Why Will Emissions Double as We Add Wind and Solar Plants (in Ontario, or France)?

From Ontario’s Electricity Dilemma (pdf slides, page 15)

• Wind and Solar require flexible backup generation.
• Nuclear is too inflexible to backup renewables without expensive engineering changes to the reactors.
• Flexible electric storage is too expensive at the moment.
• Consequently natural gas provides the backup for wind and solar in North America.
• When you add wind and solar you are actually forced to reduce nuclear generation to make room for more natural gas generation to provide flexible backup.
• Ontario currently produces electricity at less than 40 grams of CO₂ emissions/kWh.
• Wind and solar with natural gas backup produces electricity at about 200 grams of CO₂ emissions/kWh. Therefore adding wind and solar to Ontario’s grid drives CO₂ emissions higher. From 2016 to 2032 as Ontario phases out nuclear capacity to make room for wind and solar, CO₂ emissions will double (2013 LTEP data).
• In Ontario, with limited economic hydro and expensive storage, it is mathematically impossible to achieve low CO₂ emissions at reasonable electricity prices without nuclear generation.