Sunshine

Apart from being good for the long-term future of humanity, striving towards zero waste seems attractive just from an efficiency standpoint. If our household is taken to be a 'system', in which a bunch of things flow in and out, then reducing the out-flow by reducing, and using more of, the in-flow, just seems better from a 'philosophy of engineering' perspective. (Or it would, if there were such a thing as 'philosophy of engineering')

But what comes in isn't just food and stuff that we buy.  There's also water, gas, and electricity.

In the case of electricity, it turns out that in Argentina 60% of it is generated by burning fossil fuels (boo!). The rest is mostly hydroelectric (yay!).  It would be nice if we could reduce or eliminate this fossil-fuel-burning input of our household.  If only there were an abundant supply of energy from which electricity could be generated at our house...

...like the sun...

Solar power seems like a nice idea and all, you know, a free, lifetime supply of emissionless energy.  What's not to like?

Firstly, I've heard that solar panel production processes aren't all that 'green'. That one-off evilness might be off-set by the long term goodness, though.

And you'd need a lot of space, I guess. If we did want to install solar panels, where would we put them?

We've got access to the roof 'terrace' of our building, and the half of it above our heads is essentially ours to use as we please.  But we can't cover our half in solar panels (even if we had piles of cash to buy them) because we already do use it.  The girls play up there every day, weather permitting, and we also want to have plants or veggies growing up there at some point. And we also use it for that oldest form of solar exploitation; drying clothes. Essentially, the 'floor' part of the roof can't be used.

That leaves two other possibilities: the roof of the portería room, which has the water tank on it, and the walls of the terrace. There is a long North-facing wall, but it's not very high, and interrupted halfway back by the light-well for the downstairs neighbours' patio.

Probably the portería is the best option: it's only accessible by ladder, so electric cables would be out of the reach of curious wee fingers, and it has a flat roof where  panels could be installed on a frame angled towards the north.  Excluding the part where the water tank is, the roof of that is 2 meters wide and 6 meters long, although we couldn't use all of that, because we still need somewhere to stand in order to access the tank to peer into it when the water mysteriously stops coming out of the tap, and to check for floating rat carcasses.

10 or 11 square meters doesn't seem like much.  Could you run an apartment on that?  How many solar panels would we need? How big are solar panels?

And solar panels are expensive, according to what I've heard. Although you're meant to be able to sell excess electricity back to the grid, and so "make money" from your panels, actually doing that isn't as easy and profitable as it's cut out to be (in NZ at least). And in Argentina, domestic power bills have been subsidised for many years, so electricity is pretty cheap for the average consumer.  I reckon those subsidies will disappear at some point, probably sooner rather than later, but at current prices, it would take decades for a solar installation to pay for itself (in terms of savings on monthly electricity bills). If we wanted to do this, I think it would be a stretch to claim it was financially 'economical'; we'd be kidding ourselves to think it would be anything but a noble (but probably futile) posture of greenitude.

However, another aspect of this has occurred to me: Every summer without fail, at about the time it gets unbearably hot and everyone (including me, now that I have it) cranks up the air-con, there are power cuts.  Sometimes patchy and sporadic, sometimes lengthy and wide ranging.  We haven't been hit ourselves every year, but in the years we have, it becomes really apparent really quickly how much we depend on electricity. I work on a computer, and over the internet, so to paraphrase Margaret Mahy, "No power, no work! No work, no pay! We're growing poorer day by day, no wonder dad is turning grey..."

But it's not just work and obvious things like light and refrigeration; Buenos Aires is flat, so to have water coming out of your 5th floor apartment tap, or even your 1st-floor apartment tap, it has to be pumped to a tank on the roof. That water pump is electric. So within hours of a power cut, we've got no water either.  And having young children takes that beyond being merely a smelly inconvenience.

So even if we could run our fridge and water pump off some solar panels, that would actually be pretty cool.  Is even that possible?

I had no idea, so I bought a book that would presumably help me find out - the Solar Electricity Handbook by Michael Boxwell.