Solar Power and STX questions

Great work!!

Hi Jim,
Thanks for the feedback. I'm still trying to understand the nuances of "net metering", which I think is at the heart of your point. I thought that in your 400W example that:
- the meter would actually run slightly backwards (since you're generating more power than you're using)
- at that point the utility has three choices (I believe):
- do nothing (which I think is the case you are stating)
- effectively pay you (at their going rate or some other rate) for the energy that you are feeding them (reduce your bill, send you a check, etc). This is what I thought WAPA does, but I did not confirm
- "credit" you for that energy; and you have some period of time to use-or-lose that credit (I think I saw 1 year time periods)

This is one of MANY what I considered "special" circumstances. Obviously they might not be "special" to everyone, but I had to draw the line somewhere or the back of the envelope look starts looking more like a dissertation.

So, some other interesting "special" cases worth looking into (if you, like I, have the engineering-curse of "engineering the heck out of everything"):
- should I tweak the angle of the cells every month to gain a bit more energy? (pain vs benefit tradeoff).
- what if my roof is tiled, or like Bombi's (thick, with foam sandwich), or cedar shake, etc?
- what if my roof (biggest section) faces more south-east, or 30 deg south of east?
- what if my roof is flat, or steep?
- if I only live in the house 3 months of the year, will I get enough value by pumping energy back to WAPA?
- if the warranty lasts 20-25 years and technology advances, what happens in 18 years if one of my panels fails?
- is there an economic benefit to getting a bigger/smaller system?
- what would it take to go entirely "off the grid"?
- when is the "best" time to jump into this renewable energy game (solar technology is advancing, energy costs are increasing, investment life, etc)

BTW, Jim, I can't tell you how envious I am of you. As I draft this reply in Virginia, I'm drawing probably 2kW and the clothes washer and dryer and dishwasher haven't even come on yet... (I really need to deal with the demand side of this equation!).

WAPA isn't clear or sure how they are going to handle net metering. There is a fellow up the road from me that has a small (less than 3Kw ) wind turbine. For the first few months he generated enough power to turn the meter backwards for the month. WAPA then replaced his meter with one that only goes forward.

When WAPA talks about net metering they have stated they won't pay/ credit you for more than their cost avoidance which they claim ia about $0.16 Kwh. They are also saying that they will limit it to 2- 5% of their customer base. Some of the problems with alternative energy sources is the dependability and when the power is available. Every windmill owner has power to sell at night, but that is when the demand is lowest.

Jim

PS: As I wrote this post the watts I was using cycled between 710 and 3,800 as the heating element in the dryer cycles on and off. Trying to convince my wife that hanging the clothes on a line would be a good way to save money, but it is a tough sell.

for clothes drying, I have a propane dryer that uses about 60-70 gallons of propane a year. Lots cheaper than an electrically heated dryer!

We're looking at putting in a wind generator at our house. Chris Hanley is putting one up on his property that sounds like it has pretty good productivity for its cost. There is legislation on the books requiring the permitting office to allow alternative energy sources such as wind generators to be installed even in neighborhoods with covenants that ordinarily wouldn't allow a tower structure to be built on a property, yet the permit office is balking at issuing permits for wind generators. A class action lawsuit is in the works to force them to comply with the legislation that already exists. I saw the wording and it is very comprehensively in favor of allowing the public to install such energy sources and makes it really hard for anyone to legally stop you from producing your own power. I am not positive if it also required net-metering and, if so, if it had any quantity limits built in.

WAPA isn't clear or sure how they are going to handle net metering. There is a fellow up the road from me that has a small (less than 3Kw ) wind turbine. For the first few months he generated enough power to turn the meter backwards for the month. WAPA then replaced his meter with one that only goes forward.

When WAPA talks about net metering they have stated they won't pay/ credit you for more than their cost avoidance which they claim ia about $0.16 Kwh. They are also saying that they will limit it to 2- 5% of their customer base.

Hi Jim, not sure where you got your info from, but net metering has been in place for USVI residents since August 1, 2007. Rates for energy going back to wapa is same rate you pay, however they have a catch and take all excess credits at years end so people arent making mini power plants and taking advantage.

Taken from www.vienergy.org:

"The total amount of power given to WAPA cannot exceed 5 megawatts in the St. Croix district or 10 megawatts in the St. Thomas/St. John/ Water Island district which is about 10% of the peak load WAPA generates daily. Approximately 5,000 customers in the St. Croix district and 10,000 customers in the St. Thomas district can participate. Customers interconnecting small photovoltaic (solar) systems or small wind systems or other renewable energy systems can deliver a maximum of 10 kilowatts (kW) monthly into the grid. Net metering will be available to certified residential or commercial customers on a first-come, first served basis until the cap is reached.
WAPA will install a single meter with two-registers to accurately measure the kilowatt hour (kWh) usage of power flowing to and from net metering customers. All energy delivered by WAPA in any monthly billing cycle will be charged at the prevailing PSC approved electric rate. Energy delivered by the customer to WAPA will be credited each month to the customer’s electric account at that same rate. At the end of each year, or if a customer discontinues service, any excess kilowatt hour credits will be granted by the customer to WAPA without compensation to the customer. "

PS, Thank You Richard for your posts, great stuff, i wanna see your dissertation next 🙂

Hi folks,

I just spoke to Radcliff at the Energy Office of STX (340.773.1082). He was very knowledgeable of this program and very easy to talk to. Here is a summary of the conversation:

- If I was producing more energy then I was using, how would WAPA handle this?
- you have to sign up for "Net Metering" and get the dual register meter.
- WAPA would credit kWhs for your later use (effectively crediting you at customer rates).

- what if I have a "negative" bill at the end of the month?
- WAPA will just roll that "credit" over to the next month.
- WAPA will not roll the credit over to the next calendar year; instead, the credit vanishes on 1 Jan

- do I need a special meter for this program?
- yes, you need to sign up for "Net Metering"
- a meter with two registers will be installed at your house

- What is the procedure to start this "Net Metering" and what are my costs:
- WAPA has forms to fill out to request "Net Metering". (They are not currently online)
- There is a $20 application fee
- You will have to show that your house electrical system is adequate (disconnect switches, more) and this might have to be inspected by an electrician (which would require a permit for any changes).

- I saw on the web site that currently, only 5000 people on STX will be allowed to participate; how many have currently signed up and what is the backlog for applications?
- only two people have currently signed up; so there is no backlog.

So, if all of this holds, then I think my back of the envelope analysis is still basically OK as is.

BTW, the VI energy website (www.vienergy.org) is pretty interesting (in a good way). You can find a few videos of interviews with people that use solar and people who sell solar. Wind power is also addressed; along with solar water heaters (which really sound attractive). I might delve into the wind power analysis next...

(tu) 😎

Is it possible to power a 25cf household refrigerator with an Energystar rating of 830KWH/year with a solar setup that costs under $1000?

I live in PR and don't want to buy a generator for the upcoming hurricane season. I want to be able to keep the refrigerator running and maybe a 250W TV for a few hours.

I don't know how much electricity my refrigerator actually uses or how often it runs. Would a 300W solar panel be sufficient? What size battery would I need?

If I could put together a system that would work I would like it to run the refrigerator every day and not just when the power is out.

Thanks,

Jeff

My suggestion to you is first buy a Kill O Watt meter for $29 - $39 then plug it into the wall and your refrigerator into the meter. It will show you how many watts your refrigerator is actually using. Leave it plugged in for a week and see how many Kwhs the refrigerator using during a week. My energy star refrigerator uses on average 111 watts per hour. In this climate it is designed to run 80% of the time so when it is running I can estimate it needs 139 watts.

Do the same thing for your TV, but for the TV you only need to know how many watts it is drawing when it is plugged in and turned on. Many TVs draw current even when they are turned off. You will want to unplug it when not in use when running on solar.

You probably can do what you want, but you will have to go to one of the solar sites and use one of their calculators to determine how many batteries you will need. Remember that during the day part of the power you are generating will be needed to recharge the batteries so you have power through the night.

You probably will be screwed if you get a cloudy day and can't fully recharge your batteries. The refrigerator will quit and no TV. Your fall back might be to use your car's alternator to charge you batteries.

Jim

Here is a question................
Lets say you are building and furnishing a house starting from scratch. And your goal is to be as much off-grid as economically possible.
PV solar power is DC and I assume the more efficient windpower generators are also DC versus AC.
So is it a good idea to furnish your house with DC appliances and fixtures, etc. wherever possible?
Keeping in mind that to run AC the DC needs to run thru an inverter which in itself will consume watts, right?
Or is it more cost effective to purchase energystar type AC consuming equipment and run them via the inverter?

Here is a question................
Lets say you are building and furnishing a house starting from scratch. And your goal is to be as much off-grid as economically possible.
PV solar power is DC and I assume the more efficient windpower generators are also DC versus AC.
So is it a good idea to furnish your house with DC appliances and fixtures, etc. wherever possible?
Keeping in mind that to run AC the DC needs to run thru an inverter which in itself will consume watts, right?
Or is it more cost effective to purchase energystar type AC consuming equipment and run them via the inverter?

Some DC appliances are much more energy efficient than their AC counterparts, that being said, DC wiring in the house and the appliance itself can be more costly. DC designs of evaporative coolers, refrigerators, water pumps and fans all use less power with DC.

DC to AC Inverters today are very efficient(up to 96%).

Many things to consider while choosing between AC and DC power. Most DC appliances run 12 or 24v. When coupled with a solar electric system, DC appliances can really shine(no pun intended)

Do a google search for "DC appliances" , "DC water pumps" or sundanzer, sunfrost refrigerators. Also google "Backwoods solar & DC" Its a decent write up.

🙂

Oh BTW!!! Net Metering info & requirements are now available at the WAPA website:

http://www.viwapa.vi/customers.asp

:@)

A report on my trip to STX:

Landed at JFK last night, got home at 11pm..The whole ride home i felt like i was speeding on the wrong side of the road. Windows were up cause it was 61 degrees outside and i was freezing cold. I was flipping through the radio stations, couldn't find anything i liked....NO reggae!! Why did i come home? Oh yeah, i remember....So i can plan my move ASAP!

My time on STX was simply amazing. Stayed at Sugar Beach and for the price and what you got it was a great deal. Would recommend it to anyone. After spending so much time on STT, STX was truly different. Both island have distinct beauty, and each is different in it own way. I loved the area West of Cane bay and the cliffs of green and tidal pools tucked away on the shore. The snorkeling was great in Salt River and cane bay.... black sting ray with white circular spots all over, think it was an eagle ray? Lots of lobster, HUGE puffer fish and some scary looking barracuda. We also caught our dinner-Conch Chowder, SO good!

The nightlife and restaurants were just as good as STT. Kurt Schindler played one night at "Parrots cove" sp?, the place got so crowded people couldn't even get up the stairs! Everyone was dancing and shaking the floor!! Woo-Hoo! The pain killers weren't bad either! I heard he will be playing there monthly now! In C'sted the "Brew Pub" and "Rum Runners" seemed to be the popular hangouts and there were a bunch of other bars with TVs and places cooking up food along the boardwalk. Want to say thank you to whoever suggested "Kim's" for the conch, we tried cajun and buttered versions and loved em both! I also loved the stuffed crab at the Bombay club in Csted, gotta have more of those! Hakim and his bother(forgot his name) own "deli/market" (Big yellow sign) near 5 corners makes the absolute best roast beef, lettuce tomato and cheese sandwiches of all time! $4.50 and its 2 meals! Great deal and perfect for when you get out of the water from snorkeling for 5 hours! Ohh.. for those that like wings, you HAVE to try them at pelican cove. Couple different versions all spectacular!

Now for the solar side of things. WAY, WAY, WAY past my expectations is all i can say. I don't want to break any rules so... Long story short...I'm moving to STX by August! Yep, right in the middle of hurricane season. It gonna be interesting. The VIEO rebate program ends and starts on Sep 30, so if we can get some jobs in before then, that means people can get 2 rebates in a matter of months instead of having to wait until the next rebate program cycle. We will see how the weather cooperates.

It was truly incredible to meet and chat to all the different people who were interested in solar. I made lots of appointments and usually had to meet people at a certain location and then go see their house to see if it was a good application for a system. It was great! The vast majority of folk had great southern exposure, near perfect roof pitch, and a solid constructed roof! The only bad part that everyone had in common was a hefty WAPA bill. All different types of people were interested, i met with: Hovensa employees, restaurant and condo owners, police officers, furniture craftsman, dive instructor, retired couples, car salesman and even a senator! Heck, i even had a 5 minute chat with the customs official checkpoint guy at the airport, he took my card and the even funnier thing, he was there the week before when my brother went home and my brother also gave him a card!! I cant wait to get back in a month.

I NEED TO RENT for AUG 1st!! I will be needing to talk with anyone who has a solid 2+ bedroom house/condo/apt. A good breeze, washing machine and a porch are all i need 🙂 Anywhere along the north shore from Cane bay to cotton valley preferred. Can pay full rent or I would like to offer to manage a property and/or make deals with solar electric systems and such. 1 year lease fine. Would also like to store a 20ft container on the property if possible.

Thanks to everyone who had great suggestions for this trip, I cant wait to get back and look forward to making STX my home for a while 😎

Cory K

Hi Cory,

I gotta tell you... I think you're in the right business for the times!

A friend of mine (the owner of the small company I now work for) is getting solar power on his house in Livermore CA. His solar provider is suggesting a 6kW system because:
- he'll be able to store power (back to the power company) through the peak hours of the day
- use the power through the night hours
- the 6kW system seems to match his usage (6kW * insolation hours = his normal daily usage)
- expected payback time is still 5-10 years (I don't think the pay back time changes with the size of your system)
- he'll pay $50k for the system (like I said, he's the owner of this small 30 person company)
- his SW facing roof can hold 6kW (I'm guessing about 450 sqft) worth of solar panels

It's got me thinking that:
- the Sun pumps down 1.5 kW of energy per square meter of area on the Earth
- about 1 kW makes it to the ground
- by today's energy usage, the average American house probably uses about 20-30kWh per day
- solar cells will become more efficient

Therefore, I really think that within the next 50 years, if you live between +- 45 deg latitudes:
- the concept of a power company delivering power to homes will seem as outdated as the horse and buggy
- industries may still need power in large volume from power companies
- the roofs of homes will be solar collectors (in shingles or equivalent coatings)
- in windy areas, wind generators will be easily incorporated into house or yard designs
- batteries will store energy for cloudy and dark hours

http://www.virginislandsdailynews.com/index.pl/article_home?id=17625048

40%, i cant believe it... I wonder who else on the whole planet pays more than the USVI. This certainly reduces the payback time for a system from 11 years to about 8....if WAPA rates stay this way for the next 8 years...cough cough :/

The good news is that there is a new bill that was completed May 17, 2008 "The Virgin Islands Renewable Energy Act of 2008" and sent to public hearing soon!! Lots of customs and excise tax breaks, no increased taxes for increased value in home due to installing a renewable energy stsyem and more.

P.S. Totally agree Richard...!!!!

"the concept of a power company delivering power to homes will seem as outdated as the horse and buggy in under 50 years"

Hi Cory,

This latest news has me wondering about two topics:
1) who is behind the tax incentives for alternative energy? I can't believe the power companies would be in favor of this (kind of like private schools competing with public schools). So, who has the clout to get this past power industry lobbies? Will the incentives get better as the price of energy increases?

2) it is too bad that new technologies take so long to get to the masses, in our society. Our US economic model is slow to trickle money down to folks, but very robust at trickling money up to the rich. The "good" news is that if ideas are good enough, then eventually they become available to everyone (30 years ago only the rich could have computers, now everyone has one or more). So, I guess we need more rich folks to "invest" in alternative energy.

So, keep up the good work! Let's get this past the early adopter group!

Just saw this on The Source: http://www.onepaper.com/stthomasvi/?v=d&i=&s=News:Local&p=1212898533

Wow! And this, by one of our own! http://www.onepaper.com/stthomasvi/?v=d&i=&s=Commentary:Open+Forum&p=1212898539

EngRMP,
Your words give away your youth and inexperience. The best solar cells based on silicon, like NASA uses, are only about 10% efficient at converting sun light to electricity. There are copper based cells that are cheaper but are only about 1% efficient. There have been physical chemists working at universities and probably industry for over 30 years that I know of that have been trying to increase the efficiency. Just saying that something will happen doesn't mean that it can happen. But there's always hope.

Ahhh, Bassman, you flatter me... I wish I was young. Inexperienced?... absolutely true.

Interesting that you bring up the age issue. My wife and I were realizing (just this week) that abundant solar energy is the first technology that we can see on the horizon, but will probably just not live long enough to really enjoy it. A sure sign of getting old.

But, I'm wondering about your 1-10% efficiency claim. That doesn't jive with numbers that I have. For example:
- a residential 2 kW solar panel (system) is about 150 sqft in size
- 150 sqft/9 = about 15 sqm
- at 1kW/sqm at the Earth's surface, that would produce 15kW (peak power) if 100% efficient
- 2kW/15kW = about 15% efficiency
- and that is just residential quality solar panels
What am I missing? I'm curious where your numbers are coming from.

My assertion of "end of a power company era" is based on 10% or greater efficiency, because in that case:
- take a 2000 sqft house
- maybe half of that roof faces south
- that's 1000 sqft of available solar panels
- 1000 sqft/9 = about 100 sqm of area
- at 1kW/m and only 10% efficiency, we would get 10kW (peak power)
- at an insolation value of 5 (for USVI, averaged over a year), that's 50 kWh/day
- which is almost twice the power that people use (if you can bank it)
So, now the problem is reduced to a mass production, manufacturing issue, as opposed to a technology exploration issue. Doesn't that seem like a problem similar to reducing the cost of High Def LCD TVs (10 years ago they couldn't even make an LCD screen with the required pixels; now they're just past the early adopter stage)?

Gallium arsenide (GaAs) multijunction based devices are the most efficient solar cells to date, reaching a record high of over 42% efficiency under solar concentration and laboratory conditions. This technology is currently being utilized in the Mars rover missions.

FYI...........here is a 56kw solar power system with an estimated payback in 5 to 7 years based on 13 cents per kw.
Just think how soon the payback would be when your paying 35+ cents per kw in the USVI's.

Hi heepajeep,
Can you try to include the link again... I can't wait to see this! But....(choke)... 56 kW!?!?!?!... that's a lot of power!

FYI...........here is a 56kw solar power system with an estimated payback in 5 to 7 years based on 13 cents per kw.
Just think how soon the payback would be when your paying 35+ cents per kw in the USVI's.

oops
http://outdoorsbest.zeroforum.com/zerothread?id=755341

That is just awesome! I didn't expect this to scale well to industry. But, I guess anything that you can take off of the grid will help the bottom line... you don't have to go completely off the grid to save money. I can't wait to see solar panel shingles... that is going to be SO cool!

I also heard from a friend of mine that the Defense Dept is one of the biggest advocates for solar power:
- fuel for them is always an issue - especially when out of country
- having a defense dept that is dependent on foreign oil is just not a good idea
- so they don't want anyone to stop any progress

Awesome array! 56k! Looks like incentives and rebates in Florida are picking up for the commercial side or they have a special PPA if they got 56k installed for $300k.. wow! Imagine If WAPA gave similar incentives!!

Yesterday there was an emergency meeting of senators and various officials on STT yesterday talking about what to do with the energy problem. The group proposed making new deals with Hovensa and WAPA, and how to incorporate renewables.

http://www.onepaper.com/stcroixvi/?v=d&i=&s=News:Local&p=1212898742

"according to Bevan Smith Jr., V.I. Energy Office director. Short- and long-term goals include retrofitting obsolete lighting and plumbing fixtures in government facilities and installing net-metered solar panels and small wind turbines, he said.
Tax incentives, loan guarantees and financing programs should also be offered so local residents can make the switch to solar panels, he added."

New bills are in legislation and new incentives/rebates for renewable energy products are on the horizon!! Specifically its an act amending Virgin Island code 12, adding chapter 23 relating to renewable energy providing for incentives and other related purposes. Proposed by senators Louis Patrick Hill and Senator Alvin A. Williams. Starts out saying the most important: "Whereas, the legislature finds that the development of renewable energy and energy efficiency are important for the future for the Virgin Islands, its energy security and the protection of the public health and environment of the people of the Virgin Islands."

On Saturday June 21st Senator Ronald Russell has asked us to come speak on his radio program about renewable energy, specifically solar electric systems and the current energy issues. We hope to have officials from the VI Energy Office and WAPA tuning in to answer any specific questions from callers as well.. The radio broadcast starts at 9:30am. If you are interested in learning about solar power and how it works in the USVI~~tune in! http://www.wstxam.com/

Cory K.