he'd faced mounting pressure from president trump for using expensive privatejets to travel on government business. the trips are reported to have cost the taxpayer more than $1 million. two other members of the cabinet are under scrutiny for their travel. thousands of catalan separatists have held a final rally ahead of sunday's planned referendum on independence from spain. the head of the regional government told the crowd he believed catalonia would become a sovereign nation. madrid's trying to block the vote, claiming it is unconstitutional. the us has warned americans not to travel to cuba and pulled half the staff from its embassy in havana after a spate of sonic attacks. more than 20 people have suffered symptoms, including deafness, dizziness and brain trauma. the cause remains a mystery. now on bbc news, click. this week... explosions. big tatts.

and goats on the loose. —— taps. the beautiful welsh countryside. home to valleys, lakes, the odd feral goat and... electric mountain. hidden inside this mountain is the denorward hidden inside this mountain is the denorwa rd pumped storage hidden inside this mountain is the denorward pumped storage power station and it is basically a monster battery. its stores energy by pumping water from this lake to a la ke by pumping water from this lake to a lake at the top of the mountain and then letting it flow back downhill, releasing that energy at times of peak demand. when you pop the kettle on during breaks in championship matches of that sport they call football, this bad boy springs into action to supplement our national grid, delivering power to our homes in underi2 grid, delivering power to our homes in under 12 seconds. an incredible

view. it's one of the fastest responding power stations on the planet and will have a nosy inside the thing later in the programme. denorwig offers a semi— renewable energy solution at a time when our national resources are being used up. as solar, wind and tidal power alternatives advance, we're craving alternatives advance, we're craving a method of using their generated energy 24/7 despite the weather or time of day and this is where batteries coming. now, this isn't your stereotypical battery admittedly. when i say battery you probably think of the ones in these. these are rechargeable lithium ion batteries. we really can't live without these. lithium ion batteries have truly revolutionised electronics. they power the mobile miracles that we use everyday. they have a high—density, meaning they can have a high—density, meaning they ca n store have a high—density, meaning they can store a lot of electricity

relative to their small size so we can easily carry them around and recharge them hundreds of times. inside cells are layers of cheats stacked together, a positive cathode, negative anode, with a separator in between filled with a liquid electrolyte. when a cell is discharged the movement of ions from one side to the other perrson at eight the flow of electrons, which then generates current to power devices. during charging, this process is reversed. whoever came up with this must have been a real genius. my name is john bannister good enough and when i was at oxford when we developed the cathode is that enabled the lithium ion battery that enabled the lithium ion battery that you used in your cell telephones and laptop computers, i didn't really think about whether the battery we were developing would—be a world —famous the battery we were developing would—be a world—famous invention. i've been very pleased to see how

it's being developed in the hands of the engineers. it has stood the test of time with electric vehicles today relying on thousands of lithium ion cells for their battery pack modules. the dependence of modern society on fossil fuel energy is not sustainable. and so one of the things we need to do is find storage of electric power generated by alternative energy sources, and also storage batteries that can power an electric vehicle with a competitive price and performance. certainly sounds like doctor goodenough‘s invention has proved good enough for 37 years but lithium ion isn't without its problems and that's led some people to look for alternate battery technology. and this summer the uk government pledged a quarter of £1 billion into the research and development of battery tech. at the

forefront of this research is warwick manufacturing group at the university of warwick. lithium ion batteries do have potential hazards and if you mistreat some of the higher energy chemistry is then yes you'll see a battery fire and potentially a rupture and so on so there's tight in eight chemistries, called iron phosphate chemistry is, which are a safe option for using public transport so on. as i reached at centre and a cell manufacturer you can play tunes with the chemistry to basically decide whether safety is your prime goal or your prime criteria or whether performance and energy is. if you look at your periodic table, all the transition metals you see, generally there is some wire in the world a scientist trying to make a battery out of those. calcium, lithium ion, sodium ion, there's a range of different chemistry is being worked on so different chemistry is being worked on so although we're working with lithium ion at the moment and we're persevering with lithium ion, there

will be more developer and is in the future as we move onto different types of chemistries. as the uk's leading automotive battery r&d centre, wmd works at the intersection between scientific interest, research and industry with the likes of nissan and jaguar land rover as close collaborators. here's a module we developed and it represents a seven to 8% improvement on the tesla battery module. that improvement has come about not through changes in the chemistry but changes in the way the module has been constructive. packing the cells tighter together while maintaining safety, improved cooling systems et cetera. at the moment cost and range of new dvs and the number of charging points available to us is an issue. manufacturers like nissan even offer up a replacement dilma diesel or petrol replacements for those wanting to go further as part of their promised scheme. as well as

batteries wmc is looking at how our charging behaviour can affect battery life too surprising results. it's made a smart algorithm that shows degradation of a car battery can be reduced by up to 10% over a year if energy is transferred back to the grid. synonymous with evs is tesla, owner of the world's biggest battery factory. due to hit peak production in 2020, the giga factory aims to produce enough batteries to power after million new electric ca i’s power after million new electric cars every yea i’. power after million new electric cars every year. tesla boss elon musk‘s ambitions go further than resolution rising our cars, though, he wants to rewire our homes too. —— revolutionising. enter the power wall, the £6,000 home battery stores energy gathered from solar panels during the day and when the sun goes down sustainably powers your pad. it's very straightforward really, not that complicated. from tesla to ikea. there seems to

bea from tesla to ikea. there seems to be a growing trend in companies creating home battery is to harness solar power. so how exactly does this work? —— batteries. tech enthusiastic terence has had solar panels for several years. more recently connecting them to a home battery, meaning he can use the power he generates and send excess back to the grid. the battery charged up1.4 back to the grid. the battery charged up 1.4 kilowatt hours, which it then used throughout the day, so that saved about 15% on energy bills. he's also using it to power his electric reo—coker and thanks to the way that the in tariffs currently work in the uk, he's being paid for the power he generates even when he uses it. but of course it's early days for the technology. one of the things we're going to see over time is these batteries will become cheaper, smaller and higher capacity. at the moment this battery is to kilowatt—hours, which is

great, but it's not quite enough for everything we want to do with it. terence is actually taking part in a community trial taking place in the rose hill area of oxford. while the usual costs for installation of solar pounders and a battery would be £5,000, here the cost of batteries is subsidised and a network has been created meaning power can be economically shared between the 82 homes, a school and a community centre that are taking part. my house generates more power than i can use so why not store it and sell it back to the grid? why not give it to my neighbours when we've got surplus. in this area, where many are living in fuel poverty, the community element of the project seems to be appreciated too. and here at this school, they're also treating it as a learning spirit is. here in this year 6 classroom you can see the

solar panels out of the window and here is the battery that is harnessing the power. now, this power is actually being used for the lighting in this room but the whole setup also teaches the kids how this works. swedish giant ikea are now selling home batteries too using the same premise of harnessing solar power and that providing electricity consumer of by the homeowner. claiming the average uk home cook up to £560 a year from their electricity bills. —— could. meanwhile british company power pole are working on giving older electric vehicle batteries a second life as home batteries. while after eight to ten yea rs home batteries. while after eight to ten years of road use a battery could start to deteriorate, it seems it could still be used in the home where demands are less strenuous, giving itan where demands are less strenuous, giving it an extra decade of use. after being taken from the vehicles

they are checked electorally, graded, reformatted and stacked together to create energy storage systems for the home. of course, as battery costs come down and capability increases, the appeal should too. so whether this idea goes mainstream most likely depends on whether the sun shines over those figures. welcome to the week in tech. maintaining the battery theme, it was panic caused on the london underground when a mobile battery pack exploded and the station had to be evacuated. and mark zuckerberg rejected claims by president donald trump that facebook is biased and anti—trump. bill gates admitted that he has ditched his microsoft phone for an android handset. the united nations has declared robots could destabilise the world

and its open a centre in the hague to monitor developments in the visual intelligence. the skies are about to get busier as autonomous passenger drones move one step closer to reality. in dubai a test flight took place of a proposed autonomous buying taxi designed by german outfit followed co pter designed by german outfit followed copter um 18 blades power the drone with passengers selecting the destination via touchscreen. meanwhile a company called passenger drones released video of itself drying is growing in europe, the human can also take the stick and ta ke human can also take the stick and take control of the 16 electric motors. amazon has announced a host of new hardware this week including new versions of its digital assistant, the echo. the echo spot features a screen that can make video calls and act as a nursery camera and the eid plus can act as a smart home hub, connecting to an controlling other devices. finally james dyson, the colourful expensive vacuum of fame, has announced plans to launch an electric car.

here's hoping it doesn't suck. back at dinorwig i'm heading deeper underground. the water comes from the late, which is about 600 metres above us, down this pipe, hits this bowl and stops. this is the biggest tap you will ever see, and they are actually six of them all in a row down there. when they need the power, this yellow arm swings up, the valve opens and we get to maximum flow of water through to the turbines through there in about six seconds. when all six are open and that's 92,000 gallons per second. or, as it

says here, 1.5 million teas. not sure if that's a earl grey or in dilma english breakfast. do we have low? do we have flow? we have flow. there it is, turbine number two spinning at about 500 rpm and when all six of these turbines are all spinning, this place produces enough electricity to power the whole of wales for 5.5 hours. now, dinorwig ru ns wales for 5.5 hours. now, dinorwig runs at about 75% efficiency because it pumps its water uphill at night using cheap electricity it buys from the national grid and charges a premium for the energy it generates during the day. if we were to move completely away from fossil fuel power stations, would that mean that this sort of power station would be able to run? in reality, if we need to pump that water up the hill we need to buy that electricity from the market somewhere, whether that's a thermal power station, a set of windmills,

gas power station, whatever it might be. why are there not more of these around? i suppose the greatest challenge is finding a suitable place in the uk to build them. you've seen yourself that you've got to have them in a specific area, it's got to have two legs, the lakes are ideally close together, good vertical separation. are not the kind of things you can easily build on the back of a wagon and reel them in somewhere. those lakes need to exist or you need to create them, so it comes with cost. so i think it's a limited amount of options in terms of locations for these places. does get lonely down here? sometimes. while this is parent our homes, curt hawkins hasn't it is on how to power our phones. a lot of us, will feel we cannot live without phones. without nexus to power in a dead battery, it can be

inconvenient. there are things you can do to save your battery: to of wi-fi, gps, can do to save your battery: to of wi—fi, gps, and any background apps, as will as to your screen. but there are apps out there which claim to save your battery. —— turn off your. these are three of the most popular battery saving android apps. they have millions of five—star reviews, suggesting people think they work. so we thought they made a good testing ground. they can't do a number of from giving your brightness, to optimising arts, to reducing your data use. so to start off, we took a new phone and hot—wired it. off, we took a new phone and hot-wired it. the voltage, the current, and the power. so if we turn the phone on, from idle, we can see that the current anti—power to the phone increases, so if we do which is power hungry, the power

spike massively. then they tested the phone baseline, with no batteries ever installed and using a small number of apps over a ten minute period. then they did the same thing with the battery savers installed , same thing with the battery savers installed, as long as the in—built batteries ever. so we can see that the power savers do seem to work. they make a small difference or battery doctor and the eu battery saver. about two or three hours. —— du. andy last makes about four hours. when you think this one is doing better? we think that is because it is the way the apps work. du sabre and battery doctor allowed you to optimise your apps, so we suspected they are laurentides frequency at which applications reached dater, whereas greenify seems to put you into a different

kind of mohd. it is a limited test of ten minutes, and conducted on wi—fi. what needs to happen now is a bigger test of hours at a time, using apps that play videos, games, or send either. you can do many of the features yourself if you organise it. but there are other things that you should do if you wa nt things that you should do if you want your battery to have a long life. if you plug your phone and when you go to bed, and it is charged after a couple of hours, that time at 100% charge, overnight, will significantly accelerate the degradation of the battery. even better for your battery's life is to keep your phone charge between 20 and 80% at all times. so remember, thatis and 80% at all times. so remember, that is 20%-80%. and 80% at all times. so remember, that is 20%—80%. thank you. but wouldn't it be nice to get to that 80% much faster? cue a very different battery technology that

can be charged really quickly. you see, the things can deliver a lot of power very quickly. so they would be much more usefulfor some power very quickly. so they would be much more useful for some this to a —— for zabadani to do a lot very quickly. instead of normal chemical charging, thisjudges by electrostatic means. it is called a super capacitor. no chemical reaction means you can charge very quickly. this drill battery, for example, goes from zero to fall in 12 seconds. you can zap and go. which sounds a pretty good name for a company, if you ask me. we use carbon nano materials. so extremely fine particles at the nano level, and a large surface area is greeted inside one of these patches that a tt ra cts inside one of these patches that attracts energy very quickly. the more surface, the more energy it attracts. the downside of super capacitors is that they cannot store as much as with the iron, so you would not want one in your phone.

they are best suited for things that need quick charging and big short bursts of power, laich tools and toys, such as the scooter. now, the lead acid batteries in a normal electric scooter, like those ones, will give you about half an hour's right time. —— like tools. they take six hours to charge. this battery gives you six minutes of charge, but only takes six minutes to charge. the next battery will take six minutes, the give you 12. so it is unlikely that your electric car will run on this technology alone. we are aiming to the automotive sector, possibly as a hybrid technology with lithium. so we do the fast charge that, and that it is the long—distance pet. we will transfer from sap and go sales to lithium, the power that we are harvesting quickly, during thejourney.

the power that we are harvesting quickly, during the journey. to that end, zap ngo is leading to charge airport pods like those at heathrow. however, my six minutes the right time are up, so for the moment, i have two lives out and go and zip off by car. back in texas, the father of the lithium ion battery shows no signs of slowing down. he is working on a new cover battery, with a surprising chemical make—up. an all glass solid—state battery. eight lady brought to me a glass which was a remarkable material, i think. she said i think we are, with a cell that could really do the trick. -- a lady. together with his colleague, goodenough claims the battery will last longer and recharge quicker. it is a competitive field. and i am a competitor. so i am hoping that the new glass that we have done will

enable us to go from liquid electrolyte to a solid electrolyte. it will make things safe as well as cheap. lengthening the life span of batteries is obviously one of the main aims of researchers worldwide, which could be why a group of researchers at bristol universities say they have developed a new type that could last thousands of years. they have created a man—made diamond that, when pressed inside a reactive field, it generates a small amount of current. —— place. was the radio she gives off is less than a banana, there are no moving parts it involves, and no maintenance required. just direct electricity generation. as well as making use of nuclear waste, the invention could theoretically power devices in places that people can't go. but was this could be years away, something hoping to charge onto shelves sooner is the prieto battery. it has a

different architecture to the standard of the island battery. —— lithium island to make iron. it promises to store more power. is my ultimate dream is to make a stronger battery. i would be more ambitious in terms of present devices, but also solves problems in terms of renewable energy, being able to store intermittent types of energy, like solar and wind. there are other concepts out that, too, such as microbialfalls earls, which use anything from saliva to other materials to generate lectures in. —— fuel cells. but we still rely on finite energy taken from mother nature to develop these devices. which is why it wmg is working to

extend its batteries, but also work out a system to give you a happy retirement, too. until then, out a system to give you a happy retirement, too. untilthen, i guess the best we can do is try and make sure the fuel that we use does not have a lasting impact on our environment. that is it from the dinorwig power station. what a pleasure it has been to visit such an unusual place. the figure we live on facebook and twitter. feel free to get in touch any time, if you have enough battery. see you. hello. some of us may get off to a fine start on saturday morning, but by looking at the big picture you can work out why that is not going to last. several weather systems queueing up

in the atlantic to come our way, so we will all have rain at some stage of the weekend and the winds will be picking up as well. this is how it looks for early rises. wales and north—west england with cloud and outbreaks of rain. a lot of cloud in the rest of england. showers spreading east as the day goes on. a lot of fine weather in northern ireland, with variable cloud and sunny spells. after morning showers in scotland, the afternoon looks drier, with fewer showers, more sunshine. there's your fine weather in northern ireland. some sunny spells in northern england as well. but for the midlands, east anglia, south—east england, likely to be a fair amount of cloud around and an increased chance of showers spreading east in the afternoon. for wales and western areas of england, we keep a lot of cloud throughout and the rain gathers again by late afternoon and into the evening. another spell of wet weather moves in and covers much of the uk as we go through saturday night and into sunday morning. the wind picking up as well. in northern ireland we have some especially heavy rain coming in by the end of saturday night.

a mild start to sunday and a mild sunday to come. it won't feel like that in the wind. cloud around. a wet morning in northern ireland. heavy rain spreading across scotland. for the rest of england and wales there will be some outbreaks spreading eastwards as the day goes on. of course it is windy on sunday. coastal gales in the west. the wet weather clearing through much of scotland and northern ireland as it brightens up. a few showers around, but the wind will get even stronger, especially in scotland. so it will be very blustery in scotland for the great scottish run and expect a lot of rain in the morning, clearing in the afternoon. there will be some rain, although not as persistent as the rain in scotland, but some outbreaks moving through during sunday. but it's close to this low pressure going into monday where we expect some really nasty wind for a time, especially in parts of scotland. the further north you are, severe gales, up to 70 mph. gusts in the northern england could be up to 50—60 mph, so that could be disruptive. showers towards the north—west and some spells of persistent rain into northwest scotland. so the weekend starts on a fine note for some,

but we will all have rain moving in and the winds picking up as well, especially sunday and into monday. hello. i'm tom donkin. welcome to bbc news, broadcasting to viewers in north america and around the globe. our top stories: president trump's health secretary quits, after using expensive private planes for government business. but as tom price departs, could others now follow? mass rallies in catalonia in support of sunday's planned independence referendum. spain says the vote violates the constitution and won't go ahead. the us cuts its diplomats in cuba by more than half and warns its citizens to stay away. it says mystery attacks have injured several embassy staff. and, at the eu summit in estonia, the head of the european commission says brexit talks "need a miracle" to keep them on track.