Actually, surprisingly, coal is already more expensive than wind and solar. The latest Lazard report is pricing utility-scale solar and wind under the cost of just the FUEL for coal-fired power stations.

What we've done in the UK is switch from coal to natural gas. That halves the CO2 emissions, and is much more flexible, it can start and stop much more quickly.

Then you ramp up wind and solar.

You only need storage when you get to the point where the renewable production completely shuts down the natural gas, but unfortunately we're a fair way from that. By the time that happens battery storage will be cheap, just a few pence per kilowatt hour extra for the stored electricity. There's technologies like vehicle to grid which can help with that- electric cars have pretty enormous batteries, that are mostly not used very much.

No, the excess is generated, otherwise that would be fraud. It's used by other people, and the non renewable generators that would have supplied them reduce their output so that demand and supply are always in balance.

They're not throwing it away.

Careful here, it actually does because, it shuts down non renewable energy on the grid they are attached to in pretty much a 1:1 ratio, so CO2 is never generated. And because CO2 is a global atmospheric pollutant, that's even true if the renewable energy is created on a grid your equipment isn't even attached to.

Nope. I'm in the UK, and the UK analogue TV signal was precisely synched to the power grid for exactly that reason.

Even so, the results are roughly what I've seen elsewhere, if you have about a days storage, that can give you about 85% renewables and then you need some generators to kick in for the other 15%. If you want 100% then you would have to either massively overbuild the renewables (which would be very expensive) or install a couple of weeks worth of storage (which also would normally be very expensive.)

No, you would set the minimum level of charge (in fact that's the way it already works, most people set the charge to 80% most of the time, because it makes the battery last longer). If you have a car that can do, say, 200 miles, and you only do about 50 miles a day, you can set the minimum to 25% or a bit higher, or whatever level you're comfortable with, and then your car can trade between that and 100% and it should make you money, based on the weather forecasts and so forth.

The latest research suggests that selling energy back into the grid may actually make the battery last longer, because the car's state of charge may be slightly lower on average than if you just wacked it to 80% every night.

When you're going on long trips you just set the minimum charge up to 100% and it tops it out. If you go unexpectedly, then you'll need to track down a rapid charger; this can give you 80% charge from empty in about 40 minutes, but that should be rare.

Actually, last time I priced electricity from a powerwall, it cost something like 0.08 UKP/kWh (about 12c/kWh) plus the cost of the electricity (solar panels in Hawaii might be as low as 5c/kWh depending mainly on the installation costs.) So it's fairly plausible they could hit 20c/kWh. Which although not fantastic is still pretty good compared to the 40c/kWh the grid costs you. But even that's only for the stored electricity; most of the electricity you could just generate and stick straight into the AC unit, so the overall cost will be between the two figures, probably nearer the solar panel cost.

That's not really true. Well, it depends a bit on the design of the heat pump and how cold it actually gets. Correctly designed heat pumps work even in Ottawa, down to -30C, which is rather colder than New York usually gets.

https://en.wikipedia.org/wiki/...

While they're not super efficient at those temperatures, they're not totally horrible, and it depends on how much time the temperature spends at these low temperatures.

> We don't need to reach zero fossil fuels. Methane for heating is probably just fine forever.

Sorry, actually the amount of CO2 produced by buildings for heating is really large, and methane is not going to cut it.

The answer is probably as much insulation as you possibly can, and heat pumps.

Actually, electricity isn't too bad. You can use heat pumps, they produce 2 or more times more heat for the electricity input. What you don't want to do is use resistive heating, that's very expensive.

The latest electric cars use solid state heat pumps for that reason, it increases the range somewhat, particularly when you're stuck in traffic. The earliest Nissan Leafs used resistive heat.

But the same principles work in buildings. It's best to insulate as much as possible though to minimise the amount of heat pump you need to use.

It's percentages that really matter. The US has a low percentage of renewable power.

There's two big problems with nuclear. One is subtle the other is pretty obvious. The obvious problem is that the cost/watt is high because of all the equipment you need to deal with a nuclear reactor and the steam cycle. You need a big heavy containment building, you need to get rid of the large amounts of waste heat; you need pumps, and redundant everything.

The more subtle problem is that because the cost/watt is high, you have to run the reactor flat-out as much as possible to bring the cost/kWh down to a sensible level.

That means that it's mostly only baseload electricity. And baseload electricity is historically the cheapest electricity. So you've got a relatively expensive way of making cheap electricity. Well, with care the economics just about work out. For baseload. But that doesn't solve the problem of where you get the peak load.

Actually heating and cooking can both be usefully electrified.

For example, my parents recently installed an induction hob (they're roughly the same price as conventional hobs now), it takes something like 20kW or something, peak. But an electric car battery can easily supply that.

You'd think heating can't be, but the trick is to insulate your building well and use heat pumps (e.g. air conditioning) to heat the building. Doing that only uses a half to one third of the energy in the form of electricity. So primary energy needed goes down. You wouldn't normally do that just from a car battery, but solar panels and wind is plummeting in price.