DIY HVAC is pretty common especially in the off-grid community these days. Most typical setup are your mini-split systems. Very simple to install - and very efficient, too.

Any grid-tied PV system you buy from a store that is UL listed will not feed energy back to the grid if the rest of the grid is down. Off-the-shelf generators pose a bigger risk than a grid-tied PV system - and they're much cheaper, too.

Regardless - there is a reason why linemen treat wires as hot at all times even when they know it's not though, you know...

Yeah - you're right. Let's leave all the windows open whenever we're running the heater or air conditioning - think of all the jobs we'll create in the gas/coal industries! :-P

Here's a thought for you - increasing efficiency let's us spend more time working on other things that improve quality of life - there's a good reason that civilization really started taking off once we figured out how to use fossil fuels to do massive amounts of work for minimal amounts of labor...

PV panel efficiency does not matter unless you are space constrained - and current PV panels are no where near 40% efficiency. PV panels currently in use range from 10%-20% efficient depending on the technology. 40% efficient panels are used where space/weight is a premium - primarily space applications - and are very expensive.

What really matters is the cost per kWh of an installed system. Right now, without subsidies, PV is between $0.15-$0.30 / kWh in sunny areas depending on the scale of the project. This makes it competitive with retail electricity prices in many areas. That's without subsidies!

The industry is working to get the price cut by 75% by 2010. At which point PV will be cost competitive or even cheaper than current grid power in many areas without the harmful emissions.

Uh, from the data in your own fine article, Petroleum (crude oil) is only half the energy of gas and coal. But looking closer that is energy production.

Looking at energy consumption, petroleum is ~50%+ more than both gas/coal - we must use it very inefficiently on average thanks to the millions of tiny combustion engines we have running around...

Actually, gas just nudged out coal for 2010. And is still leading so far in 2011.

Well said - they're mixing up range numbers all over the place. There's a reason why there's standardized tests for these types of things and using different test results on makes things more confusing for the consumer.

Which is why using resistive heating is extremely wasteful unless you have electricity to throw away (perhaps if you live in the northwest right now where they currently have too much hydro and wind and not enough transmission lines to move the power out it makes sense to use resistive heat). When you have gas furnaces well above 95% efficient at turning fuel into heat and getting it in your house - that's really hard to beat.

But if you use a high efficiency air source or ground source heat pump - all of a sudden things look a lot better - you can get 2-5x the energy you put into the heat pump into your home - so you put 1 kWh into the heat pump compressor and you get 2-5 kWh of heat in your house. Now electric heating costs basically the same as gas heating per kWh - and you have the opportunity to source that energy from renewable sources instead of oil or gas.

Assuming a cost of about $1.75/watt installed, about 35 GW of wind. Wind typically has a capacity factor between 30-40% depending on how effectively it is sited. Newer sites tend to have higher capacity factors, so let's assume 35% average or about a constant 12 GW of power.

Nuclear typically has a capacity factor of appx 90%.

Here's some data on capacity factors of the US grid: http://www.eia.doe.gov/cneaf/electricity/epa/epat5p2.html

In the end it's probably easiest to look at cost per kWh before a project is built - and cost to run the plant after it's built. For those reasons once they're built nuclear and renewables typically have a very high capacity factor (fuel is cheap or free once built) compared to coal/gas plants.

It typically takes a panel a couple years to "break even" on energy costs. Everything after that is gravy. Given that panels are typically warranted to produce at least 80% of their rated power for 25 years it's over a big positive.

Oil/gas is only "cheaper" because current pricing of oil/gas/coal does not account for it's externalities.

For example, a recent study puts the unaccounted for price of coal in the US somewhere between $140-$242 billion dollars a year.

http://green.blogs.nytimes.com/2011/02/17/tallying-coals-hidden-cost/?partner=rss&emc=rss
http://onlinelibrary.wiley.com/doi/10.1111/j.1749-6632.2010.05890.x/full

If these costs (in effect subsidies) were paid for, wind (and other renewables) would be very cost competitive with coal without any additional subsidies.

As it is, subsides for renewable energy just help level the playing field.

Definitely - which is why legislation is needed to make the utilities cooperate. And legislation is needed to prevent neighbors from preventing the installation of small scale, on-site generation (the states that lead in these areas have such legislation in place). For example, in CA, HOAs can't keep you from installing your own solar system. And the utilities have to provide means for net-metering when you do generate your own electricity.

Most utilities are set up so that they don't profit off of power generation (those costs are passed directly to the consumer and typically have to be approved by a regulatory board) but they do profit off infrastructure improvements (also regulated).

That does tend to discourage utilities from using locally generated power in some cases as it reduces the need for long distance, expensive high power transmission lines.

Well - Nimby doesn't like solar in the deserts - but Nimby does like solar on roof tops and over parking lots.

Do you realize that over 10 million light vehicles (cars, SUVs, pickups) are sold every year? So slightly less than that are recycled each year.

The bigger challenge will be convincing buyers to buy 1 million EVs over the next 5 years. Even though that sounds like a big number, that is only 2% of the market and hybrid vehicles still only have around 2-3% of the market and that's after being widely available for 7 years. Even then - one hybrid in particular - the Prius is vastly more successful than any other model with about half of all sales.

So which is it - solar panals are too expensive or your already have a solar array? Looking at your later post... Or are you just confused?

Anyway, to dispel your claim of $50k (the cost of 2 Priuses) only being good enough to generate about 7 kWh/day...

The cost of solar PV installed before rebates is currently between $5-7 / DC watt - let's use $6 / watt.

So $50k will buy you about a 8 kW array.

Using PVwatts and assuming you live in San Francisco, your typical system this big will generate over 11,000 kWh / year or 30 kWh / day. You could drive your Nissan LEAF over 37,000 miles / year or 100 miles / day using the EPA's estimate of 3.4 mi / kWh.

So in reality, a $50k PV system will buy you a large enough system to power over 3 typical EVs over 12,000 miles / year. And that system should last 25 years with minimal maintenance. (Never mind that the $50k system is 30% off = $35k thanks to federal tax credits and you can very often get additional rebates depending on where you live).