While this question seems simple enough, the answer, unfortunately, is a bit more complex. If the question were, “is now the right time for clean energy solutions?”, the answer would be a resounding YES! Whether you’re concerned about depleting finite resources, the environmental impact of extraction, or the impact of carbon emissions on our atmosphere, there is little if any question about our need to move beyond carbon based fuels.
Any move away from carbon based fuels, however, needs to address the issues that make those fuels popular. While not infinite, supplies of coal and natural gas are currently plentiful, readily available, and relatively cheap. Power generation from these fuels can be adjusted as needed and is available 24 hours a day, 7 days a week, year round. From a business’s or a grid manager’s perspective, these are all very important issues.
So how does solar stack up? Let’s look at the same issues of supply, availability, expense, and reliability. We also need to discuss the environmental impact since that is one area where carbon based fuels do poorly.
Supply: Obviously, supply is not an issue. The sun, while technically not infinite, is about as close as we can get in a finite world. And it sends energy our way whether we use it or not so we’re not impacting the environment in any way by utilizing it.
This is one of the biggest problems with solar. It only works when the sun is up. For example, at ourheadquarters, we average 5.26 viable solar hours per day, which is fine if you only need power for 5.26 hours per day. For 24-hour availability, however, adequate storage to supply the 24-hour need is required as well as enough production capacity to fully charge the storage devices, which leads us into the next issue.
The costs have been coming down, but solar generation systems are still somewhat expensive to build. On the other hand, since the energy from the sun is free, that expense is made up over time. Storage systems, typically batteries, however, add a substantial amount to the expense of building a PV solar system while also increasing the amount of required maintenance. With storage, the return on investment can be 20 or more years out which is not far from the expected life span of the solar components and perhaps 10 years beyond the expected life of the batteries. In other words, you might never achieve a positive return on investment relative to grid power costs.
In addition to the night/day cycle, weather can also have a significant impact on solar availability. Where I live, temperature inversions can create a trapped layer of pollution and fog (smog) that very effectively blocks sunlight - sometimes for weeks on end. During these periods, solar panels will generate little if any power. Unfortunately, it still isn’t financially feasible to build storage systems that anticipate such long periods of non-production. Backup power sources, from the grid or alternative generation systems, are still essential.
While solar power generation, per se, creates no harmful environmental by-products, if we examine the bigger picture including the entire life-cycle of solar panels, for example, there can be significant environmental impacts.
There is the impact of mining the raw materials and of refining those materials and producing the panels. Depending on the type of panel, hazardous materials are utilized in the production of the photo-voltaic wafers and are even incorporated long-term in some of the thin-film solar panels. These materials can be very damaging to the environment if not handled with extreme care. Substantial amounts of water are also required for the manufacturing process. Finally, shipping the panels to their intended destination, and then properly disposing of or recycling those panels at the end of their life each contribute to the environmental impact.
There are also impacts not related to the manufacturing process. For example, utility scale solar farms can cover large tracts of land and damage the habitat of wildlife and the land itself. Finally, many people find solar panels to be aesthetically unappealing and consider them to be a form of visual pollution. This is obviously a matter of opinion but it evokes rather severe reactions in some.
As long as you don’t expect solar to provide 100% of your power requirements, the reliability and availability issues can become much less relevant. When solar produces, the facility or home derives its power therefrom. In areas where net metering is allowed, excess solar power can be sold back to the grid, creating a credit for future power needs. If this credit is equivalent to what you pay the utility for power, then it is a good trade-off. This works especially well for residential customers who are typically billed only for simple KWH consumption. In fact, sized correctly, residential solar production can totally offset the utility charges for power. Utilities, however, incur a cost for buying, managing, and transporting this excess power and they are beginning to impose charges to help offset their costs, so be prepared to get less back than the excess you provided.
On the other hand, in commercial and industrial environments there are usually other components to the power bill that solar cannot offset and might even make worse. For example, if your utility includes a penalty for low power factor, the addition of solar will often cause power factor to drop even lower and the penalty to go up. In the Rocky Mountain Power region, this increase in power factor penalties can sometimes be enough to offset any savings in KWH consumption. Make sure you understand how you are billed by the utility and how solar might impact that bill. It is frequently more complicated than simply replacing KWH.
So is now the right time for solar?
If you are a residential customer and the utility allows net metering and the exchange rate is good and you can afford the costs of buying and installing the system, then the answer could easily be “yes!” Additionally, many solar companies offer programs relieving the home-owner of any up-front costs. These can be attractive but usually come with long-term commitments. Make sure you can live with those commitments.
For everyone else, it comes down to what you hope to accomplish. If you are a business that simply wants to impress your customers with your “green” initiatives, then you can justify it, at least in part, as a marketing expense. If it is important to you to help pioneer responsible energy use, then the limited return on investment might be worth the cost. But from a pure economics point of view, there might be other alternatives that provide a better return on your investment. Before taking the leap, be sure to do your homework.