500-acre Hybrid Solar Energy Plant comes online in Florida

What does the utility do with the waste heat from the NG CHP ? It is not as if Floridians are shivering in their homes without space heating. By the way, the video on the website you linked to uses a Prius to emphasize the 'hybrid' nature of the plant. lol

The New York Times has a little more information: $USD 476 million for 75 MW capacity -- works out to $6.3 an installed watt. Sounds expensive, since they only expect to collect 2 kwh/watt*year.

For perspective, this solar farm is mated to an NG plant with 20x the capacity.

 

Reporting like this really annoys me. Over what period of time, I ask? Per year, over the life of the facility, or maybe they use fortnights. It's typical of today's reporting.

Tom

 

I thought I read over the expected 30 year lifetime of the solar farm. Beats me why 30 year life.

 

That was on a different line. You could assume that both statements related to that time frame, but grammatically and logically there is no reason to make that assumption.

Tom

 

600,000 Barrels of oil @ 1700 kWh per barrel = 1020 Million kWh. 75 Megawatt plant @ 5 hours per day of peak sun, produces 375,000 kWh per day. Or something like 1020 Million in about 7 years. On the other hand: 41 billion cubic feet of gas @ 0.29 kWh per = 12 Billion kWh So, 87 Years. Color me confused. [Note: math, after much alcohol.]

 

From the included linked to link
FPL | Martin County Solar

From that link and fpl's history that the savings are from inefficient generation they were doing before it was built. You were using the energy in the fuel itself, so if you factor that in FPL probably will save that much fuel over doing nothing. If you plug in 30 years, a figure of just under 40% efficiency for gas, and a little lower for oil you will get their numbers. In a previous pr they stated that their new cc power plant was 50% more efficient. You can use 60% efficiency for the new cc FPL is installing at another location.

btw: the heat is not waste it is the reason for the electric generation. The heat is pumped to produce steam in the steam turbines of the existing cc plant. The other turbines in the plant are gas. I'm sure this cut the cost of building the solar portion of the hybrid generation, and removed the need to supply additional cooling water.

 

Look at this [ame="http://en.wikipedia.org/wiki/Solar_Energy_Generating_Systems"]link[/ame] that shows energy production over 4 (5?) years and nameplate capacity for the SEGS plants in the Mojave desert.

No where near 5 hours a day of nameplate peak power, average yield is 21% of capacity or about 2 hours a day equivalent.

 

Today's reporting? Lack of understanding of rate vs quantity in reporting has been bugging me for over 50 years.

 

The quality/quantity ratio of the reporting itself hasn't exactly improved in that time, either.

 

The availability of good reporting to most people has improved, but you need to actually look for it. Previously in the thead better reporting on this was linked http://www.nytimes.com/2010/03/05/business/05solar.html?pagewanted=2&_r=2 .

From it you could learn that this is just a pilot of a new type of plant aimed at reducing costs of solar. It also talks about problems with renewable, and gives clarification on the costs.

I am still not sure how oil savings got in the article and if FPL is shutting down or even has oil power generation. Thirty years was likely used as the payback time of the investment in the solar section of the plant. I am unsure of the hurdle rate.

http://www.greentechmedia.com/articles/read/Solar-Augmented-Power-Production-as-per-EPRI/

Using FPL's numbers I get levelized 30 year cost of 13.8 cents per kwh. Normally you would discount that, but add in the benefit of CO2 and other savings - cost of land use.

 

The way the Wiki article uses Capacity Factor could be confusing. The Wiki article doesn't say it, but working backwards from the numbers in the article, the 21% Capacity Factor is based on the nameplate rating of the turbines running 24 hours per day, not the potential output of the solar capture system.

If you go to their "SEGS plant history and operational data" table.

Total net turbine capacity for the 8 plants adds up to 354 MW.

Gross annual solar production of electricity for the 9 plants adds up to 655,544 MW Hr/Year average for 1998-2002.

That equals (655,544 MW Hr/yr)/354MW = 1852 MW Hr/Yr per MW net turbine capacity.

That equals 1852/365Day=5.07 MW Hr/Day per MW of net turbine capacity.

5.07/24hrs = 0.211 which is where their 21% came from.

They are actually doing quite well considering the sun doesn't shine 24 hours a day.




.

 

The 'life' of the plant is really more then that. While arbitrary that is when many of the components may need to be replaced. It would still be cheaper to replace those items then build a new plant or trash the existing one.

 

I would love to know some more details on how it works. A youtube video is nice but does not really fill in the missing pieces.

Does it have completly separate turbines for the solar or does the solar feed the same turbines as the gas system?

It does look like a great idea though, and Florida needs this kind of thing due to their dependence on oil fired electricity.

 

Not technically correct,, the sun does shine 24 hours a day,, it just doesn't shine in any given place 24/7 except in the high latitudes in the celestial summer.

That said, at the average N. American latitude, the sun averages over 10 hours a day over the calender year. Taking into account the time change between the east cost and the west, (3 clock hours, closer to 4 in the north) the availability (to the grid)of solar in the US is ~ 13-15 hours a day.

With proper time shifting of loads, the amount of power that can actually be generated ( and used) by solar is very significant. For example, A/C loads are generally highest (across the country) in the afternoon, exactly the time of greatest solar harvest. To design and build a grid system based on our current inefficient use patterns would be repeating old mistakes.

So while few would argue that solar would represent a 100% replacement for current energy, with some subtle and not so subtle changes in our use patterns, the viability of solar as a real solution is obvious.

A huge coming change in the way we use energy is the EV and PEV. There will come a shift in consumption patterns, but there will also come a huge un seen opportunity. Consider this question. The rub against PV solar is that you can't use it at night. Also consider that the only Pv users that can use it at night are those with batteries, (Like me in my off grid house) Batteries might seem like a logical extension of PV solar,, except, they double the cost of any PV installation, and halve the efficiency.

But consider the idea of a EV, which carries a large battery on board, that is bought and paid for. A typical usage pattern for a car is that it sits ~ 23/7, not going any where. If you had an EV, and it was plugged in 23/7 to the grid, it could take advantage of solar output anytime there was power available, but it could also sell back to the grid for those times of peak demand. For example, you could program your car to buy power when it was say $.05 kwh, and sell back power when it was $.10 kwh, all the time ensuring that there was enough power to get home from work that night (or what ever parameter you need) All the technology to do this exists today and is in no sense exotic, pie in the sky.

Now imagine this,,, In the US we buy ~ 15 million cars per year. If in the next ten years 1/2 of these were EVs, that would be ~ 40 million EVs plugged into the grid in 10 years, each with a large battery, the cumulative effect of which would be to provide the large, disaggregated battery bank that would allow the excess Pv to be stored for night time use, effectively allowing solar to power the grid 24/7. The other advantage that these EVs would bring to the equation, by being available to cover peak spike loads on the grid (loads that may only happen a few times a day for a few minutes) one could significantly reduce the idle spinning capacity that is always on line just to cover that short spike.

Once again, would it be able to replace 100%? of course not, but it shows how by thinking outside the box, the solutions to our energy issues are not always, "drill, baby drill", or more nukes, or more coal.

Icarus

 

Solar + Wind + Conservation

Maybe a grid that informs consumers when excess capacity is available. An EV that charges accordingly would be pretty cool
I can imagine a consumer in effect saying "charge anytime during the night you want so long as I end up with 'x' kwh in the am.

I know that EVs are a promising on-demand storage in the eyes of utilities, but I am skeptical many consumers will agree to the deal. For one, the car owner will not know how much range the EV has, and second the owner would have to trust the utility to not degrade the battery, or compensate market value.

 

It won't happen over night. With any new technology there is a learning/acceptance curve. People will learn the range, and besides the cars are smart enough to know their own capacity. If for example you need to drive 25 miles to get home tonight, you could easily imagine a touch screen that says "how far do you need to drive today?" Enter!

As for degrading the battery. Once again, the cars are pretty smart. Look at the Prius battery. It only operates in a state of charge range between ~ 60-70%. Never fully charging, never fully discharging. The cars can take better care of themselves than their owners can.

Icarus

 

This one is using the existing steam turbine from the combined cycle gas plant. This increases the efficiency of the solar, as the exhaust from the gas turbines gets the temperature of the water to the right point. Here is a repeat of the quote from the NYT article.

 

Companies are working on gps input to energy estimation. BMW has done a lot of work on this. I would think a good interface would allow the user to program safety margins, and the next time for a charge. We already have smart grids in some cities, which allows my home to do things like lower the air conditioning when there is peak demand. This same technology allows the user to control when the car is charged. Most parts of the country don't have smart grids ..... yet. I have no idea if the car companies know how much grid buffering the car batteries can do.

 

As posted on another thread, there was a quite interesting piece on "All things considered" yesterday, 3/16/11 on "boutique sized" Pv installations. Typically Co-ops that are larger and more efficient (both economically due to scale and production wise due to ideal site locations as opposed to compromise residential roof locations) than standard home installations. They are at the same time smaller than a large utility sun farm, and therefore don't need the considerable grid up grade as is typically needed for a larger scale system.

These "Goldilock" (just right sized) systems are a great alternative because they can get built way faster, and with much less overhead cost than a big system, and they are more efficient that a home owners system.

( I would provide a link, but my satellite connection is quite slow this morning.)

Icarus