SolarPowerNerd
Solar energy has enormous potential, but it’s not without real drawbacks. Before you invest, it helps to understand the challenges honestly.
Here’s what limits solar power today and what’s being done about each issue.
Taming the Weather
A key issue with solar power is the unpredictable nature of weather. Solar relies on harnessing the power of the sun, and at night or during poor conditions, it becomes impossible to generate energy.
Solar power depends on direct sunlight. Most places in the U.S. have about seven hours of sunlight a day on average, but only three to five hours of direct sunlight.
That window varies with season, location, and other factors.
If you only have three to five hours of direct sunlight, a cloudy afternoon could ruin the generating capacity for that day. Tree coverage and geographical location further limit the window and coverage area for solar generation.
Not everywhere is suited to solar, and certainly not all the time. While California may be well suited, Boston is far less so.
But does that matter?
If California gets five hours of direct sunlight and Boston gets one, aren’t they both better off? Not necessarily.
That brings us to the second major limitation: cost.
Paying for the Sun
Solar installations are an expensive investment. While some argue that even one hour of direct sunlight helps move away from fossil fuels, it’s not reasonable to expect people and businesses to invest heavily for a low payoff.
One estimate suggests it would cost the U.S. $4.5 trillion to go 100% renewable. The key cost comes from storage and transportation of solar power, plus an inherent contradiction.
Solar energy generates power when there’s sunlight, but that’s when we need the least power. Most electricity is needed in the evening and night for heat and lighting.
There’s a clear gap between when energy is created and when it’s used.
That’s why solar requires large-scale investment in storage facilities to house energy for extended periods, not just overnight but through lengthy cold spells too.
While $4.5 trillion is about 25% of U.S. annual GDP, fossil fuels globally receive over $5 trillion in subsidies each year. There are clearly some funds available to offset solar costs.
Costs for the Average Home
Solar is still expensive for the average homeowner, but it’s decreased significantly. In 2022, the average national cost was $2.99/watt, with the average system around 6 kilowatts.
That means the average system costs roughly $13,000 after tax credits.
The good news: costs are declining rapidly. A decade ago, a similar system would have cost over $50,000.
As demand grows, prices will continue to fall. But the environment doesn’t have time to wait.
Governments must accelerate investment in solar energy to increase technology development and lower prices for average homeowners.
Efficiency Is the Key
Solar is expensive partly due to the technology and raw materials involved. Another related issue is efficiency.
Today’s solar panels are inefficient. If a panel receives only three hours of direct sunlight, it needs to maximize that time.
Unfortunately, a lot of direct sunlight goes unused.
The average panel’s efficiency is about 20%. Some systems record higher figures at a higher cost, and some record lower at less cost.
Energysage ranked providers with the highest topping out at 22.8% in 2022. Even at that level, almost 80% of sunlight hitting the panel is wasted as heat.
We’re not using the sun to its full potential, and that’s a key limitation. Dust particles resting on panels further reduce efficiency, meaning maintenance costs are an ongoing issue.
Panels must stay clean to absorb as much sunlight as possible.
Work is being done to improve efficiency, but it’s driving costs higher. Understanding why panels remain so inefficient helps explain the overall challenge.
A Mountain to Climb
Geographical location directly impacts sun exposure and how much direct sunlight you can count on. But the geographical problem goes further.
The ideal solar setup is a wide-open space with large panels in a field or a detached home with a clear roof. It’s not always possible to build these systems.
The world is increasingly urban. Some estimates suggest the world is now 50% urban and increasing steadily.
For those in apartment buildings or in the shadow of tall buildings, solar doesn’t offer a clear solution.
It’s hard to place panels on the side of a home and receive meaningful benefit. Even if panels were placed on top of an apartment building, dividing the resource among all residents would make the benefit tiny.
Solar works best for low-density urban and rural areas where residents have space to install a system. Modern living is moving further away from individual homes with front gardens, and overpopulation only adds to the challenge.
Solutions Exist
Those in lower-density areas may be able to offset the demands of those in higher-density areas. If a farmer can produce 200% of their energy needs, they could sell some back to the energy company.
This type of solution has already worked in several places. These entrepreneurial activities incentivize people to invest in solutions that benefit both themselves and others who can’t generate their own power.
Work must be done for apartment residents to successfully lobby for solar panels on their building roofs. Legislation needs to lower the barriers without placing all the cost on one resident.
Keeping It Clean
Why is solar tipped to become the leading energy solution before 2050? Because it’s perceived as an environmentally friendly renewable solution using an abundant resource: the sun.
But how good for the environment is solar really? According to KubyEnergy, installed solar solutions produce emission-free energy for more than 30 years.
However, the manufacturing process is far less positive.
The energy to manufacture solar panels is greater than for other forms of energy production. It requires raw materials transformed into photovoltaics with far more precision than something like coal processing.
Quartz must be mined, processed, cleaned, heated, and combined with other materials. Nitrogen trifluoride is used to manufacture solar cells and is a greenhouse gas 17,000 times more potent than carbon dioxide.
The energy required upfront is high and there are dangerous chemicals at play. However, KubyEnergy estimates the payoff period is short, only 2-4 years before the solar panel has overcome these front-loaded problems.
The net result remains positive.
Ready to Recycle?
A tougher issue is recycling. Solar panels have a long lifespan, but the materials used to create them include hazardous chemicals that shouldn’t be left in a landfill.
Today, in many cases, that’s exactly what happens.
Lu Fang of the China Renewable Energy Society highlighted the issue in 2017. By 2050, China alone will have created retired solar panels totaling up to 20 million tonnes.
Solar panels contain lead, copper, aluminum, and crystallized silicon. These can’t simply be left in a landfill.
Some companies are creating sophisticated recycling methods. But the money and effort required currently exceed what’s recouped, so recycling isn’t happening at a large scale.
When panel volume increases, economies of scale should bring costs down.
One approach is including recycling costs in the initial purchase price. While this increases the price and may lower demand, it would offset the environmental burden facing panels at end of life.
Time Is Running Out
The largest obstacle facing solar is time. All the problems listed have potential solutions, but they must be addressed quickly to solve the energy and environmental crisis.
Nuclear plants are being shut down and coal plants are being phased out. Many now think there’ll be an electricity shortfall unless solar can solve its problems fast.
One estimate suggests that photovoltaic systems must be significantly expanded from 2021 onward with sufficient storage capacity to address the coming energy shortage.
Frequently Asked Questions
Is cloudy weather a major limitation for solar panels?
Yes, solar panels still generate electricity on cloudy days, but at reduced capacity. Depending on cloud thickness, panels may produce 10-25% of their rated output.
This is why battery storage is so important, as it lets you bank excess power from sunny days and use it when production drops during overcast weather.
How long do solar panels last before they need replacing?
Most solar panels come with 25-year performance warranties, and many continue producing electricity well beyond that. Panels degrade about 0.5% per year on average, so after 25 years they’re still operating at roughly 87% capacity.
The bigger concern is component failure in inverters, which typically last 10-15 years.
Why don’t solar panels convert more sunlight into electricity?
Current silicon-based panels have a theoretical maximum efficiency around 33%, limited by the Shockley-Queisser limit. Much of the sun’s energy arrives as wavelengths that silicon can’t convert.
Researchers are working on multi-junction cells and perovskite materials that could push practical efficiency above 30% in the near future.
Is solar energy viable in northern climates?
Solar works in northern climates, just less efficiently. Germany, one of the world’s top solar producers, gets less sunlight than most U.S. states.
The key is proper system sizing, optimal panel angles, and pairing with adequate storage. Longer summer days can partially offset shorter winter production for annual balance.
Final Thoughts
Solar energy has huge benefits, but it’s far from a perfect solution. Those who lobby against solar have plenty of ammunition given the limitations it faces.
While none of the limitations are without solutions, the combination of problems creates uncertainty. That’s bad for businesses, consumers, and the environment.
Companies hesitate to invest, homeowners worry about the payoff, and the world can’t afford to wait.
Government funding, subsidies, and incentives must support development of renewable energy solutions. The materials used to create panels are a key issue, and work must be done to increase economies of scale or find alternative technologies that bring costs down.
The most important obstacle is time, and the moment to act is now.
