The Conference of Mayors adopted clean air policies in 2017 and 2018 to support cities
transitioning to 100 percent renewable energy and success depends on developing enough
renewable power production capacity and renewable energy generation. The Energy Information
Administration (EIA) reports that renewables provided 17% of electricity generation in 2016: 20%
from nuclear and 63% from fossil. A review of trends in energy generation capacity and energy
generation suggests renewables are on the rise and fossil is fading, but in the fossil category natural
gas continues to rise. These trends have implications for cities transitioning to 100% renewable
Changes in Power Production Capacity – 2011 to 2018
Federal Energy Regulatory Commission (FERC) data reported changes in utility scale power
production units measured in gigawatts (GW) from 2011 to 2018.
• The fossil fuels had a net loss of 37.8 GW of production capacity.
• Natural gas nameplate capacity grew by 53 GW
• Coal and oil declined a combined 90.8 GW
• For every I natural gas GW capacity increase there is a 1.7 reduction in coal and oil GW
Power production capacity growth indicates preferential investment in renewables.
• Nameplate power production capacity for three renewables (geothermal, solar and wind)
grew a combined 82.9 GW from 2011 to 2018.
• For every 1 renewable GW capacity increase there is a 0.9 GW reduction in coal and oil
• For every 1 natural gas GW capacity increase there is a 1.4 GW capacity increase in
renewables power production capacity.
Net Energy Generation by Source – 2006 to 2016
An analysis of EIA data on net energy generation (measured in megawatt hours MWh, etc.)1 from
2006 to 2016 indicates dynamic shifts are occurring.
• Fossil energy generation has declined by 8 percent from 2006 to 2016
o But natural gas increased energy generation by 561 TWh to 1,378 TWh in 2016.
• Wind and solar, the standout renewable energy generators, increased 235 TWh to 609
TWh of clean energy in 2016.
• Effective capacity limits like intermittency handicaps renewables. A 1 MW wind
generator, due to effective capacity factors, can generate only 62 percent of the net
energy generated by a 1 MW natural gas plant.
• Net energy generation by renewables is growing at 40 percent of the rate of growth of
natural gas energy generation
11 Watt-hour, kilowatt hour KWh, megawatt hour MWh, gigawatt hour GWh, terawatt hour TWh.
Renewable Energy Transition: Measuring Progress
The Conference of Mayors adopted policies in 2017 and 2018 to support city efforts to transition
to 100 percent renewable energy. Public benefits of such a transition include cleaner air and a
reduction in climate stressing carbon emissions. Local governments have been actively pursuing a
transition for practical reasons as well – it diversifies energy sources and rebalances production
capabilities geographically offering both redundancy and resiliency. Recent research by the
Conference of Mayors in partnership with the Center for Climate and Energy Solutions indicates
a broad array of local renewable energy activity. This report examines two measures of progress
toward 100 percent renewable energy in our cities: growth in design capacity (how much power
production is installed), and net energy generation trends (how much electricity is produced).
These measurements signal positive progress – preferential investment in renewable technology
production capacity and growth in renewable energy generation share.
Many cities are participating in the renewables transition process directly and often indirectly as
they interface with a variety of energy technologies. The Federal Energy Regulatory Commission
(FERC) reports 18 utility scale- wind and 118 solar in new build or expansion projects between
January and May of 2018. The comparable 2017 period included 43 wind and 216 solar projects.
Collectively, thousands of local projects initiated in the last 10 years have had an impact, and
renewables are gaining on conventional sources in design capacity and net electricity generation.
Electricity capacity and generation information published by FERC2 and the U.S. Energy
Information Administration (EIA)3 are reviewed to measure national trends in capacity additions
and net electricity generated by different fuels (coal, natural gas, petroleum) and different sources
(geothermal, wind, solar). Together, this information provides a snapshot assessment of the level
and trajectory of the transition to clean energy.
Installed Capacity by Energy Source Demonstrates Gains in Renewables Investing
Installed capacity (also referred to as design capacity or nameplate capacity) is the intended fullload sustained output of a power plant. Simply put, a 20 MW electric generating facility has a
‘design capacity’ to produce 20 MW of electricity on a continual 24/365 basis. Installed generating
capacity was reviewed using several time periods of FERC data and estimates published for 2016
by the EIA, (Table 1 and Table 2).
2 FERC releases information on installed capacity by energy source on a frequent basis, and the information is used
by the Commission in exercising its authority. Cities are interested in the same information and what the
Commission thinks about that information. 3 EIA releases estimates of installed capacity based on surveys and other reporting requirements of generators of 1
MW or more. EIA also publishes information on net generation by energy source. Cities are interested in these data
for the same reasons as interest in FERC information.