PDQ Mobile wrote:I suggest that given the figures and installation that you have at present, an Electric Vehicle would simply be using conventionally generated electric?
And therefore still nowhere near carbon neutral.
EV's doing average mileage need about 200Wh, call it 600Wh for 8 hours of daylight.
Easily within a solar installation's capabilities.
You can't be self sufficient without battery backup. Most of the time you simply can't use the power produced so it just ends up being dumped on the grid. And when you do need power you tend to need a lot. Most home EV chargers are 7Kw, 3Kw for an electric kettle and another Kw or so for lights, TV and any bits and pieces.
Fortunately apart from the famous soap opera tea breaks demand tends to be sporadic so you can rely on your neighbours solar installations to fill in the gaps.
Obviously as batteries become more commonplace (or grid tied EV's) then your battery/EV can be relied on to provide power during high demand and soak it up as demand falls - both for you personally and the system as a whole.
Now we no longer have the 4Kw "limit" for some people it makes more sense to put a larger array on their roof.
If I was Cugel I'd sneak a few extra panels up there anyway. His inverter may limit the power to 4Kw but more panels mean its more likely to produce 4Kw even on dull days (and obviously more power during the winter).
I believe (but it's worth checking) even in his case he can legally add more panels without issues as long as his inverter is limited to 4Kw.
Micro inverters are a good thing for scaleability. You can just keep adding panels as and when - plus they're less fussy about panels going into the shade.
The balance between electricity used and electricity generated is the first issue. It is possible to reduce electricity use yet still maintain all the electrical gubbins you want or need. This requires a lot of fiddling about with various energy-conservation or cost-reducing things.
For example, our hoose is very heavily insulated indeed so doesn't throw heat away. This reduces the load on the ground source heating pump. Other heat-generating electrical things (e.g. a cooker) also have their "waste" heat heating the house, so the heating system thermostat will turn the ground source heating pump down another notch.
Another costly use of electricity is to heat washing and dish washing machine cold water to operating temperatures. Ground source heat costs far less, as does the associated hot water so we're installing a thermostat-controlled valves to put water as warm as the washing machine program allows into the machine instead of the much colder water of the cold tap.
The hoose has only the most modern & efficient LED lighting, which saves a lot over old fashioned incandescent bulbs but also a significant amount over first generation LED bulbs. The modern ones are specified to last longer too.
I'm sure there'll be other ways to reduce the electricity usage whilst maintaining the "service level" in terms of electrical gubbins to do this and that.
The second issue to how to generate (and store) more electricity at a reasonable cost and without buggeringup the existing payback arrangement. Separate solar panels and a battery, not connected to the grid, seems one route. How to install it all and how to use it are the issues.
I hope to buy more solar panels and use them to feed a big battery that can be used for sporadic things, such as woodworking; perhaps also for low-capacity circuits such as the lighting. But it looks like the grid will always be needed not so much as a supplier as a supply-smoother - always there no matter what the weather does to your solar or wind power.
The electric car costs a lot less to tun than buying oil-fuels and, more to the point, it doesn't itself pollute with the engine. Well, it won't when the grid supplies electricity only from renewables and the gas-fired power stations are gone along with the coal burners.
At present we're making a small profit on selling solar electricity but this is because of an inherited high pay-back rate. We have to generate/save a bit more to get our electricity production in terms of KWh equal or exceeding our usage. We will get there, one way or another.