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Comment by icegreentea | Hacker News Reader

Not exactly the same - especially since water gets drawn out of reservoirs (typically) so there's already significant buffer, but here's a plot of water consumption in Edmonton during Canada's gold medal olympic hockey game back in 2010.

http://chrisblattman.com/2010/03/08/graph-of-the-day-canadia...

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Water can be stored almost losslessly, with cheap fixed costs (e.g. the many cisterns in a household, e.g. the iconic watertank that appears in US movies). Transporting water long distances usually has large fixed costs, and has massive marginal costs if it has to go uphill.

Electricity is expensive to store, both marginal costs (losses) and fixed costs (plant). Pumping water into hydro-electric lakes is a reasonable solution at present but: 1. pumping has significant marginal losses, 2. usually lakes can't be placed near significant urban loads (desireble to reduce network failure risk, and optimise network loading), 3. hydro-electric lakes are often hard engineering (earthquake risks, difficult to get good potential energy storage if flat land), or politically difficult (consent, water rights), etc.

We need to invent better systems that can profitably sell peak load and buy off-peak load (or buy constant load). Especially for periods of a day or even longer. That would also solve a lot of issues with eco-friendly power (solar, wind). Especially that can absorb huge amounts of load (e.g. overnight). Especially that can absorb and release load within sub-minute periods. Big engineering :-)

This is why wind and solar are good partners with hydro. They're more unreliable due to weather but if you have the wind or sun available to generate more power than you need, you can use the excess power to pump water uphill into a hydro lake and store it for later. So even though it's a lossy operation as you say you're basically getting it for free. And like the video showed, hydro is very responsive to short term load demands so if the wind falls off you can quickly start up a hydro plant, as opposed to something like coal or gas which takes much more effort to start/stop.

Theoretically you can put wind/solar much closer to urban centres but in reality the NIMBYs don't want them either near cities where they can be seen or in remote areas which are typically areas of natural beauty.

Windmills are already causing major network problems.

http://www.bloomberg.com/news/2012-10-25/windmills-overload-...

I would guess due to a design flaw in the market rules (or the rules for the interaction between different national markets).

I think most large windmill turbines are designed to be able to be feathered to limit electricity production - they need some way to not fail when winds exceed generator constraints - but maybe designs use wind stalling or other dynamics to prevent that? Alternatively they could build dumping loads close to the wind power - e.g. warm some seawater with big resistors!

Edit: I love the quote "Wind farms in West Texas earlier this year were paying utilities to use their electricity on particularly gusty days because they can still earn $22 a megawatt-hour in federal tax credits." LOL.

There looks to be lots of solar both in urban and rural locations in the UK, thanks to generous grants/assured tariffs.

Prof David MacKay talks about equalising supply from wind & solar with pumped hydro and electric vehicles in his excellent book, page 190 onwards: http://www.inference.phy.cam.ac.uk/sustainable/book/tex/sewt...

Electrical cars with "smart" chargers. The chargers will have two settings. Express (high price, uninterrupted charging), and Economy (low price, maybe even free (fixed cost), charging controlled by the power grid, "full by the next morning").

This is has been the dream/vision of the power companies in Denmark for at least a decade. It is usually brought up when the government pressure them to generate more power from wind. Current level is 20%, goal is 50% by 2020.

Even 20% is more than is practical in isolation, but we export peak production to Germany, Norway, and Sweden. The two later have hydropower production (and no earthquakes), which can be lowered when cheap Danish excess wind power is available. Not sure that can be scaled to 50%, especially as Germany has similar plans.

I have read that electric cars will be the new "smart grid" connected appliances. Once say 50% of people have an electric car, which is probably usually left plugged in on the driveway, that's a huge amount of battery power available nationally, ready to be fed back into the grid as needed.

Something like this: http://www.ted.com/talks/donald_sadoway_the_missing_link_to_... ?

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