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> Wind is of course great, but is it enough?

Yes, basically.

Solar is going to be the dominant power source globally, because most human beings live closer to the equator than europe. In Europe wind is and will be a big part of the solution, particularly so in the north and near water.

If wind will be enough, why build solar in UK at all?

Well it's cheaper than gas, even before you add a carbon price, which makes it much, much cheaper, so that's a good reason to build it in parallel.

Price is roughly equal with wind, maybe a little more expensive than onshore wind and a little less than offshore.

And the outgoing Conservative party has effectively banned onshore wind in England.

But eventually as deployment grows you'll hit seasonality constraints that solar doesn't hit closer to the equator. Wind correlates with demand better in this region.

If, for achieving zero emissions, all capacity needs to eventually covered by wind anyway, then building out all that solar seems pointless. That money would be better spent on wind.

> If, for achieving zero emissions, all capacity needs to eventually covered by wind anyway...

This is wrong. Solar is zero emissions too, even if the economics are slightly less advantageous.

Both are intermittent sources, so building 100% of either increases risk and requires additional storage. Plus, some areas are more amenable to solar than wind.

Step 1: get summer to zero as cheaply as possible.

Step 2: evaluate the combo of sources to get winter to zero.

Step 2 will likely involve insulation, potential energy storage (pumping water uphill to turn a turbine later), high thermal mass "heat batteries", solar that got us to 0 during the summer, wind, and water and maybe even nuclear.

Wind is weaker in summer

We need to bite the bullet and start building out district heating systems. Use waste heat from industry, use heat directly from nuclear sources, build solar concentrators with huge thermal batteries. There's no shortage of available heat energy, the problem is just transport.

If we can just pipe steam or hot fluid into houses, we don't incur any sort of losses by converting the energy to electricity first.

This results in a lower net energy consumption because we're using heat that would have otherwise been rejected into the atmosphere to heat homes.

> One problem is that the highest solar power output is around mid-day,

Tariffs that reward charging electric bikes, cars and home backups at these times can also really help.

> The other problem is the country uses a lot of power for heating during the winter

Sadly I doubt the UK will ever be able to move away from winter gas. It's hardwired into many heating appliances and, as you say, it's challenging for batteries to shift the load.

Does targeting charging ebikes make any sense? If the average bike is 500Wh, and bikes mostly aren't completely depleted (a trip to the shops might only take 10% of the battery) then you're talking about maybe 100-200Wh normally. And you're probably charging from a normal wall socket, so there's no easy way to signal to the bike when to charge. Please don't say "add WiFi", bikes should not have WiFi and don't need it.

So, how would tariffs targeting ebike charging even work? Telling people "put WiFi on your bike so we can tax you" is a poor strategy that guarantees noncompliance, its load isn't particularly different from other wall-plug appliances so if the tariffgot too high then people would just pretend they're using the microwave, and the total electrical cost of charging might be under 10 cents, so a 10% tariff would be less than 1 cent - so who would even care?

I’d intend for consumer tariffs to have much lower pricing during periods of high solar output.

It doesn’t particularly matter whether consumers use it for charging a bike or powering a washing machine. The battery charging examples came to mind as the most “shiftable” consumption sources, but anything would do.

>I'm not sure what the solution to the latter problem is

Heat batteries - basically, a bunch of insulated sand/rocks that you heat up, and then later you use the heat directly for heating.

To be crystal clear: I am NOT talking about batteries that output electricity.

Heat batteries are literally dirt-cheap, and you can dump excess midday summer solar into them and they'll keep for months.

The only problem is that heat is hard to transport and heat batteries are necessarily large (due to the cube-square law) which makes it hard to build them hyper-local. For residential buildings that means you'll want district heating.

Heat batteries aren't a good choice for everything or everyone, but reducing grid load is a numbers game so they don't need to be - they just need to load-shift most heating, and everyone else can use heat pumps.

They are building one in Finland that is 90 GWh with simple technology! That would be an absurd project with current electric batteries. It’s a lot of easier to scale a big insulated pool of water or sand and heat it up with any waste heat and energy through the year. Only works for heating but many places need heating

Solar to hydroelectric dam long term storage is the best bet for summer vs winter, and similar things of that nature. Trouble is you need to ask Scotland nicely to act as your big battery for hydro, and there is a point where you run out of places to go. Your next best option is to increase the interconnection to the European grid.

Will the capacity be sufficient?

According to https://www.withouthotair.com/, no.

I think green hydrogen generation and other types of long term storage are required for the seasonal problem but they are quite expensive and/or inefficient currently. However, the UK has a lot of wind during the winter, this can mitigate the problem significantly.

Some balance of 4 things - wind is stronger in winter, overbuild solar, import solar, seasonal storage like hydrogen. But clearly it's preferable to be near the equator and not have to deal with that issue.

Batteries can often be used twice a day. They can buy cheap power in the middle of the night and resell it in the early morning peak.

YMMV depending on local supply and demand patterns