Solar Power - a DIY guide

Hello and welcome to Just Have a Think. I'm Dave Borlase and this week I'm going to be having a think about how technology and collective action have been coming together over recent years to make some real reductions in human climate impact. I'd also like to find out if collective action has really got a role to play in the future or whether we're going to be just reliant on our governments to make all the decisions for us. So I went to have a look at some numbers behind the initiatives I've already talked about in the previous programs. This is an article from Businesswire showing that the move to LED lighting around the world removed half a billion tons of CO2 from our emissions in 2017. That's a 1% reduction just by changing our light bulbs. In Europe in 2015 the move towards renewable energy cut CO2 emissions in that year by 10% and that number is growing fast. Even the installation of water meters with their resultant 12% reduction in water use helps to reduce the carbon footprint by reducing the amount of energy required in a chemical waste treatment. These are all significant reductions on a global scale but they only come about when large numbers of people change their habits collectively rather than individuals thinking that their contribution is so insignificant that it's not worth bothering. Here's some other examples of where we can easily all do our bit. Uncle Attenborough gave us a good talking to about this stuff back in Blue Planet earlier on in the year and as a result of the public outcry, which is another example of collective action at work, the microbeads in this product and others are going to be banned from sale in July 2018. I'm personally not going to wait till then, I'm going to cut that up and dispose of it carefully. Here's another one. In fairness manufacturers have gone to great lengths to make the plastics that we use for these bottles much more recyclable these days but it's still pretty mental for us to be walking around with one of these in our hand in a western society. This is a 750 milliliter bottle and to make this bottle of water requires two and a half liters of water. This thing is also 750 milliliters but it's a reusable plastic bottle I got off Amazon for seven quid. Fill it up from the tap, it's the same water, does the same job. Folds up to that size, stick it in your pocket, easy. Then of course there's the direct energy that we all use every day. I'm sure we've all got one of these and probably most of us have got one or two of these as well. Well today there are 4.9 billion smartphones in the world and 1.4 billion electronic tablets. An already mind-boggling number that's rocketing upwards as the developing nations race to come online. Charging all these devices was estimated to have used 39,000 gigawatt hours of electricity in 2017 which means absolutely nothing until you realize that it's the amount of power you need to run two million homes for a year. These things are solar-powered chargers. This one's even made of nice recycled materials like bamboo. This is called ReSound which is a bioplastic, who knew? You stick them on your windowsill for a day and they charge up and then they charge your phones for you. This one's got 4,000 milliamp hours of charge which is a couple of iPhones worth. This one has got 10,000 milliamp hours worth of charge which is four iPhones. On a bigger scale domestic micro power generation is gaining traction all over the world as the hardware prices tumble and the technology to link it into distributed networks improves. This is a great example of collective action and it's set to be one of the most dramatic and powerful changes our society makes in the coming years as we'll have a little look at later on. So last year I took the plunge and decided to have a look at solar power systems for my own home but before going ahead and getting a professionally installed version done on the main house I thought I'd have a bit of a go at a DIY version. Let's have a look. When I bought my house I was very fortunate that the previous owners had already built a garden cabin which they use as an office. It's proved a really useful living space for us and last year before deciding whether to invest in a full solar power system for the house I decided to have a go at putting in a small DIY version on the cabin so I could learn about how it all works and not cause too much devastation if I cocked it up. Solar power works best on south facing roofs. Our house faces southwest so it's not perfect but it's good enough to get plenty of usable sunshine. I'll put links in the description section to all the websites where I got the various bits of kit but this is a very brief summary on how it all works. Essentially the sun hits the solar panels and the photovoltaic cells in the panels produce electrical power. These panels are rated at 12 volts and 300 watts and I've connected them in parallel which is positive to positive and negative to negative so that keeps the voltage the same but doubles the current to give an overall power output of 600 watts. Physics tells us that means the current can be up to 50 amps which is a big current so you need a big fat 10 millimetre squared cable, that's the size of a cable they use for cookers and power showers and things. That runs through this trunking down under the cabin and into a charge controller in this box. This thing regulates how much charge goes into the batteries and prevents them getting cooked. Also crucial to make sure everything's properly earthed by the way. The batteries are what's known as deep cycle AGMs. There's millions of YouTube channels all about different types of batteries so I'm not going to get into those details here. Suffice to say that these are what people use on boats and in caravans and Winnebago's and they're ideal for solar power systems if you don't want to go to the expense of lithium-ion batteries. These are 12 volts and 230 amp hours. You may remember the equation P equals IV from school. Power in watts equals amps times volts so 12 volts times 230 amps gives us 2760 watt hours or roughly 2.8 kilowatt hours. There's two batteries connected in parallel so that's a potential power output of 5.6 kilowatt hours. Lead acid batteries really don't like being discharged more than 50% though so I've got a usable supply of about 2.8 kilowatt hours which is 2800 watts for one hour. I've got a Mac, a TV, a stereo, a small fridge and a few lights in the cabin all of which add up to about 350 watts so there's enough oomph in these batteries to keep all those appliances all running at the same time for about eight hours. Next stage is an inverter. This thing takes the 12 volt direct current supply from the batteries and converts it into a 240 volt alternating current that I can use for my cabin appliances. Then we come to this little box of tricks. I've got two devices in here that protect my batteries from discharging too much without me having to worry about constantly unplugging stuff from the solar power and plugging it back into the mains. This display is the readout from something called the low voltage detector. It's got its own connection to the batteries and if they drop below a certain level of charge this thing switches off the circuit to prevent them draining any further. So let's have a look inside the box to see how we keep the power on when that happens. This thing here is a relay. A relay is essentially a very clever switch. You get a power input to an electromagnet at the top which selects between two other different power inputs at the bottom depending on whether the magnet is on or off. My little relay's got a 12 volt powered electromagnet driven directly from the batteries via the low voltage detector. Then it's got two 240 volt AC power supplies at the bottom. One's coming in from the inverter outside and one's coming in from a main supply via this plug. If the low voltage detector is on then the magnet pulls a little brass arm across to make a circuit with the inverter and if the low voltage detector is off the power to the electromagnet stops working and instantaneously the arm flicks back over to make a circuit on the other side with my mains power. It happens so quickly that I don't even notice so much as a flicker in the lights or on my computer screen. And that's it DIY solar. Here's a really good manual you can get from Amazon and here's some basic costs. You can get a basic setup with a 100 watt panel, a charge controller, a battery and inverter for around 200 quid. This size of system is ideal if you want to put some power into a shed for some lights and a couple of sockets or any outdoor space or area where your mains power doesn't reach and you don't want to go to all the expense and hassle of getting a spark in to run a completely new circuit. My setup is larger and it cost me just over a thousand pounds but bear in mind that I make use of this cabin every day. In fact it's where I film and edit these videos so I'm getting about 700 kilowatt hours of free energy per year which is saving me about 100 quid a year. So I'm looking at a 10 year payback but my electricity is free and it's causing zero carbon emissions. So how does all this link in with the United Nations Sustainable Development Goals that we've been looking at in recent weeks? There are a couple of Sustainable Development Goals that make a reference to technology. Number nine is Industry, Innovation and Infrastructure and number 11 is Sustainable Cities. This guy is called Jeremy Rifkin. He is an American economic theorist and political advisor. Back in 2007 Jeremy started working with the European Union and in particular Angela Merkel in Germany to implement what he calls the third industrial revolution. We are asleep. This is a wake-up call. This is about our survival. So we need to step back and take a look at how we create a new economic vision for the world. It better be compelling. We need a game plan to deliver on that vision. It needs to be quick. This new revolution is all about communication, energy and transport and it's based on a five pillar infrastructure. Pillar one is a binding commitment by the European Parliament to move to 20% renewable energy by 2020 and 27% by 2030. That's a mandate not a suggestion. Everyone has to do it. At the end of 2016 the figure stood at 16.9% and we're on course to hit the 2020 target. In Germany it's 32% of their total power right now in solar and wind and in Portugal in March the country made enough renewable energy through wind power to power the whole country for the month. Pillar two is to convert every single existing building into a green micro power plant by utilizing photovoltaics for solar on the roofs, turbines on sidewalls to capture the power of the wind and geothermal energy from underground systems. These technologies are already well established and they're being used already by millions of people across the continent. Pillars one and two have already created hundreds of thousands of new jobs in the renewable energy and construction industries to implement the required systems and infrastructure and as we go through the first half of the 21st century millions more will be created. Pillar three is to embed large-scale energy storage across the continent. This really is the linchpin that makes renewables economically and practically competitive compared to traditional fossil fuels. Tesla recently installed 100 megawatts of battery storage in Australia, the largest in the world so far, and similar installations are being put in all over Europe and it's estimated to be a 250 billion euro market by 2025. Pillar four, an energy internet. A new smart grid that takes electrical energy that your micro generation building doesn't need at any given time and using sophisticated software sends it in an instant to where it is needed, which could be anywhere in Europe. It's already happening in some areas and according to PR Newswire more than 200 million European households will have smart meters by 2023, only five years from now. Pillar five, transport of goods and people using electric vehicles and autonomous driving technology. According to a very conservative estimate in Bloomberg one in six vehicles will be electric by 2025. These vehicles will be a supplier of electrical energy to the smart grid as well as being a user. That's already happening in some parts of Europe as well. Cars sit unused for 90% of their life. In the new smart grid system a car gets charged up on cheap nighttime electricity and if the owner knows they don't need a full charge the next day they simply tap a few keys on an app and sell some energy back to the grid in the morning peak demand period. That way the vehicle is helping to smooth the energy demand curve in the morning and the car owner is getting paid for the privilege. It's the synergies between these five pillars that creates an environment for a completely new way of organizing our social infrastructure towards what will hopefully be a more sustainable future. In the last 15 years the world has already democratized the way we share information at near zero transaction cost as a result of the internet. Kids nowadays instinctively collaborate and share free ideas through open source software and forums and that is a dramatic change in our society. Within a very short time scale, a few years at most, we're going to be sharing energy collaboratively across countries and continents in exactly the same way as we share information across the internet today. That is a revolution and it's coming fast. It may not be too grandiose to suggest that our future depends on our ability to act collectively and collaboratively as a species. So in my little weekly program here I'm going to continue investigating and learning about all the ways that we can do exactly that. Anyway that's it for this week. Please do hit the red subscribe button below and share the link with your friends. It really is the best way to raise the profile of the channel. Thank you very much for watching, have a good week and remember to just have a think. See you next week!