Joe Blake
6th January 2015, 22:15
Been a long time coming ...
During my electronics apprenticeship in the mid 1960s I was introduced to the concept of photovoltaic power and once I grasped the potential of this power (pardon the pun) I had a thought in my mind that I'd like (a) a vehicle which was solar powered and (b) a house which generated all its electricity from the sun.
Several years ago I achieved the first of these with a brace of solar assisted recumbent tricycles.
http://i82.photobucket.com/albums/j245/saxeharp/house/trikes02_zps15485cb6.jpg
On 24 December 2014 I achieved the second goal with the commissioning of a solar hybrid power system, which takes me (virtually) off-grid. I say "virtually" as I am still connected to the grid and under the Western Australian Government's Renewable Energy Buyback Scheme (REBS) I have a contract with the utility Western Power to sell my excess power, and if needs be I can import power to charge the batteries of the system. To date (7 January 2015) I have exported roughly 37 units (kWh) and imported a single unit. The day I imported the unit the temperature at my back yard digital weather station peaked at 45 degrees C. My air conditioner, a small wheel-around refrigerated unit, struggled but managed to keep the indoor temperature down to a comfortable 26 degrees. The necessity to import power came when I ran the aircon after sunset, and the batteries took up the load.
Those who know me will not be surprised that I now produce a graph.
http://i82.photobucket.com/albums/j245/saxeharp/house/impvexp_zpsb7d800e2.jpg
It shows how much power I imported and exported since Jun 2013.
So what have I got?
In June 2009, I installed 5x210 watt SunPower PV Panels ($7,720) and one Kaco Powador 1501xi grid connected inverter ($2,275). Total cost including installation and delivery, $12,570. There were various government subsidies involved, but they have mostly disappeared, so I'll ignore them for present purposes. Several months later I installed a further 3 PV Panels, bringing the capacity of the PVs up to 1,600 watts, the capacity of the inverter. (3x$1,454 plus installation.) Estimated cost including GST $5,500
In June 2013, I installed a duplicate system consisting of WSP 260P6 Poly 260 panels ($557.20 each) plus a Kaco Powador 2002 1.65kW inverter, with $1,000 installation. Cost including GST roughly $5,900
In July 2014 I began moving to install a hybrid solar/grid system which consisted of batteries and inverter. The inverter is SP Pro 24v 2.8kW and the batteries were 12 x 67OPzV420. I also had a powder coated metal box to store the batteries and keep them away from prying fingers and screwdrivers. The estimated capacity of the batteries is 453 Amp Hours at 24 volts. Due to ongoing technical issues final cost is not settled yet, but the batteries were $4,620 and the inverter $5,033.60. Installation is still to calculated, as is that of the box, but a rough quote (for the box) was about $1,800. (About the size of a medium sized chest freezer it doubles as a light duty work table.)
http://i82.photobucket.com/albums/j245/saxeharp/house/chest_zpscf8afa4f.jpg
http://i82.photobucket.com/albums/j245/saxeharp/house/batteries_zps5da25fae.jpg
If you look at the bottom of the central inverter, you can see a black rod pointing downwards, a wireless antenna which links to my desktop computer so I can read instantly the state of play.
The inverter/controller is a gorgeous piece of tech wizardry which is supposed to do all sorts of things. However, I'm still learning the ropes with the software but from my initial experience it seems that the power from the panels goes into the SP Pro and is allocated as the user desires via settings. Generally, the priorities are to send sufficient power to the domestic circuit, followed by charge the batteries, then any excess goes to the grid and is sold sold under REBS
The technical issue I mentioned previously is that the initial Kaco inverter is (as I understand it) too old to communicate to the SP Pro, so therefore the SP cannot "manage" this power in the same way as it does with the newer Kaco. As it stands this "invisible" power is still used by the domestic circuit, but cannot directly charge the batteries. However, it appears that the invisible power frees up power from the new Kaco system which can go to the batteries or grid as required.
In summer time this is not a huge problem as there is an excess of solar power and when the batteries are on"float" (ie fully charged) several times during the day the system can be momentarily observed cutting the feed so as not to exceed the maximum AC voltage (265 volts) going to the grid. The practical difficulty is that, despite the fact it is sitting on the western side of the roof, the older system generates more power earlier in the day than the eastern panels. In summer time the (eastern) panels are shaded by a tree, but there is no benefit in cutting it back since the sun is at such a low angle it's pretty well irrelevant. When the sun is in the west, those panels are shaded by a tree so power cuts off at about 16:30 hours or so. Since the shade also affects my neighbour's panels we are in discussion as to what action to take about this shading. (He's considering installing a hybrid solar as well, but his planning is still under way.) In practical terms the western shading means that I have to turn the aircon off when this happens, otherwise it starts dragging power from the batteries while there is still lots of daylight.
However, in winter time, I suspect I will need the older inverter's input, but that remains to be seen. The shading by trees is mitigated as the sun moves to the north and goes into a shallower angle, so those two factors may cancel themselves out. I also have to bear in mind that during winter, I have about a fortnight or so worth of (random) days when I have to boost the solar hot water system. (I have a gas stove to heat water if it becomes absolutely necessary.)
There are a couple of options for the suppliers to take. ("Avant Solar" to give them a plug.) Firstly, to leave as is. At the moment I'm living with not (except for a solitary example) importing any power, even during the hottest of hot days to date (Jan and Feb are the traditional hot time of the year) and yet the house does not get uncomfortably warm. Secondly, is to buy an up-to-date inverter. (Whether I can resell or trade the old one in depends on a review by the Federal government.) Thirdly, seek out a way of upgrading the older inverter.
The government review is that into the Renewable Energy Target ("RET"). Without going into the politics there has been a look at the RET which currently is to see 20% of all energy generated in this country generated renewably. At present it seems that all renewable generation equipment is supposed to be new. If, as is expected, the RET is changed, then there may be a market for second-hand inverters and panels. I'm leaning towards gambling on the foreseen change happening and buying a new inverter and reselling the old one. Time will tell if it's a good bet.
So how is it performing at this moment? For me the figures speak for themselves. Cost. I look at it like this. Totalling up all the purchase and installation costs, over 6 years, I've outlaid roughly the price of a 2014 Subaru Forester ($31,000?). I have no running costs, smaller depreciation, I'm using it 24 hours per day instead of it sitting in the garage or in a parking bay chewing up money, it saves (even makes) me money instead of costing, it's easy on the environment, it can still be very useful if I decide to buy a hybrid car. (The batteries for an electric car can be used to store excess energy.)
Oh, and in the event of the grid going down due to lightning strike or fire or whatever, I'll be able to carry on as normal, except probably a line of people at my front door wanting to borrow a cup of electrons, or recharge their smart phone or whatever. :bigsmile:
I've imported a single unit of power since Dec 24 2014. On the morning of the absolute worst day, the state of charge (SoC) of the batteries was down to 55%. On a normal day, before the eastern panels begin to charge the batteries, the SoC is roughly 60%. My current settings are such that if the battery DOES need to be recharged other than renewably, I can take power from the grid during "off peak" and get a much reduced price for that power. (14.59 cents per unit as opposed to about 49 cents during "peak" time.) And what's best is I haven't (as yet) needed to change my pattern of consumption. On a good day, such as today, to add 0.1% to the SoC takes under 30 seconds. Under a heavy load, it can take nearly 2 minutes. That is without the input from the older inverter.
Winter, except for the boosting of the solar hot water system, will probably be on the plus side of the ledger since as of the last 6 winters I've not needed to use any artificial heating because the house is well insulated.
http://i82.photobucket.com/albums/j245/saxeharp/house/quickview_zps159536b1.jpg
The front panel shows a quick view of the state of proceedings. When the "charging mode" is on "float" it starts to send power out to the grid, as the batteries are full. The "full view" of the software has sufficient toys for the geekiest geek to play with.
http://i82.photobucket.com/albums/j245/saxeharp/house/dataview_zps66c15705.jpg
I commenced my electronics apprenticeship in January 1965. It's now January 2015. It took me a while, but I finally got to where I wanted to be.
During my electronics apprenticeship in the mid 1960s I was introduced to the concept of photovoltaic power and once I grasped the potential of this power (pardon the pun) I had a thought in my mind that I'd like (a) a vehicle which was solar powered and (b) a house which generated all its electricity from the sun.
Several years ago I achieved the first of these with a brace of solar assisted recumbent tricycles.
http://i82.photobucket.com/albums/j245/saxeharp/house/trikes02_zps15485cb6.jpg
On 24 December 2014 I achieved the second goal with the commissioning of a solar hybrid power system, which takes me (virtually) off-grid. I say "virtually" as I am still connected to the grid and under the Western Australian Government's Renewable Energy Buyback Scheme (REBS) I have a contract with the utility Western Power to sell my excess power, and if needs be I can import power to charge the batteries of the system. To date (7 January 2015) I have exported roughly 37 units (kWh) and imported a single unit. The day I imported the unit the temperature at my back yard digital weather station peaked at 45 degrees C. My air conditioner, a small wheel-around refrigerated unit, struggled but managed to keep the indoor temperature down to a comfortable 26 degrees. The necessity to import power came when I ran the aircon after sunset, and the batteries took up the load.
Those who know me will not be surprised that I now produce a graph.
http://i82.photobucket.com/albums/j245/saxeharp/house/impvexp_zpsb7d800e2.jpg
It shows how much power I imported and exported since Jun 2013.
So what have I got?
In June 2009, I installed 5x210 watt SunPower PV Panels ($7,720) and one Kaco Powador 1501xi grid connected inverter ($2,275). Total cost including installation and delivery, $12,570. There were various government subsidies involved, but they have mostly disappeared, so I'll ignore them for present purposes. Several months later I installed a further 3 PV Panels, bringing the capacity of the PVs up to 1,600 watts, the capacity of the inverter. (3x$1,454 plus installation.) Estimated cost including GST $5,500
In June 2013, I installed a duplicate system consisting of WSP 260P6 Poly 260 panels ($557.20 each) plus a Kaco Powador 2002 1.65kW inverter, with $1,000 installation. Cost including GST roughly $5,900
In July 2014 I began moving to install a hybrid solar/grid system which consisted of batteries and inverter. The inverter is SP Pro 24v 2.8kW and the batteries were 12 x 67OPzV420. I also had a powder coated metal box to store the batteries and keep them away from prying fingers and screwdrivers. The estimated capacity of the batteries is 453 Amp Hours at 24 volts. Due to ongoing technical issues final cost is not settled yet, but the batteries were $4,620 and the inverter $5,033.60. Installation is still to calculated, as is that of the box, but a rough quote (for the box) was about $1,800. (About the size of a medium sized chest freezer it doubles as a light duty work table.)
http://i82.photobucket.com/albums/j245/saxeharp/house/chest_zpscf8afa4f.jpg
http://i82.photobucket.com/albums/j245/saxeharp/house/batteries_zps5da25fae.jpg
If you look at the bottom of the central inverter, you can see a black rod pointing downwards, a wireless antenna which links to my desktop computer so I can read instantly the state of play.
The inverter/controller is a gorgeous piece of tech wizardry which is supposed to do all sorts of things. However, I'm still learning the ropes with the software but from my initial experience it seems that the power from the panels goes into the SP Pro and is allocated as the user desires via settings. Generally, the priorities are to send sufficient power to the domestic circuit, followed by charge the batteries, then any excess goes to the grid and is sold sold under REBS
The technical issue I mentioned previously is that the initial Kaco inverter is (as I understand it) too old to communicate to the SP Pro, so therefore the SP cannot "manage" this power in the same way as it does with the newer Kaco. As it stands this "invisible" power is still used by the domestic circuit, but cannot directly charge the batteries. However, it appears that the invisible power frees up power from the new Kaco system which can go to the batteries or grid as required.
In summer time this is not a huge problem as there is an excess of solar power and when the batteries are on"float" (ie fully charged) several times during the day the system can be momentarily observed cutting the feed so as not to exceed the maximum AC voltage (265 volts) going to the grid. The practical difficulty is that, despite the fact it is sitting on the western side of the roof, the older system generates more power earlier in the day than the eastern panels. In summer time the (eastern) panels are shaded by a tree, but there is no benefit in cutting it back since the sun is at such a low angle it's pretty well irrelevant. When the sun is in the west, those panels are shaded by a tree so power cuts off at about 16:30 hours or so. Since the shade also affects my neighbour's panels we are in discussion as to what action to take about this shading. (He's considering installing a hybrid solar as well, but his planning is still under way.) In practical terms the western shading means that I have to turn the aircon off when this happens, otherwise it starts dragging power from the batteries while there is still lots of daylight.
However, in winter time, I suspect I will need the older inverter's input, but that remains to be seen. The shading by trees is mitigated as the sun moves to the north and goes into a shallower angle, so those two factors may cancel themselves out. I also have to bear in mind that during winter, I have about a fortnight or so worth of (random) days when I have to boost the solar hot water system. (I have a gas stove to heat water if it becomes absolutely necessary.)
There are a couple of options for the suppliers to take. ("Avant Solar" to give them a plug.) Firstly, to leave as is. At the moment I'm living with not (except for a solitary example) importing any power, even during the hottest of hot days to date (Jan and Feb are the traditional hot time of the year) and yet the house does not get uncomfortably warm. Secondly, is to buy an up-to-date inverter. (Whether I can resell or trade the old one in depends on a review by the Federal government.) Thirdly, seek out a way of upgrading the older inverter.
The government review is that into the Renewable Energy Target ("RET"). Without going into the politics there has been a look at the RET which currently is to see 20% of all energy generated in this country generated renewably. At present it seems that all renewable generation equipment is supposed to be new. If, as is expected, the RET is changed, then there may be a market for second-hand inverters and panels. I'm leaning towards gambling on the foreseen change happening and buying a new inverter and reselling the old one. Time will tell if it's a good bet.
So how is it performing at this moment? For me the figures speak for themselves. Cost. I look at it like this. Totalling up all the purchase and installation costs, over 6 years, I've outlaid roughly the price of a 2014 Subaru Forester ($31,000?). I have no running costs, smaller depreciation, I'm using it 24 hours per day instead of it sitting in the garage or in a parking bay chewing up money, it saves (even makes) me money instead of costing, it's easy on the environment, it can still be very useful if I decide to buy a hybrid car. (The batteries for an electric car can be used to store excess energy.)
Oh, and in the event of the grid going down due to lightning strike or fire or whatever, I'll be able to carry on as normal, except probably a line of people at my front door wanting to borrow a cup of electrons, or recharge their smart phone or whatever. :bigsmile:
I've imported a single unit of power since Dec 24 2014. On the morning of the absolute worst day, the state of charge (SoC) of the batteries was down to 55%. On a normal day, before the eastern panels begin to charge the batteries, the SoC is roughly 60%. My current settings are such that if the battery DOES need to be recharged other than renewably, I can take power from the grid during "off peak" and get a much reduced price for that power. (14.59 cents per unit as opposed to about 49 cents during "peak" time.) And what's best is I haven't (as yet) needed to change my pattern of consumption. On a good day, such as today, to add 0.1% to the SoC takes under 30 seconds. Under a heavy load, it can take nearly 2 minutes. That is without the input from the older inverter.
Winter, except for the boosting of the solar hot water system, will probably be on the plus side of the ledger since as of the last 6 winters I've not needed to use any artificial heating because the house is well insulated.
http://i82.photobucket.com/albums/j245/saxeharp/house/quickview_zps159536b1.jpg
The front panel shows a quick view of the state of proceedings. When the "charging mode" is on "float" it starts to send power out to the grid, as the batteries are full. The "full view" of the software has sufficient toys for the geekiest geek to play with.
http://i82.photobucket.com/albums/j245/saxeharp/house/dataview_zps66c15705.jpg
I commenced my electronics apprenticeship in January 1965. It's now January 2015. It took me a while, but I finally got to where I wanted to be.