What this “experiment” is
Nothing here was measured, simulated or tested by this site. The title uses the word experiment loosely: this is a thought exercise. The idea is to picture an electricity system leaning heavily on renewable sources and ask what would have to work for it to be reliable. Any numbers below are hypothetical and chosen only for easy arithmetic.
The main renewable sources
Renewable sources draw on energy flows that are naturally replenished.
- Solar. Photovoltaic panels turn sunlight directly into electricity. Solar thermal plants use mirrors to heat a fluid and drive a turbine.
- Wind. Turbines convert moving air into electricity, on land or offshore.
- Hydropower. Flowing or falling water turns turbines. Reservoirs let operators release water when power is needed.
- Geothermal. Heat from underground is used for electricity or direct heating where conditions allow.
- Biomass. Plant or waste material is burned or converted to fuel. Whether it is truly low-carbon depends on how it is sourced.
Each has different strengths. Hydropower and geothermal can run steadily where they exist, but they depend on geography. Solar and wind can be built in many places, yet their output follows the weather and the time of day.
The variability problem
Electricity grids must keep supply and demand balanced at every moment. Conventional plants fueled by coal, gas or nuclear material can generally be turned up or down on request. Sun and wind cannot be commanded, which is why they are called intermittent renewables.
A hypothetical example: suppose a region uses 100 units of power at a given hour, and its solar farms produce 120 units at midday but 0 at night. At midday there is a surplus of 20 units. At night the region needs the full 100 from elsewhere. Averaged over a 24-hour day, with 12 hours of 120 units, the farms would produce 1,440 units, while demand over the day would be 2,400 units. In this made-up case solar alone covers only 60 percent of daily need (1,440 / 2,400 = 0.6), and the timing is wrong as well. Real systems combine several sources so that their weaknesses partly offset one another.
Storage
One response is to save surplus energy for later. Battery storage is the most discussed option, and batteries can respond within moments, which helps smooth short swings. Larger or longer-lasting needs may call for other approaches, such as pumping water uphill to run back down later, or making and storing a fuel such as hydrogen energy. Each has costs, energy losses and space or material needs. How much storage is enough, and for how many hours or days, is an active question that depends heavily on local weather and demand patterns.
Grids, demand and flexibility
Moving power from where it is generated to where it is used requires transmission lines, and building them can take years and face local opposition. Good wind and sun are often far from large cities.
Demand can also be managed. Smart grids use sensors and software to see conditions in real time, and some systems can ask willing customers to shift use, for example by charging vehicles or running appliances when power is plentiful. Linking grids across wider areas can help, because weather differs between places. Digital tools such as forecasting may also help operators anticipate output, and the wider internet of things supplies much of the metering data.
Other issues
- Cost. The cost of solar and wind equipment has fallen in many places, but total system cost includes storage, grid upgrades and backup.
- Materials and land. Panels, turbines and batteries need materials and space, and manufacturing has its own environmental footprint.
- Reliability and stability. Traditional turbines provide inertia that helps keep frequency steady; grids with more inverter-based sources need other ways to supply that stability.
- Fairness and jobs. Changes in energy systems affect workers and communities tied to older industries.
- Growing demand. Electrified transport, heating and large data centers may add to demand.
What is uncertain
Experts broadly agree that renewables are growing and that storage and grid upgrades are central. They disagree on speed, on the best mix, and on the role of other options such as nuclear fission or the longer-term prospect of nuclear fusion. The honest answer to “what will the energy system look like?” is that it will probably differ by region, and projections should be treated as possibilities.