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| ints:solar_electricity [2025/11/28 20:07] – created asimong | ints:solar_electricity [2025/12/17 04:30] (current) – external edit 127.0.0.1 |
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| ## What is solar electricity? | ## What is solar electricity? |
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| Solar electricity is the generation of electricity from the power of the sun, via photovoltaic (PV) cells. It is different from [solar water heating](http://lowimpactorg.onyx-sites.io/lowimpact-topic/solar-hot-water/), where water passes through panels to be heated directly, and no electricity is generated. | Solar electricity is the generation of electricity from the power of the sun, via photovoltaic (PV) cells. It is different from [solar water heating](/watr/water), where water passes through panels to be heated directly, and no electricity is generated. |
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| The solar electricity produced this way (and also from batteries) flows in one direction only, and so is called direct current, whereas electricity from the UK national grid is alternating current, as the flow of electrons changes direction 50 times per second. Direct current can be stored in [batteries](http://lowimpactorg.onyx-sites.io/categories/batteries) to power 12 volt appliances. However, these are more expensive and less readily available than ordinary domestic 240 volt appliances, so batteries and an inverter can be used to convert the 12 volt direct current to 240 volt alternating current. | The solar electricity produced this way (and also from batteries) flows in one direction only, and so is called direct current, whereas electricity from the UK national grid is alternating current, as the flow of electrons changes direction 50 times per second. Direct current can be stored in [batteries](/batt/batteries) to power 12 volt appliances. However, these are more expensive and less readily available than ordinary domestic 240 volt appliances, so batteries and an inverter can be used to convert the 12 volt direct current to 240 volt alternating current. |
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| Alternatively, the panels can be connected to the grid through a solar grid inverter with a meter to record how much electricity has been generated, whether it's used in the home or exported . A grid-support system is one where batteries are also included to store surplus electricity that would have been exported into the grid. This can then be used to buffer loads taken from the grid later in the day - the loads are shared between the batteries and the grid to reduce grid consumption. Battery damage is prevented by a battery management system (BMS) to prevent both over-discharge and over-charging. | Alternatively, the panels can be connected to the grid through a solar grid inverter with a meter to record how much electricity has been generated, whether it's used in the home or exported . A grid-support system is one where batteries are also included to store surplus electricity that would have been exported into the grid. This can then be used to buffer loads taken from the grid later in the day - the loads are shared between the batteries and the grid to reduce grid consumption. Battery damage is prevented by a battery management system (BMS) to prevent both over-discharge and over-charging. |
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| The first thing to do is find out how much electricity (in kilowatt-hours, kWh) you use in a year (check your bills - a kWh is a unit of electricity on your bill), and think about ways to [reduce your usage](http://lowimpactorg.onyx-sites.io/lowimpact-topic/energy-saving/): switch lights off when you leave the room; don’t leave appliances on standby; use a laptop (c. 18 watts) instead of a desktop (c. 180 watts); use Savaplugs and [low-energy lighting](http://lowimpactorg.onyx-sites.io/lowimpact-topic/led-lighting/) and appliances; don’t overfill kettles; think about [solar hot water](http://lowimpactorg.onyx-sites.io/lowimpact-topic/solar-hot-water/) and a [wood-burning stove](http://lowimpactorg.onyx-sites.io/lowimpact-topic/wood-stoves/), and whether you need so much electrical gear at all. | The first thing to do is find out how much electricity (in kilowatt-hours, kWh) you use in a year (check your bills - a kWh is a unit of electricity on your bill), and think about ways to [reduce your usage](/ensa/energy_saving): switch lights off when you leave the room; don’t leave appliances on standby; use a laptop (c. 18 watts) instead of a desktop (c. 180 watts); use Savaplugs and [low-energy lighting](/ledl/led_lighting) and appliances; don’t overfill kettles; think about [solar hot water](/watr/water) and a [wood-burning stove](/wstov/wood_stoves), and whether you need so much electrical gear at all. |
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| A typical UK family will use about 3000-4000kWh per year, but if you're single with no children and / or reduce your electricity consumption, that figure might be 2000kWh per year. Taking the annual amount of sunshine into consideration, this will require a 2.4kW system. But any size system will help save money and carbon emissions. | A typical UK family will use about 3000-4000kWh per year, but if you're single with no children and / or reduce your electricity consumption, that figure might be 2000kWh per year. Taking the annual amount of sunshine into consideration, this will require a 2.4kW system. But any size system will help save money and carbon emissions. |
| There are currently no financial incentives for new installations, but with huge reductions in the cost of parts over the last 10 years, it’s eminently sensible to fit your own system. As you extend your grid solar system there will be a point where you're exporting more than half of your power. As rules continue to change about whether and how much you get paid for the power you export to the grid, this could be the time to fit a diverter that monitors any potential export and instead of letting this happen, diverts the power that would have been exported into a dedicated load, like your immersion heater, storage heater, or electric vehicle; see video: | There are currently no financial incentives for new installations, but with huge reductions in the cost of parts over the last 10 years, it’s eminently sensible to fit your own system. As you extend your grid solar system there will be a point where you're exporting more than half of your power. As rules continue to change about whether and how much you get paid for the power you export to the grid, this could be the time to fit a diverter that monitors any potential export and instead of letting this happen, diverts the power that would have been exported into a dedicated load, like your immersion heater, storage heater, or electric vehicle; see video: |
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| | _Installing a grid diverter to prevent export to the grid._ |
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| _Installing a grid diverter to prevent export to the grid._ | |
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| One of our course tutors (in the days before feed-in tariffs) installed panels and an inverter costing £3000, metered the electricity they produced, and compared the results to putting £3000 in the bank and paying his electricity bills from that. After 18 years the money in the bank was gone, but his PV system had paid for itself 6 years previously, and was still generating electricity. So payback times can be very project-specific, and can often be cost-effective even without government incentives. | One of our course tutors (in the days before feed-in tariffs) installed panels and an inverter costing £3000, metered the electricity they produced, and compared the results to putting £3000 in the bank and paying his electricity bills from that. After 18 years the money in the bank was gone, but his PV system had paid for itself 6 years previously, and was still generating electricity. So payback times can be very project-specific, and can often be cost-effective even without government incentives. |
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| The cost can’t (easily) be reduced by self-build (like solar hot water), because the manufacturing process is too high-tech, but you could self-install if you have the know-how. Of course you could use PV in combination with a [wind turbine](http://lowimpactorg.onyx-sites.io/categories/wind-generators) to take advantage of all weather conditions. | The cost can’t (easily) be reduced by self-build (like solar hot water), because the manufacturing process is too high-tech, but you could self-install if you have the know-how. Of course you could use PV in combination with a [wind turbine](/wind/wind_generators) to take advantage of all weather conditions. |
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| Other factors to consider with solar electricity are: is your roof south-facing? Is it big enough? (if not, panels could be located on a frame in the garden or on a flat roof) Is it shaded? (If just one of your panels is partially shaded, it can affect all the panels in your system). If you're using [batteries](http://lowimpactorg.onyx-sites.io/lowimpact-topic/batteries/) they need to be deep-cycle (able to be continuously drained and re-charged) with a charge controller to prevent overcharging. | Other factors to consider with solar electricity are: is your roof south-facing? Is it big enough? (if not, panels could be located on a frame in the garden or on a flat roof) Is it shaded? (If just one of your panels is partially shaded, it can affect all the panels in your system). If you're using [batteries](/batt/batteries) they need to be deep-cycle (able to be continuously drained and re-charged) with a charge controller to prevent overcharging. |
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| ## Free online course | ## Further resources |
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| Here’s our free [online course](http://lowimpactorg.onyx-sites.io/solar-electricity-course/) on all aspects of solar electricity. The tutor is Andy Reynolds of [theInfoWorks](https://www.youtube.com/@TheInfoworks). Note that the course is slowly slipping out of date, but there's lots of free information on there that you might find useful. | - free [online course](http://lowimpactorg.onyx-sites.io/solar-electricity-course/) on all aspects of solar electricity. The tutor is Andy Reynolds of [theInfoWorks](https://www.youtube.com/@TheInfoworks). Note that the course is slowly slipping out of date, but there's lots of free information on there that you might find useful. |
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