The Falling Cost Of Solar And What It Means For Energy Sovereignty

Swanson's Law — the observation that solar photovoltaic module prices fall approximately 20 percent for every doubling of cumulative shipped volume — was first articulated by Richard Swanson of SunPower Corporation in 2011, though the underlying data pattern had been observable since at least the 1970s. It is an empirical regularity, not a physical law, but it has proven remarkably stable across four decades and multiple technology generations.

The mechanism behind learning curves in manufacturing is not mysterious: accumulated production experience enables process optimizations, defect reductions, economies of scale in materials purchasing, and incremental engineering improvements that compound. Each of these is individually small. Cumulatively, across doublings in production volume, they are transformative.

Solar module prices fell from approximately $76 per watt in 1977 to under $0.20 per watt in utility-scale procurement by the mid-2020s. This is a reduction of more than 99.7 percent. No manufactured product of comparable complexity and capital intensity has followed a similar trajectory over a similar timeframe.

What makes this especially significant is the pace of capacity doubling. Global installed solar capacity crossed 1 terawatt in 2022. Projections from IRENA and Bloomberg New Energy Finance suggest it will cross 5 terawatts before 2030. Each of these doublings, if Swanson's Law continues to hold, implies another 20-25 percent cost reduction. The technology is not approaching a floor yet. Silicon purification, panel efficiency, balance-of-system costs, and installation labor all have further room to fall.

Energy economists use "levelized cost of electricity" (LCOE) to compare the full lifetime cost of different generation technologies on a per-kilowatt-hour basis. LCOE accounts for capital costs, financing, fuel costs, operations and maintenance, and the expected operating life of the asset.

In 2010, the global average LCOE for utility-scale solar PV was approximately $0.38 per kilowatt-hour — more expensive than nearly every conventional electricity source. By 2023, it had fallen to a global average of approximately $0.044 per kilowatt-hour, and new contracts in sunnier markets were being signed at $0.01 to $0.02 per kilowatt-hour. These numbers represent electricity that is cheaper than coal, cheaper than natural gas, cheaper than nuclear, and cheaper than any other form of mass electricity generation that has ever existed.

The disruption this creates for fossil fuel economics is structural, not cyclical. When the cheapest source of new electricity generation in most of the world is also the one that requires no fuel, produces no emissions, has few moving parts, and can be deployed at any scale from 100 watts to 100 gigawatts, the incumbents face a problem that cannot be solved by efficiency improvements to their own technology.

The relationship between falling costs and sovereignty opportunities is not automatic — it requires active planning to capture. The pattern of technology cost curves creates time-limited windows in which early adopters gain structural advantages that compound over time.

Nations that built solar manufacturing capacity when costs were still moderate — most notably China, which deployed massive state investment in solar panel manufacturing starting in the mid-2000s — now dominate the global supply chain and capture a disproportionate share of the value created by the technology they helped make cheap. The industrial policy lesson is that waiting for a technology to become obviously cheap before investing in it means missing the industrial capture window.

For households and communities, the parallel insight is that each year of delayed solar adoption is a year of continued dependence on external energy supply chains. A household that installed a solar system in 2015 at $2.00 per watt has already recouped that investment through avoided electricity bills and is now operating on essentially free electricity. A household waiting for prices to fall further is rational in a narrow sense but is simultaneously paying utility bills that have, in many markets, increased faster than inflation.

The sovereignty calculus is not purely financial. A household that controls its own power supply is insulated from grid outages, rate increases, utility policy changes, and the political instability that can interrupt centralized energy supply. These non-financial benefits are real and substantial. They do not appear in LCOE calculations because LCOE does not measure resilience, independence, or the political value of self-determination.

The falling cost of solar is inseparable from the falling cost of battery storage. The two technologies are synergistic and have followed parallel learning curves. Lithium-ion battery costs fell from over $1,000 per kilowatt-hour in 2010 to under $100 per kilowatt-hour by the mid-2020s — a reduction of more than 90 percent in the same period that solar costs were collapsing.

The combination of cheap solar generation and cheap storage is the technological basis for energy sovereignty at any scale. Without storage, solar requires grid connection for reliability (or accepts the limitation of daytime-only power). With adequate storage, a solar-plus-battery system provides power continuously without grid dependence. As storage costs continue to fall, the system configurations that achieve full independence become financially viable for a growing fraction of the global population.

Grid-scale storage has crossed a threshold where it is now economically rational to overbuild solar and store the excess rather than to maintain gas peaker plants for grid stability. This changes the economics of grid operation at the utility level and further erodes the case for new fossil fuel infrastructure.

The falling cost of solar does not guarantee its adoption. Several structural forces slow the transition in ways that benefit incumbent energy systems:

Stranded asset protection: Utilities and fossil fuel companies have large balance sheets tied to existing infrastructure. Regulations in many jurisdictions prevent stranded assets from being written off quickly and instead allow utilities to recover sunk costs from ratepayers, effectively taxing distributed solar adopters to subsidize the infrastructure they are no longer using.

Permitting and interconnection friction: In the United States, the average time from solar project application to grid interconnection approval exceeds five years for large projects. Regulatory processes designed for 20th-century utility structures impose costs and delays that are not inherent to the technology but are real barriers to deployment.

Financing access: The economies of home ownership, creditworthiness, and access to capital mean that the households with the greatest need for energy cost reduction are often the least able to access upfront financing for solar installation. Community solar programs, on-bill financing, and pay-as-you-go models partially address this, but structural inequality in capital access remains a binding constraint.

Supply chain concentration: The rapid fall in solar manufacturing costs has been accompanied by extreme geographic concentration. Chinese manufacturers produce approximately 80-90 percent of global solar panels. Supply chain disruption — whether from trade policy, geopolitical conflict, or logistics failures — represents a real risk to continued rapid deployment.

For individual households and communities, the implication of the cost curve is to treat solar-plus-storage as infrastructure, not as an optional upgrade. Every new building that lacks integrated solar generation capability is being designed for a past energy economy. Every community that does not plan for distributed energy resources is leaving resilience and economic sovereignty on the table.

For national planners, the implication is that the industrial policy window for solar manufacturing is not permanently open. Countries that intend to build domestic solar manufacturing capacity — and the sovereignty advantages that come with it — must act before the market is fully locked in to existing supply chains.

The cost of solar will continue to fall. The question is who captures the sovereignty value that fall creates.