Cool, I'm hoping to get into grid tie at some stage, The government here are introducing a scheme where they actually payback right now
they don't. I'm not sure what standards you have to keep to, is it just island protection that it needs to protect electric workers when an outage occurs ?
I'd have to upgrade to a 48v turbine as well but I'd like to keep a battery setup also.
If your utility meter is mechanical, then so long as it doesn't have a ratchet for one-direction only, you already have net metering and they don't know it.
Grid tie in the US we have UL1741, anti-islanding so if the grid goes down the inverter shuts down.
With net metering we get a credit equal to retail, use grid as storage.
With time of use rates, credit is is dollars not watt-hours, number of watt-hours we get in return may be more or less than we produce (guess which way the time schedule is biased.)
My area now pays a small $0.04/kWh cash credit that carries over to next year, may cover the $10/month fee (which is a bargain compared to buying batteries.)
New "Rule 21" grid-support regulations call for inverters to remain on-line for a while during grid voltage/frequency excursions. There is so much PV that if all disconnected at once the grid might shut off.
Grid-tie is economical, a fraction the price of utility rates. Normally done without batteries, sometimes batteries optional.
Batteries are nice for backup during power failures, but likely not cost-effective. Although, DIY prices can be (if you don't kill your battery along the way.)
My AGM batteries cost $0.50/kWh over their life. Some DIY batteries cost $0.05/kWh. I put grid-tie PV at $0.05 or less. Your wind will vary.