Emissions of greenhouse gases comes from a variety of sources – solutions must address the diverse technologies behind emissions. To begin with – however – reducing population pressure is best addressed through better health, education and welfare outcomes best achieved primarily through optimal economic development.
Some 26% of global greenhouse gas emissions come from the burning of coal, natural gas, and oil for electricity and heat. It is the largest single source of global greenhouse gas emissions. Black carbon – although an aerosol and not a greenhouse gas – has an overall greater warming effect.
“The key to solving for both climate and poverty is helping nations build innovative energy systems that can deliver cheap, clean, and reliable power.” http://thebreakthrough.org/index.php/programs/energy-and-climate/our-high-energy-planet
Here’s some technology costs from the World Energy Council. There are a number of technologies – including renewables – that have costs of generation less than US$100/MW. These are levelised costs – they include construction and operation – as well as a capacity factor – but exclude distribution and backup costs. Some technologies – gas, coal, nuclear – can be utilised more than 90% of the time. Solar and wind provide power for some 30% of the time depending on local conditions. Beyond about 5% of installed wind and solar capacity backup generators and/or storage is required – with considerable impact on system costs. Yet other technologies – biomass, landfill gas, hydro, geothermal – can have high capacity factors but are physically limited to areas that have available resources.
At this time, the cheapest generating system is based on coal and gas – with relatively small scale opportunistic generation using hydro, landfill gas, wind, geothermal, biomass, etc depending on resource availability, local construction and operating costs and local distribution costs that vary with technology. Distribution costs – for instance – are higher for large, centralised plants and lower for smaller, distributed generation. Solar for daytime cooling of commercial buildings may reduce distribution costs. Large nuclear plants may need continent spanning distribution systems.
The ideal generating plant is a small, modular system with a high capacity factor. There are in fairly obvious candidates. The General Atomics Energy Multiplier Module is one of many advanced nuclear designs – and one of the half dozen or so designs seeking US regulatory approval. It turns this conventional nuclear waste;
into energy with much less and safer waste products. The reduction in the volume of waste on the left is almost off the scale.
The reduction in radioactivity can be compared to the waste from conventional nuclear – decay to safe products over hundreds rather than many thousands of years.
It does this through recycling fuel through a high temperature, fast fission process. This utilises much more of the available energy in fuel. It does this without reprocessing or enriching uranium.
These plants are designed to be factory manufactured, delivered to site on a truck, dropped into a concrete bunker and operate untouched for 30 years. The much increased utilisation of fuel means that available resources – conventional waste, uranium, thorium – are sufficient for 1000’s of years of global energy demand. These plants can’t melt down and the waste can’t be used in nuclear weapons.
A single unit provides enough electricity for 350,000 people living a western lifestyle. As it is helium – and not water – cooled with a small footprint it can be sited anywhere. The high efficiency, modular capability and low capital cost reduces cost over conventional nuclear by 30% making it competitive against gas and coal fired plants.
Coal and natural gas prices will increase over the next few decades – even without carbon taxes – as resources are exhausted. The advanced nuclear designs produce constant heat – but demand peaks at certain times of the day and seasonally. This leaves open another possibility to utilise the heat that would be otherwise wasted. High temperature production of hydrogen.
‘Essentially, the electrolytic cell consists of a solid oxide electrolyte with conducting electrodes deposited on either side of the electrolyte. A mixture of steam and hydrogen at 750-950ºC is supplied to the anode side of the electrolyte. Oxygen ions are drawn through the electrolyte by the electrical potential and combine to O2 on the cathode side. The steam-hydrogen mixture exits and the water and hydrogen gas mixture is passed through a separator to separate hydrogen.
Because using heat directly is more much efficient that first converting heat to electricity, the overall efficiency of the high-temperature system is much higher. That assumes, of course, that you have a readily-available, non fossil-fuel-based source of high heat available—i.e., that you have an advanced high-temperature nuclear reactor or an adapted solar energy system at hand.’ Green Car Congress
The hydrogen produced can be combined with carbon dioxide captured from the atmosphere to produce liquid fuels.
Thus solving another 13% of the greenhouse gas emission equation. Solving the remainder – including black carbon – requires changed productive systems and practices over a number of sectors.
• Industry (19% of 2004 global greenhouse gas emissions) – Greenhouse gas emissions from industry primarily involve fossil fuels burned on-site at facilities for energy. This sector also includes emissions from chemical, metallurgical, and mineral transformation processes not associated with energy consumption.
• Land Use, Land-Use Change, and Forestry (17% of 2004 global greenhouse gas emissions) – Greenhouse gas emissions from this sector primarily include carbon dioxide (CO2) emissions from deforestation, land clearing for agriculture, and fires or decay of peat soils. This estimate does not include the CO2 that ecosystems remove from the atmosphere. The amount of CO2 that is removed is subject to large uncertainty, although recent estimates indicate that on a global scale, ecosystems on land remove about twice as much CO2 as is lost by deforestation. 
• Agriculture (14% of 2004 GHG emissions) – global greenhouse gas emissions) – Greenhouse gas emissions from agriculture mostly come from the management of agricultural soils, livestock, rice production, and biomass burning.
• Transportation (13% of 2004 global greenhouse gas emissions) – Greenhouse gas emissions from this sector primarily involve fossil fuels burned for road, rail, air, and marine transportation. Almost all (95%) of the world’s transportation energy comes from petroleum-based fuels, largely gasoline and diesel.
• Commercial and Residential Buildings (8% of 2004 global greenhouse gas emissions) – Greenhouse gas emissions from this sector arise from on-site energy generation and burning fuels for heat in buildings or cooking in homes. (Note: Emissions from electricity use are excluded and are instead covered in the Energy Supply sector.)
• Waste and Wastewater (3% of 2004 global greenhouse gas emissions) – The largest source of greenhouse gas emissions in this sector is landfill methane (CH4), followed by wastewater methane (CH4) and nitrous oxide (N2O). Incineration of some waste products that were made with fossil fuels, such as plastics and synthetic textiles, also results in minor emissions of CO2.