As we transition toward a cleaner energy future a great deal of emphasis is being placed on the ability of wind and solar power to replace fossil fuels for electricity generation.
In this blog post, we explore the practicalities of renewable energy sources for powering the grid.
Wind and Solar are Intermittent
One of the most commonly cited limitations of wind and solar is that they are intermittent power sources. Solar only produces when the sun is shining and wind only produces when the wind is blowing.
According to Charles Frank in his Brookings article, ‘Why the Best Path to a Low Carbon Future is Not Wind or Solar Power,’ a typical wind plant in the US operates at 25 per cent of full capacity and a solar plant at 15 per cent. A coal or natural gas fired plant can operate at close to full capacity on a year-round basis, and Frank calculates that it takes six solar plants and almost four wind plants to produce the same amount of electricity as a single coal-fired plant.
Investments in Energy Storage are Needed
A significant issue with wind and solar power is that they do not necessarily produce during peak demand times – for instance, when people are home cooking their evening meals and turning on the lights and heating. To be truly effective as energy sources, storage is required.
According to the World Resources Institute, battery storage has seen the swiftest global price drop among all technologies, from nearly $600/MWh in 2015 to about $150/MWh in the first half of 2020. This bodes well for the future, but in the meantime, significant investment in battery storage is needed before wind and solar can play a major role in electricity generation.
A Cautionary Tale
In 2017, Germany announced that it had produced 85 per cent of its electricity from renewables. At the same time, energy prices in Germany soared, and they were emitting more carbon dioxide per unit of energy than any other European country.
That’s because Germany was supplementing wind and solar with coal during extended periods of overcast and calm weather.
In the UK, meanwhile, they focused on carbon reduction. Displacing coal, the UK powered their electricity grid using a combination of wind, solar, nuclear and natural gas. This focus on emissions reduction resulted in a drop of 47 per cent from 2012 to 2016. At 240 grams per KWh, the UK’s 2016 carbon dioxide emissions were less than half of Germany’s.
Managing a Diversified Electricity Generation System
Because wind and solar cannot produce the reliable, 24/7 energy we require without back-up from other sources, decarbonizing the power system is a complex challenge. Natural gas, hydro and nuclear all have the ability to produce a reliable, affordable supply of low-carbon electricity, even at times of peak demand. Wind and solar also have great potential, but only once issues of cost and storage have been addressed.
Stay tuned to this blog, as we will continue to publish stories about the technologies and innovations that are helping to reduce emissions.