The energy needs of the world’s economy seem to be easy to model. Energy consumption is measured in a variety of different ways including kilowatt hours, barrels of oil equivalent, British thermal units, kilocalories and joules. Two types of energy are equivalent if they produce the same number of units of energy, right?
For example, xkcd’s modeler Randall Munroe explains the benefit of renewable energy in the video below. He tells us that based on his model, solar, if scaled up to ridiculous levels, can provide enough renewable energy for ourselves and a half-dozen of our neighbors. Wind, if scaled up to absurd levels, can provide enough renewable energy for ourselves and a dozen of our neighbors.
There is a major catch to this analysis, however. The kinds of energy produced by wind and solar are not the kinds of energy that the economy needs. Wind and solar produce intermittent electricity available only at specific times and places. What the world economy needs is a variety of different energy types that match the energy requirements of the many devices in place in the world today. This energy needs to be transported to the right place and saved for the right time of day and the right time of year. There may even be a need to store this energy from year to year, because of possible droughts.
I think of the situation as being analogous to researchers deciding that it would be helpful or more efficient if humans could change their diets to 100% grass in the next 20 years. Grass is a form of energy product, but it is not the energy product that humans normally consume. It doesn’t seem to be toxic to humans in small quantities. It seems to grow quite well. Switching to the use of grass for food would seem to be beneficial from a CO2 perspective. The fact that humans have not evolved to eat grass is similar to the fact that the manufacturing and transport sectors of today’s economy have not developed around the use of intermittent electricity from wind and solar.
The reasons why the Green New Deal won’t really work are fairly subtle. A person really has to look into the details to see what goes wrong. In this post, I try to explain at least a few of the issues involved.
 None of the new renewables can easily be relied upon to produce enough energy in winter.
The world’s energy needs vary, depending on location. In locations near the poles, there will be a significant need for light and heat during the winter months. Energy needs will be relatively more equal throughout the year near the equator.
Solar energy is particularly a problem in winter. In northern latitudes, if utilities want to use solar energy to provide electricity in winter, they will likely need to build several times the amount of solar generation capacity required for summer to have enough electricity available for winter.
Figure 1. US daily average solar production, based on data of the US Energy Information Administration.
Many people are concerned that we have an oil problem. Or they are concerned about recession and the need to lower interest rates.
As I see the situation, we have a problem of a networked economy that is not functioning well. A big part of this problem is energy-related. Strange as it may seem, energy prices (including oil prices) are too low for producers. If debt levels were growing more rapidly, this low-price problem would go away.
The “standard way” of encouraging more debt-based purchases is by lowering interest rates. But we are running out of room to do this now. We also seem to be running out of economic investments to make with debt. If expected returns on investment were greater, interest rates would be higher.
Without economic investments, demand for commodities of all kinds, including energy products, tends to stay too low. This is the problem we have today. Our debt problem and our energy problem are really different aspects of a networked economy that is no longer generating enough total return. History suggests that these periods tend to end badly.
In the following sections, I will explain some of the issues involved.
 Our problem is not just that oil prices are too low. Prices are too low for practically every type of energy producer, and in many parts of the globe.
We often hear the statement, “When oil supply is lower, oil prices will rise because of scarcity.” Now, we are getting to see firsthand whether oil prices really do rise, as oil supplies become more scarce.
Figure 1. Figure from the OPEC Monthly Oil Market Report for August 2019 showing world and OPEC oil production by month.
Figure 1 shows that world oil supply hit a peak in November 2018 and has declined since then, mostly because of a decline in OPEC’s production. So, total oil production seems to be down for about eight months, relative to the peak in November 2018.
Despite this big cutback by OPEC in its oil production, prices have not responded as OPEC had hoped:
Figure 2. Average monthly spot Brent Oil prices, based on EIA data.
Powering the world’s economy with wind, water and solar, and perhaps a little wood sounds like a good idea until a person looks at the details. The economy can use small amounts of wind, water and solar, but adding these types of energy in large quantities is not necessarily beneficial to the system.
While a change to renewables may, in theory, help save world ecosystems, it will also tend to make the electric grid increasingly unstable. To prevent grid failure, electrical systems will need to pay substantial subsidies to fossil fuel and nuclear electricity providers that can offer backup generation when intermittent generation is not available. Modelers have tended to overlook these difficulties. As a result, the models they provide offer an unrealistically favorable view of the benefit (energy payback) of wind and solar.
If the approach of mandating wind, water, and solar were carried far enough, it might have the unfortunate effect of saving the world’s ecosystem by wiping out most of the people living within the ecosystem. It is almost certain that this was not the intended impact when legislators initially passed the mandates.
 History suggests that in the past, wind and water never provided a very large percentage of total energy supply.
Figure 1. Annual energy consumption per person (megajoules) in England and Wales 1561-70 to 1850-9 and in Italy 1861-70. Figure by Tony Wrigley, Cambridge University.
Figure 1 shows that before and during the Industrial Revolution, wind and water energy provided 1% to 3% of total energy consumption.