cloud, wind and rain in keith lucas. cloud, wind and rain in the forecast today but it will not bea the forecast today but it will not be a complete write—off. mild and largely dry weather for central and eastern parts of the country. windy wherever you are with outbreaks of rain, especially west scotland, north—west england. drizzle across wales in south—west england. brighter skies returning from the west and temperatures today 14—18. tonight that front pushes towards the east taking the rain away. we are the east taking the rain away. we a re left the east taking the rain away. we are left with windy conditions overnight, particularly across scotland, northern ireland and northern england. showers building here. dry for some and mild with the strength of wind keeping things frost free to start monday. very strong wind across scotland for the monday morning rush hour. we could see 60 mph. less windy further south but wherever you are, blustery with heavy showers in the north and west. dry to the south—east and cooler thanit dry to the south—east and cooler than it has been at iii—18d. goodbye for now. are a

hello. are a this is bbc news. the headlines at 11.31 one the first day of the conservative conference, theresa may says she's sorry the party didn't win a majority at the general election. spanish riot police have clashed with voters in catalonia as they try to stop an independence referendum organised by the regional government. the catalan leader has condemned what he called police brutality. the low—cost travel company, monarch, has been granted a 24—hour extension to its licence to sell package holidays. and an air france flight was forced to make a sudden diversion when it lost part of an engine over the atlantic. now on bbc news, click. this week... explosions. big taps. and goats on the loose. the beautiful welsh countryside.

home to valleys, lakes, the odd feral goat and... electric mountain. hidden inside this mountain is the dinorwig pumped storage power station and it is basically a monster battery. it stores energy 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 under 12 seconds. it's an incredible view. it's one of the fastest responding power stations on the planet and we'll have a nosy inside the thing later in the programme.

dinorwig 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 a method of using their generated energy 24/7 despite the weather or time of day and this is where batteries come in. 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 every day. they 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 sheets 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 facilitates 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 isjohn bannister goodenough and when i was at oxford when we developed the cathodes that enabled the lithium ion battery that you use in your cell telephones and laptop computers, i didn't really think about whether 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 fossilfuel 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 dr 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 technologies. and this summer the uk government pledged £250 million 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 chemistries

then yes, you'll see a battery fire and potentially a rupture and so on so there's tight innate chemistries, called iron phosphate chemistries, which are a safe option for using public transport so on. as a research 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 somewhere in the world there is a scientist trying to make a battery out of those. calcium batteries, aluminium batteries, lithium sulphur batteries, sodium ion, there's a range of different sodium ion batteries and so on. there's a whole range of different chemistries being worked on, so although we're working on lithium ion at the moment and we're persevering with lithium ion, there will be more developments in the future as we move onto different types of chemistries. as the uk's leading automotive battery r&d centre, wmg works at the intersection between scientific research and industry with the likes

of nissan and jaguar land rover as close collaborators. here's a module we developed and it represents about a 70—80% 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 constructed. packing the cells tighter together while maintaining safety, improved cooling systems, etc. at the moment cost and range of new evs and the number of charging points available to us is an issue. manufacturers like nissan even offer up a replacement diesel or petrol replacement for customers needing to drive longer distances as part of their promise scheme. as well as batteries, wmg is looking at how our charging behaviour can affect battery life, to 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 gigafactory aims to produce enough batteries to power after million new electric cars every yea i’. tesla boss elon musk‘s ambitions go further than revolutionising our cars, though, he wants to rewire our homes too. enter the powerwall, 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 be a growing trend in companies

creating home batteries to harness solar power. so how exactly does this work? 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 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 vehicle and thanks to the way that feed—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 two 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 panels and a moixa 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 experience. here in this year 6 classroom you can see the solar panels out of the window and here is the battery that's 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 consumable by the homeowner, claiming the average uk home could up to £560 a year from their electricity bills. meanwhile british company powerbolt are working on giving older electric vehicle batteries a second life as 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 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 a week when panic was 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 it's opened 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 flying taxi designed by german outfit volocopter, 18 blades power the drone with passengers selecting the destination via touchscreen. meanwhile, a company called passenger drone released video of its self—flying drone testing in europe. the 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 echo plus can act as a smart home hub, connecting to an controlling other devices. finally james dyson, of colourful expensive vacuum 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 lake, which is about 600 metres above us, down this pipe, hits this valve and stops. this is the biggest tap you will ever see, and there 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, that's 92,000 gallons per second. or, as it says here, 1.5 million cups of tea. not sure if that's a earl grey or english breakfast. do we have flow?

we have flow. there it is, turbine number two spinning at about 500rpm 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 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 wouldn't 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 is 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 lakes, the lakes are ideally close together, good vertical separation. they're not the kind of things you can easily build on the back of a wagon and wheel 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 such places. does it get lonely down here? sometimes. whilst this is powering our homes, kat hawkins has got some top tips to help power our phones. for a lot of us, we feel we can't live without our smartphones. and so when the battery dies and we don't have access to power, it can be a massive inconvenience. now, there are things you can do to save your battery: dim your brightness, turn of wi—fi, gps, and any background apps you don't need to use. but there are a number apps out there which claim

to save your battery. do they actually work? greenify, battery doctor and du battery saver are three of the most popular battery—saving android apps. they've got millions of five—star reviews on google play, suggesting people think they work, so we thought they made a good testing ground. they claim to do a number of from dimming your brightness, to hibernating or optimising your apps, or reducing your data being used. soto start off, this team took a brand—spanking new samsung galaxy j3, and hot—wired it. the voltage, the current, and the power. so if we turn the phone on, from idle, we can see and using a small number of apps over a ten—minute period. then they did the same thing with the battery savers installed, as well as the in—built

battery power saver, which comes installed on the phone. so we can see that the power savers do seem to work. they make a small difference for battery doctor and du battery saver — about two or three hours, by the looks of things. and then greenify actually makes a difference of about four hours. when you think this one is doing better? we think that is because it is the way the apps work. so du battery saver and battery doctor, they offer you an option to optimise the performance of your apps, so we suspect they are reducing frequency at which applications access mobile data, making them run less in the background, whereas greenify seems to put you into a hibernation mode when you put your phone into idle. but interestingly, the most efficient seems to be the android power saver, the one that comes on the phone when you get it from the factory. but this is currently a limited test of ten minutes, and all conducted on the wi—fi. what needs to happen now is a bigger test of hours at a time, using apps that stream videos, play games, or use gps.

the team here has not yet determined whether the apps do everything they say they do, but do think you can do many of the features yourself, if you're organise enough. but most want to use their phones hassle—free, so the apps help with the underlying management. but there are other 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's charged after a couple of hours, that time at 100% charge, overnight, will significantly accelerate the degradation of the battery. even better for your phone battery's life, max says, is to keep your phone charged between 20 and 80% at all times. so remember, that's 20—80. thank you, kat. but wouldn't it be nice to get to that 80% much faster? cue a very different battery technology that can be something like this.

instead of of the electrochemical charging in normal batteries, this charges 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 full 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, which are extremely fine particles at the nano level, and a large surface area is greeted inside one of these pouches, that attracts energy very quickly. the more surface, the more energy you can attract. the downside of super capacitors is that they can't store as much as lithium ion, so you wouldn't want one in your phone. they are best suited for things that need quick charging and big short bursts of power, like tools and toys, such as the scooter.