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Winter has passed, giving us time to sit and review how our solar furnace worked.  It’s a bit tricky to evaluate exactly how effective it was since we made several other changes to the house last fall (sealing up gaps around windows, turning our thermostat down to 59) but we feel it made a huge difference.  Here are our thoughts and I’ll dig into the numbers down below.

The Good

• Mmmmm, warm.  We enjoyed the sunny days when the solar furnace raised our indoor temperature to 72 while our gas furnace thermostat stayed set at 59.
• Warm air did circulate fairly well through our house (although it did stay warmest in our living room, which is where Will has his home office and where the dog likes to spend her time).
• The solar furnace reduced our output of carbon dioxide by 1,792 pounds between the electricity and natural gas conserved.
• Since this was a demonstration project cost-shared by SIREN, it was a low-cost way for us to enjoy solar technology.

The Bad

• Solar furnaces do absolutely nothing when it’s cloudy and can not fully replace a regular furnace.  (Having one made me much more conscious of when we have sunny days.)
• Our dollar savings were pretty minimal, about $52 for the season.
• Payback time would be 58 years (40 if you get the tax rebate) but “normal” people would see higher savings (see note below)

The Ugly

• Someone who keeps their thermostat at 70 during the day would see much, much greater savings because they would be replacing a lot more gas/electric furnace time.
• Someone who relies on electricity for heat would see much greater savings because it’s more expensive than a gas furnace (even counting both the gas and electricity needed to run a gas furnace).
• Someone who lives in a place with more expensive electricity would also see higher dollar savings – our electricity is nominally 9.7 cents per kWhr, which is really about 12.5 cents with the fees added in.
• It’s likely our solar furnace would be even more effective if we increased the thermal mass in our home to absorb that heat on sunny days and keep it longer into the night.  We could also use more insulation in our attic and crawlspace.
• All these numbers should be taken with a grain of salt as we changed a lot of variables at once, which is a common challenge as people green their homes – who wants to make just one change and wait a whole year to document how effective it was?!

Now some numbers.  Last winter (November 2009-April 2010) we used about 352 CCF of natural gas (one CCF = 100 cubic feet of gas) while this past winter with the solar furnace (November 2010-April 2011) we used about 236 CCF.  That’s a reduction of about 33%.  Will took a look at the outdoor temperatures and overall they’re pretty comparable from winter to winter.

Part of the savings we saw is due to lowering the thermostat on our gas furnace.  We turned our thermostat down about six degrees during the day, from 65 to 59, and about 3 degrees at night, from 62 to 59.  Past studies have shown that homeowners reduce their energy usage about 1% for every 8-hour period per degree.  However, we’re guessing those studies were looking at people turning their thermostat down from 72 degrees and we’d expect energy savings to be smaller as you get lower.  (This is because it takes more energy to heat when there’s a larger differential between the outside air temperature and the inside air temperature.  Somewhere I saw a very pretty exponential curve showing this but I of course can’t find it right now.)

Let’s say down in our temperature range the savings is more like 0.6% for every 8-hour period per degree.  So during the day (roughly 16 hours) we would save 0.6% x 6 degrees x 2 time periods = 8%.  At night (roughly 8 hours) we would save 0.6% x 3 degrees x 1 time period = 2%.  That gives us 10% total.

We also caulked around all our windows and insulated our electrical outlets and attic doors.  Past studies say that can reduce energy usage 10-15% but our house really seemed pretty tight beforehand so let’s say it was just 8%.

The solar furnace is the rest, (so 33% – 10% – 8% =) 15% savings.  Not enormous but we enjoyed a much more comfortable home since the solar furnace would routinely heat our house up to 68 or 70 while we left our gas furnace thermostat at 59.  Dollarwise, our energy is cheap and therefore our savings were modest.  We pay about 55 cents per therm/CCF.  So our overall gas savings for the winter was a modest $64 ($0.55 x 116 CCF).  Out of that, only about $27 can be attributed to the solar furnace (45% of the total savings).

However, our gas furnace also uses quite a bit of electricity to run the fans.  Again, I had to back calculate to estimate how much since we can’t put a kilowatt on our furnace.  Our total electricity usage for the 2009-10 winter was  about 1943 kW-hrs over 6 months.  For the 2010-11 winter, it was 1,156.  That’s a difference of 787 kW-hrs but a big chunk of that can be attributed to our new refrigerator, which we found uses 1.9 kW-hrs less per day, or about 342 for the winter.  That leaves us with an overall reduction of 445 kW-hrs (a 22% savings over last year), which at 12.5 cents each would be a savings of $55.  Out of that, about $25 can be attributed to the solar furnace (about 45% of the savings) while the rest is due to the lower thermostat and weatherizing.

So our total solar furnace savings = $27 from gas + $25 from electricity = $52. That means our payback time on a $3,000 solar furnace system (installed price) would be about 58 years.  Not super.  However, there is a big tax rebate available that will refund 30% of the system cost, bringing the price down to $2,100 and the payback time to 40 years.  Still pretty slow but we are very sure the savings would be much better for someone who normally keeps their thermostat around 68 or 70.

In terms of carbon dioxide, we saved both on natural gas and electricity.  Natural gas generates about 12 pounds of CO2 per CCF of natural gas (according to the Carbon Fund).  So 116 CCF x 12 pounds = 1,392 pounds of carbon dioxide saved.  Electricity generated from coal generates about 2 pounds of CO2 per kW-hr (according to Kilowatt Coal).  So 200 fewer kW-hrs would mean 400 fewer pounds of carbon dioxide generated.  (As a side note, natural gas actually produces less carbon dioxide than coal if you convert everything to kW-hrs for a side-by-side comparison but in this case we’re sticking with CCF since that’s what appears on the gas bill.)

Total carbon dioxide savings?  1,792 pounds from the solar furnace, or about 9/10ths of a ton.  Whew!

So, our bottom line conclusions are:

• Qualitatively, we really like our solar furnace.  It really cranks out the heat and we enjoy waiting to see when it will magically kick on and give us hot air from the sun.  On sunny days it will run from about 11:00 to 4:00 and can easily heat the house up 10+ degrees.  The fan isn’t too loud and with our open floor plan, the warm air circulates fairly well.  We have considered putting in a fan or two towards the far end of the house to improve circulation even more but have decided we like having our main living area be the warmest and our bedrooms be the coolest.   We would like to experiment with adding a little more thermal mass to the house (to soak up the heat and radiate it back into the house at night) and of course more insulation.
• Quantitatively, we’re a little disappointed in the payback time but we think that’s mostly because of our radically low furnace thermostat setting.  The solar furnace performs the best during the spring and fall “edge” seasons when there tends to be more sun and a lower differential between indoor and outdoor temperatures.  If you’re determined to keep your indoor air temperature at 68 or 70, your furnace will run a lot during those periods and the solar furnace can make a huge offset.  However, we were often opening our windows during those periods to let the “warm” 60 degree air into our house.  And even during the coldest and darkest parts of winter, the gas furnace never really had to run very much to keep the house at 59 so there wasn’t a lot of usage to offset.

I’m going to try to get some data from two other friends who have solar furnaces who I believe keep their gas furnace thermostats at a higher setting, to see what they have observed.  I would also love to figure out how the solar furnace compares to installing insulation, in terms of return on investment.  What kind of savings would you see from $3,000 worth of insulation?  Maybe that will be our next experiment…

**UPDATE**  Our friend Woodie Bessler ran through some calculations to see how a $5,000 investment in a solar furnace from RREAL compares to buying $5,000 in photovoltaic panels at $5/watt and using them to run an electric heater.  His conclusion?  The solar furnace produces more heat in BTUs.  This made us feel good about our system.  However,

1. The output is comparable if the cost of PV panels drops to about $3.85/watt.
2. Excess electricity from the PV panels can be used to power other things, whereas excess heat from the solar furnace will do nothing (and may even be undesirable).
3. An even better option may be to use PV panels to power a geothermal heat pump, which would produce three times the heat, meaning an equivalent amount of heat could be produced for about half the cost.

You can see a pdf of his calculations here.

Since heating is usually a household’s largest expenditure of energy and the cost is low, insulating your house is one of the most cost-effective conservation techniques around. An even cheaper option is to insulate yourself, but how much good can that possibly do? We don’t often think about our clothing as insulation, but as long ago as 1946, scientists have examined the insulative value (similar to the R-value of house insulation) of clothes, which allows us to figure out what impact it would have.

These researchers created a scale that allows you to figure out your comfort level based on air temperature, activity level, and clothing. Their baseline, 1 ‘clo’, is the amount of clothing a normal person would need to wear to be comfortable sitting around at 70 degrees. 1 clo is the equivalent of wearing a business suit with normal underwear. To figure out the clo value of an outfit, you just add the clo values of each individual item.

Some common clo values are 0.1 for a short-sleeved T-shirt, 0.2-0.4 for a sweater, 0.25-0.35 clo for pants, and 0.22-0.77 clo for a long skirt.

For every 2 degrees Fahrenheit, you need 0.18 more clo to be comfortable (or you need to be more active). A pair of extremely insulating long underwear can be purchased for $25 and provide about 0.36 clo, which would allow you to drop your thermostat 4 degrees! Depending on where you are and what you’re heating with, that could save 15% on your heating bill.

I had a hard time believing those numbers, but I recently got a good pair of long underwear and they’ve made a huge difference in comfort.  That makes it pretty clear that insulating yourself can have a huge benefit, especially if you’re currently wearing just a T-shirt and slacks!

How can something as simple as long underwear be so efficient? Air is a good insulator, so keep still air near your body helps insulate you tremendously. Your body is already producing heat too, so all you have to do is trap it rather than using a lossy process like a heat exchange to produce heat. Best of all, you only have to hear the small area right around your body rather than a whole room or even a house.

Last year, my biggest problem was keeping my hands and feet warm. Since I primarily work from home, I had to have warm enough hands that I could type comfortably. Luckily, I’ve found that keeping the rest of your body warm keeps your hands warm too, even without gloves! When your head and torso are cold, your body adjusts by drawing heat away from your extremities. Warming your head and torso mean that your body leaves them alone and your hands and feet stay comfortable even when it’s well below 60F.

If you’d like to learn more about clos, I highly recommend the article in Low Tech Magazine that introduced me to the concept and the clo numbers I listed above (and more)!

I swear this was trendy in 1985

I’ve never been known for my stellar fashion sense (see photo, circa 1985) but my wardrobe has seemed particularly stagnant lately so I was excited when my friends Maggie and Siri invited me to the Second Annual Ladies Clothing Swap and Tea Party.  I don’t know how it compared to last year but this year’s event was AWESOME.  About thirty or so women showed up with bags of clothing that was quickly sorted by type – pants in one pile, dresses in another, t-shirts across the way…  The hostesses had made cute little handwritten signs for each pile and carefully propped up mirrors in strategic places around the room.

And then we all dove in.  Well, actually, it was one of those amazing instances of smooth flow without any direction or authority.  At any given time, there were some women trying on outfits while others gathered in the kitchen to drink tea and others found a cozy corner to sit and chat.  I had a wonderful time expanding my wardrobe but it was really the sense of connection with all these other women that made it an exceptional event.

I call it “eco-socializing” – an excuse to get together and strengthen the feeling of community while also achieving an ecological goal; in this case, efficiently recycling clothing by trading it with others.  Granted, a clothing swap may not be as obviously constructive as a barn raising or as altruistically beneficial as a volunteer river cleanup but I still think it’s an integral part of building a green society.  These are the kinds of events we need to be fostering in our towns and neighborhoods, along with canning parties, sewing circles, and leftover exchanges.  They don’t have to be about saving the planet; just about finding a way to spend some time with friends and neighbors while sharing resources in order to reduce waste and reinforcing shared beliefs about green living.

I suppose saving poor souls like myself from fashion tragedies is a worthy goal too.

It’s spring in Indiana, which means the weather is playing nasty tricks on us.  Yesterday it was 70 degrees and sunny; today it was 30 degrees and snowing lightly.  That’s a bit dramatic even for us local yokels but a couple of false starts before spring truly sticks are pretty common.  I thought I’d take advantage of the cold weather to showcase some snowy footprints I spotted during a women’s retreat a few weeks ago staying in a little cabin in the woods.

My friend Lisa is actually a much better Nature Nerd than I am and was able to identify all the footprints we spotted while I focused on capturing them on film.  (Check out our flickr page for footprints from deer, raccoons, possums, and other critters.)   I was most excited by the turkey tracks because I think turkeys are super cool.  This is mostly from when I housesat for my boss out in the boonies one summer and got to see turkeys walking across a meadow at sunset, surrounded by fireflies.  They looked like little dinosaurs with only their reptilian heads sticking above the grass.

Wonder what turkeys eat in the winter?  Well, as we followed their tracks around camp we came across this pile of cracked acorns.  They look like a lot of work to me but I’m guessing turkey beaks are more efficient at these sorts of tasks than I am.  I believe turkeys also depend on different kinds of seeds in the winter, including corn or other grains from nearby farm fields.  They probably were quite happy at the camp where we stayed, which had a variety of habitat types including open meadows, wooded ravines, a lake, and nearby farm fields.  In the summer they add berries and insects to their diet.

We saw quite a few animal tracks in the snow, especially around the creek, but I figured we probably wouldn’t see any animals themselves as I am not a particularly lightfooted hiker.  We were also working hard not to slip on the icy trails and generally paying more attention to our conversation than any efforts to be sneaky.  However, an hour into our hike we came up a hill and suddenly spied a flock of turkeys running down the trail from us.  Sorta.  They were pretty far off.  Can you see them?

Here’s a cropped version of the photo where they’re a little easier to spot.  Lisa tried to get closer but they are surprisingly fast runners with their bobbing little heads.  They also seem undaunted by steep hills and underbrush that left me panting.  Guess I am not cut out to be a wild turkey!

Ah, well.  We weren’t really planning on a turkey dinner anyway so I’m just happy we caught a glimpse.  Maybe next year we’ll see that beaver…

Even with our reduced electrical usage, installing enough solar panels to meet our average needs just isn’t cost-effective for us yet. Photovoltaic (PV) prices have dropped a lot in recent years so even though we can’t afford a big system, there are a couple of cheaper options for trying out solar energy on a small scale.

Before our first big train trip last year, I bought a small (and cheap!) solar charger for my cell phone. It’s about the size of a box of cards and has two suction cups so that it can be placed directly onto a window. Despite costing less than $30, the solar panel has a battery behind it so that you can charge the battery first and then hook up your phone later. That turns out to be a really good thing because it takes over a week to charge fully!

Something that I didn’t realize before getting this solar charger is that most solar panels require direct sunlight. When I put the charger on a south-facing window, it didn’t charge at all, despite getting indirect sunlight for most of the day. I had to place it on our east-facing window, where it got 1-2 hours of direct morning sunlight, for it to charge.

More recently, we won a much nicer (and more expensive–$90 or so) Soleo charger as part of the SIREN Energy Challenge. This solar charger has a built-in battery with three panels attached, each a bit larger than the first charger I got. When it’s open, the charger looks a bit like a tilted flower, with solar panels for petals (you put a pencil, included, through the center to keep it upright). The advantage of this charger is that you can rotate it so that it gets direct sunlight throughout the day. The drawback is that you do have to rotate it. This one only takes 2-3 sunny days to charge (or a little less than a week if you don’t rotate it) plus it has a larger battery (more capacity).

Both chargers have a bunch of adapters for changing a variety of cell phones. The Soleo also includes a USB adapter so that it can charge or run a USB-powered device. It can also be charged by USB if need be.

We have three different devices that we’ve tried with the charges: a normal cell phone, an iPhone, and an e-reader. Neither charger has a very accurate charge indicator, so it’s hard to know exactly how well they work, but the cheap charger would charge the cell phone fully and have some juice left over or charge the iPhone by half to three-quarters. It couldn’t charge the e-reader because it doesn’t have a USB adapter. The Soleo can charge the phone about five times from full or the iPhone once or twice. It can charge the e-reader about as well as it can charge the iPhone.

Are we saving any money? Not really. Cell phones, even power-hungry ones like the iPhone, and e-readers just don’t draw that much power. Over the course of a year, each phone probably uses less than a kWH each, so even if we charged all of them by solar, we’d be saving well less than a dollar a year. And, unfortunately, we can’t charge them by solar all of the time because they run out of power faster than the solar cells charge their batteries (especially during those cloudy winter days we’ve been having).

On the other hand, the chargers provide a lot of convenience under certain circumstances. On our latest trip, Maggie forgot her phone’s power cord but was able to charge it using the solar panel. I can also leave one of the solar chargers in my bag in case I need to use my phone more than normal. The cheaper one especially could be left in a car window to charge and you’d have it handy if you needed to quickly recharge a small electronic device.

The real issue is that most of the things we use draw a LOT of power compared to the amount of electricity a small solar panel can provide, even on a sunny day. If we were willing to keep our phones off more often or to use only small LEDs for lights, a small solar charger like these two would be enough to make a significant dent in our use. When compared to the amount of electricity a television or computer uses, the difference amounts to a rounding error.

I’d recommend getting a small solar panel to most people so that they can play with it, figure out the benefits and drawbacks of solar without a huge investment, and get a better sense of how much power a kilowatt-hour actually is!

I am so ready for spring.  I can’t stop garden planning and I’m ready to run out and start DOING things if only it would be warm & dry for two days in a row (don’t want to overly compact the soil).  I also need to spend a little time creating a [sigh] budget.  I wish I were either fabulously wealthy or super skilled at transforming society’s garbage into useful structures like trellises and fences and grape arbors and outdoor showers.  But as I am neither, I have to prioritize and I’m having trouble.

So right now I’m focusing on one of my ideas that doesn’t need to be implemented just yet: planting some vines to help shade our south-facing window.  It has been lovely to have this winter (although I might try to beef up our curtains next year with some thicker insulating fabric for night time protection) but in a couple of months we’ll shift gears to keeping heat OUT of our house and this year I’d like to do it with plants.  We already have some trumpet creeper vine that grows all over the front porch railing so I think with a few well-placed structures we can coax it into a window-shading growth pattern.  Hmmm, that sounds a bit like some sort of nasty disease but I mean my goal is to have the vines grow up and over the porch to keep out the sun but I also want to maintain a view from the window to the garden plus it would be nice to have sun on part of the porch for my solar cooker.

There’s also the design challenge that our porch already has a roof overhang that is relatively low (like the ceilings in our house, about 7.5 feet).  There isn’t a good place to hang brackets to suspend wires, as suggested in the Carbon-Free Home, and I’m afraid if I put any sort of pergola on the porch it would feel really low (especially if the plants sagged at all).

So here’s what I’ve come up with (as translated with my crude drawing skills).  On the left is a trellis that would run east-west, creating a truly shady spot in front of our front door.  On the right is a trellis that would run north-south (perpendicular to the house), nestled in the corner next to the stairs.  I would connect them with 4 or 5 wires running parallel to the roof overhang, where vines could grow and help shade out the noontime sun but leave the southeast corner of the porch uncovered so I could set up my solar cooker.

Next step: Life-size mockups with giant pieces of cardboard lurking in my garage and some leftover bits of kite string.  I think there’s a good chance this set up might be a little too low for comfort, although we might not know for sure until we grow some vines and see how dangly they are…  But you know we’re game for experiments!

The 2010 Energy Showdown is now officially over and we kinda won! Okay, we didn’t win the grand prize, but we won the 3rd and 4th quarter prizes, saved about $300, and expect to save more in 2011. As a whole, participants reduced usage by over 11 megaWatt-hours (that’s over 11,000 kWh!). Since Indiana’s electricity is produced almost entirely by coal, that’s a reduction of 22,000 lbs of CO₂!

At the SIREN meeting this week, some of the other families talked about their experience in the showdown. One thing that struck me was the diversity. The 1st quarter winners were a married couple who’ve been slowly improving their house over the past 5-6 years. The 2nd quarter (and eventual overall) winners were a family of four, who didn’t want to make any significant lifestyle changes. The 3rd and 4th quarter winners were us, who have pretty good habits, but were willing to try some pretty crazy stuff.

Despite our willingness to try things out, in the end, we didn’t have to do anything particularly difficult. Getting a new refrigerator was painless, as was caulking and sealing areas around the windows. Line drying was sometimes annoying, but wasn’t particularly bad. We’ve decided that 56 degrees is too cold, but we’ve discovered that we’re comfortable at 59.

I think that the biggest obstacle for most people to reduce their consumption isn’t the difficulty or discomfort, but the fact that usage is pretty much invisible. There are so many things that use electricity, and in such a hidden way, that it’s really difficult to know what your biggest energy hogs are. From the perspective of activities, it’s also difficult to know what things cost. How much electricity do you actually use to watch a movie? What if it’s streaming through a computer? How does that compare to playing video games? It’s hard to tell.

I think that if people had a sense of how much electricity (and money) they could actually save by changing their behavior, they’d do it. If my non-eco friends found out that it cost twice as much to watch a movie on TV as through their laptop, I think a lot of them would switch. I’ve talked about this some before, but I think it bears repeating. It doesn’t take crazy lifestyle changes or lots of money to make a significant dent (over 20%) in usage. You just have to spend the time to make the consequences of your activities more visible, at least to you. One way to start is to use a Kill-A-Watt to identify the appliances in your house that are the energy hogs (e.g. refrigerator, space heater) and look at the Energy Star ratings to know what benefits you might get from upgrading – as well as thinking about cutting usage entirely if you can (e.g. ditch that extra refrigerator in the garage).

It’s also extremely useful to track daily electrical usage overall to get a sense of your normal usage. This helps capture some of that hidden electrical usage – like water heaters, dryers, and furnaces that don’t plug into regular outlets – and also gives a baseline for comparing when you make changes. If you lower your thermostat from 59 to 56, how much energy do you save? We found it saved about 0.5 kWh/day and decided that wasn’t really worth it for the added discomfort. What if you line dry your clothes instead of using the dryer? We found it saved nearly 6 kWh/use and decided that was TOTALLY worth it (although we still sometimes use the dryer when it’s raining or freezing outside).

There are a lot of painless ways to reduce electrical usage but it can be hard to know where to start and which changes to embrace. With that in mind, Maggie and I are preparing to teach a class in energy conservation through People’s University (a city program where anyone can offer a class for their fellow citizens) and we’re also planning to publish an e-book for people who want to try it at home on their own. The class will meet two hours a week for four weeks and have homework assignments in between – like tracking daily electrical usage at the meter and measuring the most commonly used appliances with a Kill-A-Watt. Our biggest goal will be teaching people how to study their own electrical usage and figure out the best way to cut back, since it’s different for everyone. Sure, we can all do a better job turning off the lights when we leave the house and making sure our houses are well-insulated but there are a lot of other small changes to be made and we want to help people understand which will work best for them.

If the Energy Showdown participants in Bloomington were able to reduce energy usage by 11 megaWatt-hours in a year, just think of what it could look like if we all made an effort! And you don’t have to turn off your water heater or your air conditioning, we promise.

We interrupt your regular greencouple postings for an update from Maggie, who is doing volunteer work in Niger.

I’ve been in Niger for almost a week and I’m starting to adapt. Several people have told me that Niamey is the calmest capital city in all of Africa but it feels pretty active and chaotic to me so I’ve enjoyed being able to get out to the villages and visit the bush country. Today I was very happy that my host and translator Boubacar was able to arrange a trip out to the Koure giraffe preserve to visit West Africa’s last wild giraffe herd.

To get there, you drive about 60 km (24 miles) east of Niamey down a very well-paved two-lane highway, passing several villages but also many stretches of open land. There was one security-checkpoint-slash-toll-booth but the toll was less than $1 and they waved us through quickly enough. When we reached the preserve, we stopped at the main headquarters to pay our 10,000 CFA entry fee (about $20) which consisted of tickets for each of us, permission to take photographs, permission to drive the car through the park, and a stipend for the park guide. They have about a dozen guides who are sort of combination park rangers and tour leaders. Their main job is keeping tabs on the roughly 300 giraffes in the preserve so they know where to take the tourists.

From there, it was all dirt roads or total cross-country travels. I felt a little sorry for our driver but I think he enjoys the adventure of back-country driving most of the time. We went past a few villages and Boubacar explained that part of the entry fees go to the village treasuries which means the locals are very motivated to protect the giraffes and report any problems such as people illegally cutting trees. He asked if there was any problem with the giraffes eating the villagers’ crops and our guide said that during the rainy season the giraffes naturally migrate to a more gravelly area further from the villages where there are plenty of tasty trees for them to nibble so that has never been an issue.

After we drove for awhile, our guide got out and rode in the back of the truck so he could scan the horizon for giraffes. Once he spotted a herd, he used a big stick to reach across the top of the truck and gesture to the driver which way to turn. (It sounds simple but I thought it was a pretty ingenious method of communicating without trying to shout over the engine.) As we got close, he would direct the driver to zigzag towards the giraffes so we wouldn’t startle them too much.

Our first group was about four female giraffes and three juveniles around 5 months old. They were fairly calm as we approached and let us get a lot closer than I expected. Our guide said for the most part the males keep to themselves except during mating season. When a female giraffe goes into heat, her urine takes on a distinct smell that summons male giraffes from miles around. They battle for dominance and the winner gets to mate. He said that female giraffes can live as long as 60 years but that the males generally only live about 35 years. I think I may have misunderstood his explanation why but what I thought he said was that the males get so distracted by the possibility of mating that they don’t eat during mating season and thus weaken themselves.

Giraffes eat something like 80 different kinds of trees, most of which have thorns. Boubacar (who is a forester by training) identified about four trees that the giraffes were nibbling on while we watched, including acacia (shown here). I didn’t get any good photos of giraffe tongues but they are quite impressive and allow the giraffes to pull leaves easily off branches. However, our guide says they are a bit picky and they prefer young leaves that don’t have an accumulation of dust so they sometimes have to search pretty hard during the dry season.

Our second encounter was with a mother and her calf, who the guide thought was less than 10 days old. Baby giraffes are not exactly small but they are very cute! They were a little more skittish than the first group so we took a few pictures and then moved on. I had asked if it might be possible to see some male giraffes and our guide said it was hard to find them but we plunged gamely onward into the bush. It felt like we had driven forever and I was starting to feel guilty for making the suggestion when our guide got in the back of the truck again and started leading us cross-country. The truck got stuck in the sand once and we pushed it out and kept going. I was really feeling ready to call it a day when we suddenly came into view of a huge herd of giraffes, 17 in all, including three gigantic males.

Male giraffes are about 3 feet taller than females, have bigger horns, and have a big bump in the middle of their foreheads. They are REALLY TALL. This herd was extremely mellow and let us get quite close to them, watching us curiously with big deer-like eyes. There were even several giraffes sitting under a tree, which the guide says is unusual to see. (It really makes me want to have two sitting giraffe statues in front of my house instead of the typical lions.)

He also explained to me that there are two races of giraffes in the park, a dark one and a light one. It took me awhile to see the difference but there were a couple of young giraffes that had pretty distinctively different coloring. We wandered around taking pictures and I was really shocked by how close they were and how big. Their faces remind me a lot of white-tailed deer but they are so much bigger! They were also fairly slow to bolt although when they did run it was impressive to watch and I have no doubt they could cover a lot of ground in a hurry if they wanted.

After a long period of gawking, we headed back to the front gate to drop off our guide. I tried to ask Boubacar how much I should give as a tip but he didn’t want to impose by quoting me a number so I spent ten minutes frantically trying to calculate in my head what might be reasonable and decided to shoot higher than lower. I grossly overtipped but, hey, it was a spectacular experience and I certainly won’t regret a few dollars in years to come. I just hope the giraffes continue to thrive as the country continues to develop.

Niger is going to see some major changes in the next few decades as the population matures. Right now 50% of the population is under the age of 15 and there is a lot to be done to find ways for them all to thrive as adults. I think it can be done and I hope it can be done in a more environmentally sensitive way than we’ve done in the United States. I’d love to find that level of appropriate technology for both countries that provides comfort and safety without being wasteful or destructive.

And if that’s too much to ask for, I hope that the last wild herd of giraffes in Western Africa will continue to survive.

For more photos, check out our flickr account.

Fellow blogger Crunchy Chicken recently launched the Winter 2010-2011 Freeze Yer Buns Challenge, encouraging everyone to turn their thermostat down this winter.  She’s open to any temperature settings that works for folks but encourages people to push their limits a bit, especially at night.  I think her target is 62 during the day and 55 at night.

I feel like we’re already participating although in a rather unique way.  We have our thermostat set at 52 degrees and are relying on our solar furnace to heat us up to a more comfortable temperature during the day.  Our main motivation is keeping our electrical bill down so that we have a shot of winning the SIREN Energy Showdown grand prize – a one kilowatt photovoltaic system!  Will also likes the idea of just acclimating to a lower indoor temperature to lower our carbon footprint all winter, since we did fairly well adjusting to life without air conditioning this summer.

For the past couple of weeks it has been unseasonably warm (several days we opened all the windows to let the warm air IN) so with the solar furnace it has been in the high sixties during the day, dropping to about 55 overnight.  Yesterday it was cold but sunny so the solar furnace ran all day and brought the temperature up to about 65.  Then last night it got cold and our furnace actually kicked on for about ten minutes this morning to heat us from 51 to 52.  It has been between 52 and 54 all day and I’ve been here working.

And you know what?  It’s cold but it’s not unbearable.  I do wish we had some sort of supplemental heat for the bathroom – I hate stepping out of a hot shower into a cold room – but otherwise it has been okay.  I wear about three layers of long sleeves plus a hat, drink a lot of hot tea, and get up to exercise every hour or two to heat my body up again.  Perhaps life with minimal heat will improve my cardiovascular health!

Or perhaps in another month or two I can coax Will into turning up the thermostat to a balmy 58.  I’ll keep you posted…

A couple months ago, Maggie talked me into giving a presentation at the Simply Living Fair about our 3-kWh Challenge (which has more details, if the presentation is too high-level for you). The presentation went very well and has some more information (and hard numbers) about our electrical use since January. In my challenge post, I clocked us in at just under 80 kWh, but the official number from Duke Energy was just 71 kWh! The difference is just because we started and stopped measuring at different times, but it still sounds good.

My presentation slides are embedded below, but I’ll add some explanation underneath to replace some of the bits where I talked.

On the graph of our electrical usage, I included one line for each year plus a bar graph series at the bottom that represents our kWh usage per day based on my readings. There’s a LOT of variation, mostly due to hot water heating, the furnace, or A/C. When we stopped using all of those things in June, everything calmed down a lot.

In the end, we used 28% of the electricity we used last year, which is a tiny 14% of the electricity used by the average house our size!

We ended up using 115 kWh in September and are on track to stay under 120 kWh in October, so we’ve been able to maintain usage at 50% of last year’s numbers.

Just looking at electricity, we’ve saved about $175 so far this year and reduced our CO2 emissions by almost 2.5 tons (coal is not a very clean source of electricity)!

We’re incredibly happy with what we’ve done so far and plan to continue trimming as we head into the heating season! We knocked out some insulation projects today that will hopefully help and we’ll certainly keep you updated about the solar furnace!