How to integrate renewables for a stable energy system

Balancing the grid is vital to reduce emissions and optimize energy costs

Of course, we already use renewables today—but they only make up around 20% of the energy mix. As a result, it’s quite easy to balance energy production and consumption with fairly small adjustments at the fossil fuel plants providing most of our power. But by 2040, renewable energy will account for a much greater fraction of the energy mix, which will in turn create much greater variability from one day to another.

With higher intra-day variability for renewable generation, balancing production and consumption will be much more difficult. Indeed, where production exceeds consumption, curtailment may even be necessary—that is, switching off renewable generation entirely. Bloomberg New Energy Finance’s Beyond the Tipping Point study forecasts that wind and solar generation could exceed total demand in some European countries with increasing frequency in the decades to come. This is particularly true for Germany during the summer months, given the country’s broad rollout of renewable solar arrays. In 2030, less than 3% of German wind and solar generation is expected to be curtailed, but this rises to 16% by 2040 without flexible energy storage.

Clearly, this isn’t ideal. We don’t want a future where our power systems must rely on fossil fuel backups, oversized renewable capacity, and regular curtailment. That’s not only a future of higher costs, but also of higher emissions. So, what’s the solution?

The importance of flexibility

To avoid the need for costly grid upgrades and back-up generation, our future electricity system must become more able to smooth out peaks and troughs in supply and demand—both on a short-term, intra-day basis and a long-term, seasonal one.

When it comes to day-to-day energy production and consumption, storage technologies are an ideal solution. With sufficient battery storage, the renewable energy supply can be rapidly increased or decreased as required. The rise of electric vehicles (EVs) offers more opportunities to balance the energy ecosystem as well. Aurora Energy Research predicts that smart vehicle charging can decrease electricity price volatility by topping up car batteries when electricity demand is low, or there is excess supply from renewable sources. In the future, it will also be possible to sell the electricity stored by EVs back into the grid at times of high demand and low generation.

On longer timescales, switching to green hydrogen as an energy storage medium makes more sense. Excess renewable production can be used to create green hydrogen for storage in fuel cells, which then augments power production during generation gaps of weeks or months, reducing the need for reserve fossil fuel plants.

Recent studies by Bloomberg New Energy Finance on Flexibility Solutions for High-Renewable Energy Systems point to greater flexibility as crucial to accelerate our transition to cleaner power. Ultimately, greater flexibility can enable the efficient integration of 80% or more renewable energy by 2040. Now’s the time to begin preparing for this power revolution—investing in the technologies that will enable our energy system to cope with the dramatic shift in how we generate and use electricity.