What Are The 2 Limiting Factors Of Solar Power?

Introduction

Solar power has seen a huge expansion over the past decade as a source of clean renewable energy. In 2016, the global installed capacity of solar PV grew by 50% with over 75 GW installed according to Solar Power Growth #1 in 2016. Solar power systems can now be found in use across residential, commercial, and utility-scale projects as the technology has improved and costs have decreased. While solar has major benefits as a sustainable energy source, there are still some fundamental limitations to how much solar can contribute to the overall energy mix.

Intermittency

One of the biggest limiting factors for solar power is its intermittency – solar panels only generate electricity when the sun is shining. This can make solar power unreliable as a continuous source of energy. As noted in an article by Scientific American, “Intermittent renewables are challenging because they disrupt the conventional methods for planning the daily operation of the electric grid” (https://blogs.scientificamerican.com/plugged-in/renewable-energy-intermittency-explained-challenges-solutions-and-opportunities/). Solar energy output varies based on the time of day, weather, and seasons. Cloudy days can significantly reduce solar electricity generation. This intermittency makes it difficult to integrate large amounts of solar power into the existing electric grid infrastructure without changes in how the grid is managed.

Storage Limitations

One of the main limiting factors for solar power is the lack of cost-effective, large-scale energy storage. While battery technology has improved dramatically in recent years, batteries are still expensive compared to fossil fuel power plants. According to a 2021 report from the National Renewable Energy Laboratory, utility-scale battery storage costs range from $175/kWh to $428/kWh [1]. This is 2-5 times more expensive than natural gas or coal power on a per kWh basis.

In addition, batteries currently lack the capacity to store solar power at scale for extended periods of time. The duration of grid-scale lithium-ion batteries is typically 1-4 hours [2]. However, solar generation can fluctuate for days or weeks due to weather variability. Without cheap, long-duration energy storage, solar cannot reliably meet electricity demand around the clock.

While promising technologies like flow batteries may eventually provide longer duration storage, they are not yet commercially viable at scale. Until energy storage costs decrease substantially and long-duration storage is proven, the intermittency of solar will require backup power from fossil fuel plants or other dispatchable sources.

Land Use

Solar farms require large amounts of land to capture enough sunlight to generate substantial amounts of electricity. As solar installations scale up to the gigawatt level, thousands of acres may be needed for a single project. For example, the Topaz Solar Farm in California covers 25 square miles of land. While solar panels can be installed on rooftops or marginal lands, utility-scale facilities often compete with agriculture and wildlife habitat for space. Concentrated solar power plants, which use mirrors to focus sunlight, require even more acreage per megawatt generated.

This extensive land use can trigger opposition from environmental groups concerned about impacts on desert ecosystems. Solar projects may fragment habitats, disrupt wildlife corridors, and require mitigation measures. However, some solar farms have created pollinator-friendly environments underneath and between panels. The challenge is finding suitable locations that avoid sensitive habitats while still receiving abundant sunlight.

Transmission Capacity

Moving solar power from sunny areas to population centers requires major grid upgrades. Currently, our electric grid cannot easily transmit large amounts of solar power over long distances. Solar energy is most abundant in remote deserts, while population centers tend to be located far from these areas. This mismatch between solar energy supply and electricity demand presents a challenge.

Major investments in transmission infrastructure would be needed to connect sunny regions with high solar potential to big cities that require a lot of electricity. New high-voltage direct current (HVDC) transmission lines that can efficiently carry electricity over hundreds of miles would have to be built. These lines are costly and difficult to site due to concerns from local communities. Upgrading the grid in this manner requires permitting, financing, and multi-state coordination.

Until expanded transmission capacity is available, the amount of solar power that can be delivered from remote solar farms to load centers will be constrained. This limits how much solar can contribute to the overall electricity mix in many regions. Overcoming the transmission barrier will require substantial time, money, and effort. But expanding transmission is essential for solar to reach higher levels of market penetration.

Upfront Costs

While solar energy offers long-term savings on electricity bills, the upfront costs of installing a solar PV system remain prohibitively high for many households and businesses. According to Solar112, “The upfront cost of residential solar installation ranges between $3500 to $16000.” [1] The cost varies based on system size, panel efficiency, permitting fees, electrical upgrades, and labor. For a typical 5kW system, expect to pay $10,000-$25,000 after incentives and rebates.

Compared to an average household’s monthly utility bill, the initial solar investment may seem daunting. As Energy Solutions Solar explains, “While the upfront cost of residential solar installation might seem expensive at first glance, a look at the bigger picture—solar’s many benefits and cost savings over time—tells a different story.” [2] Over the system’s 25+ year lifetime, solar panels can provide electricity at less than half the cost of utility power. But the steep upfront price tag remains a major barrier, especially for low-income households.

Innovative financing options like solar leases, PPAs, and community solar help mitigate the upfront cost hurdle. But more support is needed to make rooftop solar affordable and accessible for all homes and businesses.

[1] https://solar112.com/solar-financing/
[2] https://energysolutionsolar.com/blog/why-solar-energy-best-alternative

Soft Costs

Soft costs make up a significant portion of the total cost for solar installations. According to a Solar Soft Costs factsheet, soft costs can account for up to 68% of the total price of a residential solar system. For utility-scale solar projects, soft costs represent up to 35% of total system prices.

Some major soft costs for solar include permitting, financing, customer acquisition, installation labor, and supply chain costs. Obtaining permits and navigating regulations can be complex and time-consuming processes, driving up soft costs. Financing costs are also a major factor, as installing solar requires large upfront investments. Solar companies must spend significant resources on customer acquisition, marketing and system design. Installation labor shortages can also constrain growth and lead to higher soft cost premiums. Overall, streamlining regulations, permitting, and financing could help reduce soft costs and allow solar to scale up faster.

Fossil Fuel Entrenchment

Despite solar power’s rapid growth, the fossil fuel industry’s political influence and subsidies create resistance that slows the transition to renewable energy. The fossil fuel industry spends millions lobbying politicians to protect subsidies and resist policies encouraging solar adoption (Forbes, 2019). This “dark money” undermines renewable progress through misinformation campaigns and defending nonrenewable energy policies (UPenn, 2023). Global fossil fuel subsidies distort energy markets by artificially lowering prices, impeding renewable growth. The US could catalyze reforming subsidies internationally and domestically by ending subsidies worth billions annually (Brookings, 2021).

The fossil fuel industry’s considerable political leverage enables it to impede policies encouraging solar adoption. Reducing this influence through subsidy and lobbying reforms could accelerate solar energy’s growth and adoption.

Aesthetic Challenges

One challenge for large-scale solar power adoption can be local opposition based on aesthetics. The visual impact of solar panels, especially on large acreages, can be a concern to those living in the surrounding communities (County by county, solar panels face pushback). Some find the appearance of solar farms unsightly and worry they will detract from the rural or natural beauty of the landscape.

This not-in-my-backyard or NIMBY opposition has stalled and even blocked solar projects in some areas. Community resistance from an aesthetic standpoint highlights the need for stakeholders on all sides to negotiate solutions acceptable to locals while allowing projects with broader societal benefits to move forward (Sunblocked: Resistance to Solar in Farm Country). Proper siting, screening, setbacks, and community engagement can help address concerns over solar’s visual impact.

Conclusion

In summary, the two key limiting factors for solar power are intermittency and storage limitations. Intermittency refers to the fact that solar power is dependent on sunlight and cannot generate electricity at night or when the sky is overcast. Storage limitations mean that cost-effective, large-scale energy storage solutions have not yet been widely implemented to store solar energy for use when the sun isn’t shining. While these remain challenges, advances in battery storage technology and forecasting to better predict the availability of solar power are helping to overcome them. There is also potential in improving grid integration and developing more flexible power grids that can handle the variability of solar generation. Overall, while intermittency and storage limitations pose difficulties, they are surmountable challenges and continued innovation and declining costs in the solar industry will further help solar become a major source of clean, renewable energy.