Joined
·
257 Posts
I´d be interested to hear about other´s solar systems, as well as thoughts on ours, for those that are into solar.
Changed my mind
I originally decided against solar thinking it would not be economical since a) we are renting, so may have to pay for the cost of moving the structure and b) we cannot sell to the grid. I bought carbon offsets instead.
But I changed my mind. Offsets don’t work on their own, we have to stop using fossil fuels as well. I also think our solar panels might inspire a neighbour or friend to do the same.
We also have regular power cuts so the system helps us with that.
I also have an EV now and I work from home, so I can charge the car whenever it is sunny, which makes the problem of not being able to sell to the grid relatively less of an issue.
Specs
In recent years we used (from the grid, before buying solar and an EV) 2.7 MWh/yr (family of 4). I anticipate +1.3MWh/yr for the car`s home charging, so 4 MWh/yr demand now or 11kWh/day.
The system is ten 325W panels (Risen) so 3250Wp. We have the system pointed due north (I am in Chile), so we can get about 5.7 MWh through the panels per year, perhaps 5 MWH after allowing for system inefficiencies. That is about 70% more than if the panels were in England, and about the same as Los Angeles and Casablanca which are at the same latitude as us.
The projection from the Chilean website Explorador Solar is we`ll get an average 10kWH per day in June/July and 17kWH/day in December/January/February.
I guesstimate about 1 MWh/yr we will have to use grid for (mainly due to cloudy days). (As of September 2020 it looks like it might be under 1MWH/year, maybe nearer 0.7MWH.) That would mean we only use 3 MWH of the solar and could waste 2 MWH/yr if we don´t make changes.
Using the Extra 2MWh
Could take extra trips in the car.
Put in another cooling fan we don’t really need just to feel ice cold in summer.
Kettle for washing the plates and shaving instead of gas on a sunny day; add another kettle´s worth to a vacuum flask for the evening or the following cloudy day.
Using the kettle to put pre-boiled water into the pans on the gas hobs at lunch time on a sunny day. This may make more sense than an electric cooker which would just add to the expensive grid electricity (39% coal) in winter and in evenings.
We have thought of the idea of connecting the solar to the hot water for showers but this is a rented property so there is a limit to how much we want to do when we may have to move out before recovering the investment. Also, there is no hot water tank; water is heated up on demand which doesn´t work as well with solar. But I might have a think about a solution for showers/washing.
We can use the electric heater in some sunny mornings to save on using the gas/heating oil ones, but obviously heating need doesn´t match well to solar availability, so this is a pretty limited option.
I did wonder if we could sell electricity to others somehow, but I can´t think of a practical idea about how to do that. I don’t think any of the neighbours has an electric car.
Energy storage
We have 4 Utracell sealed lead acid UCG 100-12 batteries (4.8kWh) but the last 25% is not used to protect the life of the batteries, then there are losses, so may be nearer 3kWH. We´ve had days where the battery is full in the afternoon and a little energy is wasted, but still ended up spending 1-2kWH overnight. I asked the installer to come back and add 2 batteries more but he said it has to be 4 which isn´t worth the spend.
I did wonder if you can get a plug-in battery of a decent size (few hundred WH to a kWH): i.e. plugs in to house socket to charge and you can unplug the battery from the socket when full and then plug perhaps the TV and set top box and a charger into it later in the evening or on the following cloudy day but so far when I googled it I couldn´t find a simple plug-in solution with no installation. But might have another look later.
I also wonder if you can buy something like a plug-in device with no installation that you could store hot water in. Something like a kettle but larger (maybe 5-20 litres) and very well insulated and running at a lower wattage (again: few hundred watts to a kW). Didn´t find anything on the first google search.
To try and reduce grid spend a little overnight, I´ve actually been charging up my computer and phone in the day time only (I work from home), and charging up my kindle and spare computer only on sunny days. I even had the idea the other day to turn down the fridge and freezer temperature a degree or two on a sunny day, and turn it back up again in the evening!
Cost
About £4000. It was actually slightly higher because we put a separate structure in the garden that can be demounted more easily and because the owner was worried about the roof. However, had it been a roof installation, it would have been a little under £4000.
I estimate this will reduce our annual electricity bill from £560 to £100, for a saving of £460. We should also be able to use more electricity to reduce on use of gas for hot water and heating, guess £80 saving per year, total £540. (Updated these figures September 2020 using latest data. I currently estimate spending £100 on electricity per year rather than initial estimate of £140.)
That gives us a best case payback period of 8 years (if no battery replacement or other components or costs in 8 years) however realistically it will probably be worse since at some point we will have to pay for moving the system to another house. There is also a chance we will have to sell the system second hand at some point for a low price, if we move to another country or somewhere we can´t install solar. So the payback is between 8 years and never.
Changed my mind
I originally decided against solar thinking it would not be economical since a) we are renting, so may have to pay for the cost of moving the structure and b) we cannot sell to the grid. I bought carbon offsets instead.
But I changed my mind. Offsets don’t work on their own, we have to stop using fossil fuels as well. I also think our solar panels might inspire a neighbour or friend to do the same.
We also have regular power cuts so the system helps us with that.
I also have an EV now and I work from home, so I can charge the car whenever it is sunny, which makes the problem of not being able to sell to the grid relatively less of an issue.
Specs
In recent years we used (from the grid, before buying solar and an EV) 2.7 MWh/yr (family of 4). I anticipate +1.3MWh/yr for the car`s home charging, so 4 MWh/yr demand now or 11kWh/day.
The system is ten 325W panels (Risen) so 3250Wp. We have the system pointed due north (I am in Chile), so we can get about 5.7 MWh through the panels per year, perhaps 5 MWH after allowing for system inefficiencies. That is about 70% more than if the panels were in England, and about the same as Los Angeles and Casablanca which are at the same latitude as us.
The projection from the Chilean website Explorador Solar is we`ll get an average 10kWH per day in June/July and 17kWH/day in December/January/February.
I guesstimate about 1 MWh/yr we will have to use grid for (mainly due to cloudy days). (As of September 2020 it looks like it might be under 1MWH/year, maybe nearer 0.7MWH.) That would mean we only use 3 MWH of the solar and could waste 2 MWH/yr if we don´t make changes.
Using the Extra 2MWh
Could take extra trips in the car.
Put in another cooling fan we don’t really need just to feel ice cold in summer.
Kettle for washing the plates and shaving instead of gas on a sunny day; add another kettle´s worth to a vacuum flask for the evening or the following cloudy day.
Using the kettle to put pre-boiled water into the pans on the gas hobs at lunch time on a sunny day. This may make more sense than an electric cooker which would just add to the expensive grid electricity (39% coal) in winter and in evenings.
We have thought of the idea of connecting the solar to the hot water for showers but this is a rented property so there is a limit to how much we want to do when we may have to move out before recovering the investment. Also, there is no hot water tank; water is heated up on demand which doesn´t work as well with solar. But I might have a think about a solution for showers/washing.
We can use the electric heater in some sunny mornings to save on using the gas/heating oil ones, but obviously heating need doesn´t match well to solar availability, so this is a pretty limited option.
I did wonder if we could sell electricity to others somehow, but I can´t think of a practical idea about how to do that. I don’t think any of the neighbours has an electric car.
Energy storage
We have 4 Utracell sealed lead acid UCG 100-12 batteries (4.8kWh) but the last 25% is not used to protect the life of the batteries, then there are losses, so may be nearer 3kWH. We´ve had days where the battery is full in the afternoon and a little energy is wasted, but still ended up spending 1-2kWH overnight. I asked the installer to come back and add 2 batteries more but he said it has to be 4 which isn´t worth the spend.
I did wonder if you can get a plug-in battery of a decent size (few hundred WH to a kWH): i.e. plugs in to house socket to charge and you can unplug the battery from the socket when full and then plug perhaps the TV and set top box and a charger into it later in the evening or on the following cloudy day but so far when I googled it I couldn´t find a simple plug-in solution with no installation. But might have another look later.
I also wonder if you can buy something like a plug-in device with no installation that you could store hot water in. Something like a kettle but larger (maybe 5-20 litres) and very well insulated and running at a lower wattage (again: few hundred watts to a kW). Didn´t find anything on the first google search.
To try and reduce grid spend a little overnight, I´ve actually been charging up my computer and phone in the day time only (I work from home), and charging up my kindle and spare computer only on sunny days. I even had the idea the other day to turn down the fridge and freezer temperature a degree or two on a sunny day, and turn it back up again in the evening!
Cost
About £4000. It was actually slightly higher because we put a separate structure in the garden that can be demounted more easily and because the owner was worried about the roof. However, had it been a roof installation, it would have been a little under £4000.
I estimate this will reduce our annual electricity bill from £560 to £100, for a saving of £460. We should also be able to use more electricity to reduce on use of gas for hot water and heating, guess £80 saving per year, total £540. (Updated these figures September 2020 using latest data. I currently estimate spending £100 on electricity per year rather than initial estimate of £140.)
That gives us a best case payback period of 8 years (if no battery replacement or other components or costs in 8 years) however realistically it will probably be worse since at some point we will have to pay for moving the system to another house. There is also a chance we will have to sell the system second hand at some point for a low price, if we move to another country or somewhere we can´t install solar. So the payback is between 8 years and never.
. 2more model 3's in our road now, 1 round the corner.
