The International Energy Agency (IEA) says that higher shares of variable renewable energy in electricity systems will require a “step change” in the requirement for flexibility, which is the capability to balance electricity supply and demand at all times so as to keep the lights burning.
The agency, which released its World Energy Outlook 2018 report this week, is forecasting that electricity will become the “fuel of choice” and is poised to play a greater role in transportation, through electric vehicles, as well as in heating and cooling.
Electricity is expected to grow by 60% by 2040, by which time the energy carrier’s share of total final energy consumption – which has already risen to 19% from 15% in 2000 – will reach 25%.
Within the power sector, wind and solar photovoltaic (PV) have emerged as the technologies of choice and are expected to make up almost two-thirds of global capacity additions to 2040.
In the report’s main scenario, dubbed the New Policies Scenario, renewables and coal switch places in the power mix, with the share of generation from renewables rising from 25% to around 40% in 2040.
The IEA’s Laura Cozzi says that, while electricity will grow at twice the pace of overall energy demand over the period, wind and solar PV will grow four times faster than electricity.
This rise in the share of solar PV and wind power means the flexible operation of power systems will take on “unprecedented importance”, with flexibility “to become the cornerstone” of the future power system.
“In the future, we will be asking the electricity system to operate in a very different way. When the sun doesn’t shine and the wind doesn’t blow we still want to keep our lights on and we will be asking the system to move up and down and match supply and demand four times more than we are asking today,” Cozzi explains.
She says that, at low levels of penetration, or below 10%, the variability of renewables can be managed using the current system flexibility available from coal and gas power plants.
In countries with higher shares of variable renewable energy, such as Germany and the UK, targeted investments are needed to unlock more flexibility, including through the extension of grids and by making grids smarter.
At some point, however, most countries will need to support specific investments in flexibility. “This means that markets for electricity will, on the one hand, need to provide electricity and, on the other, need to value flexibility more and more to ensure that investments in energy storage and demand-side response are made in a timely manner,” Cozzi explains.
The IEA also warns that today’s power market designs are not always up to the task of coping with rapid changes in the generation mix.
Revenue from wholesale markets is often insufficient to trigger new investment in firm generation capacity, which could compromise the reliability of supply if not adequately addressed.
Over the forecast period, the report sees thermal power making the biggest contribution to flexibility worldwide, as interconnections and pumped storage hydro each provide further flexibility of around 150 GW.
“Batteries are starting to contribute too, including behind-the-meter,” the report states.