Can We Have 100% Clean Energy?

Achieving 100% clean energy is theoretically possible but faces significant challenges. Clean energy refers to renewable energy sources like solar, wind, geothermal and hydro power that produce little to no greenhouse gas emissions.

This article examines the feasibility and challenges of transitioning the world’s energy system to 100% clean sources by 2035. With climate change accelerating, many experts argue this rapid transition is necessary to avoid the worst impacts of global warming and meet the goals of the Paris Agreement.

Table of Contents

Current Energy Mix

The current global energy mix is still heavily dominated by fossil fuels like oil, coal, and natural gas. In 2019, around 84% of global energy consumption came from fossil fuels while only 11% came from renewable energy sources like wind, solar, hydropower and biofuels according to the International Energy Agency. The share of renewables in electricity generation is higher at around 27% globally, but still far below fossil fuels which make up around 63% of global electricity generation.

The trajectory is moving in the right direction but slowly. The share of renewables in global electricity generation increased from 19% in 2010 to 27% in 2019. Many countries have set renewable energy targets like generating 50-100% of electricity from renewables by 2030 or 2050. But there is still a long way to go to fully transition away from fossil fuels which still make up the majority of the energy mix today.

Growth of Renewables

Renewable energy sources like solar and wind have seen rapid growth in recent years thanks to falling costs and supportive policies. According to the International Energy Agency (IEA), renewables are projected to contribute 80% of new power generation capacity through 2030 under current policy settings, with solar alone accounting for nearly 60% of additions (IEA). Global renewable energy capacity is forecast to reach 7,300 gigawatts (GW) by 2028, up from 3,100 GW in 2021 (Reuters). However, growth must accelerate further to reach climate and sustainability goals. The IEA projects renewables need to expand even faster, reaching over 10,000 GW of capacity by 2030 to put the world on track for net-zero emissions by 2050.

Challenges

There are several key challenges to integrating high levels of renewable energy onto the electric grid. Two of the biggest relate to the intermittent nature of wind and solar power. As noted in the RatedPower article Challenges of integrating renewables into today’s power grid, the variability and unpredictability of wind and solar require more flexible grid operations and infrastructure. Energy storage solutions are needed to store excess renewable generation when the wind is blowing or sun is shining and release it when renewable output drops.

Massive investments in transmission infrastructure upgrades and expansion are also required, according to the Greening the Grid toolkit overview on grid integration issues. This allows movement of renewable energy from source to demand centers and helps balance variable renewable supply. As outlined in the FutureBridge article Grid Integration Challenges and Technologies, distributed energy resources like rooftop solar can also strain distribution systems not designed for two-way power flows.

Finally, costs are a major challenge. Building out renewable generation, storage, transmission, and distribution upgrades needed for high renewable grid integration requires massive capital investments. Policies to incentivize buildout and equitably distribute costs are critical.

Solutions

There are several key solutions that can help enable a 100% renewable energy grid:

Energy storage technologies like batteries and pumped hydro power can store excess renewable energy when supply exceeds demand and discharge it when needed. Large-scale batteries are becoming more cost-effective (https://www.nrel.gov/grid/renewable-energy-integration.html). Pumped hydro also provides large-scale long-duration storage. Smart inverter technology can also help batteries provide more grid services.

Improving transmission capacity and building out high-voltage direct current (HVDC) lines allows movement of renewable power from source to demand centers. Strategically placed HVDC lines have great potential to balance variability and supply needs across wider geographic areas (https://rmi.org/the-solution-to-grid-reliability-go-bigger-and-bolder-on-renewables-and-energy-storage/).

Demand management through smart devices, smart meters and time-of-use pricing can shift flexible electricity demand to match renewable generation. This avoids curtailment and balances load.

Increased electric vehicle use enables their batteries to help balance the grid when plugged in. Vehicle-to-grid integration can turn EVs into grid assets.

Overall, a more flexible grid with a diversity of supply, storage assets, controllable loads, and transmission capacity can readily integrate high levels of renewables.

Role of Policy

Government policy has a major role to play in enabling the transition to 100% renewable energy. Key policy tools include subsidies and incentives for renewable energy, carbon pricing mechanisms, and phasing out fossil fuel subsidies.

Providing subsidies for renewable energy such as wind and solar can help make these emerging technologies cost-competitive with fossil fuels. Subsidies help overcome initial cost barriers and support investment in renewable energy infrastructure. Policymakers can offer tax credits, feed-in tariffs, renewable energy certificates, and low-interest loans as incentives for adoption.

Putting a price on carbon emissions through carbon taxes or emissions trading schemes creates a financial incentive for industries to transition away from fossil fuels. Carbon pricing changes the economics to make polluting more expensive, and clean energy more cost effective.

Phasing out subsidies for fossil fuel production and consumption can help remove market distortions that favor status quo energy sources. Removing subsidies for coal, oil, and natural gas can be an important complement to incentives for renewable energy and carbon pricing.

Well-designed policies enact all these approaches in parallel to accelerate the transition to renewable energy while managing the impacts on stakeholders.

Public Opinion

Public support for renewable energy in the United States is strong. According to Pew Research Center polling in 2016, 89% of Americans favored expanding solar power and 83% supported more wind power. At the same time, more divided views existed on expanding fossil fuels and nuclear power.

More recent 2022 Pew polling indicates growing support for transitioning from fossil fuels to renewable energy sources like wind and solar power. Nearly three-quarters of U.S. adults believe the country should focus on developing alternative sources even if it means less emphasis on traditional energy. Additionally, around two-thirds say they would be willing to pay more each month to increase renewable sources. There remains some reluctance, however, in completely abandoning fossil fuels in the short-term.

Case Studies

Several countries and states around the world have made significant progress towards 100% renewable energy. Here are some examples:

Iceland generates 100% of its electricity from renewables, primarily hydropower and geothermal. It benefits from abundant natural resources for renewable energy production.

Denmark sources over 40% of its electricity from wind power. Supportive policies, subsidies, and coastal access have enabled major wind energy growth.

Paraguay produces over 90% of its electricity from hydropower from the massive Itaipú dam. However, reliance on hydropower brings risks from drought.

The state of South Dakota generates over 80% of its electricity from hydro and wind. Favorable geography and policies aided the transition.

These examples show that high shares of renewables are achievable with the right natural resources, government support, infrastructure investment, and public engagement.

Conclusion

The goal of achieving 100% clean energy is an ambitious one that faces both technical and economic challenges. However, with rapidly improving renewable energy technology, falling costs, and supportive policy frameworks, it may be feasible in some regions over the next few decades. Places with abundant renewable resources, low population density, and political will are most likely to get there first.

For more populated, developed areas, the path will be longer. A diverse mix of renewable sources, storage technology, transmission infrastructure, and continued efficiency gains will be needed. Even then, the last 10-20% may require carbon capture or offsets. However, with the right incentives and investments, a near 100% clean energy system is physically possible in most regions by mid-century.

The biggest barrier is not technical but economic and political. The transition will require substantial upfront capital investment, as well as reforms to energy markets not designed for high renewables. With the urgent need to decarbonize and growing cost-competitiveness of renewables, the outlook is promising. But it will take bold policies, public support, and a whole-of-economy approach to get there. The clean energy transition is well underway, but sustaining the momentum in order to achieve 100% clean energy will require unprecedented commitment and collaboration.