Solar panel, or photovoltaic (PV), technology has seen some impressive improvements in the past decade, bringing high-tech into a price range everyday users are better able to afford. The question remains: Is it really practical for camp? Well, it depends. Following are a brief look at how solar systems work, a few possible camp applications, and, finally, their safety and care.
How Do Solar Systems Work?
When thin plates of silicon are exposed to sunlight, electrons are literally knocked loose from the silicon atoms. Connecting wires to the plates gives the negatively charged electrons a place to escape. By connecting a bunch of these plates by wires, like batteries in a toy, you increase the flow of electrons. Just like that you have an electrical current. The current only happens, though, when the sunlight is beating electrons from the wafers. Batteries, with their own electrochemical magic, receive the current and store the energy until there is a demand.
This all sounds simple enough, and in its most basic form, it is. However, as mentioned just a moment ago, batteries have their own “magic” that must be properly cared for to work correctly. A functional PV system requires a battery maintainer device as well. Imagine your everyday insulated jug, probably like several you have in the dining hall or out on the soccer pitch. It’s a cylinder about 12 inches in diameter, maybe 18 inches tall, and has a small spout near the bottom to fill a cup. To fill the jug, you pop the top off the cylinder and open a faucet. The level in the jug rises evenly until it’s full, then one of two things happens: A watchful person will shut off the faucet, or the jug overflows. Imagine now that the jug isn’t a straight cylinder but an upside-down cone — wide at the bottom, narrowing towards the top. With a constant faucet flow, the level rises faster and faster as the jug fills. To completely fill the jug without it overflowing, the filler must be extra attentive. This is exactly the situation with battery charging; each type of battery (wet cell, gel pack, whatever) has its own “shape,” and therefore a specific pace at which it can receive a charge. Unlike overfilling the jug that just dumps some water, “overflowing” a battery can mean expelling explosive gas or dumping acid.
To make things worse, “a little bit is better than nothing at all” is not true when it comes to batteries. Over a fairly short amount of time, a crust will form on the plates inside the battery, reducing their surface area and lowering their ability to both charge and discharge. So a solar system battery maintainer must have pretty sophisticated functions beyond detecting when the battery needs to be charged. It must also recognize what the battery charging “shape” is and prohibit charging when not enough sunlight is available to do any good. Like so many other cases, you get what you pay for. A maintainer with more features will cost more. In the long run, though, you will get more power from your batteries (as they charge fully every time), and they will last much longer. And ultimately, isn’t economy, efficiency, and savings why you’re looking at solar systems in the first place?
One other often overlooked component of the system is wiring. Many do-it-yourselfers think that these are inherently safe, low-voltage systems. In many ways, they are pretty safe. However, there are wiring codes and requirements specifically for PV systems, and these should be honored to the letter. Under no circumstances should “direct current” (DC) be confused with “can’t hurt you.” DC can and does heat wires, and it will start fires. Last year’s series of cell phone battery fires should tell anyone that.
What Can You Do with Solar Power?
Anyone with an equestrian program and pasture for the horses knows what a great application solar power is for low-voltage fencing. Facilities that have other livestock and problems with predators appreciate solar electric fences too. In addition, PV has been a prime component of the RV industry’s research and development, and they’ve brought lots of products to market that work well with solar power. Further, with the consumer interest in LED lighting, those systems also are well adapted to solar, DC power. So, from powering a small refrigerator at a remote aid station to store medicines to lighting a cabin in the wilderness, PV can be an excellent alternative to the cost and effort to properly install power lines. (I say “properly” only because of the untold number of camps I’ve visited with pump wire strung through and attached to trees. For safety’s sake, please don’t ever do that. And if you’re doing that now, please undo it. It is unsafe for a list of reasons as long as my arm.)
PV is becoming much more common in remote water and sewage applications as well. For example, many camps may have a tall water storage standpipe. Those are filled by well pumps that are most often on lower ground and may be hundreds of feet away. Power lines usually stop at the well house. The trouble is water that stands in storage can become stale without air and internal circulation. Residual disinfectant can drop to unacceptable levels. Camps that run winter programs may find that the water freezes. All of these situations can be remedied with small PV power plants mounted to the top of the tank, which receives plenty of sunlight to make them work. Companies like SolarBee make circulator and aeration systems to solve stagnation, aeration, and freezing problems. Other firms have stepped up and developed chemical feed pumps to work on 12-volt systems. Water availability, quality, and chemistry are all improved without running a separate power line to the tank.
Like anything else, though, PV systems require care and maintenance. Panels are delicate because the silicon wafers are sandwiched between layers of glass. They generally do not endure impacts well, so areas that see frequent hailstorms need to make special provisions. That may include polycarbonate covers, which will reduce the amount of sunlight getting to the panels, so more panels may be required to get the needed electricity. Systems are, of course, intended to be in the sun. While the PV process uses a certain piece of the light spectrum, the sun also delivers UV light that will degrade and deteriorate plastic insulation that coats wires and covers connections. These will deteriorate over time and must be replaced to keep the system running well.
Even with the best maintainer, batteries won’t last forever. Those, too, have environmental requirements for proper disposal. Most regions collect a deposit when batteries are purchased as an incentive to return the spent units for recycling and rebuilding. As an aside, this is where traditional wet cell batteries are the better ecological choice, because those components can all be recycled. Modern “gel” systems generally are not and end up in the landfill.
Finally, you might find it interesting to know that NASA’s Mars rovers, Spirit and Opportunity, were intended to function for 90 Martian days. Their systems were so remarkable and robust that they lasted over six years. NASA has supposed that Spirit’s PV system failed (probably from dust accumulating on the panels), however the Opportunity mission continues. With proper design, which included careful selection of the solar panels, wiring, and the equipment to be powered, NASA got much more for our tax dollars than they had ever imagined.
In the past decade or so, and as the energy market has waxed and waned, some camps have been approached about collaborations with a corporate entity of some sort proposing to install solar panels “at no cost to camp.” Camp property benefits from the solar power when camp is occupied/in session. The corporate partner then keeps profits when power is sold to the grid. The details of the arrangement vary, but there are pieces of the whole arrangement that camp leadership should keep in mind and questions that must be answered to your satisfaction. Think through what has to happen and who is paying for every step along the way. For example:
- If the panels are to go on roofs, who is providing the structural analysis, assurance, and insurance for that additional load (with and without snow)?
- How is the roof replaced with them on it, and what effect do the mounts have on the roofing warranty?
- Who is responsible for securing the building permits, whether building mounted or on their own structures?
- How much of the financial arrangement is based on government subsidies, and how long are those in effect?
- Where is the company based, and where is its support based if something goes wrong, needs a repair, or there is an accident of any sort that requires immediate assistance?
- Who actually owns the equipment, and who is responsible financially for removing the system when that time comes?
- The financial breakeven on large installations is usually years away, and the company that’s proposing it has to be financially sound enough to survive to the point of experiencing a return on the investment. Is camp expected to wait also?
These are just the simplest and most basic of the issues that need to be resolved to your satisfaction, and in writing, before committing to any sort of arrangement like that.
Still, camp doesn’t need to be full of rocket scientists to let the sun work for it. And your remote corners of camp are every bit as good a spot to put space technology to work as the next rock from the sun. Find local experts who can help you solve any problem, and start looking to the sky. Your best solution might be closer and cheaper than you thought.
Rick Stryker is a professional engineer who is passionate about camps and the opportunities that they provide. He’s always delighted to answer e-mail questions at email@example.com.