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Comment by nhebb | Hacker News Reader

I'm making a lot of assumptions here, but you could argue that the solar panels do not need a long lifespan. What they need is a mounting framework that has a long lifespan, including robust hardware that interconnects with the electrical system. If the conversion efficiency of the panels will improve every few years, the cheapest panel possible would be a better benefit, as long as they are easily replaceable and recyclable. This would provide a more cost effective system in the long run.

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I think your arguments ignore many of the actual economic costs of a solar panel installation. The mounting framework is the cheapest part of the structure. The solar panels themselves are expensive, but the major issue with your idea to re-install them every few years would be the labor costs. It takes a few hours and a few men to install the panels, so throwing in $1000 every 2-3 years would make this type of quick-replace plan non-cost effective.

I'm not an expert in solar panels by any stretch, but my understanding that the two major breakthroughs we need are a) how to make the solar panels themselves more efficient over a long life-span. Typically they lose 2-4% of their efficiency every year, meaning 20 years down the road, they've lost 50% of their energy power. b) a more efficient converter from the DC generated by the solar cells to the AC we put back into the grid.

Let me re-iterate: as long as they are easily replaceable

In others words, design it with replacement by do-it-yourself homeowners in mind. I looked up the spec for one and it was 1250x800 mm (~4x3 ft) and weighted 12 kg (~25 lbs). That's a little awkward for one person to cart up a ladder, but what if they were half the size and had a strap handle on the side? What if they used quick disconnects for mounting? If you set out with these as design goals, then I'm sure a feasible solution could be found.

Most people don't especially like going up on their own rooves to install things. Some folks don't mind, but it's still a big disadvantage.

But most people probably know someone who doesn't mind or who can help them do it. In other words it doesn't have to be a $1K job for everyone.

Smaller panels can make it easy to replace gradually, acouple here, a couple there...

I agree. You either make things last a long time and not fail, or you make them very easy and cheap to replace.

How common is it for homeowners to have a friend replace roofing tiles for them? Such a job is as easy or easier (and cheaper in terms of materials) than replacing solar panels.

In practice such things are not common at all, people don't have friends who will just go up on roofs and do serious work. The best you can hope for is something as easy as installing Christmas lights (which doesn't even require getting on the roof itself, just up to the eaves).

That's the idea, it shouldn't be in the same class as replacing roofing, it should be in the same class as repainting your shutters, or cleaning your gutters.

> so throwing in $1000 every 2-3 years would make this type of quick-replace plan non-cost effective.

$1000 every two years is less than $50 month.

I'd happily pay $50/month for all my electricity.

We're not saying $50/month would pay for all the electricity, it would only pay for its replacement costs every 2-3 years. You still need to pay the $20,000 for the solar panels themselves. And it's a misconception that solar panels replace all your electricity needs. Doing the math last year here in Texas, it only covered 20% of my needs in the summer, 75% of the needs in the winter.

You probably don't have enough space then. In most locations and for most homes or businesses, you can easily replace over 80% of your grid power. You could even replace 100% but the risk there is that most utilities have "no negative net metering" regulations approved by the local PUC that mean if you produce more than 100% of what you use, the utility keeps it for free. This makes installing a system at close to the limit uneconomic (and is also one of the reasons that Germany has more installed solar per capita despite far less favorable solar radiation than the US).

Also you get huge subsidies in Germany for putting in solar power to the net.

Typical degradation rates for crystalline silicon solar panels is 0.5% per year. When you read about efficiency being an area of innovation it's conversion of solar radiation into electricity that's usually the issue. Inverters are 95% efficient (the other 5% goes off as heat) but there is R&D going on to improve this. The other innovation is micro-inverters - meaning each panel has it's own inverter. This means that a panel that is shaded only loses production from that panel. In a central inverter system, partial shading can kill production for the entire string - meaning all panels connected to that inverter. The tradeoff for micro inverters is higher expense and some would say more maintenance and points of failure, although there are counter arguments I won't bore you with.

The cost of installing new panels can be quite high, depending on where they are installed. Also I'd be worried of a format war - I bet that each manufacturer comes up with his own standard, which would lead to higher prices for the replacement and the possibility that your format disappears from the market in a couple of years.

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