What a beautiful blizzard. Last week it was great fun to watch and even more fun to walk in, but in the back of your mind you know that there is warm and safe shelter. A few years ago Sandy shattered the illusion of guaranteed safety. We were without power for nearly two weeks. Two weeks that saw subfreezing temperatures and a drop of household temperature to figures commonly associated with the refrigerator. Although the furnace burns natural gas, it requires electricity to run a large fan and to power the controller circuitry. Saturday morning, as the storm intensified, that memory returned and I turned the thermostat up a few degrees to buy a bit more time 'just in case'...
Somewhere, probably within a hundred miles, a large turbine was spinning under the blast of superheated steam from boiling water. The turbine was coupled to a massive complex of copper and iron all intricately interwoven into a twisted form. It has two basic pieces - one that spins and one that doesn't. A large magnetic field is created by one part and the other interacts with it generating an electric current. That's it. There are only two major moving parts - the turbine wheel and half of the generator. Once created the power needs to be connected to users. Large copper bars are connected to the generator at a special location. They extend to a large transformer and wind around a specially shaped piece of iron. Another piece of copper winds around another part of the transformer to boost the voltage of the electricity so it can efficiently be sent a long distance over high voltage transmission lines. As it nears the house it enters another set of transformers that reduce the voltage to levels household devices can use.
In principal it is just that simple. I turn up the thermostat and the blower motor on the furnace comes on putting a slightly higher load on the turbine wheel. It's all connected and responds at a good fraction of the speed of light. If one of the wires breaks everything comes to a halt along that path that wire is on. A tree branch falling on a power line can do just that. If load can't be moved more frightening and expensive damage is done - transformers and other components overload and burn out. There aren't that many spare large transformers in the world and production takes time.
We usually think of electricity as the transmission of energy from a source to load. Because it is ephemeral it is convenient to think of it in terms of power .. the rate at which energy is used. Since our needs vary throughout the day, there needs to be a near instantaneous management of supply to meet the demand. It practice the system is very complex and poorly understood by non-specialists. Much of the initial engineering was done in the 20s and 30s using large and very expensive physical models of portions of the grid. These were effectively large analog computers - among the most impressive ever made. Expensive, but driven by a huge desire. We talk about how important our mobile devices and computers are, but try living without electricity in Winter conditions for a few weeks and make a choice between your phone and electricity.
To deal with instantaneous changes in demand there needs to be a massive overcapacity relative to average demand. This is most apparent in during the Summer in hot cities where special turbine powered generators are used to supply peak air conditioning loads that go well beyond the normal capacity of the grid. In fact average demand during the year is about 30% of total generating capacity. Some of the capacity is very inexpensive - a few cents per kilowatt-hour - while turbine powered generation during peak demand can go for over $2.00 per kilowatt-hour. There are seasonal and weekly components to the demand curves that are regionally predictable and used to adjust the generators that respond slowly. But on a minute to minute level there is a spiky "fur" to the curve. This is difficult and expensive to manage. The chart shown is power demand in the UK during Andy Murray’s 2013 Wimbledon victory against Novak Djokovic and its corresponding demand-reducing powers (red line, below). The dip is 1.6 gigawatts - about two large power stations. A larger increase in demand occurred in 2011 when millions switched on their televisions to watch a royal wedding. In the US there is a massive impact during the Superbowl - particularly during halftime.
During the blackout of Sandy two expensive sources of local electricity became important. Primary batteries and fossil fuel powered generators. The batteries went into flashlights and portable radios. An alkaline C cell stores about ten watt-hours of energy - that translates to about $100 per kilowatt-hour .. a big change from the 15 cents or so you probably pay your power company.1 Home scale generators are also be expensive. A rugged natural gas unit in sized to run a furnace fan, refrigerator, a few lights and a computer or two, can cost as much as a furnace and requires maintenance. Electricity from them is too expensive when the grid is working, so you can be talking about hundred of dollars per hour for electricity over the lifetime of the unit. That said, electricity is so important than these and cheap portable gasoline generators sold like hotcakes in the Northeast for about a year after the storm.
Storage can be part of a practical electricity solution, but you have to pay attention to costs and scale. Microgrids with combined heat and power generation can work well for industrial complexes, universities and even large apartments. There has been a surge of construction in the Northeast in the past few years - the cost of being without power is just too high. Larger scale storage can be practical, but only to a point. Mostly it is pumped hydro. Water is pumped against gravity to a physically higher reservoir when power is inexpensive and, when power is needed, water from the high reservoir is allowed to run downhill spinning a turbine attached to a generator along the way. The problem is there aren't many location with the right geography to do this inexpensively.
Dozens of other schemes exist. Apart from leveling the cost of power and reducing the need for new generating capacity, it is often seen as necessary for intermittent renewable sources of power. After all, the Sun doesn't shine all day and the wind isn't always blowing. Batteries have been rapidly dropping in price. There are a few niches where they currently make sense, but in general they need to come down by at least an order of magnitude. For this reason many consider renewables capped at a rather small scale.
With solar and wind you worry about capacity factor - system's predicted electrical output in a year of operation to the nameplate output. For solar this is generally in the 20 to 25% range with wind being somewhat higher. You also have to worry about the capacity of the portion of the grid these systems are coupled to. In many parts of the US and Europe wind turbines need to be feathered in high winds as there is insufficient demand in the portion of the grid they serve for the power they could be generating at that moment.
It turns out, if you just rethink the grid, the need for storage can be greatly reduced - at least in the US.
The US has a section in the Southwest that can generate enormous amount of power from photovoltaics. There are also several regions that with rich wind power potential. The current grid fragmented and difficult to manage. Shipping power more than five hundred miles is not very common and the capacity isn't great. The structure was largely designed from the 20s to the 50s and I'd characterize it as held together with piano wire and chewing gum at this point. It needs to be replaced.
Consider these high resolution (in time and space) animations of solar and wind potential in the 48 states2
There rush by, but it turns out that you can make use of the production in various parts of the country if you can just move the power over great distances. We now have the technology to do that with ultrahigh voltage direct current power transmission. I've done a bit of modeling in the area suggesting that storage isn't as important as most people think. Now more detailed studies suggest you could get rid of all coal power generation, assume no growth in nuclear, and come in somewhat under current energy costs in about 15 years with massive increases in large wind turbines and PV farms - although the wind turbines are the real key. You still need to have some large natural gas plants, but in one study CO2 emissions are down 78% over 1990 levels.3 Other types of pollution drop drastically too. Here's an animation showing power transmission:
Think of it as an interstate electric transmission system on par with the Interstate Highway System. It isn't clear if the mandate to build it can be mustered up, but it may be a solid path forward. A huge and important opportunity.
1 If we didn't have rechargeable batteries, primary cells would be a major expense for cellphones - figure about $300 to $400 a year in batteries.
2 From the Cooperative Institute in Environmental Research partnership of NOAA and CU-Boulder. From Nature Climate Change - a paper
Future cost-competitive electricity systems and their impact on US CO emissions
Alexander E. MacDonald, Christopher T. M. Clack, Anneliese Alexander, Adam Dunbar, James Wilczak & Yuanfu Xie
Carbon dioxide emissions from electricity generation are a major cause of anthropogenic climate change. The deployment of wind and solar power reduces these emissions, but is subject to the variability of the weather. In the present study, we calculate the cost-optimized configuration of variable electrical power generators using weather data with high spatial (13-km) and temporal (60-min) resolution over the contiguous US. Our results show that when using future anticipated costs for wind and solar, carbon dioxide emissions from the US electricity sector can be reduced by up to 80% relative to 1990 levels, without an increase in the levelized cost of electricity. The reductions are possible with current technologies and without electrical storage. Wind and solar power increase their share of electricity production as the system grows to encompass large-scale weather patterns. This reduction in carbon emissions is achieved by moving away from a regionally divided electricity sector to a national system enabled by high-voltage direct-current transmission.
3 Electric power generation is about 40% of total power use in the US. A shift to electric vehicles requires more electricity - this technique is very useful for that as the cars have local battery backup that can be leveraged.
Someone asked for my chili recipe. I tend to throw beans in together, but based things on an old recipe someone sent a decade or more ago. The base recipe is very good, but I usually am doing slight variations. Use it as a starting point and move out..
here's my response:
Here’s the base recipe I use for the chili … someone sent it to me years ago and I only follow it roughly. In the Winter sticking to canned veggies usually wins .. particularly for tomatoes. I also used canned beans for this as it is thrown together on snowy days.. all cans are the 12-15 oz size here. On beans just throw in whatever you want. I usually go mostly black and pinto, but pick one, all or off the list… On the peppers usually do two red and one green,, the author was going for color. It is way better if you stew plum tomatoes down into a sauce unless you have a great store bought sauce - I haven’t found a good plain one, but in a pinch its ok. The masa/cornmeal is the trick. I also usually go for 2 c of broth and 1 of beer (Sukie has the rest:-) Of course the chili powder section is where you may want to go wilder, but this is a good basic filling chili
• 2 Tablespoons Olive Oil
• 4 cloves Garlic, Minced
• 1 whole Large Onion, Diced
• 1 whole Red Bell Pepper diced
• 1 whole Yellow Bell Pepper diced
• 1 whole Green Bell Pepper diced
• 2 whole Carrots, Peeled And Diced
• 2 stalks Celery, Diced
• 1 whole Jalapeno, seeded and Finely Diced
• 3 cups Vegetable Broth
• 1 can Plain Tomato Sauce
• 3 oz Tomato Sauce Paste
• 1 can diced Tomatoes + Chiles
• 1 teaspoon Ground Oregano
• 1 Tablespoon Ground Cumin
• 2 Tablespoons Chili Powder
• 1 can Kidney Beans, Drained And Rinsed
• 1 can Pinto Beans, Drained And Rinsed
• 1 can Garbanzo Beans, Drained And Rinsed
• 1 can Black Beans, Drained And Rinsed
• 1/4 cup Masa or Regular Cornmeal
• 1/2 cup Warm Water
In a large pot, heat the oil over medium heat. Add the garlic, onion, 3 colors of bell pepper, carrots, celery, and jalapeno, then cook for about 5 minutes, stirring occasionally, until starting to soften. Add the oregano, cumin, chili powder, and salt. Stir and cook for a few more minutes.
Pour in the broth, tomato sauce, and tomato + chiles. Stir, bring to a boil, then reduce the heat to low, cover, and simmer for 30 minutes. Add the beans, stir, then cover and simmer for 30 more minutes.
Mix the masa with the warm water and stir it into the pot. Simmer for 15 more minutes. Taste and adjust seasonings.
Serve with cilantro. Non vegans go for cheese or yogurt