Thursday, June 26, 2008

Array Control example

Here is an example of how a PV array owner might use the ability to control the output.

Let’s set up two arrays side by side; the second one has my control technology, and the first one doesn’t. Otherwise the two arrays are identical. The control technology allows a range of power outputs for any given light level, for comparison purposes, we’ll assume the default operating setting is in the middle of its range.

Summer day with full sun:

PV array 1: produces 90 units of power
PV array 2: produces 95 units of power (range can be set anywhere from 80-110 units)

Cloud blocking 10% of the sunlight comes along

PV array 1: production drops to 81 units of power
PV array 2: production drops to 85.5 units of power (range can be set from 72-99 units)

The cloud remains in the sky, and the operator decides to set PV array 2 to produce 95 units of power (again)

PV array 1: produces 81 units of power
PV array 2: production increases to 95 units of power (range can be set from 72-99 units)

The cloud goes away

PV array 1: goes back to producing 90 units of power
PV array 2: production increases to 104.5 units of power (range can be set from 80-110 units)

The operator decides to put PV array 2 back on default setting (i.e. to the middle of its range) just as things were at the start of the example.

PV array 1: produces 90 units of power
PV array 2: produces 95 units of power (range can be set anywhere from 80-110 units)

The default need not be placed in the exact middle of the range, I just did that to help illustrate. One could increase production to meet a demand spike just as easily as offsetting a decrease in light levels…but in that case PV array 1 would produce 90 units continuously, and PV array 2 can produce more power—say 105 units—for as long as necessary. Although now PV array 2 would be operating near the top of its range, and could only increase output by 5 more units at most.

Tuesday, June 24, 2008

Controlling Solar PV

If a utility could control how much power they get from a solar PV array, would they invest?

I’m aware that one of the major objections cited by non-solar enthusiasts (I must admit I’ve never actually met a solar opponent!) is the lack of control over the output from a PV array. This issue is sometimes called "intermittency".

If a PV owner were able to turn a knob and (basically at will) adjust the amount of energy produced by 10% of the total capacity (up or down), would that make a difference?

What if they could adjust up/down by 20%?

Is there a point (and what would it be?) where utilities would feel comfortable in investing in solar PV arrays?

I know a way to do just what I’m suggesting. Will it change how utilities view solar?

Wednesday, June 04, 2008

Congratulations to Senator Obama!

What an achievement. For Obama, for the Democratic Party and for our nation.

Senator Obama started as a true long-shot candidate, but throughout his campaign, his hopeful message, sharp, timely and cogent (not to mention correct) criticism of the Iraq war, and calls to change Washington have inspired millions. His insurgent candidacy was funded by millions of small donors rather than a small number of millionaire donors/lobbyists. Although he ended with a narrow victory over the “inevitable” candidate Hillary Clinton, which she seems unwilling to acknowledge, it still counts.

I’m amazed that Clinton didn’t even acknowledge the fact that Obama had crossed THE threshold for the Democratic Party nomination last night. She said she would make no decisions “tonight” to raucous cheers from her supporters. Her speech last night conceded nothing, sounded much like every other campaign speech and exhorted supporters to visit (i.e. donate) to her campaign website. “Decisions”? other than acknowledging reality, I’m not sure what exactly she needs to decide. By not even acknowledging his status as presumptive nominee, her words/actions seem designed to undermine the legitimacy of the process.

How this “posture” by Hillary brings the party together mystifies me. If Clinton wants a spot on the ticket, or a post in the Obama administration (should he win) she is pursuing an unusual if not outright bizarre path to follow.

In light of the fact that Clinton has said she would “consider accepting the VP slot”, I suggest that Obama respond by stating that he will “consider Clinton as a running-mate” along with all the other potential VP candidates.

Clearly any politician in Obama’s position would consider adding the number 2 contender in an incredibly close election to create a “unity ticket”. There are strong arguments for combining their firepower. Hillary has strong and committed support, and Obama needs to win her supporters in November.

Nevertheless I don’t think Clinton would make a good VP for some of the same reasons I didn’t think she would make as good a presidential candidate. She is polarizing—she has almost perfectly divided the Democratic Party. She has high negative ratings. She is married to Bill. She would undermine Obama’s change message, etc.

While Obama/Clinton could potentially represent a unity ticket, it would almost certainly make for a divided administration. A Hillary VP (and Bill) could cause lots of trouble if Obama chooses a policy she doesn’t agree with. And if she really does believe she would make a better president, I doubt she would feel any deference or loyalty to Obama. Not that I think an Obama administration must be like the “loyal bushies” but four years of continual power struggle within the administration would be disaster.