Today is the day. The solar panels Jack has been dreaming of for such a long time are finally being installed on the roof of his house as well as a storage battery in the basement. This is a good opportunity for Jack to share a little bit more of his profound knowledge about solar energy with his niece.
Jack: Come on Lucy, while we’re watching the experts installing more of the latest technology for our household, I will explain some more details to you regarding solar power. Our government has planned to have 2 million homes equipped with solar energy, 24000 commercial rooftops and 2000 solar farms by the end of 2020.
Lucy: Oh, this sounds like a lot and I always thought this wouldn’t be possible with your kind of weather.
Jack: The UK is one of the largest markets in Europe and experts estimate that in this way around 50000 well-payed green jobs could be created by 2030 if we continue to put so much effort into it. Solar systems have made it possible that we have produced more electricity with renewables than with nuclear plants for the first time this year.
Lucy: That’s a truly amazing achievement, I would say. But can you tell me, Uncle Jack, how is solar power actually generated? I understand that the energy which is radiated by the sun is turned into electricity, but how?
Jack: Well, I’ll try to explain it in simple words. Solar panels are made up of photovoltaic cells. By the way, you also have these in calculators which you are more likely to be familiar with. The word »photovoltaic« means electricity from light, because photo means light and voltaic means electricity. These photovoltaic cells consist of semiconductors such as mostly silicon and transform the incoming sunlight into electricity. Inside the solar cells are thin semiconductor wafers which form electric fields that are positive on one side and negative on the other. When light strikes the cells, some of it is absorbed within the semiconductor material. This energy knocks electrons loose that will flow freely and thus create electricity which in turn can power light or a tool for example. And when you connect a number of solar cells to each other in an electrical circuit, mount them in frames, then you have photovoltaic modules.
Lucy: Why do you know so much about this subject?
Jack: Quite simply, because it’s a major investment that you make when you have such solar panels installed. Therefore, it only makes sense to dive into the subject to see whether it’s really worth the money and being a technician, I find it extremely interesting.
Lucy: But what happens to all the solar power that you don’t use?
Jack: Good question, my dear. The peak time for solar power generation is in the middle of the day, when the sun is at its highest point. This, however, is also when most people are at work and can’t use it and so the electricity just goes into the grid. In the evening when you’re back home, the sun has gone down and you have to pay for the electricity you use. And this is exactly why I’ve also ordered a solar battery. In this way all the unused electricity produced during the day is stored and I can use it whenever I need it. Moreover, you can get better deals when you buy solar panels and a storage battery at the same time and can invest the money you have saved in a better battery, which makes you more independent of the National Grid.
Lucy: How much does a solar battery cost?
Jack: Well, that depends on the battery’s capacity, material, lifespan and the installation process. The more electricity a battery can store, the more expensive it will be, of course. At the moment you generally pay between 2000 £ and 7000 £. I’ve chosen a reliable one with a decent lifespan. It’s neither the cheapest nor the most expensive one.
Lucy: Wow, that’s quite a price! Are you sure it’s really such a good investment?
Jack: Well, don’t forget that my energy bills will be much lower, not to forget the carbon footprint which will be reduced. And when there’s a power cut, it will still operate independently. Moreover, prices charged by the electricity companies have constantly risen over the last few years. So, in my opinion, it’s a big step towards self-sufficiency and the benefits outweigh the initial expense.
Lucy: Oh yes, I see, this really makes sense. By the way what size does the battery have and where in the house do you have it installed?
Jack: Well, even though I normally live all by myself, it’s a relatively big house, so my battery has the size of a kitchen fridge. It generally depends on the capacity that you need. A 2 kWh battery for example is roughly the size of a microwave and can be mounted on the wall. Since the battery I have chosen can only be located indoors, they have to put it in the basement. I’ve cleared some space especially for this purpose. Due to its dimensions it must be placed on the floor. As a rule of thumb, a 3-4 kilowatt peak (kWP) solar panel system will be enough for a three-bedroom house. It has around 12 – 16 panels and produces approximately 2500 kWh of electricity per year. So, in this case you’d need a solar battery with around 3 - 6 kWh of capacity. And this is exactly the model that I have chosen, even though I’m usually a one-person household. But it might give me the chance to go completely off-grid.
Lucy: But tell me, how much electricity can a solar battery hold?
Jack: We’re talking here about the capacity of a solar battery, that is how much electricity it can hold. This is measured in kilowatt hours and a kilowatt hour is equivalent to one kilowatt of power sustained for one hour. The general capacity of today’s solar batteries is 3-7 kWh, but there are also smaller and larger models, of course. It’s, however, not only the capacity that counts but also the battery’s power rating. This means how much electricity can be delivered by the battery at any one time, which is measured in kilowatts. So, if your solar battery has a high capacity but a low power rating, it can hold a lot of electricity, but you can’t power many things at once. On the other hand, you can stack most models on the market today, just in case one is not enough, just like LEGO bricks. And the same is true when you want to expand the solar PV system. Instead of building a bigger one, you can simply add panels to the existing system.
Lucy: And how long do they last, considering their high price?
Jack: They normally have a warranty period of 10 years.
Lucy: What? And then they stop working?
Jack: No, absolutely not. But it’s like with your mobile phone. Constantly charging and discharging its battery leads to wear and tear and so it operates at a reduced level. For a solar battery, this would probably be something like 70% and you might have to replace it after roughly 15 years. By the way, some trains in the UK are now running on a rail line which is powered completely by a solar farm. There are roughly 100 solar panels at the trackside that supply renewable electricity for signalling and lights. The final goal, of course, will be to directly power the trains that use this route from next year on already. As of 2024, our government aims to get away from diesel-powering the trains on the entire rail network. Billions of pounds will be spent in this way.
Lucy: Pretty advanced technologies that you use in your country. Not bad. But what are solar farms?
Jack: These are large areas of land with interconnected solar panels next to each other with the purpose of harvesting large amounts of solar energy at the same time. They’re mostly located in rural or agricultural areas and are very big, up to 100 acres sometimes. They feed directly into the National Grid. You can also call them solar fields or solar parks. But whatever you call these, we’ll call it a day now, Lucy. I need to have a talk with my colleagues. Looks like they’ll be finished for today any time soon.
GrammarThe Past Tense also has a progressive form, which is called the Past Continuous or Progressive. (Verlaufsform der Vergangenheit).
Forming the Past Continuous/ProgressiveThe past simple of ‘be’ = was/were + verb + ‘ing’:
- I/he/she/it was working.
- We/you/they were working.
For negative sentences: ‘not’ has to be used:
- I was not (wasn’t) working when the secretary came in.
- They were not (weren’t) driving home when the accident happened.
- Were you having lunch when the boss came in?
- Why was he lying on the ground when the lights went out?
- Weren’t you watching TV when the telephone rang?
Use the Past Continuous/Progressive
- To talk about an event that was going on when another began: They were having a video conference when the fire alarm went off. What were you doing when I phoned you? I was watching TV. I wasn’t working. (Was hast du gerade gemacht als ich dich angerufen habe? Ich war dabei fernzusehen. Ich habe gerade nicht gearbeitet.)
- To talk about an action that was already in progress at a certain time in the past: What were you doing at 7 pm last night? I was watching TV. (I started watching TV before 7 pm and continued after 7 pm.) Five years ago, we were living in Rome. She couldn’t come to the party. She was working in the office.
- To talk about actions happening at the same time in the past: While the electricians installed the solar PV system, Jack and Lucy were watching. The secretary was writing the report while James was making a telephone call.
|Past Simple||Past Continous|
- two weeks ago
- in 2007
- last Monday
- When the children came home, Mary was cooking lunch. − When the children came home, Mary cooked lunch.
- Mary had already started cooking when the children came home. − The children came home, then Mary cooked lunch.
Vokabelliste »Solar panels and batteries«
zu Teil 19