Natural gas is being promoted as a "bridge fuel" to a clean energy future, and even as an abundant, long-term energy source. The claims are audacious, but do they match with reality?
Advocates — bolstered by recent publicity over claims of large discoveries of unconventional natural gas sources (i.e., shale gas) in the U.S. — are promoting gas as a "clean" alternative to coal for electricity production and petroleum for transportation. Indeed, some climate change activists and coal opponents have encouraged the conversion of existing coal-fired power plants to burn natural gas until renewable energy sources can effectively scale up.
Meanwhile, other environmentalists, as well as some journalists and policymakers, are voicing opposition to shale gas production based on concerns about the health and environmental impacts of hydraulic fracturing ("hydrofracking") technology.
The stakes couldn’t be higher, but a lack of data and rigorous analysis about the feasibility, risks, and rewards of natural gas could lead us down a dangerously false path. While a few recent studies have examined some aspects of the natural gas question, none has provided a comprehensive, systemic analysis of the role it can and should play in our nation’s energy future.
In May 2011, Post Carbon Institute will release a report for policymakers, NGOs, and foundations that provides an objective, easily accessible analysis of the following:
- Recoverable, affordable supplies of conventional and unconventional natural gas in North America, including the latest actual production and depletion rates.
- Technical feasibility and scaling considerations of converting existing coal-fired plants to burn natural gas.
- The greenhouse gas impacts of natural gas plant conversion from a full-cycle point of view (point-of-use, production, transport, venting, methane leaks, carbon capture and storage, etc.), as compared to coal.
- The environmental and human health impacts of horizontal drilling and hydraulic fracturing.
- Implications of these findings for water and agriculture, particularly the risks of water contamination, the fresh water stocks required for production of shale gas, and the impacts on availability and cost of industrial fertilizers.
- Implications of these findings for transportation, particularly the oft-proposed widespread conversion of auto and truck vehicle fleets to run on compressed natural gas (CNG), including feasibility, infrastructural costs, time-to-build, and throughputs required.
Only a thorough examination of these questions — including how they impact one another — can provide sufficient information and perspective to determine the best policy direction.
Abstract
Natural gas has increasingly been touted as a "bridge" fuel from high carbon sources of energy like coal and oil to a renewable energy future. This is based on renewed optimism on the ability of horizontal drilling and hydraulic fracturing to access natural gas from previously inaccessible shale gas deposits. A review of the latest outlook of the U.S. Energy Information Administration (EIA) reveals that all eggs have been placed in the shale gas basket in terms of future growth in U.S. gas production. Without shale gas, U.S. domestic gas production is projected to fall by 20% through 2035.
Shale gas is characterized by high cost, rapidly depleting wells which require high energy and water inputs. There is growing controversy about the impacts of hydraulic fracturing on the contamination of surface- and ground-water, as well as the disposal of toxic drilling fluids produced from the wells. Moratoriums have been placed on shale gas drilling in New York State and the Province of Quebec. Other analyses place the marginal cost of shale gas production well above current gas prices, and above the EIA’s price forecast for most of the next quarter century. An analysis of the EIA’s gas production forecast reveals that record levels of drilling will be required to achieve it, along with incumbent environmental impacts. Full cycle CO2 emissions from shale gas may also be far worse than previously understood, and possibly worse than coal.
Even assuming the EIA forecast for growth in shale gas production can be achieved, there is little scope for wholesale replacement of coal for electricity generation or oil for transportation in its outlook. Replacing coal would require a 64% increase of lower 48 gas production over and above 2009 levels, heavy vehicles a further 24% and light vehicles yet another 76%. This would also require a massive build out of pipeline infrastructure, gas storage, refueling networks and so forth. A logistical, geological, environmental and financial pipedream.
Although natural gas is not a silver bullet, there are many things that can be done to lower emissions and fuel requirements and thus improve energy security. More than half of the coal fleet is more than 40 years old. Many of these plants are inefficient and have few if any pollution controls. As much as 21% of coal capacity will be retired under new EPA regulations set to take effect in 2015. Best-in-class technologies for both coal- and natural gas-fired generation can reduce CO2 emissions by 24% or more and reduce other pollutants. Capturing waste heat from these plants for district heating can provide further increases in overall efficiency. The important role of natural gas in the industrial, commercial and residential sectors, for which there is no substitute at this time, must also be kept in mind. Natural gas vehicles are likely to increase in a niche role for high mileage, short haul applications.
Strategies for energy sustainability must focus on reducing energy demand and optimizing the use of the fuels that must be burnt. At the end of the day hydrocarbons that aren’t burnt produce no emissions. Capital- and energy-intensive "solutions" such as carbon capture and storage are questionable at best and counterproductive to the whole notion of energy sustainability at worst.
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