stored using electricity to push its weight uphill. when you want to take the energy out, you let gravity pull the train back down, using the friction of braking to slow the train in order to make power. it's the same way hybrid electric cars like the prius work. you see those wind turbines there behind me, they're completely still, even though there is clearly plenty of wind right now. it's not because they're broken, it's because there's no more room to store the energy they would create. and that's a problem the gravity train will solve. when you're into excess energy production, use it to power the train up a hill, and when you want the energy back,

you just send the train back down again. this demo train carries almost five tonnes uphill, storing energy as it goes. a full—scale installation will return 80% of the stored energy, which is not quite as efficient as a huge dam, but has a lot less impact. the amount of energy we store is the weight of the train times the height of the hill. simple mathematics. so the more weight and the higher the hill, the more energy we can store. we need long, gently sloping plains. but we had clients who approached us and said well, i only have steep, rocky, craggy mountains, so we've developed a new variation on the aries technology at almost vertical. in october, the company breaks ground on the first full—scale aries in the state of nevada. it'll be used to fine tune the inconsistent energy flows that are a natural part of using solar and wind power. minute by minute, it will trim

the imbalance between load and generation on the grid, so our trains may need to go uphill for a minute, they may need to go downhill forfive minutes, they're constantly acting like a large flywheel, that allows the grid to stay at exactly 60 hertz. it's early days yet and the concept has still to be proved in nevada, but it could help solve one of the renewable industry's biggest conundrums right now, balancing the ebb and flow of nature—made energy in a more sustainable way. after we run 30 or 40 years providing energy storage and helping people, we can remove all of our facilities very quickly, 96% of them can be either repurposed or recycled, so only 4% of our facilities could ever go into a landfill. and we're trying to reduce that. and we can then plant some native vegetation and six months later,

you never know our facility was there. that was kate on a roll in california. back at babcock, i'm going for a solar—powered spin in an autonomous shuttle, with its chief financial officer. so i guess the motivation for having these autonomous vehicles is that you're encouraging families here to not have as many cars. correct. i think our thought is that over time, most families in the us have a two—car family. and so our hope is that we can get from a two—car to a one—car family. where you have a car for the family, perhaps, but if you have it a car for a commuterfor work, you won't need it anymore, you can take an autonomous shuttle or an autonomous vehicle to work. and so over time, which will take a long time perhaps, there are no cars. but i think, realistically, within the next 10—15 years, you could see a time when you go from two car to one car. you think the us government at the moment doesn't understand? i think they get it. i think they're getting it.

the government's a little slow to move, typically. in major cities, major metros, where traffic and pollution are an issue, technology can come in and save a lot of that. i think governments are willing to step up and make sure this comes to fruition. and we're seeing that slowly. what we're hearing and reading about is a lot of the major urban cores are going to become, there'll be restricted access, if you're driving your car and you're trying to get there, you can't get there — up to a certain mile, three miles outside of the city core, you can't get into the city core without being in an autonomous vehicle, for instance. but outside of autonomous vehicles, i mean, building a city or a town that is sustainable, i mean, you're not going to be able to do this in colder, more crowded parts of the world. no, i think that's right. i think this is fairly unique. we've a unique situation here where we have the benefit of scale. there's not a lot people who own 18,000 acres of land. that's a big chunk of dirt. along with autonomous shuttles, babcock has its own water and waste facility, and as well as reclaiming water, there's a restriction on the amount

that you're allowed to use. the tin roofs reflect heat, making homes 10% better at keeping cool, and the ranch‘s on—site gym is environmentally friendly too, it's powered by the treadmills. 0ne incentive to get off the couch, i suppose. it is a commendable vision to build a town with all these sustainable values, but i can't help thinking that you can only really do this when you are building a community from scratch. i mean, could you imagine trying to retrofit an existing town with all of these technologies? you'd basically have to tear up the infrastructure and tear down all the buildings and start from scratch anyway. babcock has been built in the style of older towns, to attract people who aren't necessarily fans of the new build feel. hi. are you expecting me? people like the kinleys. mind if ijust step inside your air—conditioning and stay here forever? yeah, yeah. they've got a robot vacuum cleaner... a coffee making fridge... no, it's set up so it

won't spill all over the place. ..and, of course, an electric car. for richard, a self—confessed geek and actual real fan of click, babcock was his calling. just reading tech blogs all the time on the internet, and it sounded fascinating to me. i liked the idea that it was environmentally friendly and was looking forward as far as energy solutions. in atlanta, we lived just downwind from one of the biggest coal polluting plants in the country, and i thought that cannot be healthy. i think of it as guilt—free living. in the uk, when you have a small town with a central area that you can walk to, it encourages walking, so it's the lifestyle. and while the buildings may look like historic florida, for me, it was also all

the technology, all the... you know, having i gigabyte of fibre optic internet to the home... yeah, you like that, you definitely like that. and that's it for the short clerk of our sustainability special —— shortcut. the full—length version is available on iplayer for you to watch right now. check us out on facebook and on twitter @bbcclick. thanks for watching, see you soon.