The change in renewable energy generation between 1949 and 2018 represents a major shift from dependence on one mature technology to a diverse portfolio. The period began with established hydroelectric power as the overwhelming source of renewable electricity, set against increasing reliance on inexpensive fossil fuels. Over the 69-year span, the energy landscape saw a political and research-driven incubation period. This culminated in a market transformation where wind and solar power fundamentally reconfigured the composition of the world’s clean energy supply.
The Baseline Era of Renewable Energy (1949-1973)
In the years immediately following World War II, the renewable energy sector was characterized by stability and limited diversity. Conventional hydroelectric power was the dominant, and often the only, source of renewable electricity available on a utility scale. This technology was viewed as reliable and economical, having been widely deployed across developed nations since the turn of the century, earning it the nickname “white coal.”
Hydropower’s reliability made it an attractive choice for grid operators. In the United States, hydroelectric power provided nearly one-third of the nation’s electricity in 1949. This high level of contribution was already beginning to decline relative to the massive growth of electricity generated from coal, oil, and natural gas.
Other renewable sources, like geothermal energy and traditional biomass, played only minor or localized roles. Geothermal plants were confined to specific geological regions. Biomass, primarily wood, was used mostly in the industrial sector or for residential heating, not for large-scale electricity generation. Hydropower capacity additions remained steady but could not keep pace with the exponential growth of the fossil-fuel-powered grid.
The Policy-Driven Search for Alternatives (1974-1999)
The energy landscape was altered by the oil crises of the 1970s, which catalyzed government interest in energy independence and diversification. These events highlighted the economic vulnerability of nations reliant on imported oil, spurring initial public sector investment into alternative energy research. This period was marked by political volatility and the realization that new renewable technologies were technically immature and expensive.
Governments began implementing early policy mechanisms, such as tax credits and research grants, to support nascent solar and wind technologies. The goal was primarily technology demonstration and resource assessment, rather than large-scale commercial deployment. Early wind turbines were small and inefficient, and photovoltaic (PV) solar panels were costly. PV was primarily limited to niche applications like satellites and remote telecommunication relays.
Progress was slow and sporadic, especially when fossil fuel prices stabilized or declined in the 1980s and 1990s, causing funding to wane. High upfront capital costs and technical challenges meant that wind and solar remained on the fringes of the electricity market. While foundational research was conducted, large-scale deployment did not materialize.
Technological Deployment and Market Transformation (2000-2018)
The turn of the millennium initiated a major period of change, characterized by the transition of wind and solar from experimental concepts to mainstream energy sources. This shift was enabled by two reinforcing factors: rapid technological advancements and substantial manufacturing cost reductions. Wind turbine technology matured significantly, with the average size and efficiency of installed turbines increasing.
Rotor diameters and hub heights grew substantially, allowing for the capture of more consistent wind resources at higher altitudes, which increased the capacity factor of wind farms. Simultaneously, solar photovoltaic cell manufacturing entered a “learning curve” phase. This meant that every doubling of cumulative production led to a predictable percentage drop in cost. Driven by economies of scale and competitive supply chains, the cost of solar PV electricity fell by approximately 85% between 2010 and 2018 alone.
The implementation of stable, long-term policy mechanisms also provided the market certainty necessary for large-scale investment. Policies like feed-in tariffs, pioneered in Germany, and Renewable Portfolio Standards (RPS) in the United States, guaranteed a market for clean electricity. As a result, wind and solar capacity began to scale up exponentially, moving from a near-zero contribution in 2000 to dominating new capacity additions globally by 2018.
The Shift in Renewable Energy Composition
The 69-year span resulted in a fundamental restructuring of the renewable energy portfolio. In 1949, the renewable sector was overwhelmingly dominated by hydroelectric power, accounting for the vast majority of renewable electricity generation. By 2018, while the absolute output from hydropower had increased globally, its relative share within the total renewable energy mix had been significantly diluted by the growth of wind and solar.
In the United States, hydroelectric power’s share of total national electricity generation fell from over 30% in 1949 to a range between 6% and 8% in recent years. This reduction in market share occurred even as the total amount of renewable generation grew substantially, illustrating a structural change rather than a decline in the output of existing hydropower facilities. Wind and solar, once negligible, grew to become the primary drivers of new renewable energy capacity.
By 2018, wind and solar had collectively become the fastest-growing components of the clean energy supply, often surpassing new capacity additions of all other sources combined. The composition of the renewable sector evolved from a single-technology market to one where variable renewable energy sources rapidly challenged the long-held dominance of conventional hydropower.