Why add solar to your home? (Part 1: environmental reasons to go solar)
The decision to go solar can seem complicated. We explain some of the reasons why solar for your home can be great.
There are a lot of reasons why homeowners want to go solar. For some, it’s about energy independence. Others do it because they want to lock in their electricity costs and save money. For others, it’s all about a cleaner environment.
That’s the focus of this article. There’s a lot of environment-related questions that you might have, so we’ve done our best to tackle as many as possible.
Is solar energy renewable?
Traditional forms of generating electricity from natural gas, coal, and oil are non-renewable. These are also known as fossil fuels because they were mostly created during the Carboniferous period between 360 and 60 million years ago.
Fossil fuels are either no longer being created or created only very slowly. Once they’re gone, they’re gone. That’s why they’re called non-renewable.
Solar energy, on the other hand, is renewable because it comes from the Sun and is effectively limitless. (At least for the next 5 billion years: after that, the Sun will turn into a red giant star and swallow the Earth. So, we’ve got a little time still.)
Wind energy, by the way, is also solar: the Sun heating the Earth’s surface causes differences in atmospheric pressure that make air move around the planet.
Hydroelectric energy is also solar, because the Sun drives evaporation that results in rain, which causes streams and rivers to flow.
What is it like having solar panels on your house?
Most days, you’ll forget that you have them. Solar cells turn sunlight directly into electrons (electricity). They don’t make any sound, emit any smoke, or look like they’re doing much of anything while this is happening. It’s a bit like magic.
If your intention is to replace a fossil-fuel powered home generator, you’ll need a battery system as well. Grid-connected solar panels that aren’t paired with a battery will shut down automatically in a blackout. But if you have a battery, your house can continue to run on clean electricity within the capacity limits of the battery.
This is a silent and totally clean alternative to having a smoky, noisy generator in your yard. Considering that people die every year from carbon monoxide poisoning because they operate their portable generators indoors, solar panels can be a huge improvement to your health as well.
Learn more about how home solar batteries work.
Can solar panels eliminate your home energy use?
Unless you completely cut ties with your utility company and go off-the-grid, you’ll still receive an electric bill. But your net electricity usage for the year can definitely be reduced to zero.
What about taking that further? Can you generate all of your home’s energy needs, including heating and cooking? Can you get rid of your natural gas or heating oil usage too?
You can. This is called a net zero home, and it’s possible if your home is super-insulated, airtight, and uses electricity for everything including heating and cooking.
You might assume that a net zero house looks like a bunker, but in fact they can look entirely ordinary or even beautiful. Here’s an article with seven fantastic examples of solar powered net zero homes.
If the environment is your top priority, a net zero house can be the ultimate expression of that. But even if you don’t go to that extreme, any amount of solar electricity you generate offsets electricity from fossil fuel power plants.
Do solar panels help climate change?
Anthropegenic (ie. human-caused) climate change is the biggest environmental issue of our time, and renewable energy can make a big contribution toward stopping it.
In the United States, electricity generation is responsible for 27% of total greenhouse gas emissions - bigger than the entire industrial sector, and about equal to transportation-related emissions.
While adding solar panels to your house might seem like a small act in the face of a planetary-scale problem, there are now about two million solar installations in the US. Added together, these are starting to displace fossil fuels in a meaningful way.
How meaningful? Not every electric grid is the same. For example, Washington state gets much of its electricity from hydroelectricity. If you add solar panels to a house in Seattle, you’ll offset some carbon dioxide from electricity generation - but not nearly as much as a solar house in Kentucky, which is coal country.
You can see how your state stacks up in our article on solar panels and climate change.
How green are solar panels really?
Solar panels don’t grow on trees - they’re manufactured. It takes energy and natural resources to do that. How much exactly?
It’s tricky to calculate because it involves the entire lifecycle of the panel including raw materials, manufacturing, shipping, and operating the panel, which could be in a cloudy or very sunny location.
However, there are some good estimates that have been done. For the type of solar panel that you would put on your house, it can take anywhere from 1 to 4 years for the panel to generate as much energy as was used to manufacture it. This is known as Energy Payback Time. After the payback time has passed, the panel is energy positive and carbon negative: it generates renewable energy that displaces dirty electricity from fossil fuel plants.
You can read more about the environmental footprint of solar panels in our article on the topic.
Can solar panels be recycled?
What happens when solar panels stop working? So far, this hasn’t been a big problem because the widespread deployment of solar is a recent phenomenon, and solar panels can last a really long time. Today, it’s common for a commercial solar panel to come with a 25 year warranty, but you can expect them to last even longer than that.
Solar cells don’t have moving parts but they do lose efficiency over time due to exposure to UV light. The newest panels today may lose only about 0.5% efficiency every year. That means even after 25 years, your panel could still be generating 88% of its original specification. That’s a lot of years of pollution-free electricity.
Eventually, solar panels do reach the end of their life. Just like with other waste streams, reuse should be a higher priority over recycling, and sometimes this is possible because panels are replaced even while they are still working because the customer wants to upgrade to newer, more efficient technology. There is a used market that already exists for these panels, and they can find a second life from buyers in the US or in developing countries.
Even so, with millions of panels being installed worldwide, the waste stream for this technology will be a growing problem. The International Renewable Energy Agency estimates that the cumulative waste stream could reach 78 million tons by 2050. This means that there will need to be a recycling solution.
Fortunately, companies are starting to step up. One example is PV CYCLE, which helps the European Union meet its recycling goals: solar panel recycling is mandatory in the EU. There are US-based companies that are starting up as well. You can read more about this in our article on solar panel recycling.
Do solar panels kill birds?
Maybe you’ve heard about solar panels killing large numbers of birds? While it is a problem, it’s more of an issue with concentrating solar plants, which use mirrors to create steam that drives a turbine.
Photovoltaic panels also occasionally pose a problem for birds because they’re a reflective surface and birds sometimes crash into them in the same way they crash into windows.
But the scale of the problem is small, especially relative to bird deaths caused by cats and power lines, which together kill more than 200 million birds a year. Also, fossil fuel power plants and their noxious emissions are estimated to kill around 14 million birds a year in the US.
By comparison the Ivahpah concentrating solar planet, which is the largest CSP facility in the US, kills perhaps 3,400 birds a year.
This means that by switching to renewable energy like solar, we’re actually helping to avoid bird deaths, not cause them. You can read more about this issue in our article.
Other environmental concerns about solar panels
There are other concerns that people have about solar panels, some of which are rooted in myths.
One myth is that solar panels cause cancer because they supposedly emit radio frequency radiation. First of all, solar panels don’t emit any more radiation than ordinary household electronics, like your television.
Second, there’s no scientific link between radio frequency radiation and disease. This is one of those internet myths that belongs in the category of conspiracy theories, like the idea that 5G cellphone towers cause COVID-19.
Another more legitimate concern is whether the panels themselves are toxic. The majority of solar panels in use today are made from crystalline silicon, which is non-toxic. The only heavy metal these panels might contain is lead, but in no larger concentrations than you might find in your phone or laptop.
Thin-film panels can contain toxic metals, but they’re designed to be durable enough to withstand the outdoor elements for 25 years or more. It’s highly unlikely they would pose a health hazard to your household. The main manufacturer of thin-film panels is First Solar, which doesn’t focus on the residential market.
Bottom line: solar energy is better for the environment
The environment can mean different things to everyone, from personal health to ecosystems to climate change. Fortunately, I think it’s pretty clear that renewable energy and solar power, while not perfect, are a far better environmental solution than fossil fuels.
- Why Distributed? from IEEE power & energy magazine
- Life Cycle Greenhouse Gas Emissions from Solar Photovoltaics from NREL
- Technology-specific Cost and Performance Parameters from IPCC
- Life Cycle Assessment Harmonization from NREL
- State-level generation and fuel consumption data from EIA