Tom Wigley's report overlooks important factors 
It is premature to dismiss gas-fired power 
generation based on the material in one report by Tom Wigley comparing a few aspects 
of coal power with a few aspects of natural gas production and use 
 
There are more options to evaluate in making a transition from coal to natural gas and to renewable energy resources.
For example, suppose your objective is to generate renewable baseload 
power from biomass that is converted into substitute natural gas (SNG).
While taking time to increase the production of of biomass resources, 
one way to save time is to build the natural gas-fired power stations 
and fuel them with natural gas during an interim transition period.
(See research at the University of Minnesota on 
solar thermal gasification of biomass )
In another option the objective might be to reduce the amount of coal 
required to generate electricity and to reduce CO2 emissions. In this 
option, coal is converted into substitute natural gas (SNG). One 
important benefit from this approach comes about because advanced gas 
turbines developed by GE and Siemens this year achieve much greater 
efficiency than is possible in coal-fired power stations. These new 
power stations need only two-thirds the coal (just 2 tons of coal out of
 every 3 tons) to generate the same amount of electricity as a 
coal-fired power station. This option can also slash CO2 emissions by 
60% or more.
(See the project to construct a 
coal to natural gas conversion plant in Illinois )
One option that is rarely considered is the use of this technology to 
remove CO2 from the atmosphere. Solar panels and wind-turbines might 
have zero CO2 emissions, but they cannot remove any CO2. If biomass is 
grown, it is removing CO2 from the atmosphere while it is growing and 
storing solar energy. During gasification, some or all of that CO2 could
 be separated and pumped into a carbon store. With this option, the more
 energy generated, the faster CO2 is removed from the atmosphere.
In summary, it is premature to dismiss gas-fired power 
generation based on the material in one report comparing a few aspects 
of coal power with a few aspects of natural gas production and use.
There is some 
more on these possibilities here  
 
There are more options to evaluate in making a transition from coal to natural gas and to renewable energy resources.
For example, suppose your objective is to generate renewable baseload power from biomass that is converted into substitute natural gas (SNG).
While taking time to increase the production of of biomass resources, one way to save time is to build the natural gas-fired power stations and fuel them with natural gas during an interim transition period.
(See research at the University of Minnesota on solar thermal gasification of biomass )
In another option the objective might be to reduce the amount of coal required to generate electricity and to reduce CO2 emissions. In this option, coal is converted into substitute natural gas (SNG). One important benefit from this approach comes about because advanced gas turbines developed by GE and Siemens this year achieve much greater efficiency than is possible in coal-fired power stations. These new power stations need only two-thirds the coal (just 2 tons of coal out of every 3 tons) to generate the same amount of electricity as a coal-fired power station. This option can also slash CO2 emissions by 60% or more.
(See the project to construct a coal to natural gas conversion plant in Illinois )
One option that is rarely considered is the use of this technology to remove CO2 from the atmosphere. Solar panels and wind-turbines might have zero CO2 emissions, but they cannot remove any CO2. If biomass is grown, it is removing CO2 from the atmosphere while it is growing and storing solar energy. During gasification, some or all of that CO2 could be separated and pumped into a carbon store. With this option, the more energy generated, the faster CO2 is removed from the atmosphere.
In summary, it is premature to dismiss gas-fired power generation based on the material in one report comparing a few aspects of coal power with a few aspects of natural gas production and use.
There is some more on these possibilities here