My electric costs are 0.035 USD/kWh here in Europe (Czech Republic).

Wth is wrong with the USA? It seems like you're getting screwed over everything. 10x electricity, 100x healthcare and education - is US market really just a bunch of colluding monopolies?

I couldn't quite believe your numbers, and couldn't find any confirmation for them: http://ec.europa.eu/eurostat/statistics-explained/images/4/4...

http://ec.europa.eu/eurostat/statistics-explained/index.php/...

Hm, that seems unusually high, really wonder where these stats come from. Is every eurostat statistic distorted like that?

Here's a chart of energy prices on a Prague energy exchange, currently it's about 30 EUR/MWh = 0.032 USD/kWh. I pay a bit more than that (incl. distribution) with a good tarif (low cost broker), but even conservative people I know who don't renegotiate energy prices get about 0.06 USD/kWh incl. all distribution fees.

That said, electric distribution network in our country is probably underinvested. Is the premium you're paying in US based on distribution network cost?

http://www.tzb-info.cz/ceny-paliv-a-energii

Still seems low for retail. In Europe, the UK has very low costs with ~12-13€c/kwh, high cost countries such as Germany are more around 25-30c/kwh (taxes and renewable energy charge).

Electric rates in the US vary widely. The $0.15/kWh rate sounds like California prices, which are notoriously high compared to other parts. Less urbanized states have lower rates, except Alaska and Hawaii.

https://www.eia.gov/electricity/state/

There's a really great 99% Invisible episode (podcast) going over all the economics & history of net metering for those interested!

http://99percentinvisible.org/episode/reversing-the-grid/

Speak for yourself. My home electricity costs right around $0.30/kWh. If you can't get a net metering contract, it's already about cost-effective to just go off-grid.

The economic calculation for one of these roofs probably looks very different depending on where you live.

Not necessarily - my home was built in 2013, with a metal roof and 5kW PV system. But because it's so efficient, I end up not just zeroing out my bill, but giving power to the grid for free (since I don't actually get paid for the power I generate, I just get credits). I have evened the odds out now to some degree with a plug-in hybrid, but I will have to see if in practice charging it will soak up some or all of the surplus I was losing...

If you live uphill from work, then that car just might help to balance the load. Early in the morning, you leave with a minimal charge, and roll down to work on regenerative brakes while topping up the batteries. After work, you spend that charge and the minimum fuel necessary to get home. You charge your vehicle in the late afternoon, not long after peak sun. Your home power controller is configured to allocate 80% of the car's battery for household usage, overnight.

If you live downhill from work, however, then the only way to use that to your advantage would be to work an evening / night shift.

When home solar installations send excess power to the grid, they also do it in the middle of the day, when wholesale electricity prices are at their highest.

For now. When 10% of people have panels, that won't be true anymore.

So cheaper prices at the time of most usage (and previously highest cost to generate or consume) which is yet another positive externality of solar power.