Brad Ideas - Is being evangelical about solar the right course? - Comments

Electric cars

brad — Wed, 06 May 2009 11:02:58 -0700

I see this talked about for electric cars, or more often for hybrid cars which, in a brown-out, would offer their dirty gasoline generators. The latter is of course not a green solution at all. I don’t see the all-electric solution happening very often. Right now the biggest barrier to electric cars is people don’t think their batteries provide enough range, and that finding a place to plug them in is a pain, and that once they are discharged not only do you need to find such a place but the car has to sit there a long time. They compare that with gasoline’s “stations everywhere, refuel for another 300 miles in 4 minutes.”

So, unless you are really sure an electric car will not be needed by its owner for quite some time, they won’t let you do this. Peak electric demand is at 4 pm, just before rush hour, and no owner driving then will let you drain their battery.

You could use the batteries of electric cars in airport parking lots and those of people on vacation and the like. That could help, though you would have to pay them for the extra cycles on their batteries which will reduce lifetime.

But none of this changes the total MWH load on the grid. Since peak load comes from natural gas (and some hydro I suspect) and base load from coal, nuclear and hyrdo, you might end up moving load from natural gas to coal with the use of batteries in this fashion.

Electric car benefits

Alphonse — Wed, 06 May 2009 10:52:21 -0700

For electric cars, add time-shifting power generation to the list of benefits.
Cars charged at home at night, driven to work, plugged into the grid which
discharges them. This reduces peak load on the conventional power
generation system. So, as anon notes above, peaker plant costs become
a factor in the equation.

In California

brad — Wed, 06 May 2009 10:51:26 -0700

This is correct, but in California you are crazy if you put up so much PV that you go net-negative on your meter. California has a tier system. You pay a low rate on your first 360 kwh, and really high rates above 720 kwh. So your goal is to get your total grid usage to about 360kwh, and then pay the cheap price for that much grid power. Or even to drop only to 720kwh. Only this way can solar compete with grid in California. If you overgenerate and take yourself below tier 3 or tier 1 or even to 0, you are paying more and your panels will never pay for themselves.

If you are doing this out of a desire to do good for the world and make it greener, as I have been learning and showing, there are far better places to spend your money making a greener grid.

I was being generous to the panels

brad — Wed, 06 May 2009 10:45:58 -0700

I am surprised at your attitude, considering how the site you point out not just backs up my numbers, but provides more pessimistic ones in many cases. It cites a current average of $4.70/watt retail, higher than the $4 figure I used, but also indicates the range is wide, and some panels have been found under $3/watt. I think it’s a good number for an aggressive shopper (I have paid less myself) but it doesn’t change the equation much if you use $4.70 — you can play with the spreadsheet and plug it in yourself.

If you think I am “peddling” (I have nothing to sell) false numbers, you need to show me what you think the correct numbers are. The solarbuzz site you refer to offers numbers suggesting a residential unsubsidized price of solar in a sunny climate of $370 per megawatt hour, higher than the number I calculated, though they rate a better $208/MWH for large industrial/generation PV plants. While a better number, it is still not good enough.

You have it entirely backwards on baseload electricity. Solar is terrible for baseload. It is good at peak load times only. (You may have just gotten your words backwards there, if so, I apologize.) However, the situation I am examining here (see the earlier articles for more detail) is the considering of a solar plant for a home or office, with the goal of reducing the use of the dirty grid. Solar, by providing power mid-day, saves a power company from having to build peak-load plants but I don’t care too much about their cost of building plants. If I am interested in making the world greener, I care how much fuel they burn, and that’s pretty related to how many MWH they have to generate. (The nuclear baseload capacity does not emit air pollution of course but people are of varying opinions on how green it is.)

If you think my numbers are wrong, show your numbers. Look, I want PV to work, I understand all its advantages, but today I can’t find math that shows that it works, that shows it as a good choice for making the world greener in terms of dirty MWH removed per dollar of expenditure on PV.

And one more thing ...

Alphonse — Wed, 06 May 2009 10:40:58 -0700

Even if you happen to live in a sunny location with a large, flat, southerly-inclined roof, regulations discourage you from putting up six times the number of PV panels you need and sending the extra to your shady neighbors. You could install the extra panels and gift the electrons back to the electric company. But if you want to sell them, welcome to the world of Being A Regulated Utility. At least in California.

A lot of what you are

Anonymous — Wed, 06 May 2009 09:25:14 -0700

A lot of what you are suggesting is inaccurate- which is unfortunate if this blog is widely read, which I suspect it isnt.

Given the fact you are still assuming $4/watt panel prices it is clear your industry knowledge is pretty low and your statements reflect that. www.solarbuzz.com lists current module pricing.

Its a shame you are peddling this.

Also- regardless of install cost, solar is one of the most effective ways of generating baseload electricity. Thus, you need to compare the return on a 'peaker plant' that only operates a few hours a day, as the numbers on those are not favorable. This opportunity cost of avoided use of such technology doesnt show up on your spreadsheet, nor should it.

Calling solar wasteful is irresponsible

Is being evangelical about solar the right course?

brad — Tue, 05 May 2009 16:45:42 -0700

The earlier post on whether solar gives the best bang per buck in greening our electricity ran into some opposition, as I expected. Let me consider some of the objections and issues.

As a recap, I put forward that if we are going to use our money and time to attain greener electricity, what matters is how many MWH we take off the “dirty” grid (particularly coal plant output.) I measured various ways to do that, both green generation and conservation (which do the exact same thing in terms of grid offset) and worked out their cost, the MWH they take off the grid and thus the cost per MWH. Solar PV fares poorly. Converting incandescent bulbs to fluorescent in your own home or even other people’s homes fares best.

A big part of the blame lies on the fact that crystalline silicon is an expensive way to make solar cells. It is, however, quite common since many PV plants started with technology from semiconductor fabrication.

Evangelical green

One frequent objection is that purchasing expensive solar panels today encourages the market for solar panels, and in particular better solar panels. Indeed, panel makers are generally selling all they can make. Many hope that this demand will encourage financing for the companies who will deliver panels at prices that make sense and compete with other green energy.

I call this being “evangelical green.” Leading by example, and through encouraging markets. While I understand the logic, I am not sure I accept the argument.