If you’re suffering for the profits of big companies, then you really need to think about your addiction, which is costing you an extra £400 per year as of today.
Big companies are making Millions of pounds in profits for your pocket, with some recording £8 Billion in the last few years. that being said Some of the top earners not only profited from your pocket directly but by government hand outs, so indirectly from your pocket.
England is not the sunniest of places, but its far from drab enough to ruin your solar power dreams. To give you some idea, we have two panels that today made 4kwh of power from the sun. This is just two panels, imaging if you had more? Most homes can fit 8 panels which would give you 16kwh of power and if you pop down to your smart meter to look at your power use today, I would think that for many homes that your going to hit that mark sometime tonight.
What are the costs and savings with solar?
Solar is a bit of a give and take, but there are quite a few options and all come with different costs or compromises. Its certainly not a one system suits all. The way to look at solar is in its value, because if it is not good value then there is no point in having solar installed.
Solar power is not free energy, as you have to buy the hardware you need first, the production of power must cover that cost, and then after than you get “free power”. This is called the ROI – Return on Investment.
Grid tied is one of the lowest cost options, but could be a fairly bad investment and here is why.
Grid tied work with the power grids and will make AC power from the solar panels, therefore you could say they make power during the day. If your out at work then you need to set timers on washing machines and driers to use that power during the day. In the evening when the suns low in the sky then your making less power from the solar and using power getting your dinner ready.
Hybrid inverters are like a grid tied inverter, but they have a battery. What happens here is that the solar power goes into the home and to the battery before is given to the big company for free to profit from you. The difference here is that when the sun is down you run the inverter from the stored energy from the battery. thus you are not paying a bill.
Off grid and Grid attached. The off grid system work without the grid and you save money by not having a standing charge as well as not paying a bill. The design of these systems needs to be more robust as you do not have a fall back to the grid.
Grid attached on the other hand plugs into the grid and works a bit like a UPS and can offer different modes of work. For example, they may power your home using the solar and battery, and if your power production is too little they will feed the grid to the home. They can also work as a ups if you get power cuts unlike most grid tied inverters.
Why do I need the power grid?
With grid tied inverters, they do not work without a grid connection, Some hybrid inverters will also not work unless they have a EPS, which is a separate off grid system.
In the UK winters can be grey and over cast therefore solar is NOT going to charge your battery, therefore you could charge from the grid at cheap rates.
If you did not want the grid, then you would use a generator to charge the battery.
If your off grid how many days would you need a generator?
Typically as an average you would need a generator for 90 days of the year if you want to do the math here, the standing charge is £237 per year, you would run a generator for around 4 hours to charge the battery. Different generators, charge rates and battery size will change that run time. – You would use a 4kw generator, but you could use a 2.2kw.
Solar battery packs.
Buying a battery is pretty simple, our 15kwh batteries are available for £1650. The current value of the battery is around £3.90 per day(cycle), meaning they pay for themselves within two years and 3 months.
The key with the battery size is that it should support your loads, The way to work this out is to half the battery capacity (or limit) and multiply this by the nominal voltage, in this case the output power will be 7.14kw.
There is a best “position” to have the current load on the battery, again in this case is 2.85kw.
We then turn back to your loads ( how much power you “normally use”) and if you are below 2.85kw then 1 battery will work okay for you, but you can run up to 7.14 kw which is well within the margins of the battery output.
The lower the load the better it is for the battery, so if you want to add a battery to get up those kWh to meet your needs, then just add a battery as the ROI time does not change. The initial cost would change.
The inverter,
Hybrid inverters are the thing to have if you still have your apron strings firmly tied to the grid. You may want to have a EPS installed which means that you can have power when the grid goes down. The key points to look out for is the actual output power.
Today I was contacted and asked about a SPH6000 which for the most part is a 6kw inverter, But its not.
It is actually a 3.2kw inverter when running on the battery, the remaining power is from the solar, so at night you and days where there is little sun, you may find that your running from the battery and are limited to the total output due to not having enough solar.
The point also here which is worth knowing is that the charge current was 65 amps, This is DC and not AC. so on the grid charge you can only charge at 3.3kw. This would mean a 15kwh battery would take a little over 3.5 hours.
This is important to know if you have a cheap rate window that’s small and these can be open for 4 hours.
The same would apply here with a grid attached inverter. but you would also need to know the pass though. The pass through is where the solar/battery does not provide the power but makes a direct connection with the grid to your home. They can be quite low. For example 35 amp will give you a load of just 8kw, 65amp will give you 14.9kw. This is always worth checking before you buy and knowing your peak power use.
Off Grid requires planning and redundancy, In such cases I would normally suggest two inverters that are paired. This means you can double your power, but also shut down on inverter so that you are conserving power.
With that in mind if you blow an inverter you always have the other to fall back on.
You will need to consider a secondary power source, such as a generator or water wheel that can provide you power when the suns so low that you cannot get a useful amount of power from it. You would also want to over size the battery capacity so that you have reserves, Also the fact that the first part of the charge can be fairly quick.
This means that you will need a good sized generator, one that also acts as a fall-back and charger. So you would be looking at a 10kw generator, this may sound odd, but lets say you are charging the battery and running the house, and you would not want to run a generator at 100% – check the power curves on the data sheet.
Note that you will want to run the generator now and then to keep it in good shape.
With off grid, you would want to over size the array, but you will want a summer and winter array to really make the system work for you. The winter sun hours are as little as 2 hours, therefore a bias for winter over the much longer summer days of around 8 hours will balance the power over the year that the standard average.
Export cash maker.
The energy trader in you may want to store power from the battery at cheap rates or from solar, and then sell it back to the grid, there are some deals around where you can get as much as 0.41p per kwh you can export.
You don’t need to have solar and you do not need to trade, but if you can buy power at 0.04p kWh to use all day, then you could save.
To fill the battery would cost £0.60 at cheap rate. it would be worth £3.25 Making you a profit/saving of £3.15 at standard rates the ROI would be about 1.4 years. = over the life of the battery you could save £31,500
If you are charging from solar, then you could make more, as well as the prices of export vary, so you could make more or less.
The cat in the bag here is that you would need a big inverter that is approved by the DNO to out put power.
Consultations.
If you’re planning on solar, you can buy hardware from us and the solar shop, but you can also have the projects managed. This means that you buy hardware at great prices and you get our expert knowledge and support.
There are other options that we do not detail on the website, that can save money and work as well as other configurations.
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