“In terms of assessing trends in globally-averaged surface air temperature as a metric to diagnose the radiative equilibrium of the Earth, the neglect of using moist enthalpy, therefore, necessarily produces an inaccurate metric, since the water vapor content of the surface air will generally have different temporal variability and trends than the air temperature.”
Surface air moist enthalpy does capture the proper measure of heat. It is defined as CpT + Lq where Cp is the heat capacity of air at constant pressure, T is air temperature, L is the latent heat of phase change of water vapor, and q is the specific humidity of air. T is what we measure with a thermometer, while q is derived by measuring the wet bulb temperature (or, alternatively, dewpoint…
You’ve heard the good news on climate: after a century or more of continuous rise, U.S. CO2 emissions have finally begun to decline, due largely to changes in the energy sector. According to the Energy Information Agency (EIA), energy-related CO2 emissions in 2015 were 12% below their 2005 levels. The EIA says this is “because of the decreased use of coal and the increased use of natural gas for electricity generation.”
Is the EIA right in making natural gas the hero of the CO2 story? Hardly. Sure, coal-to-gas switching is real. But take a look at this graph showing the contributors to declining carbon emissions. Natural gas displacement of coal accounts for only about a third of the decrease in CO2 emissions.
Courtesy of the Sierra Club Beyond Coal Campaign, using data from the Energy Information Agency.
By far the biggest driver of the declining emissions is energy efficiency. Americans…
So we were sitting around the fire at the fish camp on the Colombia a few days ago, and a man said “Did you hear about the scientific study into meat preservatives?” We admitted our ignorance, and he started in. The story was like this:
“A few years ago there was a study done by some University, I can’t remember which one, but it was a major one. What they did was to examine the corpses of people who had died in Siberia, and those that had died in Washington State. Now of course the people in Siberia weren’t eating meat preservatives during their lives, and the Washington people were eating them. And when they dug up the graves and looked at the bodies, guess what they found?”
Much of our efforts to reduce carbon emissions involves fairly complicated and advanced technologies. Whether it’s solar panels, batteries, flywheels, or fuel cells, these technologies have typically required public support to bring them to scale at a reasonable price, along with significant regulatory or legal reforms to accommodate these new ways of doing old things, […]
The report describes ways that California could unlock more private investment in energy efficiency retrofits, particularly in commercial buildings. This financing will flow if there’s a predictable, long-term, measured and verified amount of savings that can be directly traced to energy efficiency measures. New software and methodologies can now more accurately perform this task. They establish a building’s energy performance baseline, calibrating for a variety of factors, such as weather, building use, and occupancy changes. That calibrated or “dynamic” baseline can then form the basis for calculating the energy savings that occur due specifically to efficiency improvements.
But the state currently lacks a uniform, state-sanctioned methodology and technology standard, so utilities are reluctant to base efficiency incentives or programs without regulatory approval to use these new methods. The report therefore recommends that energy regulators encourage utilities to develop aggressive projects based on these emerging metering technologies that can ultimately inform a standard measurement process and catalyze “pay-for-performance” energy efficiency financing, with utilities able to procure energy efficiency savings just like they were a traditional generation resource. […]
Jim Barrett, Chief Economist, for ACEEE, The American Council for an Energy-Efficient Economy, writes an excellent blog on the ACEEE website about an initiative by the Bank of America to increase investments at the community level.
Bank of America’s Energy Efficiency Financing Program shows path to combining energy savings and community development
If you spend any time with the energy efficiency crowd, you will often hear us call it the lowest cost energy resource out there. What you will never hear us say is that energy efficiency is free. Efficiency can do many great things: It saves money, cuts pollution, increases productivity, and creates jobs. What it can’t do is defy one of the fundamental laws that governs all investments—it takes money to make money.
We want to get money flowing into well-designed energy efficiency projects, especially those that can do the most good where it is the most needed…
Does it make a difference if our models of energy and the economy are overly simple? I would argue that it depends on what we plan to use the models for. If all we want to do is determine approximately how many years in the future energy supplies will turn down, then a simple model is perfectly sufficient. But if we want to determine how we might change the current economy to make it hold up better against the forces it is facing, we need a more complex model that explains the economy’s real problems as we reach limits.We need a model that tells the correct shape of the curve, as well as the approximate timing. I suggest reading my recent post regarding complexity and its effects as background for this post.
The common lay interpretation of simple models is that running out of energy supplies can be expected to be our overwhelming problem in the future. A more complete model suggests that our problems as we approach limits are likely to be quite different: growing wealth disparity, inability to maintain complex infrastructure, and growing debt problems.Energy supplies that look easy to extract will not, in fact, be available because prices will not rise high enough. These problems can be expected to change the shape of the curve of future energy consumption to one with a fairly fast decline, such as the Seneca Cliff.