I have a modest set of solar panels on an entirely ordinary house in suburban London. On average they generate about 3,800kWh per year. We also use about 3,800kWh of electricity each year. Obviously, we can't use all the power produced over summer and we need to buy power in winter. So here's my question: How big a battery would we need in order to be completely self-sufficient? Background …
I recently got a solar system and came to the conclusion that if you can sell power back to the grid (not everyone can) for some reasonable percentage of what it costs to buy it, then it will always be worth it to be connected (assuming you already are).
Quite simply, if you have enough solar capacity to get you through the winter (no house is going to have months of battery storage), then you will always be creating far more than you need in the summer. Selling this excess will easily cover any costs associated to being on the grid.
Also at current prices batteries are good for backup power only, it’s always cheaper to sell excess power to the grid in the day and buy it back at night than it is to have battery capacity to get through the night. I worked out it would take 40 years for our battery to pay for itself (assuming the battery kept a constant battery capacity for 40 years…) but less than 10 years for the rest of the system to pay for itself.
We can’t, but we can do net metering, meaning we can offset costs but not get paid. So the best investment is to pay nothing through Dec. 31 and keep costs manageable at the start of the year (net metering ends with the calendar year).
Only while there’s a surplus. Our net metering arrangement effectively forfeits any surplus at the end of the year. It obviously can vary by region and how much you’d get from surplus vs specifics of the net metering policy, but I think getting paid for surplus is simpler and easier to plan around.
I disagree, but in not in your situation so I can be wrong.
Unless you are producing way, way more electricity than you can use I think net metering is a great arrangement for the customer. (Not so much for the utility company)
The electricity is usually bought by the utility company at a much lower cost than what the customer is paying. Because the generation cost is only a percentage of the cost, there is taxes, maintenance of the grid …
For example in France we pay 0.1952€/kWh, but the utility is buying the solar electricity produced by household at 0.04€/kWh.
Meanwhile with net metering your electricity is virtually bought at the same price as what you are buying your electricity for.
Net metering is potentially better, as you are effectively getting free night usage based ob day generation. My setup pays me, but I get paid 20c per Kw (NZ dollar) and pay about 30c to buy, so there’s a 10c difference. Just as long as whatever you lose on 31st Dec is not too high, you’d be better off than me.
I recently got a solar system and came to the conclusion that if you can sell power back to the grid (not everyone can) for some reasonable percentage of what it costs to buy it, then it will always be worth it to be connected (assuming you already are).
Quite simply, if you have enough solar capacity to get you through the winter (no house is going to have months of battery storage), then you will always be creating far more than you need in the summer. Selling this excess will easily cover any costs associated to being on the grid.
Also at current prices batteries are good for backup power only, it’s always cheaper to sell excess power to the grid in the day and buy it back at night than it is to have battery capacity to get through the night. I worked out it would take 40 years for our battery to pay for itself (assuming the battery kept a constant battery capacity for 40 years…) but less than 10 years for the rest of the system to pay for itself.
We can’t, but we can do net metering, meaning we can offset costs but not get paid. So the best investment is to pay nothing through Dec. 31 and keep costs manageable at the start of the year (net metering ends with the calendar year).
Net metering is great, much better than being paid for the surplus.
With net metering the grid is basically an free, infinite, 100% effective battery.
Only while there’s a surplus. Our net metering arrangement effectively forfeits any surplus at the end of the year. It obviously can vary by region and how much you’d get from surplus vs specifics of the net metering policy, but I think getting paid for surplus is simpler and easier to plan around.
I disagree, but in not in your situation so I can be wrong.
Unless you are producing way, way more electricity than you can use I think net metering is a great arrangement for the customer. (Not so much for the utility company)
The electricity is usually bought by the utility company at a much lower cost than what the customer is paying. Because the generation cost is only a percentage of the cost, there is taxes, maintenance of the grid …
For example in France we pay 0.1952€/kWh, but the utility is buying the solar electricity produced by household at 0.04€/kWh.
Meanwhile with net metering your electricity is virtually bought at the same price as what you are buying your electricity for.
Net metering is potentially better, as you are effectively getting free night usage based ob day generation. My setup pays me, but I get paid 20c per Kw (NZ dollar) and pay about 30c to buy, so there’s a 10c difference. Just as long as whatever you lose on 31st Dec is not too high, you’d be better off than me.