14 ways solar power costs will decrease... sharply? really?

I was using this definition: "having an old-fashioned attractiveness or charm".

Can be. It depends on how the wood lot is managed, and how you burn.

It is a power measurement. It refers to land use rather than measurements of the panels themselves. If you want to know how many acres a 10 GW solar farm will take, it is a good first guesstimate.

 

Solar thermal plants are much more efficient than PV (well, typical non-multi junction space quality stuff) so you'll capture a lot more energy w/CSP vs a PV array. You can store excess as heat more cheaply and efficiently than batteries. What are we arguing here again anyways? Are we just spliting hairs about energy accounting?

 

If Americans would just stop being so F'g wasteful, total energy demand would drop by half easily. Solar thermal is around 70% efficient. The remainder needed is much more palatable and doable.

Addendum: Just saw Tripp's post. I mean air and water heating with solar, not conversion to electricity.

 

I am really not sure. My figure of 2 W/m^2 is for PV only. I think I have caused more confusion than clarity by trying to correct an impression that solar thermal allowed more energy since you could use it at night. Solar thermal's power per area is higher than that generally. Sorry for the confusion.

 

naw, doesn't allow more energy, but the storage of excess capacity is way cheaper which means the production factor of said plant is higher which makes the energy cheaper.

 

Agreed, this is what I meant - I was at work towards the end of the day and hurrying up to reply.

Actually, the line wasn't installed properly. The ash had no where to go as it cooled. It took me a little while to get the burn properly set. The liner was bent to a 90 degree angle inside the chimney, and then went to a horizontal section, then another 90 down to the stove. I've now gotten a "T" installed in the chimney. When I can afford to, I will get an exterior clean-out installed into the chimney so the liner can be totally removed. It was not originally thermostatically controlled, but there is one on it now. I was running it essentially 24/7 during Dec - Feb on the lowest setting. Prior to and after those months, I would manually make adjustments within reason for when I would allow it to run.

Agreed. But it's not a material that is drilled, mined, harvested, etc specifically for this use. It's made from the byproduct from another purpose and I would rather burn that than oil. I also have a heat pump (air based), but once you get below about 40 degrees, it runs continually and isn't nearly as comfy a heat as the furnace.

 

I think the 2W/m2 is a fairly specious argument. He's talking land area as if land dedicated to wind power couldn't be used for other purposes. For example, you could have wind turbines (dammit, they don't mill anything!) deployed on the same area that was producing algae for use in bio-oil. How would that affect the numbers, well the W/m2 would certainly increase. And what about roof-tops, etc? That land that's already in use, so putting PV on top doesn't really increase our land use at all.

And of course, efficiency... the US has something like 908GW of generating capacity. I'd be quite shocked if we couldn't reduce our demand by 25% simply by being less wasteful. So, right there we only need to replace 681 GW with greener capacity. Also, some of that capacity is hydro, so we can leave that in-place. The US gets about 10% from hydro so that 68GW we can leave alone.

so now we're down to what, about 613? That's still a lot of energy, but through continued efficiency gains (remember, Europeans use half as much energy as we do) and utilization of a varierty of complimentary energy sources, I don't see any insurmountable problems. We have to change the way we think about things and it wouldn't be cheap to overhaul things, but then again, there are enormous hidden (and not so hidden) costs in the bau case. this is a storm in a tea cup.

 

So, to be clear, you are suggesting that a solar farm will only take 2 watts per sq/meter? So, 2wh per hour over the course of the day, say 6 hours= 6 wh per sq/meter? I think that is a ridiculously low estimate. That may be a world wide average, but factoring in weather and seasonal averages world wide is quite silly (and using that in a design equation) if you are building a solar array in W. Texas for example,, or in Yellowknife NWT either!.

Icarus

 

I think the utility solar PV here is about 20 wp/sq meter but there is a great deal of buffer land for future use, so it could be much more dense. I think ivanpah CSP is about 400 MWp on 16 sq km which would be about 25 wp/sq meter again with very large buffers. I'm sure the Mojave or Arizona or even west texas would be much more efficient as Icarus says, so those ivanpah Megawatts peak will turn into many more GWh over the lives of the plants.

Wind often goes on ranches and does not really bother the cattle or crops. This solar farm does probably need a dedicated space for the panels which is a big benefit of roof mounted solar.

 

I am not sure where you got that impression. That certainly wasn't what I was trying to say.

Which is why I included 'conservation'.

 

Not Peak Watts. Actual Watts.

Now scale that 80MW plant up to 1GW or more. If we are talking about replacing oil or coal or uranium, we need to think large (or ubiquitous, of course). A Nuclear plant is roughly 1 GW.

Heck maybe 2 W/m^2 is a bit pessimistic. We'll see when they start building multi-gigawatt solar farms.

 

My air source ductless mini-split heat pump has a heating EER of 12.6, which I believe translates to a COP of 3.7.

That rating is for a certain fixed outdoor temperature. The HSPF rating is 10, which would translate to a seasonal average COP of 2.9, over whatever temperature and load profile the EPA uses to define HSPF.

A smaller unit in the same line is rated EER= 14.5, HSPF = 11, which should mean COPs of 4.2 and 3.2.

 

My savings from using a wood stove for primary heat are not quaint. We burned 90 gallons of oil to heat our house last year.

 

The 400 MWp CSP plant in my example is the biggest proposed solar plant in the US. The local one will for a short period of time be the largest PV farm. PV doesn't really want to or need to be GW size. When you get to 100 MWp or larger CSP has clear advantages.

I included the peak to find out how you want to scale for your numbers. Perhaps divide by 4 to compare it to a gas or nuclear power plant rating. I have no idea what a good number is, but at least here our peak demand does correspond to peak sun.

As I said in my previous post I would not expect to replace coal or nuclear with solar. Wind, biomass, and natural gas are needed to replace those power sources.

 

I have a large south-facing completely unobstructed roof ready for panels, but it won't be seeing them until it doesn't cost $20k+ (after rebates/incentives) to cover "most" of my electric bill--and I heat with gas. A 50% reduction in cost may make the numbers doable but even then I'm not so sure, at 25% the price of current it would definitely be an attractive option.

 

I heat my house entirely with a wood stove. The wood stove is quaint (has old fashioned charm) which is why I can get my sweetie to stoke it. If it was a huge box in the back yard, it would be my chore alone.

 

GW farms are where you are going to get your highest energy density though. Thus, anything else increases the area required.

I note (with some amusement) that, although many people are arguing against the 2 W/m^2 number, no one claims to have actually done the math.

Throughput is around 20% of peak. 25 Wp/m^2 is therefore around 5 W/m^2; perilously close to my 2 W/m^2. Feel free to do the math with 5 if you like.

Solar is more reliable than nuclear (though probably not coal). The important metric is not, percentage of time on, but rather how much storage you would need to makeup for down time. Solar storage only needs to last for the demand of 19 hours or so. A nuclear plant is down for 6 months at a time (under normal circumstances). And as you said, it coincides with peak usage, making it a near perfect peak plant.

 

I just think it's a silly number. It's probably true the way he's calculating it though seems odd. What's the point? We know it would take a lot of area to produce the energy, but so much of that is dual use (roof top solar, wind farms in wheat fields, etc) that I just don't see it as being an issue. In the UK, where you have 61 million people in an area the size of Colorado, I can see there being issues w/wind turbines (he calls them mills, which makes one suspicious) crammed in everywhere. But wind won't be the only solution to the problem.

 

How seriously have you looked at reducing your consumption vs offsetting it w/solar? The first step of any solar project should be reducing the amount of energy needed. Maybe you've done that already, but maybe you haven't.

 

As Tripp suggests, conservation. As we say. I the solar worldwide, the first task to do for cost effective solar is conservation, followed by more conservation, and then some more conservation.

If you are looking at a installed cost of ~$20k, you be for rebate/tax credit cost night be ~$40k. At that price one mint be looking at a grid tie system in the 8kw range. Depending on site conditions and location that system might generate 30-40 kwh/day on average.

I would argue that if you are consuming this much power, there are probably some pretty simple ways one could reduce this consumption.

Just as comparative side bar, we live six monts a year with off grid solar, (which is ~1/2 as efficient as grid tie). We have 400 watts of panels, and we use between 500 and 800 wh/day. Granted we are extremely conservative with our power use, but it does illustrate that much can be done to reduce consumption.

Icarus