Top Frequently Asked Questions
Yes and no. While hydraulic fracturing has been used in energy development since the late 1940s, uncconventional development of gas using high volume, slickwater hydraulic fracturing from long laterals with multi-well pads and clustered drilling has only become possible in recent years and is still being developed. The differences between conventional "fracking" and the new suite of technological advancements, as well as impacts of this much more intensive practice, is explained in detail by Dr. Tony Ingraffea in the video playlist below.
Definitions for 'conventional' and 'unconventional' are not static, and some extraction activities that were considered unconventional 10-15 years ago(for example coalbed methane) are now considered 'conventional', at least in the United States.Generally speaking, the distinction between conventional and unconventional resources is a matter of permeability.
Permeability is a measure of how easily fluids can flow through the target rock. High permeability reservoirs (conventional fuels), while relatively low in volume, allow for productive flow with relatively low technological and energy input demand. As the 'low-hanging' fossil reservoirs are depleted, development moves on to more energetically expensive extraction in lower permeability reservoirs - often with greater environmental impact. As development continues down the resource pyramid, resource volumes increase, but the permeabilities are so low that new technological advances (i.e. unconventional drilling and stimulation methods)are needed to produce the resource in commercial quantities. The technological and energy intensity required to develop these reservoirs may result in much higher environmental impacts.
Yes. While high-volume hydraulic fracturing (HVHF) - a mechanical stimulation process - is probably the most commonly known due to protests around the globe in recent years, chemical stimulation is also commonly used in complex and some reservoirs.
For the Monterey shale in California, tetonic activity has created extensive folding of formations and sedimentation of the natural fractures. Sedimentation further reduces permeability and folds limit the use of long laterals. Acid matrix and acid-fracture stimulations can bypass these geologic hurdles through injection of large quantities of solvents (typically hydroflouric acid) to dissolve the sediment and rock around the production target.
Hydroflouric acid (HF) is highly volatile, corrosive, and highly toxic. The majority HF is used and recycled in industrial and manufacturing processes and is highly concentrated (50%+). Highly concentrated solutions are unlikely to be used in well stimulations, as the corrosive acid would eat through well casings. Historically, environmental exposures have often occured through spills, such as the 2012, hydroflouric acid spill in South Korea. This spill killed 5 workers, severely injured 18 additional workers and emergency personnel, and required the evacaution of thousands of local residents. Despite evacuations, many residents experienced respiratory damage due to the spill. A similar spill occuring in California's heavily populated oil producing regions could be catastrophic - particularly in the L.A. basin, where the topography tends to trap air masses.
Renewable energy is often challenged on the ground that it does not actually reduce carbon emissions, either because energy is consumed during the production of wind turbines and solar panels, or because intermittency causes inefficient ramping of coal and gas power plants. It is true that renewable electricity resources are not emission-free, but lifecycle analyses indicate that most emit much less carbon than natural gas or coal combustion (for a visualization of the range of estimates in the scientific literature, see the LCA Hybridization Tool).
Renewable energy can displace not only coal and gas but also oil consumption. In the United States, oil is used primarily as a transportation fuel. However, switching transportation from gasoline to electricity is a critical measure for achieving deep emissions cuts (Williams 2012). Running cars off of electricity reduces carbon emissions (Hawkins 2012) and is approximately four times more efficient than using gasoline (Offer 2010). Hybrid and electric vehicles (EVs) are steadily increasing their market share, supporting the transition away from gasoline. The speed of this transition will likely depend on how quickly EV prices continue to drop and driving ranges extend. The vehicle fleet tends to replace itself approximately every ten years, allowing new vehicle technologies to be ramped up relatively quickly as the technology matures. Powering a fleet of EVs on a coal-fired electric grid does not greatly reduce carbon emissions compared to using gasoline, but significant carbon mitigation is achievable if EVs are charged from a grid powered primarily by renewables (Hawkins 2012).
The largest challenges in the transportation sector are those of reducing emissions from planes and heavy duty trucks, which require very dense fuel, such as diesel and jet fuel, and are not easily electrified. Aviation and freight trucking account for nearly 30% of U.S. greenhouse gas emissions from transportation, and these emissions are expected to grow if stricter efficiency policies and performance standards are not enacted (Greene 2011).
Renewables are expensive. Won't switching to renewable energy resources cause electricity prices to soar?
Actually, the price of electricity from wind and solar resources has been dropping rapidly and is competitive with fossil fuel generation in many places. According the U.S. Department of Energy, the average price of electricity from utility-scale solar power plants dropped from $0.21/kWh in 2010 to $0.11/kWh in 2013 – less than the average residential price of $0.12/kWh (U.S. DOE 2014). Rooftop solar systems typically benefit from net metering rates and various incentives, but their rapid growth suggests that they are also growing increasingly economically competitive. In 2012 alone, distributed solar capacity in the U.S. increased by 36% while installed costs dropped by 12%, and renewables made up more than 50% of new installed generation capacity. Of the five states with the most installed wind capacity – Texas, California, Iowa, Illinois and Oregon (Gelman 2013)– four had electricity prices lower than the national average as of October 2013 (U.S. EIA 2013). Furthermore, renewable resources provide price stability because they are not dependent on widely fluctuating fossil fuel prices, improving energy security and providing a hedge against fuel price spikes (Bolinger 2009).
Costs of wind and solar generation are likely to keep falling as installed capacity grows. Considered within a broader context, the social and environmental impacts of fossil fuels, including health impacts of air pollution and economic costs of climate change, mean fossil fuels are much more costly to society than renewables (Jacobson 2009; McCubbin 2011).
The high installation rates of wind and solar systems suggest that the capital costs of renewables are not prohibitive, and as capacity grows these costs continue to fall. In 2012, over half of new generation capacity in the U.S. consisted of wind or solar and installed costs of solar dropped 12% (Sherwood 2013). Rooftop solar can be added in small increments, reducing the need to invest in a large central power system many years out. Many strategies for financing exist. Individuals can buy rooftop solar, or it may be financed by third parties. Clean Power Finance directs large sources of capital towards distributed solar installations, while Mosaic provides financing through crowdfunding. New funding tools like securitization are just beginning to hit the market. Falling costs and a diversity of funding approaches will continue to lower the barriers to renewable energy growth.
But substituting current energy demands with renewable energy will require a massive scaling-up of renewable capacity. Is it feasible?
National and state-level data suggest renewable capacity can expand quite quickly, but continued expansion will require strong political support.
From a national perspective, electricity generation from wind and solar in the U.S. remains very low, but it is growing quickly. Wind power provided 4.3% of total U.S. generation in October 2013, nearly triple its 1.5% contribution from October 2008. Over the same years, utility-scale solar generation increased by a factor of 15, but reached only 0.3% of total U.S. generation (U.S. EIA 2013). Accounting for distributed rooftop solar likely doubles this number (Sherwood 2013). Looking at a number of individual states, however, rates of renewable electricity generation and growth are much higher. In October 2013, solar accounted for 2.5% of utility-scale electricity generation in California (U.S. EIA 2013), and again, distributed installations mean total solar generation was likely double that amount. From October 2008 to October 2013, the percent of generation in Texas from wind grew from 5.2% to 9.1%, and in Minnesota from 10.5% to 17%. In May of 2013, wind provided nearly 21% of electricity generated in Minnesota. Furthermore, a large fraction of new installed capacity is now from renewables: in 2012, 12% of new generation was solar and 41% wind (Sherwood 2013).
Currently, renewable energy capacity is being added to supply new generation to meet demand growth and replace retiring fossil fuel-powered plants. However, accelerating the transition to renewable energy may eventually require replacing fossil fuel plants before they reach their projected retirement age. This early retirement may present an economic challenge by creating "stranded" capital investment in these plants.
But don't we need just as much fossil fuel capacity to "back up" intermittent wind and solar generation?
A poorly planned grid may indeed require a large amount of fossil fuel capacity to back up variability and intermittency on the grid if renewable energy penetration increases. A number of strategies can be employed to reduce the variability introduced by wind and solar systems. Integrating wind turbines over a large geographical area, for example, greatly reduces the variability in their output (Czisch 2001). Demand response and energy storage, such as pumped hydroelectric power or batteries, can be used to smooth wind generation, and potentially at lower cost than using a combustion turbine (Kintner-Meyer 2011). The electric load on the grid can also be met by using a range of many different types of renewable resources together, like wind, solar, hydropower and geothermal, which smoothes variability (Hart 2011). Improved weather forecasts can also greatly reduce costs by allowing system operators to better manage unit commitment of different generators (G.E. Energy 2010). Taken together, these approaches can greatly reduce or eliminate the need for "backup" fossil generation.
Like all electricity generation, renewables have some environmental impacts, but lifecycle carbon emission estimates show that emissions from wind and solar, while non-zero, are much lower than for fossil fuels. Lifecycle consumption of water varies by technology, but is also estimated to be much lower than that of coal and gas generation. Note, however, concentrated solar power requires significant cooling and may use more water than some fossil fuel generation.
Solar panels often incorporate many toxic chemicals, which can have health and environmental impacts during production and disposal, but for this reason companies such as First Solar have instituted "cradle-to-grave" policies that guarantee that all panels will be recycled at end-of-life (Miles 2005).
Wind turbines are often faulted for bird and bat deaths, but estimates indicate that bird deaths caused by fossil fuel generation are approximately 30 times larger than those from wind turbines, due in part to negative environmental impacts such as mountaintop removal in coal mining and loss of habitat, and even flying into cooling towers (Sovacool 2009).Also, older hazardous turbines are actively being replaced with new models to minimize these impacts (CA OAG 2010).
Many wind turbines in the U.S. have been in operation for decades. As an example, the hundreds of wind turbines running at the Mesa Wind Project in Southern California were first brought online in 1984, according to data compiled by the U.S. Geological Survey (see: USGS Windfarm Map). Similar to fossil fuel plants, wind turbines require maintenance and upkeep. However, scheduled and unscheduled maintenance takes wind turbines out of operation for only up to 2% of the time, while on average U.S. coal plants were brought offline for maintenance over 12% of the time from 2000-2004 (Jacobson 2009). After more than thirty years in operation, the wind turbines at Altamont Pass in California are being replaced with newer models, not because the old ones have worn out but because newer turbines are more efficient and safer for birds (CA OAG 2010).
I've heard several different numbers for the global warming potential of methane. What does global warming potential mean and what is the correct value for methane?
The global warming potential or GWP, offers a simple metric assessing the cumulative (direct and indirect effects) climate forcing potential of individual trace greenhouse gases relative to carbon dioxide over a specified time interval. Because the metric is time-dependent and often updated with improved understanding of complex atmospheric chemical interactions, a singular 'right' answer isn't available. The best value, scientifically, is that which is based on the most recent understanding of atmospheric chemistry and intergrated over an appropriate time-frame. The most current (AR5; 2013) values for methane are 34 (100 year time interval) and 86 (20 year time interval).
A note on policy vs. science in GWPs, as this seems to be where most of the confusion around GWPS comes from: In 1995, the Intergovernmental Panel on Climate Change (IPCC) estimated GWPs for methane over 20 (56), 100 (21), and 500 (6.5) year time intervals. The Kyoto Protocol (UNFCCC), first drafted in 1996, adopted the IPCC estimates and arbitarily affirmed the use of the 100 y time frame. Since then the IPCC has updated methane GWPs several times, though the the UNFCCC has reaffirmed the use of the older data and choice of the 100 y timeframe as a way to ensure consistency in reporting across countries and the ability to measure progress in meeting goals over time relative to when goals were drafted. As such, the 100 year convention and use of outdated values are simply policy decisions, and are not based in science.
Carbon dioxide emissions are a problem, but the most recent climate modeling, as shown in the figure below (Source: UNEP 2011), indicates that even dramatic and immediate cuts in CO2 emissions will not stop mean global temperature increases in time. The only way to curb rising temperatures and stave off tipping points is to immediately cut short-term climate forcing chemical species such as methane and black carbon.The gold and orange regions of the chart represent critical increases in mean temperature that are expected to trigger climate feedbacks which will further accelerate warming and usher in a new climate range never before experienced by humans.
PSE first shined a light on wellbore integrity issues back in 2011. Since then, a number of industry 'experts' have attempted to discredit our research with a variety of erroneous assertions and confusion over terms used when discussion well and wellbore integrity. The following aims to clarify the finer details of the wellbore integrity issue in unconventional oil and gas wells.
Assertion 1: Sustained Casing Pressure (SCP)does not reflect an impairment; pressure build-up may result from normal temperature fluctuations during production
Sustained Casing Pressure, or SCP, is defined as "pressure in any well annulus that is measurable at the wellhead and rebuilds when bled down, not caused solely by temperature fluctuations or imposed by the operator." Pressures resulting from normally occuring temperature changes due to production is termed unsustained casing pressure. SCP is indicative of a loss of zonal isolation at some point along the wellbore in at least one of the cement or casing barriers.
Assertion 2: Wellbore integrity failure is a rare event. In fact, GWPC (2011) and King & King (2013) report rates of less than 0.5%.
Complete well failure, defined as the failure of all barriers to an extent that allows for migration of target fluids, is indeed a rare event. The rates cited from King & King and other sources to support assertions of that well integrity is not a serious problem refer to complete well failure. This is very different than wellbore integrity failure. The difference between a well and a wellbore may seem just a matter of semantics, but it is critically important in this discussion. Wellbore integrity failure refers to an impairment of one or more barriers resulting in the loss of zonal isolation between formations and potential migration of shallow and intermediate formation fluids outside the well. This issue is much more common, with failure rates ranging from 6.2% to more than 40% (ingraffea et al. 2014).
Misinformation in the Media
This platform will address misinformation and misdirection commonly found in popular media, the blogosphere, and in industry advertising. Updates to content will be made as we are alerted to claims which need to be fact checked.
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